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Making a Carbon Kevlar 1" tube


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So I've made my own tiller extension using the dry sleeve materials from Rock West Composites - https://www.rockwestcomposites.com/materials-tools/braided-sleeves-tapes


So I wanna make another one, only longer - 7' or so @ 1" diameter. The problem I had the first time was getting it off the copper tube mandrel. Was a major problem and I don't repeat that. Had to use a "come along" to separate them..... I did not use mold release wax last time but I'm not convinced  that will solve the problem but I did buy some....... And, every video I've found making tubes like this shows a hydraulic tool separating the two pieces.

Anyone have any ideas of how I can ensure that I avoid this problem??? Appreciate any advice!!

Thanks!

 

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Dave

Never done it, but I have prowled the red-neck end of the interwebs looking at this process, as I want to make some carbon tube some day. I have read or seen people use florescent light tubes as the mandrel; they were not happy with the remnants of broken glass inside the tube. I have seen others use a steel mandrel which they coated in a thick layer of candle wax. Thick layer. They laid the CF over the wax, and when cured, poured very hot water inside the mandrel, which heated the wax and let them pull the CF from the mandrel. The problem I saw with the thick wax was lumpy and resulted in an uneven layup. I bet you could smooth the wax first for a better result. 

Snubs

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12 minutes ago, silent bob said:

Use a waxed fluorescent tube bulb. After it’s cured, smack it on the workbench to break the bulb.  Don’t breathe the dust!

Thanks Bob..... That article said the guy tried that and was left with broken glass stuck to the inside plus I need a 7' tube not bigger than 1" dia. So not sure 8' bulbs come that small!!??

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I’ve used another way to get the first thin laminate off he mandrel.  
Wrap the mandrel with a strip of cloth once around and interpose a strip of poly film where the cloth comes around to lap itself.  
If there’s no bond in the cloth encircling the mandrel,  it’s more easily broken loose from the mandrel.

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Provided there is some sort of release between the laminate and the mandrel surface, once upon a time used an aluminum mandrel to make a glass epoxy tube.  Stuck due to shrinkage even with the saran wrap on the tube.  Stuck a bunch of ice cubes into the aluminum tube.  Was able to separate after a while.  Forgot how long since that was ages ago. Check the coefficient of thermal expansion for the copper pipe.  May need to stick it in a walk in box overnight and then hustle.  

No guarantees on 7 feet of grab.  Maybe have one end of the laminate with a loop glassed on, and a loop on the other end of the mandrel with the laminate not going fully to that end.  Once it moves life gets better.  Getting it to move without breaking the part is key.  Good luck. 

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if you can find it.    heat shrink plastic.  the kind of thin plastic that you would find around of box in a retail store https://www.uline.com/BL_2406/Uline-Shrink-Tubing

they make it in tubes.    totally encase your mandrel in the tubing,  heat shrink it down with a heat gun, being careful not to over heat and burn a hole, to the mandrel.  to be sure I would probably do two layers.

 this way the epoxy and carbon never touch the mandrel.I used this method for several plugs of small RC sailboat hulls Ive made to  get the glass to release from the plug.

 

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The industry standard approach is an aluminum mandrel that is fabricated in two pieces with a slight taper, so you can hammer one out after cooling with liquid nitrogen or dry ice. Use a teflon based mold release; we use Miller-Stephenson products, but McLube Sailkote will work fine as it was derived from teflon based mold release coatings. Anything else will bind during the hammering out process.

The other option, which is somewhat reasonable, is to turn/cut a XPS foam plug that also has a long hollow center shaft for a copper pipe, as otherwise even 100psi XPS foam is floppy and your final shape won't be straight.

Finally, done right a sleeved joint isn't a bad idea, as it will make getting 2 say 3-4' sections off a mandrel much easier than one long 8' section. BTW, this is also why I happily fork over the $200 for an 8' carbon tiller extension, and do what I can to avoid paying shipping on said tiller.

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I've done it with the copper tube method and had to use a come along to pull it out. I sprayed it with hair spray and i felt like I could have pulled it out by hand however I prepared for the worst by setting up the come along in my basement. 

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On 7/21/2019 at 3:09 PM, DaveK said:

Great article @JoeBleaux and Thanks @12 metre

Both are great ideas.... I like the thin lamination of fiber glass first and then cut it length wise to pre release. I'll also have to get some foam for testing as well!!

