• Announcements

    • UnderDawg

      A Few Simple Rules   05/22/2017

      Sailing Anarchy is a very lightly moderated site. This is by design, to afford a more free atmosphere for discussion. There are plenty of sailing forums you can go to where swearing isn't allowed, confrontation is squelched and, and you can have a moderator finger-wag at you for your attitude. SA tries to avoid that and allow for more adult behavior without moderators editing your posts and whacking knuckles with rulers. We don't have a long list of published "thou shalt nots" either, and this is by design. Too many absolute rules paints us into too many corners. So check the Terms of Service - there IS language there about certain types of behavior that is not permitted. We interpret that lightly and permit a lot of latitude, but we DO reserve the right to take action when something is too extreme to tolerate (too racist, graphic, violent, misogynistic, etc.). Yes, that is subjective, but it allows us discretion. Avoiding a laundry list of rules allows for freedom; don't abuse it. However there ARE a few basic rules that will earn you a suspension, and apparently a brief refresher is in order. 1) Allegations of pedophilia - there is no tolerance for this. So if you make allegations, jokes, innuendo or suggestions about child molestation, child pornography, abuse or inappropriate behavior with minors etc. about someone on this board you will get a time out. This is pretty much automatic; this behavior can have real world effect and is not acceptable. Obviously the subject is not banned when discussion of it is apropos, e.g. talking about an item in the news for instance. But allegations or references directed at or about another poster is verboten. 2) Outing people - providing real world identifiable information about users on the forums who prefer to remain anonymous. Yes, some of us post with our real names - not a problem to use them. However many do NOT, and if you find out someone's name keep it to yourself, first or last. This also goes for other identifying information too - employer information etc. You don't need too many pieces of data to figure out who someone really is these days. Depending on severity you might get anything from a scolding to a suspension - so don't do it. I know it can be confusing sometimes for newcomers, as SA has been around almost twenty years and there are some people that throw their real names around and their current Display Name may not match the name they have out in the public. But if in doubt, you don't want to accidentally out some one so use caution, even if it's a personal friend of yours in real life. 3) Posting While Suspended - If you've earned a timeout (these are fairly rare and hard to get), please observe the suspension. If you create a new account (a "Sock Puppet") and return to the forums to post with it before your suspension is up you WILL get more time added to your original suspension and lose your Socks. This behavior may result a permanent ban, since it shows you have zero respect for the few rules we have and the moderating team that is tasked with supporting them. Check the Terms of Service you agreed to; they apply to the individual agreeing, not the account you created, so don't try to Sea Lawyer us if you get caught. Just don't do it. Those are the three that will almost certainly get you into some trouble. IF YOU SEE SOMEONE DO ONE OF THESE THINGS, please do the following: Refrain from quoting the offending text, it makes the thread cleanup a pain in the rear Press the Report button; it is by far the best way to notify Admins as we will get e-mails. Calling out for Admins in the middle of threads, sending us PM's, etc. - there is no guarantee we will get those in a timely fashion. There are multiple Moderators in multiple time zones around the world, and anyone one of us can handle the Report and all of us will be notified about it. But if you PM one Mod directly and he's off line, the problem will get dealt with much more slowly. Other behaviors that you might want to think twice before doing include: Intentionally disrupting threads and discussions repeatedly. Off topic/content free trolling in threads to disrupt dialog Stalking users around the forums with the intent to disrupt content and discussion Repeated posting of overly graphic or scatological porn content. There are plenty web sites for you to get your freak on, don't do it here. And a brief note to Newbies... No, we will not ban people or censor them for dropping F-bombs on you, using foul language, etc. so please don't report it when one of our members gives you a greeting you may find shocking. We do our best not to censor content here and playing swearword police is not in our job descriptions. Sailing Anarchy is more like a bar than a classroom, so handle it like you would meeting someone a little coarse - don't look for the teacher. Thanks.

Archived

This topic is now archived and is closed to further replies.

Heriberto

Carbon Epoxy Wet Layup Ratio

16 posts in this topic

I'm laying up carbon floorboards. I'm using 2 plys of carbon (2 plys of 3K plain weave on bottom, 2 plys of 6K twill on top), sandwiching 1/2" polypropylene honeycomb. I measured the carbon (573g) and honeycomb (556g) to estimate epoxy, wetted it, vacuum bagged it, and the unfinished part came out at 1520g, which means 391g of epoxy. That equates to 40.5/59.5 epoxy to carbon ratio. Approx. 40/60.

