Epoxy, brushes, CF tow, oh my!

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joel
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Epoxy, brushes, CF tow, oh my!

Post by joel » Mon Aug 01, 2022 6:50 pm

Hi everyone.

After reading and re-reading the soundboard and brace design sections of "the books", I've reluctantly come around to the idea of epoxy and CF for the braces. I'm a CF and epoxy newbie.

I've searched the forum for suppliers of CF tow and thanks to Martin for this link: http://carbonfiber.com.au/ . Does anyone know of other Australian suppliers that supply relatively small lengths of tow? 60m of 12k is probably a lifetime supply for me, so bulk suppliers probably won't suit me.

They supply West system epoxy too. Has anyone experience with other epoxies?

Does anyone know where to get extra long working time hardener?

I haven't found *any* references to epoxy application brushes. Anyone have tips, tricks, or ideas for good, easy to use application brushes and where to get them?
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Dave M
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Re: Epoxy, brushes, CF tow, oh my!

Post by Dave M » Tue Aug 02, 2022 1:41 am

Joel I have been happy with West system epoxy. I don't try to do too much bracing in one go so haven't run into the glue setting on me.

For applying I use cheap artists paint brushes. They need to be reasonably stiff and I often need to cut down the amount of bristle. You can get them cheap enough that the single use doesn't hurt too much.

I'm in the UK and was able to buy just 1 metre of CF cloth, which itself is going to last me a long time! I can't help you in Oz but would expect someone - perhaps a hobbyist supplier to offer this.

It is quite hard to work cleanly - well worth having a practice particularly at getting the CF strands to sit where you want them. Believe me your early attempts are not going to look Trevor's beautiful clean builds! But after a few one can get them looking reasonable.

Good luck Dave
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Trevor Gore
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Re: Epoxy, brushes, CF tow, oh my!

Post by Trevor Gore » Tue Aug 02, 2022 8:30 am

It's best not to buy tow, but to buy cloth and pull threads from the cloth. The cloth spec. is in the book. I get mine from these guys: https://allnex-brookvale.business.site/ . I use artist brushes from Bunnies or try a $2 shop. Use WEST epoxy, 105 resin and 207 hardener (the 207 can be used when grain filling, too). WEST is widely available.

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lamanoditrento
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Re: Epoxy, brushes, CF tow, oh my!

Post by lamanoditrento » Tue Aug 02, 2022 9:58 am

Hey Joel, we've used Westsystem and Botecote. I'd say the lower the ratio the easier it is to deal with in small batches so Botecote's 2:1 is a bit easier to measure out than the westsystem's 5:1. Botecote also has a longer open time about 30mins and if you need more you can add some TPRD.

We use cheap small brushes that come in a box of 100 or so, but actually if you wash them out with metho before they cure you can reuse as the cheap bristles are plastic. Also I use a popsicle stick more than the paint brush.

My advice when trying to to lay tow and epoxy is you don't need much, so go sparingly. Basically any squeeze-out clean-up will leave a ugly mess.
Trent

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56nortondomy
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Re: Epoxy, brushes, CF tow, oh my!

Post by 56nortondomy » Tue Aug 02, 2022 4:31 pm

Liked Trent I use botecote and have found it to be very good. Less is more with epoxy, don't use too much or it'll be a real mess like Trent said. I bought some tow on eBay and am still using it, probably done around 30 guitars with it and still plenty left. Wayne

Dave M
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Re: Epoxy, brushes, CF tow, oh my!

Post by Dave M » Wed Aug 03, 2022 1:44 am

Oh and many people have had bad reactions to epoxy so wear some nitrile gloves. D
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Allen
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Re: Epoxy, brushes, CF tow, oh my!

Post by Allen » Wed Aug 03, 2022 5:59 am

BoteCote is the best epoxy I've ever used, especially in small batches like we regularly use for instruments. They have a tropical hardener that is the only one I use being up in the tropics.
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peter.coombe
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Re: Epoxy, brushes, CF tow, oh my!

Post by peter.coombe » Wed Aug 03, 2022 10:01 am

I got my carbon fiber tow from http://carbonfiber.com.au/. There is enough in one roll to last me a lifetime. Note that 60m is still quite a small roll. I also bought some CF cloth at the same time, but that is still unused in the container. I have been using West Systems epoxy, and measure it out with small syringes. There are many ways to skin a cat.
Peter Coombe - mandolin, mandola and guitar maker
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joel
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Re: Epoxy, brushes, CF tow, oh my!

Post by joel » Wed Aug 03, 2022 6:49 pm

Thanks all for your expert advice! I really appreciate your input!

I'm looking at Bote Cote very closely. I like the low VOC and 2:1 mix ratio.
- If God had intended us to drink beer, He would have given us stomachs. - David Daye.

- The mouth of a happy man is filled with beer. -

quartpopt
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Re: Epoxy, brushes, CF tow, oh my!

Post by quartpopt » Thu Aug 04, 2022 1:24 pm

Handy hint: I found it worthwhile to buy two syringes from local chemists...cheap...10ml and 3ml for the resin and hardener. Find two small jam jars, height more than the length of the syringes. Cut holes in the lids, dia to suit syringes. No need to clean out syringes, just put them in hanging on the lid, ready for next time.
A friend who does bindings on fishing rods with epoxy has used same ones for more than 2 years.

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joel
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Re: Epoxy, brushes, CF tow, oh my!

Post by joel » Fri Aug 05, 2022 5:29 pm

quartpopt wrote:
Thu Aug 04, 2022 1:24 pm
Handy hint: I found it worthwhile to buy two syringes from local chemists...cheap...10ml and 3ml for the resin and hardener. Find two small jam jars, height more than the length of the syringes. Cut holes in the lids, dia to suit syringes. No need to clean out syringes, just put them in hanging on the lid, ready for next time.
A friend who does bindings on fishing rods with epoxy has used same ones for more than 2 years.
Brilliant!
- If God had intended us to drink beer, He would have given us stomachs. - David Daye.

- The mouth of a happy man is filled with beer. -

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