I have used this method to make a 3''x12' carbon tube for a radar pole.  It worked great.

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I have successfully made carbon tubes using 3 different methods. Each has its use but the method you are trying to use  over a mandrel you either have to make a mandrel that will collapse or use candle wax. I have tried many other methods to release the finished tube but  the laminate shrinks making it very difficult to remove no matter what you have used as a release agent.

Get your copper pipe mandrel and spin it using a drill and rough it up with 80 grit sand paper. Then melt candle wax and paint it on while the pipe is spinning slowly. You may find it easier if you have  a support at each end and someone to drive the drill to spin the tube. Once covered in wax you can smooth the wax out again spinning with a heated metal plate.  I use a 4 inch metal scraper with the flat of the blade as the plate. The roughing up with sand paper gives the wax something to hold onto making it easier to stick to the pipe as you end up with around 1mm (40 thou) covering on the mandrel.

Do your laminating and once the resin is cured pour boiling water down the pipe. The wax melts and the new carbon tube slides off as easy as can be.

I probably have pics of the setup somewhere if needed. But it really is dead easy.

BTW:- if the tube is too large a dia for the drill an eye bolt in the drill and a bolt thru the end of the pipe to attach the eye bolt would work because you are only spinning slowly.

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16 hours ago, The Mad Hatter said:

I have successfully made carbon tubes using 3 different methods. Each has its use but the method you are trying to use  over a mandrel you either have to make a mandrel that will collapse or use candle wax. I have tried many other methods to release the finished tube but  the laminate shrinks making it very difficult to remove no matter what you have used as a release agent.

Get your copper pipe mandrel and spin it using a drill and rough it up with 80 grit sand paper. Then melt candle wax and paint it on while the pipe is spinning slowly. You may find it easier if you have  a support at each end and someone to drive the drill to spin the tube. Once covered in wax you can smooth the wax out again spinning with a heated metal plate.  I use a 4 inch metal scraper with the flat of the blade as the plate. The roughing up with sand paper gives the wax something to hold onto making it easier to stick to the pipe as you end up with around 1mm (40 thou) covering on the mandrel.

Do your laminating and once the resin is cured pour boiling water down the pipe. The wax melts and the new carbon tube slides off as easy as can be.

I probably have pics of the setup somewhere if needed. But it really is dead easy.

BTW:- if the tube is too large a dia for the drill an eye bolt in the drill and a bolt thru the end of the pipe to attach the eye bolt would work because you are only spinning slowly.

I like this idea too..... when I ordered the mold release wax, I thought that it would be to do just that. Then the instructions stated it was more like waxing a car wax. That's when I thought I was fuked and should start this thread.

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The other two methods that I have used with success :-

1-  Cut a slot in the mandrel pipe and insert a thin bar to keep the slot open just a couple mm.  Make it so the bar can be removed after cure. This is easy if the width of the bar is less than the internal dia of the pipe and another long object is inserted that holds the bar in place by spacing it off the opposite inside wall.  I just use shinny packing tape applied lengthways as mould release and it also seals over the slot. If worried about release over such a length you could apply the mould release that you bought but resin usually releases from packing tape pretty easy. After cure pulling out the long object should be easy and this will allow removal of the bar, then twisting the mandrel back and forth will help  it release and pull the tube off. 

2- The next method is more involved again but great with large dia tubes. Get a pipe that has an inside dia of the required outside dia of the tube you want to make. Cur it in half lengthways. I use alloy tube as it is easy to cut with a metal blade on my bandsaw.  I line the inside of the mould with shinny packing tape. I make up a long bag from plastic and packing tape . Just use laminate made from uni and cloth. Wrap the laminate around the bag dimensioned to give a small overlap in the finished tube and put it inside the mould. Hold the mould together with hose clamps and inflate the bag. The result is a shinny smooth black tube. There are a few tricks that I have not detailed but if you were actually going to use this method I'd go through them. As I said this is great for larger dia tubes. The smallest dia tube I have made using this method is 27mm using 33mm alloy pipe with 3mm wall as the mould and hose clamps every 6 inches. Great method for tillers and cross arms in multihulls plus a heap of other applications.

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@The Mad Hatter #2 method sounds a bit complicated. I've been repairing my stick in the shop that broke a week ago. In fact it's been broken several times. I made the first tube wall thickness too thin. Oh and which tri is that in your icon pic?? Looks nice!! I have mk1 sprint 750.