 

My question for the experts: is this too dry? Especially for honeycomb core that seems to have a somewhat abosorbent laminating surface?

 

Total Panel weight is about 3.351kg/sqm (0.67lbs/sqft)

Cost is equating to about $20/sqft.

About an hour- two hours of preprep (prep surface, cut peel ply, breather, plastic and carbon*) and 30-45 minutes of laying down two layers of ply, honeycomb and hooking up vacuum bag system.

 

 

*Biggest time was cutting the templates (paper) and sizing the foam to fit in the boat. This is the same time it would take no matter what the floorboard material.

Share this post


Link to post
Share on other sites

The ratio seems a bit dry - prepregs are 35-40% resin. It is not a structural part so not much risk. (I would put the heavy ply down in tension). May want to try a different core next time - PP does not stick to anything w/o pretreat.

Share this post


Link to post
Share on other sites

PP doesn't stick to anything? This stuff has a find of fuzzy coating that wicks epoxy. I was doing everything as per instructions....

Share this post


Link to post
Share on other sites

This was the very first panel I've ever made, I was shooting for 50/50, and yes, this is not really structural and is also the most hidden of the panels I will do, so I'm not super worried about this one. Just like sending a newbie to floor the closets, I want to get the techniques down.

 

Ultimately if I do structural panels, it would be good to know the right target ratio because there seems differing opinion. I could maybe use a film that limits epoxy release, but the breather wasn't completely saturated, so I don't think it was the vacuum (plus it was pretty warm here). Also, this honeycomb was picked because of the purpose, for structural panels I would likely use a different core depending on what is recommended. Whether that is aramid or Penske or whatever.

Share this post


Link to post
Share on other sites

I'm laying up carbon floorboards. I'm using 2 plys of carbon (2 plys of 3K plain weave on bottom, 2 plys of 6K twill on top), sandwiching 1/2" polypropylene honeycomb. I measured the carbon (573g) and honeycomb (556g) to estimate epoxy, wetted it, vacuum bagged it, and the unfinished part came out at 1520g, which means 391g of epoxy. That equates to 40.5/59.5 epoxy to carbon ratio. Approx. 40/60.

 

My question for the experts: is this too dry? Especially for honeycomb core that seems to have a somewhat abosorbent laminating surface?

 

Total Panel weight is about 3.351kg/sqm (0.67lbs/sqft)

Cost is equating to about $20/sqft.

About an hour- two hours of preprep (prep surface, cut peel ply, breather, plastic and carbon*) and 30-45 minutes of laying down two layers of ply, honeycomb and hooking up vacuum bag system.

 

 

*Biggest time was cutting the templates (paper) and sizing the foam to fit in the boat. This is the same time it would take no matter what the floorboard material.

 

Hey Herbi - Wet layups usually yield a 50% fiber to resin ratio - Vac bagging you get a slightly lower value (like what you got) - and a properly prepared infusion will get a slightly lower than vac bag - 35% ish. there are a bunch of factors that can contribute to higher or lower contents, but I'd say you are in the ball park indeed

Share this post


Link to post
Share on other sites

PP doesn't stick to anything? This stuff has a find of fuzzy coating that wicks epoxy. I was doing everything as per instructions....

 

Looks like it has a nonwoven scrim for adhesion - should be fine if you followed the directions. Shorty has new teak and holly floor boards this year - they look nice. Attach some pics when finished - do you plan to leave the carbon in a clear finish?

Share this post


Link to post
Share on other sites

PP doesn't stick to anything? This stuff has a find of fuzzy coating that wicks epoxy. I was doing everything as per instructions....

 

Looks like it has a nonwoven scrim for adhesion - should be fine if you followed the directions. Shorty has new teak and holly floor boards this year - they look nice. Attach some pics when finished - do you plan to leave the carbon in a clear finish?

 

 

Saw Shorty's pics, that looks cool!

 

Here's what happened with mine, I was going to go with a single layer of carbon and put a layer of bamboo veneer on top, but then I got the sticker shock! $180/4x8 sheet! Holy fuck! since my floor boards would be 28" wide in most points I would have tons and tons of waste and it would have taken me three sheets. So I bagged that and put an extra layer of carbon on both sides. I suppose one layer on the bottom would have been fine (in tension) but I figured to play it safe.

 

Haven't decided on a clear finish or not, I'm actually thinking about painting the tops to put non-skid in it. But I suppose I could do that in the clear coat. What do you think? Vegas?

 

Oh, and Vegas, thanks for the info!

