1 : 1 Fiberglass Laminating Epoxy Recommendations?

I'm familiar with and have used the BSI 1:1 laminating epoxy product (20 Minute Finish Cure). Was wondering if another manufacturer sells a 1:1 laminating epoxy in larger bottles than BSI's 13 oz. bottles, which seem to be the largest size from BSI. Thanks!

I like SystemThree T-88.

Why is 1:1 important?

I've been using WEST System's 105 Resin and usually their 205 hardener. I also like that the make a number of different fillers that are great for making it thicker to do things like fillets. I've built a few canoes with it & as a woodworker I've been using it for maybe 30+ years.

https://www.facebook.com/pg/westsystemepoxy/shop/?rid=46415783201&rt=6&referral_code=page_shop_card

Nevermind......

The OP wants a 1:1 ration epoxy:hardener not some other type.

I do not know of any other 1:1 laminating epoxies.

Zpoxy makes a very good one, but only comes in little bottles that I know of. it is 1:1.

rharshberger said:

The OP wants a 1:1 ration epoxy:hardener not some other type.

I do not know of any other 1:1 laminating epoxies.

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No response to "Why 1:1?"

One of the reasons I use WEST System is that it was developed by the Gougeon Brothers who were boat builders. They tried to make it as least toxic as possible because they worked with it.

llickteig1 said:

No response to "Why 1:1?"

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Yes. A good question. WEST System sells mini-pumps for their resins & hardeners since it is a 5 parts resin to 1 part hardener. One pump of each gives you the correct mix. Very slick.

Ease of use?

David Schwantz said:

Ease of use?

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Ease of use? For what? 1:1 or West?

llickteig1 said:

Why is 1:1 important?

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I second this, there is nothing hard about mixing a 3:1 mix ratio when you have a scale.

Also I recommend the Adtech 820 resin system sold by soller composites.

I made a fiberglass tube years ago with it and it turned out beautiful. Here is a picture.

Yup- ease of use was the only reason. I've used the 4:1 (I think) ratio before with the pumps. Worked great. I'll use it again if here are no other options. Was just curious.

If you haven't done so, using a small scale with at least 0.1g accuracy makes metering epoxy very easy and very accurate even - in small batches. It is honestly no more difficult using West Systems at 5:1 vs another system that might be 1:1.

Thanks for the input. I haven't tried the scale method. I have used the metered pumps before.

I've also used the old-fashioned method of measuring one ounce of water into the disposable mixing cup (a 16 ounce plastic Dixie cup), making a tick mark on the outside of the cup, adding another 4 ounces of water, making another tick mark on the outside of the cup, and using that as a template for future mixes. Did the same with 2 ounces + 8 ounces, etc.

Worked well for the fiberglass skin of a rather large pyramid-shaped project a few years ago- McDonnell Douglas "Delta Clipper".

I also use the dixie cup, but only the bathroom ones as they are non waxed.

US Composites has a 1:1 hardener to be used for layups and laminating using their 150 thick resin which, oddly enough they say is not for laminating.

I'd email them first.

Hey REK, if I may ask, how did you make that tube? Do you have a surface grinder?

Generally 1-1 ratio epoxies are not laminating resins. They are glues.

West Systems was mentioned. It is easy enough to get and I've used it for various things. But it is not a good choice outside wooden boat building. It's the same reason it is a very good choice for wooden boat building. The Tg is too low and there is nothing that can be done about it. Out on a sunny day the temperature can exceed the Tg and the cured epoxy goes through a phase change from a polycrystalline solid to an amorphous solid with loss of structural properties. So it gets weak (until temp passes back below Tg and it then recrystallizes) and warps very easily. Not good for anything aerospace. Not good anywhere near a motor. West has about the lowest Tg around and that was deliberate. It helps it creep along when wood changes dimension. In a sense, when it gets hot, it gets to destress. As long as the wood is the majority structure and the glassing is a barrier coating, that is fine. But again, not a good choice for rockets!

Any other laminating resin will start with a higher Tg once cured. Furthermore, a post-cure heat treating cycle will further raise the Tg and further improve the physical properties of the cured composite. Laminating resins should come with instructions on how to do that, from the manufacturer.

Gerald

MikeyDSlagle said:

US Composites has a 1:1 hardener to be used for layups and laminating using their 150 thick resin which, oddly enough they say is not for laminating.

I'd email them first.

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It should work for laminating but it's a job getting the stuff worked into the glass. Watched a friend spend a helluvalotta time glassing a large NikeSmoke using thick resin. Good thing he used a slow curative because it took quite a bit of effort to get the glass fully wetted out.

jmmome said:

Thanks for the input. I haven't tried the scale method. I have used the metered pumps before.

I've also used the old-fashioned method of measuring one ounce of water into the disposable mixing cup (a 16 ounce plastic Dixie cup), making a tick mark on the outside of the cup, adding another 4 ounces of water, making another tick mark on the outside of the cup, and using that as a template for future mixes. Did the same with 2 ounces + 8 ounces, etc.

Worked well for the fiberglass skin of a rather large pyramid-shaped project a few years ago- McDonnell Douglas "Delta Clipper".

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I've use the same method to measure, now I mostly use a scale. Both have worked well.

prfesser said:

It should work for laminating but it's a job getting the stuff worked into the glass. Watched a friend spend a helluvalotta time glassing a large NikeSmoke using thick resin. Good thing he used a slow curative because it took quite a bit of effort to get the glass fully wetted out.

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Yeah I suspected it would work, it's just funny they say the 1:1 hardener is for laminating with their thick stuff only, but elsewhere on the same page it says the thick stuff is not to be used for laminating. Maybe the hardener is super thin, I haven't used it. Nor have I laminated anything.
I'm not picking on US Composites. I have used their 150 and now use their 635 extensively with various fillers.

Raka is 2:1

Bob Smith Industries makes a 20-minute 1:1 epoxy that is used for fiberglass layups. I learned to laminate using this epoxy many years ago:

https://bsi-inc.com/hobby/finish_cure.html

Ultimately switched to Mr 3:1 Fiberglass Branded epoxy years later.

I bought it, unfortunately it was cold out. It turned into a solid mass. I heated up as they instruct but later re-solidified.

REK said:

Also I recommend the Adtech 820 resin system sold by soller composites.

I made a fiberglass tube years ago with it and it turned out beautiful. Here is a picture.

View attachment 404019

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David Schwantz said:

Hey REK, if I may ask, how did you make that tube? Do you have a surface grinder?

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I hand rolled it with 6oz. Fiberglass from ACP Composites. I then finished it using peel ply.

The fine texture from the peel ply helps from having to sand so much, but it still needs to be sanded down.

JDcluster said:

I bought it, unfortunately it was cold out. It turned into a solid mass. I heated up as they instruct but later re-solidified.

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Dang, how cold is it over there? It usually takes 30 degrees or less for it to do that.

If possible store the resin inside where it is warm, trust me, you don’t want to keep on having to thaw it out.

I found Pro Marine 521 works well for laminations. It's thinner than allot of the other epoxy systems.
5:1 mix.

I ordered it when it was cold out. It was out in the cold for too long before I got home from work.

REK said:

Dang, how cold is it over there? It usually takes 30 degrees or less for it to do that.

If possible store the resin inside where it is warm, trust me, you don’t want to keep on having to thaw it out.

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