 

Here's a couple of pics of the existing one....

9BFF9E49-D99B-440C-BC12-B79727896840_zps

stick1_zpsefejigsu.jpeg

 

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30 minutes ago, wlrottge said:

Hey Dave, I have a couple of new carbon tiller extensions that are easily long enough in San Antonio if you are interested.

Thanks man!! But a lot of this is the fun of making the tube itself. I recently met a woman that I'm dating and she is kinda of a gear head about cars. I mentioned that I needed to make another extension and she asked if she could be involved so this is something we are gonna do together this weekend.

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5 hours ago, DaveK said:

@The Mad Hatter #2 method sounds a bit complicated. I've been repairing my stick in the shop that broke a week ago. In fact it's been broken several times. I made the first tube wall thickness too thin. Oh and which tri is that in your icon pic?? Looks nice!! I have mk1 sprint 750.

Method 2 is a bit complicated but it makes a beautiful tube. It is best used on larger dia tube s that you want a perfect finish on. They used to use that method to make the carbon beams for A class cats. (They probably filament wind these days.) I think it would be very difficult to make a tube much smaller that 27mm using that method. Really small dia tubes are best made coating a mandrel in candle wax. I made quite a few for fittings as a part of the build of the tri in my icon. So to answer your question that is an F85RS with the taller carbon mast. I bet you love sailing the Sprint 750.    image.thumb.png.39308c5260d4bd32b20ea0b4bea03302.png

image.thumb.png.6494dc94f8d8c1b0c2877e01595dd4f7.png

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Last tiller extension I made

*cut a tube in half the long way .

*run a “science class” rubber tube through the  center of the  reinforcement fiber 

*lie the wet out mess in half the sliced tube

* clamp the tube shut with many hose clamps

.* blow up the hose with about 15 pounds of air 

wait

put a vacuum on the hose to collapse it 

take the clamps off your pipe

Enjoy your shiny tube 

 

 

 

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12 hours ago, The Mad Hatter said:

That should of been F85SR

I'd love to sail your boat much more than mine!! Absolutely gorgeous boat!! Wish I had the money, time and knowledge to build one!!

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9 hours ago, Gouvernail said:

Last tiller extension I made

*cut a tube in half the long way .

*run a “science class” rubber tube through the  center of the  reinforcement fiber 

*lie the wet out mess in half the sliced tube

* clamp the tube shut with many hose clamps

.* blow up the hose with about 15 pounds of air 

wait

put a vacuum on the hose to collapse it 

take the clamps off your pipe

Enjoy your shiny tube 

 

 

 

Fred, I think that is Mad Hatters method number 2. Not sure where to find 7' condom that 1" in diameter......

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DaveK,

Buy from China. They sell carbon tubes online for stupid cheap. If you can't find the length you want buy two shorter tubes and splice them together. (there's a ratio for the splice too)

The secret with making tubes like that is mandrel, heat and vacuum. (autoclave) When you heat the mandrel it expands. When you let the mandrel cool it contracts. When you do it right you shouldn't need hydraulics or a come-along, the mandrel just falls out (or comes out easy). From an engineering perspective, there should be a ratio of resin to fiber (glass, Kevlar, carbon, graphite, etc.). The combination of a vacuum plus a heated and expanding mandrel helps compress the layup schedule and remove excess resin. The heat also kicks/cures the resin. Once it's kicked then you let it cool. As it cools the resin finishes curing and the mandrel contracts. Once it's cool the mandrel should be small enough it basically just falls out of the tube. 

P.S. If I remember correctly, Aluminum has something like a 30-33% greater thermal expansion coefficient than copper. You want to be using aluminum tubes for mandrels. 

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22 minutes ago, me like sail said:

Buy from China. They sell carbon tubes online for stupid cheap. If you can't find the length you want buy two shorter tubes and splice them together. (there's a ratio for the splice too)

Do you have a recommended supplier (besides randomly browsing aliexpress or the like)?

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26 minutes ago, Alex W said:

aliexpress

A while back I was building a 3D printer and looking for carbon tubes for axis sliding rails. I stumbled on 1,000 Chinese websites selling carbon tubes for stupid cheap. Aliexpress had a bunch. Others you had to kinda research who the Amazon seller was to get to their direct website. 