Share this post


Link to post
Share on other sites

If the floorboards are truly flat...you might consider using pre-cured facesheets secondarily bonded to the honeycomb core. With good wet-out, squeegee, and proper vaccuum-bagging you can easily obtain a 35% resin content in the facesheet and have high confidence that the laminate is not dry/voidy. Then, with perhaps some slightly thickened glue (mix in some microballoons) lightly applied to the scrim of your honeycomb (or the inner-sides of your facesheets) you can consolidate the facesheets and core into a nice, rigid panel. The worry with a wet layup over honeycomb under vacuum is the possibility of depositing a BUNCH of adhesive INTO the honeycomb cells rather than into the lamintes. Your weight ratio quotes may or may not be accurate as you don't really know WHERE the glue ended up. (In the lam or in the cells??)

(main reason solid core, be it foam or balsa, or whatever is TYPICALLY used with vacuum infusion techniques...the honeycomb cells are seen as VOIDS when under vaccuum and unless specific efforts are made to avoid doing so...will collect A LOT of excess resin)

 

 

Interlaminate (layer-to-layer) compaction of fiber (and consequently interlaminate shear strength) is also a challenge over honeycomb as the 'layered' contact BETWEEN cells is somewhat minimal...a pre-cured laminate on the otherhand is uniformly consolidated...CAVEAT: cell size of the honeycomb can play a huge role in the final results as well....I would argue that wet layups do better with smaller cells whereas precured laminates can bridge larger cells more readily....

 

My $.02 (...but probably worth about what you paid for it!....Your mileage may vary!)

 

Good Luck.

Share this post


Link to post
Share on other sites

That is really interesting. This honeycomb product does have a scrim that soaks resin (see the picture above), so that part I think is "safe", but I understand what you are saying about uneven compression/consolidation. In fact, on the top side, there is a patterned print-through of the cell structure where the carbon was sucked down very slightly into the honeycombs.I have no idea what that does, but it creates a less flat surface. It would significantly increase the production time and cost to create flat plates and secondary bond them to the honeycomb. Twice the surfaces needed, three times the bagging. Not worth it for what I'm doing, but it's an interesting and useful idea.

Share this post


Link to post
Share on other sites

Beat the crap out of the test sample. If it survives your resin ratio and wetout is good.

 

Carbon and honeycomb comes with the unavoidable pinhole issue. The simple answer is to put a layer of thin, thin fiberglass scrim in there. The carbon weave is coarse and you can't get the interstitials to consistently wet out. The thin layer of scrim will wet out fully. If you want proof, weigh your trial horse then immerse it in water for an hour and reweigh. Don't want the honeycomb cells to fill with water.

 

Getting the epoxy to grab the relatively small surface area of the honeycomb can be tricky. I would use a generous quantity of thickened epoxy on the side of the carbon that bonds to the honeycomb.

 

Use shower board from Home Depot under the vacuum bag to eliminate dimples. Stuff is $12 for a 4x8 and is perfect for the job. It's masonite with one hard, white surface.

Share this post


Link to post
Share on other sites

PP doesn't stick to anything? This stuff has a find of fuzzy coating that wicks epoxy. I was doing everything as per instructions....

 

Looks like it has a nonwoven scrim for adhesion - should be fine if you followed the directions. Shorty has new teak and holly floor boards this year - they look nice. Attach some pics when finished - do you plan to leave the carbon in a clear finish?

 

 

Saw Shorty's pics, that looks cool!

 

Here's what happened with mine, I was going to go with a single layer of carbon and put a layer of bamboo veneer on top, but then I got the sticker shock! $180/4x8 sheet! Holy fuck! since my floor boards would be 28" wide in most points I would have tons and tons of waste and it would have taken me three sheets. So I bagged that and put an extra layer of carbon on both sides. I suppose one layer on the bottom would have been fine (in tension) but I figured to play it safe.

 

Haven't decided on a clear finish or not, I'm actually thinking about painting the tops to put non-skid in it. But I suppose I could do that in the clear coat. What do you think? Vegas?

 

Oh, and Vegas, thanks for the info!

 

Hell if it doesn't see sunlight peel-ply the business surface and wha la - lowered resin content and a non skid surface - done...go sailing

Share this post


Link to post
Share on other sites

So I looked in the mirror, found 222lbs of dumb meat and had it jump up and down on this piece as hard as possible on the center of it with support only on 28" centers. Next to no flex, no creaking, cracking or weird sounds. I could probably drive a truck on it. I think it's good....

Share this post


Link to post
Share on other sites

This piece wound up right at 50/50.

Share this post


Link to post
Share on other sites