Official Luthiers Forum!

I can't take credit for this idea , as Sylvan Wells was one of the first to use this and he lite a fire under me to try it.
I have to say that the results are outstanding. I did experiment a few times on headstock veneers and electric bodies first. I am in the process now of building a high end BRW Red spruce guitar. As most of use that have worked with BRW know , there are 2 kinds of Brazilian , that which is cracked and that , that is going to crack. So in light of the success of the initial try outs I have sealed and filled my latest build. What surprised me was the speed and how well this worked over any method I used in the past , and this is what I did.
I started with the back , using thin CA , and a paper towel. Do be careful as the paper towel will start the CA to activate and will get hot. I have 4 towels folded and ready. I just squirted CA in a swirl pattern on 1/2 of the back and wiped it with the grain . This took all of 10 seconds , then I stand away as the glue activates . I also throw the towel on the floor as the exothermic thermic reaction gets pretty hot. In a few minutes I did the other side. Keep in mind you need to have good ventilation.
After just a few minutes I sanded with 220 grit. The back was filled very well and sealed. The sides I did holding it so I could work smaller areas and have the CA stay in one area and not drip and run. This also was ready in no time. It took less time than I imagined and I have a level surface to start my finishing. I will be shooting a sealer coat on this soon and will post the progress. I plan on taking some pictures and posting this technique on my website.
For what it is worth , try this technique on something small and you can see that for rosewoods , this is a very worthwhile method.

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

I've used CA to fill with for a year or so, because of Sylvan. One thing I do, that I believe is a good idea is throw the used paper towels in a metal fire resistant container. The kind that's used to store oily rags. I throw all my towels, rags ect in there. I don't know if this stuff can spontainelsy (<sp?) combust, but it doesn't hurt to be safe. If the pores are big enough I use medium CA. It gives you a little more working time. I wear my paint respirator when doing it but the smell is still pretty rough. I tried using a cotton cloth instead of paper towels, and I ended up with a cloth glued to the guitar. I believe Rod True applies it with a razor blade.

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

are you implying that by using CA as a grain filler that it will help prevent splits in BRW in the future?

you didn't out and out state that, but you did make a reference to the fact that BRW might be nicknamed crackwood....

What I am saying about the CA is that it will wick into any mirco cracks that exist in your wood. This will help that crack from opening in the future.

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

This is very interesting as I have posed many questions on this. The most annoying part is the fumes. But I NEVER heard about or experienced this heat thing you are talking about. I have used CA on my fingernails (I play the guitar too!) and never felt anything like heat. So, what am I missing here? I have used it as filler and again, no heat.

Mike

BTW, I agree about sanding AS it activates. This may be a key point missed by some. There seems to be an "elastic" period in the process where sanding not only abrades, but compresses the material conformally into the pores.

CA has an exothermic reaction and yes it gets hot. Put some CA on a piece of scrap and wear a pair of gloves , wipe the CA with a paper towel and you will see some smoke. It does get hot

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

John, just wanted to make sure I wasn't reading something into your post that wasn't there...

Mike
Not a problem , we are here to share information , and if you have a question ask , that is what we are here for

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

I have used CA in cracks like this in none guitar woodworking projects and that is my expierence that it prevents further opening of the cracks. Now i just use what I usually have on hand which is loctite brand either a standard CA or a gel version. My question is what type would you use for grain filling and what volume of CA would it take to do the average back and sides? CA is pretty expensive compared to say a oil based grain filler like Por-O-pac. So is it cost effective? Would you also use this method for necks? Thanks...Mike

I buy CA in 8 ounce bottles from a local building supply/hardware store. I pay ~$30 for an 8 ounce bottle, and it will do several guitars. I suspect Rockler, Woodcraft and other online stores sell in bigger bottles too. I believe the Loctite bottle Lowes and others sell are less than an ounce.

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

Thanks woody. Yes the loctite are under an ounce.

Thanks for this information John. Am I reading correctly that the thin CA filled the pores in 1 applicaton? And you did 1/2 the back at once?

Will CA "pop" the grain figure the way that epoxy will?

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Formerly known as Adaboy.......