If I remember correctly, the biggest difference between the inexpensive tubes (some are made in America too so not just cheap Chinese stuff) and the super expensive tubes was the structural integrity. A lot of the US companies sell composite tubes and specify loads, strength, ANSI, etc. A lot of the cheaper tubes don't specify anything structural. OP wanted a tiller extension which is why I suggested "buy something cheap from China and call it a day". 

I don't remember any exact sites but I do remember looking at the structural integrity numbers and thinking: I guess this is why Hall closed. You can buy a carbon pole from China for less than it cost them to make. Throw some jaws on the ends and you've got a $2k pole for about $500. *edit: $2k spin pole for less than $500

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Hall closed their doors for other reasons, bread and butter are rigs not tubes. More on topic, some of those cheap Chinese tubes, and even expensive Chinese tubes aren't even carbon, rather just glass. Not saying they don't make plenty of carbon tubes, but be careful what you buy. No I don't have a good source as generally I buy American for carbon. There is a big difference between pultruded and proper stock as well; check rockwestcomposites to get an idea of the delta there. They are expensive so not the best option. Forte does a nice tube at reasonable prices if looking at larger diameters.

On the A-Cat front, beams are now made in female molds with pre-preg high modulus carbon and bladder molded in an autoclave. 9 layers of high mod carbon top and bottom with 0.090" front and back walls minimum (likely more, I haven't cut one upon). They then get bonded into the boat. The mid 2000's saw filament wound beams but it quickly progressed to molded for the laminate control and increased stiffness. Beautiful F85RS!

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14 hours ago, DaveK said:

Fred, I think that is Mad Hatters method number 2. Not sure where to find 7' condom that 1" in diameter......

Almost. I have found the optimum to be 35lbs. I have done 50lbs psi but that forced a little too much resin out and left the laminate a little starved.  By putting a plug in each end of the mould I only need a bag made of thin plastic and packing tape because it only needs to provide a seal. The mould takes all the load. A length of electrical conduit inside the bag provides something to wrap the laminate around. When cured just twisting the bag makes it come away from the laminate.

Using the  mandrel and candle wax method I usually use and excess amount of resin for the wet out knowing that when I  grip the tube and spin it after laminating I will  compresses the laminate, removing the excess resin. Then I wrap it in peel ply with just one long 2 inch wide strip while spinning it and that further compresses and then same deal with duct tape. One of my tubes was  short 1 inch dia from glass  for fittings to take the bridle lines from the spinnaker  pole to the floats. I remember dropping one of these tubes and it sounded like steel when it hit the floor.  As with everything else on the boat I calculated the resin content of the laminate and it was @ 36%.  Normally I would think this too low but seemed to be OK , possibly  due to the amount of compression after wet out.

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23 hours ago, Gouvernail said:

Last tiller extension I made

*cut a tube in half the long way .

*run a “science class” rubber tube through the  center of the  reinforcement fiber 

*lie the wet out mess in half the sliced tube

* clamp the tube shut with many hose clamps

.* blow up the hose with about 15 pounds of air 

wait

put a vacuum on the hose to collapse it 

take the clamps off your pipe

Enjoy your shiny tube 

 

 

 

Done that way would make for a very interesting experiment.

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On 7/23/2019 at 1:11 PM, The Mad Hatter said:

I have successfully made carbon tubes using 3 different methods. Each has its use but the method you are trying to use  over a mandrel you either have to make a mandrel that will collapse or use candle wax. I have tried many other methods to release the finished tube but  the laminate shrinks making it very difficult to remove no matter what you have used as a release agent.

Get your copper pipe mandrel and spin it using a drill and rough it up with 80 grit sand paper. Then melt candle wax and paint it on while the pipe is spinning slowly. You may find it easier if you have  a support at each end and someone to drive the drill to spin the tube. Once covered in wax you can smooth the wax out again spinning with a heated metal plate.  I use a 4 inch metal scraper with the flat of the blade as the plate. The roughing up with sand paper gives the wax something to hold onto making it easier to stick to the pipe as you end up with around 1mm (40 thou) covering on the mandrel.

Do your laminating and once the resin is cured pour boiling water down the pipe. The wax melts and the new carbon tube slides off as easy as can be.

I probably have pics of the setup somewhere if needed. But it really is dead easy.

BTW:- if the tube is too large a dia for the drill an eye bolt in the drill and a bolt thru the end of the pipe to attach the eye bolt would work because you are only spinning slowly.

