Official Luthiers Forum!

1) I want to use carbon fiber in the neck of my next guitar. What is the correct type of epoxy to use? As an add-on to that question, do you put the bars flush with the neck surface, or inset them a bit and put wood shims on top so that there is an all wood surface to glue the fb to?
2) I'm sick of zpoxy. I liked system 3 for porefill but LMI will no longer ship it to Canada. Can I use any slow cure clear epoxy? Are all epoxies more or less alike? Is there a Smith brand equivalent, as there is a dealer near me?
I guess that's more than two questions...
Thanks kindly...

Most any slow cure epoxy will work fine to bond CF, Smith's should work but after recently using it on some compressed laminate (think phenolic sheeting) and seeing some bond failures under load, it would not be my first choice of glue in a composite to wood situation.

I would not use these same ‘slow cure’, high strength bonding products to pore fill. Formulations that are specifically made for that purpose contain a high degree of solids. These solids act as 'fillers'. They are usually silica based powder (think very finely ground glass powder) and give body to the resins so they fill pores and other imperfections more easily, but they also make these epoxies very easy to sand and that is a very important consideration.

Some can and do use slow cure high strength to fill and get in early to flat the application back before it has fully cured.....not a good idea if you wish to avoid developing sensitivity issues down the track IMHO.

Cheers

Kim

Ok, what's is your first choice in a composite wood combo?

Can you recommend a clear epoxy porefill that is not system three?

Thanks

I would look at something with a higher MOE, Smith's is a really good epoxy for lutherie not least because it cures quite hard so it has a low MOE. i.e. its more brittle and this is great for wood to wood but it does seem more incline to sheer when unmoving composites are involved. I would suggest that just about any 24hr hardware variety epoxy will work just fine for bonding CF to wood because theses multi purpose formulations are made not to be extreme in either way as far as MOE goes so they are able to do more things well enough rather than one thing exceptionally well.

As for pore filling, I will leave that one to greater bodies of experience as mine still itches from my last epic adventure with Zpoxy. One thing I will add is that you should probably consider having a fan operating to blow the fumes from your exposed skin when using epoxy regardless of which one you choose...it can be 'really' nasty stuff if your not careful and it can turn around to suddenly bite regardless of how many times you have used it in the past and had no issue at all.

Great stuff yes, but treat it with respect or you can very easily come away looking second best.

Cheers

Kim

I think that the last time I was in Exotic Woods in Burlington that they had System 3 epoxies. You may want to give them a call and see. They don't list all of their epoxies on the website. I'm sure they could ship it to you

http://www.exotic-woods.com

Josh

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Josh House

Canadian Luthier Supply
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A&M Wood in Cambridge sells West System as well.

Alex

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"Indecision is the key to flexibility" .... Bumper sticker

For an application like that whats wrong with your standard hardware store epoxy Devcon or some such thing?

I've never tried the System 3 but I have tried Zpoxy for the first time. What don't you like about the Zpoxy?



Todd,

In your epoxy pore filling video I think you mention that West Systems is a lot harder to sand back than Zpoxy. Is it a major PITA or just a little tougher?

Kevin Looker

edit:
Is it the amber color of the Zpoxy that you don't like?

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I'm not a luthier.
I'm just a guy who builds guitars in his basement.
It's better than playing golf.

Yes, it is the amber color I dislike. I keep getting a splotchy look. I want to go back to clear to give my skill level a little help...
Thanks everyone...

I've used the West system epoxy for several years now and I like it better than any other epoxy I've tried. It's available in a clear formula that makes a great pore filler. Be sure and get the dispensing pump kit - it helps a lot and prevents problems with mix ratio (which System 3 was very sensitive to). Also, it's not that tough to sand at all.

What you'll usually find in a hardware store is Devcon 5 minute and Devcon Extra Strength that sets in approx. 2 hours.

The 5 minute never gets really hard and rigid. I've seen joints 10 - 15 years old that actually seemed softer and more pliable than new. I think it's OK for somethings but experience has shown me not to trust it to anything significant.

The 2 hour stuff is better but I still would not use it for an instrument. I would recommend West System for that.

I have made quite a few target rifle stocks using sitka spruce, carbon fiber sheet, and cloth. I like West System epoxy.

I use 5 minute epoxy for pore filling, sand back to wood, and find the brand does not matter.

For carbon rods to wood I currently am using loctite slow set. Every other brand I've tried has also worked.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.