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RImike

West Systems Shelf Life (and other epoxies)

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Hello,

I was recently working with West System to build my sons Halloween costume (he's going to be Bumblebee from the new transformers movie Bumblebee) and I was laying some cloth and the resin I used took about 2 days to fully cure (55% humidity in 65 degrees F). It was a little darker in color (almost an amber color) than I remember it being however I attributed it to being a slow catalyst. This got me wondering if the hardeners have a shelf life. Do they? for reference they've been stored in my basement where it's always 55% humidity and about 65-70 degrees in temp.

Also can "other" brands of 5:1 epoxies be laid up over West Systems (such as Total Boat)? To expand on that, can the West Systems and Total Boats resin/hardener be mixed together before kicking? I have small amounts of each I've accumulated over the years but not enough for a full project so I'm wondering if I could be a skinflint and combine it all. 

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RImike,

   West Systems epoxy and most epoxies have near infinite shelf life. I went through this with a friend who had 3+ layups never cure, even after switching to new hardener and new resin. I explained up front  (before he spent more money!) that the pumps go bad, very quickly in my experience. I never trust them unless they are used regularly and cleaned regularly, but for most home-sized repairs I much prefer to mix by weight rather than relying on the pumps. Sometimes that can get you into trouble as well, as the scales can go bad.

I would highly advise against mixing resin systems in a single wet layup, especially on anything you care about structurally. What you can do is a partial layup, i.e stop a few layers in , peel ply the part, then continue the layup with the different resin system 24+ hours later (7 days would be better to get a full cure on the initial resin used). Its not ideal as you don't get a chemical bond, rather just a mechanical bond with the subsequent layers but what do I know!

-Sam

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https://westsysteminternational.com/en/west-system/west-system-105-epoxy-resin

 

With proper storage, WEST SYSTEM 105 Epoxy Resin and hardeners should remain usable for many years, especially if the containers are kept closed in order to prevent contamination. Over time, the resin will thicken slightly which, in turn, will require extra care when mixing.

Both resin and hardeners should be stored at room temperature. Indeed, if the resin freezes and thaws out many times it can cause crystallisation. If this happens, however, it is a simple matter to dissolve the crystals by warming the resin to 50°C and stirring for a while.

 

i to have experience the color change, and the pump failures when doing my model boats...

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Surprisingly the color change in the hardener doesn't really seem to matter much. Still its one reason I prefer Resin Research over West Systems, as I find it more U.V stable, plus its the RR Pro series is a stronger product (designed for use with fiberglass/carbon, much like Pro Set at 1/2 the cost).

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Good info there, does the thickened resin effect the metering via the pump? 

There is no structure involved, just making a 73' VW beetle body off a foam plug. I found out over the weekend that he has a Halloween party at Preschool on Friday and he needed it 5 days sooner than I had planned for so I rushed the layups. I just have to make up the imperfections in the fairing tonight. Tomorrow it's getting sanded/primed/painted and Thursday its getting the final assembly. 

Cheers, Mike. 

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1 hour ago, RImike said:

Good info there, does the thickened resin effect the metering via the pump? 

There is no structure involved, just making a 73' VW beetle body off a foam plug. I found out over the weekend that he has a Halloween party at Preschool on Friday and he needed it 5 days sooner than I had planned for so I rushed the layups. I just have to make up the imperfections in the fairing tonight. Tomorrow it's getting sanded/primed/painted and Thursday its getting the final assembly. 

Cheers, Mike. 

go to a restaurant supply store and get a small digital scale,  one that will go from grams to a couple of lbs..    I measure everything out by weight and only use the pumps to move material from the cans to  airtight jars which are used to pour my amounts..   105/205 is 5/1 weight ratio..

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I have used 10 year old West System where the hadner was very dark and it cured normally. These were relatively small quantities and I used syringes to measure the resin and hardener. NB West is sensitive to the mix ratio

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Epoxy resin can crystallize but simply putting the container in warm water will liquefy it again.

I have used epoxy that was unknown age but at least 10 years old with no problem.

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The pumps get a bit clogged and you think you are getting a full shot of resin or hardener but do not. Thus mix ratios are off and you get bad cures.

I always use a digital postal or kitchen scale, accurate to 1 gram. Smallest batches are around 20 grams, biggest about 7.5 kg. You have to work quickly with 7.5 kg of mixed resin :)

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Just save the risk and get more accurate mixes and buy some decent scales. 

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What's wrong with graduated Dixie cups or larger graduated containers for larger quantities.

They've always worked just fine for me and there's no messing about with sticky scales.

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If you're going to mix epoxy by weight (which I've always done) don't be like me and discover that the reason you always run out of hardener before resin after years and years of mixing epoxy is that quite often, the hardener is lighter in weight per a specific volume than the resin. In fact, the brand of resin I use these days has a 5:1 by volume mixing ration, but the needs to be mixed at a ratio of 100 grams resin to 17 grams hardener when measured by weight.