Just done this, tube came out reasonable, although my wax surface wasnt very smooth, which im paying for... I now have a nice 3ft, 3/4in tube thats very very waxy on the inside. Any hints for tidying it up? 

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38 minutes ago, Nodrog said:

Just done this, tube came out reasonable, although my wax surface wasnt very smooth, which im paying for... I now have a nice 3ft, 3/4in tube thats very very waxy on the inside. Any hints for tidying it up? 

It takes a bit of practice to get the wax surface really smooth. But it is something you can work on until happy as there is no time limit like you have once the resin is mixed.

A heated flat metal plate in the form of a 4 inch scraper and heat gun usually gives me a good surface. 

Keep pouring boiling water down the tube. It will melt the wait and wash most of it out but  it out.   I use a funnel and find a way of holding the tube so I don't scold myself.  If I need to glue to the inside of the tube I put something over the wax like  a layer of packing tape or plastic to separate the wax and laminate.    

As far as the outside I strip the duct tape and peel ply off before taking it off the mandrel and spin it with the drill and sand it with course sand paper. If I need a pristine  external finish I use a mould as describe method 2  above.

 

 

 

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On 7/22/2019 at 9:11 PM, The Mad Hatter said:

I have successfully made carbon tubes using 3 different methods. Each has its use but the method you are trying to use  over a mandrel you either have to make a mandrel that will collapse or use candle wax. I have tried many other methods to release the finished tube but  the laminate shrinks making it very difficult to remove no matter what you have used as a release agent.

Get your copper pipe mandrel and spin it using a drill and rough it up with 80 grit sand paper. Then melt candle wax and paint it on while the pipe is spinning slowly. You may find it easier if you have  a support at each end and someone to drive the drill to spin the tube. Once covered in wax you can smooth the wax out again spinning with a heated metal plate.  I use a 4 inch metal scraper with the flat of the blade as the plate. The roughing up with sand paper gives the wax something to hold onto making it easier to stick to the pipe as you end up with around 1mm (40 thou) covering on the mandrel.

Do your laminating and once the resin is cured pour boiling water down the pipe. The wax melts and the new carbon tube slides off as easy as can be.

I probably have pics of the setup somewhere if needed. But it really is dead easy.

BTW:- if the tube is too large a dia for the drill an eye bolt in the drill and a bolt thru the end of the pipe to attach the eye bolt would work because you are only spinning slowly.

Lack of fiber tension/pre-tension and resin to fiber ratios is only issue with this method. What you suggest would never pass an engineering standard other than "good enough". 

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So a couple of things.  Al mandrel as has been discussed.  The thread seemed to start as an ad for Rock West.  I know something about them.  They do a good job for sure and for all I know maybe they outsource to China now.  I'm not in China. Maybe you are.  You decide.  Beyond this take it to PA.  Other options have been discussed.  You decide if you want to spend time making a tube or making what you actually need.

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2 hours ago, me like sail said:

Lack of fiber tension/pre-tension and resin to fiber ratios is only issue with this method. What you suggest would never pass an engineering standard other than "good enough". 

If you spin the mandrel and grip it with a gloved hand you wind the laminate very tight and this removes excess resin. I weighed everything during my build and that includes when making tubes and I achieved resin to fibre ratios from 36% to 50%.   No failures.

I originally used this method 20 yrs ago to make carbon tubes with a 3/8inch internal dia to take bolt rope for catamaran trampoline. The tubes were  built into the gunwale of the hulls and a slot cut with diamond blade in power saw. Tramps never pulled out so it was much better than the alloy tracks others were using.

 

 

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I have found using .05 Mylar sheet with double stick tape on the rod with Johnson paste makes the carbon sleeve slide off. 

Question - Was the choice aesthetics when you chose carbon over s-glass if you were using Kevlar in your tube. S-glass in this application may have merit as it is more flexible, it means that glassfiber typically has a higher ultimate breaking point than a tube shaped home made carbon fiber product. 

