stablilizing hairline crack during glue up

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Romeo Suave
Posts: 23
Joined: Sun Jan 08, 2012 3:04 pm

stablilizing hairline crack during glue up

Post by Romeo Suave »

I am making an electric guitar based on a carvin through neck. I cut down the body portion .5" to accept a cap of the same dimension. The cap is Kauri and cost about $150. It cupped upward. I boiled a kettle of water and glued the lamination on the carvin with Gorilla glue which needs water to activate. The top has flattened out, but there is now a couple of hairline cracks in it. I suspect the best approach is to fill the cracks with super/crazy glue. What do you recommend?
Romeo Suave
Posts: 23
Joined: Sun Jan 08, 2012 3:04 pm

Re: stablilizing hairline crack during glue up

Post by Romeo Suave »

I went ahead and glued the top on due to the cupping, hoping that gluing it will stabilize it, I will be gluing the rest of the body up in a few days,
Steve Senseney
Posts: 673
Joined: Fri Jan 06, 2012 2:45 pm

Re: stablilizing hairline crack during glue up

Post by Steve Senseney »

Wait a few days. You may have more cracks to fill.

If you are dealing with a burl pattern, it might be best to fill any voids with the cyanoacrylate glue.

If you have a linear split in along a grain line, you might try to fit a sliver of wood in the split. For this kind of repair, I would use hot hide glue, as it is nearly invisible, and does not interfere with finish.
Randy Roberts
Posts: 466
Joined: Sat Jan 07, 2012 9:11 pm
Location: Omaha, NE (a suburb of Iowa)

Re: stablilizing hairline crack during glue up

Post by Randy Roberts »

Romeo,

Don't use thin CA (superglue) on Kauri ! It will dramatically discolor this wood. You might be able to get away with one of the thicker CA formulations, trying to prevent the glue wicking into the surrounding wood, or try to flood some shellac into the crack to try to seal the walls of the crack and then CA, but if there was ever a reason to "test on scrap" this is it. Epoxy also will also discolor it compared to the surrounding wood .

One option might be to leave the cracks, accentuating that fact that this is definitely an "old" wood <g>

However you deal with the cracks, Kauri benefits from sanding down through much finer grits than you would normally go. The finer the grit, the more the chatoyance of this wood blossoms.

I would seal it with french polish and then use whatever finish you were going to use. The examples I've dealt with are extremely soft, so harder the better on your finish. I've only built accoustics so I don't have an experience with how you are using the wood, but I think using it on an electric guitar face sounds awful problematic due to how soft this wood is. Let's just say this wood "relics" easily.<g>
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