AFAIK, Wests doesn't mention compensating for density for 5:1 mixes (although the 3:1 epoxy/hardener combos need to be mixed at 3.5:1 by weight), but I found that I run out of hardener sooner using West epoxy and always had issues with it overheating in cup much more so then the brand I now use even though I was using it at a 5:1 ratio by weight, too, at the time. This was actually the reason why I actually gave up on Wests in the first place. I got tired of running out of hardener and having my cup of epoxy getting steaming hot and kicking to soon.

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11 hours ago, SloopJonB said:

What's wrong with graduated Dixie cups or larger graduated containers for larger quantities.

They've always worked just fine for me and there's no messing about with sticky scales.

Its more accurate

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9 hours ago, toecutter said:

If you're going to mix epoxy by weight (which I've always done) don't be like me and discover that the reason you always run out of hardener before resin after years and years of mixing epoxy is that quite often, the hardener is lighter in weight per a specific volume than the resin. In fact, the brand of resin I use these days has a 5:1 by volume mixing ration, but the needs to be mixed at a ratio of 100 grams resin to 17 grams hardener when measured by weight.

AFAIK, Wests doesn't mention compensating for density for 5:1 mixes (although the 3:1 epoxy/hardener combos need to be mixed at 3.5:1 by weight), but I found that I run out of hardener sooner using West epoxy and always had issues with it overheating in cup much more so then the brand I now use even though I was using it at a 5:1 ratio by weight, too, at the time. This was actually the reason why I actually gave up on Wests in the first place. I got tired of running out of hardener and having my cup of epoxy getting steaming hot and kicking to soon.

Almost all resins will have a volume and a weight ratio on the containers and the data sheet, the more specific big lamination resins only have a weight ratio in my experience.

And as for it kicking faster because of more hardener than needed..............??????????? :wacko:

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1 hour ago, mad said:

Almost all resins will have a volume and a weight ratio on the containers and the data sheet, the more specific big lamination resins only have a weight ratio in my experience.

And as for it kicking faster because of more hardener than needed..............??????????? :wacko:

I was talking about the resin I use. Not yours.

 

Newsflash. Adding more hardener than needed to epoxy causes it to kick faster. Try it sometime.

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4 minutes ago, toecutter said:

I was talking about the resin I use. Not yours.

 

Newsflash. Adding more hardener than needed to epoxy causes it to kick faster. Try it sometime.

West system is just one of many...............oh yes, speak to an epoxy chemist, you might learn something.

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2 days after the application it finally hardened up. Speaking of different brands, who makes Total Boats 5:1? What are peoples experiences with it compared to West Systems? 

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To avoid sticky scales wrap in plastic wrap or put in a ziplock bag. Change as needed.

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8 hours ago, mad said:

West system is just one of many...............oh yes, speak to an epoxy chemist, you might learn something.

I was actually stating in my original post that I got sick of Wests, per se, and referred to over heating (and associated rapid kicking) of it compared to the other brands of epoxy I use. Now, I don't want to be critical of West epoxy, but IMHO it's not as good to apply as other brands when used within the environment in which I personally use the stuff. Some of their fillers are good, but fumed silica, ground glass and wood flour are a lot cheaper to buy directly. Mechanically, West's may, or may not, be better? My boats haven't fallen apart Gilligan's Island pancake glue style as yet, though, so I'll stick with what I use now, for now.

Be that as it may, whilst epoxy is indeed a chemical reaction and not a catalytic one, I'll grant you that, try adding 10% more hardener to your mix in a tropical environment and see what happens.

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On 10/24/2018 at 12:54 PM, SloopJonB said:

What's wrong with graduated Dixie cups or larger graduated containers for larger quantities.

They've always worked just fine for me and there's no messing about with sticky scales.

put your electronic scales inside a seal-able plastic bag to protect it from the drips.

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On 10/25/2018 at 5:45 AM, Zonker said:

To avoid sticky scales wrap in plastic wrap or put in a ziplock bag. Change as needed.

Particularly important when you steal them from the kitchen! :-)

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19 hours ago, morwood said:

Particularly important when you steal them from the kitchen! :-)

Good grief, yes! I've got a mangey old set that I use, but they were on the boat one time and I needed to do some glassing at home so I snuck into the house and borrowed the missus's brand new scales she uses to mix her hair dye concoction and who knew that mopping up spilled epoxy with acetone causes paint and numbers and plastic and stuff to dissolve??

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18 hours ago, IStream said:

That how you got your toe?

Yes. For modesty purposes, I photoshopped a toenail onto the picture of the forcibly removed appendage.

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Also - do not steal the "good" sewing scissors to cut fiberglass from your wife. I still remember the screams...

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And definitely don't get caught using the oven to cure a small pre-preg part!!! :ph34r: 

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But cooking powder coat is O/K.

"Honey, would you move the transmission so I can take a bath"

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