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Well anyways.... let me try to post some pics here of what we attempted to do. I chose the wax method

Rough wax

IMG_0100.thumb.jpg.8e4bed3a6ba47f8ffffb3fc95d9c36d4.jpg
 

Flat ironing the wax out

IMG_0104.thumb.jpg.fab341fced1a2f8ade0270c884c13fc0.jpg

Carbon layup wet out and wrap

 

IMG_0108.thumb.jpg.561e732bdb2accfa342a78d1fb075406.jpg

 

IMG_0110.thumb.jpg.4edc663aa8a33087a916dcbe87a47bba.jpg

IMG_0111.thumb.jpg.ebd87afd5f805d4dd785c8abf0decab0.jpg

Top layer of Kevlar Carbon

IMG_0116.thumb.jpg.c26c171e0d847f3f574952893a7b0515.jpg

Very small pits that can be filled

IMG_0120.thumb.jpg.b00864d2f681cacf3bd48be590cbe4ed.jpg

Bitter end cutoff mandrel... need more wall thickness. Will layup more material later. But hopefully will get extension off mandrel today

IMG_0123.thumb.jpg.d93ec1c2dbd4a1b675da79c9bd3c3147.jpg

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Looking good.

After making a couple of these I realised that it paid to  do as much work  as I could  while on the mandrel.

It is just  easier to handle and the ability to be able to spin the tube while on the mandrel helps if I want to sand it as a part of the finishing process or prepping it 

to be glued into a fitting or structure.  This may not apply in your case  but it has on projects I have worked on.

Very interested in seeing some pics of your  tube when you have the final layer on.

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I got the two pieces apart..... It's pretty hot here in Texas so I just threw it up on the roof for a few hours and let the wax melt. Had to drill a hole in the mandrel and tie spectra to a fence pole to pull it off. I'll clean them both up and then put them back together to make the final layup when I get more material. Ordered the neon green from Solar Composites this time so we will see what that looks like... lol

IMG_0140.thumb.jpg.84efb60b7c5dee21545c5695fe0cbbe7.jpg

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That reminds me of another project where I had to put a sleave over a wet out laminate.

The wing net rails for my tri were modelled from an A class wing mast section because that made a comfy seat when on the rails and the way I planned it would be the same weight as 50mm alloy tube that was specified.

I had a mate cut the wing sections from corecell foam a bit over 3metres long with his CNC mqchine

The laminate was carbon uni between two carbon sleaves.  One sleave on and wet it out , put on the uni, wet it out  and then the other sleave over the wet uni.

I found the easiest way of doing this was to put the sleave on inside out. So I anchored the sleave at the start and as it went on I turned it inside out.

Makes no diff to the end result but way easier to apply because I was slipping the sleave over itself before the resin could come through and stop it from sliding easily.

This way the sleave only makes contact with the wet laminate exactly where it has to be along the length of the section. 

If my project I  would sand the tube made so far  to make sure the second layer will have a good bond and I would coat it in resin too and then apply second sleave the way I did my wing net rails..

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That is a neat setup as you could do any dia tube. The video did work and looks good. You are lucky to have someone to help with such projects.

I usually just drill a hole in some timber and spin my tube in that. In the case of large dia tubes like the 90mm spin pole socket  I had to make up an axle for the tube. (I also made a collapsible mandrel for that one so not quite the same. But spinning to compress the layup gives a really good structure. Not tried doing that with a sleave , it may not work as it can't really wind up the layup like it does when using   cloth .  I have  uni between the layers of cloth if that is needed and that works well.)  When I made the wingnet rails with uni sandwiched between sleaves over the corecell wing section I vacuumed it to compress the layup.

Here is a pic of making the short glass tube for my carbon side stay fittings.

 

 

SAM_0326.JPG

SAM_0327.JPG

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Why are you putting it on so "chunky", that is going to be a nightmare to pull out. Every time I've made carbon tubes, I would simply polish the copper tube to a mirror finish then wax it and then spray it with hairspray. After the lay up cured I would simply pull it out by attaching one end of the pipe to to my truck and the carbon tube to a bollard and pull it out and sometimes I didn't even have to do that. The result was a perfectly smooth surface inside and out. 

"waxing" is like buffing a car, not making a candle...

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1 hour ago, RImike said:

Why are you putting it on so "chunky", that is going to be a nightmare to pull out. Every time I've made carbon tubes, I would simply polish the copper tube to a mirror finish then wax it and then spray it with hairspray. After the lay up cured I would simply pull it out by attaching one end of the pipe to to my truck and the carbon tube to a bollard and pull it out and sometimes I didn't even have to do that. The result was a perfectly smooth surface inside and out. 

"waxing" is like buffing a car, not making a candle...

