Official Luthiers Forum!

I'm shopping for an epoxy for glueing fingerboards and neck blocks on a cutaway. What are your favorite types and brands?
Clinton

Loctite Extended Time...cures in 90 minutes but I leave it clamped for 12 hours. I've used it on 7 FB's so far and like it.

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JJ
Napa, CA
http://www.DonohueGuitars.com

For overall strength System 3 is very good but very unforgiving of mixing ratios. DOES NOT sand well but that should not be a factor with gluing the fretboard?

It seems to me with such a large contact area almost any decent slow cure (30- 90 minutes) epoxy should create a fairly bullet proof bond. I did it once with 5 minute. Did I say ONCE?

I have the System 3 30 minute and Z-Poxy's 30 minute and would trust either one to do the job.

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Thank You and Best To All

I use WEST epoxy, but it's probably not the most convenient for instrument-building. You need to measure it fairly carefully, and the standard pumps put out more in a single 'shot' that you are likely to need. The alternative is to load up syringes with resin and hardener- that tends to be messy.

Any decent epoxy should cure harder than softer woods like mahogany, so they will all be tricky to sand, especially with a softer pad. Sometimes a cabinet scraper can help.

The good news is that the joints you are talking about (FB, neck blocks) are quite undemanding on the glue joint, so any epoxy with the right working time should do the trick.

Cheers
John

I checked Stew-Mac,they had their name on the bottle. LMI had Smith All Wood Epoxy. I noticed no one mentioned any of those two. I'll check my Lee Valley catalogue. I thought that Z-poxy was for pour filling? Clinton

West Systems 105 resin and 205 hardener.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

Clinton here's a thought. I just used some Z-Poxy 30 minute to do some laminations and the viscosity is much higher than their Finishing Resin. Makes it pretty difficult to work to a nice thin layer.

I would very tempted to use their finishing resin for a fretboard as it will work very thin and should squeeze out very nicely.

Should also be plenty strong for the purpose even though the label may say the wrong thing on it.

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Thank You and Best To All

For fretboards? I uselepages 5 minute. Sealer, System 3 clearcote

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Greg
http://garibaldiinstruments.com/

That's what I've been up against, too thick to get a good squeeze out with the epoxy I'm using. Maybe the thin stuff for pour filling would be a solution. Thanks. Clinton

Hesh...The Loctite stuff sands well...I've never had a joint show on a neck to fb either. I don't know how fussy it is to mix ratio. I weigh everything just because I'm anal...and I have a triple beam balance.

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JJ
Napa, CA
http://www.DonohueGuitars.com

[QUOTE=crich] That's what I've been up against, too thick to get a good squeeze out with the epoxy I'm using. Maybe the thin stuff for pour filling would be a solution. Thanks. Clinton[/QUOTE]

Don't forget the finishing resin takes 6-8 hours to cure.

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Thank You and Best To All

I like system 3, I've also used Smiths from LMI. No problems with either, although I prefer system 3 for my double tops so I've been using that on my finger boards also.

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Jim Watts
http://jameswattsguitars.com

I did some construction work for Steve Smith (Smith's Epoxy) years ago. He is a mad scientist. He made a bunch of caulk, put it in tubes, and told us we had 10 minutes to finish the job!

I have used his penetrating epoxy for years and it is very forgiving in the mix.

Cool guy!

Kurt

Another idea is to thin the thicker 30 minute varieties with alcohol if viscosity is a problem.

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Thank You and Best To All

I really like MAS brand. I've been using it for many years - primarily for boat building. I've never used epoxy on an instrument.

The resin is low viscosity, and, if you use the "Slow" hardener, you have a lot of working time - at least an hour. You should let it cure a day before unclamping, though, and it sands very well after about 2 days, depending on temperature.

If you use any epoxy as a glue (even thicker epoxies), you should add thickener, so that it doesn't soak into the wood and starve the joint. The strongest method is to first paint both surfaces with the un-thickened epoxy, then thicken some with wood flour or Cab-O-Sil (fumed silica) to about the consistency of peanut butter, and apply that to the joint before assembling and clamping.

MAS sells pumps, also (ratio is 2 parts resin to 1 part hardener) and each pump is a pretty small amount, so it should be convenient for use on guitars.

Phil

[QUOTE=LarryH] Another idea is to thin the thicker 30 minute varieties with alcohol if viscosity is a problem.[/QUOTE]
Be careful thinning epoxy with solvent if you are using it as a structural adhesive- a few percent is the max recommended. Most of the time warming is a better method of getting it to flow, but that can affect the working time with the faster epoxies.
Epoxy can work well even if it seems too viscous compared with standard woodworking glues.
A few test pieces which you allow to cure then split apart is the best answer, and the expense (wasted epoxy) is a small price to pay for peace of mind.
John

I've used Stew-Mac's slow cure, and I like it a lot. Now, I haven't used it in any lutherie application, but here's what I know...one-to-one mix ratio; decent open time (haven't reached its limit yet); can be spread very thin--I used it to glue together two 20" X 24" pieces of MDF. I mixed up half the bottles, which seemed like more than enough. When it hit the untreated MDF, though, it didn't seem like I'd even get coverage on half the sheet. However, I applied some elbow grease, and with a plastic spreader I was able to get a whisper-thin coat on the whole thing. It goes much further than you think it will. It was enough to get a solid bond, too. Good stuff!

The only downside I've found is that, in cool conditions (60deg.F or so) the resin becomes gel-like and won't flow out of the bottle. Warming it up restores it, though, and it seems to then cure quite well in the same conditions.