Did you say "thin CA" John? Doesn't it wick through the wood and stain the inside surface? I was thinking Sylvan and others used medium or thicker.
Terry

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It's not what you don't know that hurts you, it's what you do know that's wrong.

As others have mentioned, you can get CA in big bottles. I got mine in 250ml bottles for something like $20 a bottle last time I bought them. Don't store them on their side in the fridge...

It definitely exotherms if there's enough of it. You'll feel it if you ever pour some liquid CA across your hand (and you'll -really- feel it if you ever use it to close up a good sized cut!)

The fumes aren't toxic per se, just annoying, so as long as you have a good crosswind you should be fine. I use a regular household-style fan blowing horizontally across the work to get the fumes out of the way when I use it on large surfaces.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

I use CPH Starbond CA. I did use thin in this test for the wicking properties . What comes through tells me I had a possible crack. This cleans up easy enough. Sylvan does use Med and I will try this on my next one. I did 2 coats of thin and it worked very well. From the wicking I saw 4 tiny wick marks that had sealed up. 2 on both sides ,so this does help glue the hidden cracks.
The fumes are bad but I have great ventilation and once I wipe I get out of the shop for a few minutes. Once the CA cures the odor stops. I pay about $50 for a pint of CA 1-800-900-GLUE

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Is it possible to use CA after you have begun FP or any other finish on a spruce top or any other wood if you find you have missed something, or will it leave a mark, halo , different colour?
Mike Mcnerney

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Mike McNerney

I used CA years ago as a pore filler, but stopped once I started using Zpoxy. I do however still use it to seal coco, ziricote, mad rw and brw .... light fast wipe, to let it seap into any micro cracks (I had originally read this in a Jean larrivee article), but instead of papertowels, I use baking parchment paper.. its like a wax paper, but not as thick, .. the glue doesnt stick to it all that well, so it hepls in spreading the CA around a bit. I use the thin stuff. Folks who use the thick stuff use a razor blade - I do use the thick on headstocks and heel caps - razor blade a little bit on, quick flat sand, and its ready to finish.

CA is very exothermic .. put a couple drops on some fine sawdust and watch it smoke ... paper towel is worse because the glue will wick UP the towel like water as you hold it .. years ago I burnt my thumb and first finger a bit holding paper towel while wiping up some CA around bindings - I only use the parchment paper now ....

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

I just used CA to fill some koa bindings and head veneers on an archtop I am building-I am sold! It works great.
I used the thick gel CA with a credit card to apply it.
It's the first time I haven't had to do additional filling with the lacquer,so I am ending up with a thinner finish.

While at Brian Galloup's some years ago, I bought some BRW from him which had worm holes. He wiped in thin CA, let it cure for a few minutes and ran it through his thickness sander. There was absolutely no sign of holes as the dust combined with the semi-cured CA and filled them smoothly. Since then, I became a believer!

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

You can put clear plastic tape on your finger and spread the CA with that. It won't burn and you lose less CA.

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Ken Franklin
clumsy yet persistent
https://www.kenfranklinukulele.com

I have a hard time deciding how far to sand back with CA. Do you just sand to flat, or do you try to leave it only in the pores? Thanks, Hugh

I only leave it in the pores, but I'm sure others do differently. I woudln't think a coat of filler(CA, epoxy or whatever) over the entire body would be great acoustically but it probably doesn't matter. About "popping" the grain? Is this grain "popped" enough?


It's filled with CA, sealed with shellac and finished with nitro.

edited for spelling

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

What do you take it down with, a RO sander with 320?

Yes, I have done this successfully on FP. Try to avoid a blob, as you'll have to sand it back down. A tiny little drop on the ding, then wick the excess up with the tip of a tissue, small shot of accelerator, then another little drop, wick up excess, repeat until you are just a bit proud of the surface. Then level with 800 grit and some oil, then resume FP'ing. Don't want to put the CA on an oily surface, or it won't adhere as well, so clean the area with a bit of naphtha first.

That would probably be a good way to do it. Everytime I touch a RO sander I ruin something. My Wife threatened to turn off the electricity in my shop if I didn't put my RO sander away. I block sand with 220, the go finer, 320. then 400 and maybe 600 depending on the wood and finish.

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/