Sounds like you are using your truck to pull it apart!? I hot iron it afterwards and its much thinner wax when done. I throw it on the roof after layup to melt wax and pull apart by hand a 7 foot section. I really doubt that will happen with car wax.... That's the whole point of this thread

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3 minutes ago, DaveK said:

Sounds like you are using your truck to pull it apart!? I hot iron it afterwards and its much thinner wax when done. I throw it on the roof after layup to melt wax and pull apart by hand a 7 foot section. I really doubt that will happen with car wax.... That's the whole point of this thread

Only if its large diameter/long.  If its a tiller extension (3/4" Od or so) and 6 feet long I can pull it apart by hand. Also how are you not getting wax penetration into the layup if it's melting at such a low temp when the resin cooks off and the pressure of the vacuum bagging? 

Also I'm not using car wax, it's like car wax and applied the same way. The result is a mirror finish which pulls out very easily and I can prep a complete mandrel ready for layup in about an hour or so.  I then lay up the cloth, bag it and turn the vacuum on and come back later that day. Then off goes the bag and onto final sand/paint. 

The trick is to make a pleat in the carbon cloth that you know will be cut off to grip it by. 

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5 hours ago, RImike said:

Only if its large diameter/long.  If its a tiller extension (3/4" Od or so) and 6 feet long I can pull it apart by hand. Also how are you not getting wax penetration into the layup if it's melting at such a low temp when the resin cooks off and the pressure of the vacuum bagging? 

Also I'm not using car wax, it's like car wax and applied the same way. The result is a mirror finish which pulls out very easily and I can prep a complete mandrel ready for layup in about an hour or so.  I then lay up the cloth, bag it and turn the vacuum on and come back later that day. Then off goes the bag and onto final sand/paint. 

The trick is to make a pleat in the carbon cloth that you know will be cut off to grip it by. 

I'm just wrapping it with marking tape after I wet it out. So no vacuum bagging and the resin is so slow, that it doesn't really get that hot plus the shop has AC. And I used the term car wax loosely. I did buy the mold release wax as stated earlier but others had mentioned in this thread that it wouldn't help so much. So that's why I tried the other method of candle wax. I really don't care what the inside will look like and nobody should see it unless the tube breaks. The pleat idea in the carbon cloth is a good idea.... I'm really just afraid to use mold release wax only as my first attempt involved a "come along" to separate the two and I do not want to deal with that again!!

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Hey, if you still have the copper mandrel you should try taking a thermos (like actual stainless vacuum thermos) and getting some liquid nitrogen. Then pour the LN into the open end on the mandrel. You should get significant shrinkage in the mandrel and the carbon will pop right off.

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On 7/24/2019 at 12:43 PM, DaveK said:

Thanks man!! But a lot of this is the fun of making the tube itself. I recently met a woman that I'm dating and she is kinda of a gear head about cars. I mentioned that I needed to make another extension and she asked if she could be involved so this is something we are gonna do together this weekend.

If you end up not marrying this gal, please send her my way. I don't have the kind of luck that it takes to meet a chick who's into carbon fiber.

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On 8/6/2019 at 7:32 AM, RImike said:

Only if its large diameter/long.  If its a tiller extension (3/4" Od or so) and 6 feet long I can pull it apart by hand. Also how are you not getting wax penetration into the layup if it's melting at such a low temp when the resin cooks off and the pressure of the vacuum bagging? 

Also I'm not using car wax, it's like car wax and applied the same way. The result is a mirror finish which pulls out very easily and I can prep a complete mandrel ready for layup in about an hour or so.  I then lay up the cloth, bag it and turn the vacuum on and come back later that day. Then off goes the bag and onto final sand/paint. 

The trick is to make a pleat in the carbon cloth that you know will be cut off to grip it by. 

Looks like I need to make a tube about 18" long.  I've got an aluminum tube that's the right size. Am I better off starting with a couple layers, breaking that free, and then going full thickness with a 2nd layup?  or just go full bore and do it in one shot?

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15 minutes ago, Raz'r said:

Looks like I need to make a tube about 18" long.  I've got an aluminum tube that's the right size. Am I better off starting with a couple layers, breaking that free, and then going full thickness with a 2nd layup?  or just go full bore and do it in one shot?

One shot, that's how it's done in the industry as you will have the best bond. Are you going to vaccum bag it or just use peel ply?  Prep is key,  when you think you have enough wax on it, put more on it. If you doubt your waxing job, then spray the mandrel with hairspray. I did a test once where I was able to remove a piece out of a mold as I didn't have any wax using just hairspray. 

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4 minutes ago, RImike said:

One shot, that's how it's done in the industry as you will have the best bond. Are you going to vaccum bag it or just use peel ply?  Prep is key,  when you think you have enough wax on it, put more on it. If you doubt your waxing job, then spray the mandrel with hairspray. I did a test once where I was able to remove a piece out of a mold as I didn't have any wax using just hairspray. 

Thanks, I'll give it a go as a one shot. I was just planning on peelply, but I could vacuum it easily enough.  It's a vertical post that will be used to hang an emergency rudder cassette off.  The heavily loaded bottom gudgeon will be bolted directly to the transom extension, but the top will need to hang off this post, which will have 2 smaller compression posts mounted on the transom.

 

 

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48 minutes ago, Raz'r said:

Looks like I need to make a tube about 18" long.  I've got an aluminum tube that's the right size. Am I better off starting with a couple layers, breaking that free, and then going full thickness with a 2nd layup?  or just go full bore and do it in one shot?

Years ago a friend of a friend was telling me about how he made shorts rods for use in radio controlled planes

He wrapped the aluminium with the wet layup and peel ply, then cooked it in the oven. The aluminium would expand and compress the layup when heated. When it was cooled the aluminium would shrink and almost fall out of the tube.

 

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Vacuum bag or not? 

Rank amateur at this, but i tried both. Vac-ing ended up giving me wrinkles where the fabric compressed around the tube. Had a much better experience wrapping in successive layers of peel ply, pulling it tighter and tighter, and then finishing off with wrapping with really tight parcel tape. Do it in a spiral pattern working down towards one end and the excess resin squeezes out at that end. I did a layer of candle wax, then wrapped that in clingfilm/gladwrap before the laminate. It all comes out from the inside when you warm it up. Was a 32mm tube about 1.5m long. 

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53 minutes ago, Rushman said:

Years ago a friend of a friend was telling me about how he made shorts rods for use in radio controlled planes

He wrapped the aluminium with the wet layup and peel ply, then cooked it in the oven. The aluminium would expand and compress the layup when heated. When it was cooled the aluminium would shrink and almost fall out of the tube.

 

I can easily build a heat-gun oven for something so small. Not risking spousal wrath cooking epoxy parts in the kitchen!

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23 minutes ago, Raz'r said:

I can easily build a heat-gun oven for something so small. Not risking spousal wrath cooking epoxy parts in the kitchen!

I agree

I think he had an old oven in the garage for making his plane parts

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14 hours ago, Rushman said:

I agree

I think he had an old oven in the garage for making his plane parts

If you aren't using prepreg you don't really need to bake it.

I've made long tubes before for my friend without baking it and he said they never broke. He used these as antenna extensions attached them to a vehicle when he did the Mongolian Rally. 

I've used prepreg in the past when making car parts such a gauge pods and such during the era of Fast and Furious and I made my own oven out of Home Depot 2" thick foam heated by an old toaster oven which I took apart. Since they were female molds I wasn't concerned with the imperfections caused by the peel ply. 

You are going to be sanding it anyways so the wrinkles from the peel ply don't matter anyways really. 

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49 minutes ago, RImike said:

If you aren't using prepreg you don't really need to bake it.

I've made long tubes before for my friend without baking it and he said they never broke. He used these as antenna extensions attached them to a vehicle when he did the Mongolian Rally. 

I've used prepreg in the past when making car parts such a gauge pods and such during the era of Fast and Furious and I made my own oven out of Home Depot 2" thick foam heated by an old toaster oven which I took apart. Since they were female molds I wasn't concerned with the imperfections caused by the peel ply. 

You are going to be sanding it anyways so the wrinkles from the peel ply don't matter anyways really. 

The conversation was a long time ago but I think the baking was for the aluminium expansion

 

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i used a super simple method that worked well. I used this method to create 2 parts ~60" long. One part is used as a SUP paddle shaft, the other for a tiller extension on my Nomad. 

Instead of a mandrel, I used a foam tube as the mold. the foam tube was for window insulation and has a hole down the center. I ran a rope (1/4" maybe?) down through the hole in the tube so that I could hang the set-up vertically, and under tension to keep it straight for lay-up and curing. Once cured, remove the line.

Caveat is that there is some lightweight closed cell foam inside my tiller (and SUP shaft). 

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