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Advice please - unfinished back - cracked - low humidity
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Author:  Corky Long [ Wed Dec 23, 2009 11:41 am ]
Post subject:  Advice please - unfinished back - cracked - low humidity
My OOO Koa/Sitka - which has been an experience in patience is now showing a crack in the Koa back. The mickeymouse humidifier I was using in the shop is apparently not up to the task. (Yeah, the family got the

The back and sides have already has been pore filled with ZPoxy - I plan to finish it with KTM 9.

What would you suggest I use to seal the crack? I'm worried that CA will wick under or degrade the Zpoxy. Would HHG be a better solution? Thanks!!
Author:  the Padma [ Wed Dec 23, 2009 12:11 pm ]
Post subject:  Re: Advice please - unfinished back - cracked - low humidity
Corky Long wrote:
What would you suggest I use to seal the crack? I'm worried that CA will wick under or degrade the Zpoxy. Would HHG be a better solution? Thanks!!



Well Corky,

Don't know about the CA wicking as me don't use Zpoxy.

However if it is a crack that has not opened up, well then HHG is noted for its ability to actually "pull the two glue surfaces together" which I wood think is a quite desirable here.

Sorry she cracked up. That crack stuff is becoming quite a bain on society the last few years.

blessings
the
Padma
Author:  Michael Dale Payne [ Wed Dec 23, 2009 12:15 pm ]
Post subject:  Re: Advice please - unfinished back - cracked - low humidity
Corky,

A photo would help but I am surprised that the Koa cracked on you. Acacias are one of the most stable species there are. How drastic was the drop in RH? How long did you allow the wood to acclimate to the shop before working it? Even with a shop that is consistently at 35% RH if the wood is acclimated to that environment it should become stable. It is a sudden changes to non acclimated wood that is the real problem not so much low RH. You should acclimate your wood for 30 days min before working it 60-90days or more is even better

Hide glue will leave the least visible joint. CA is a bit easier to deal with and Titebond is fine as well.

Now I am assuming that the cracks are tight and closed. If not the body needs to be re-humidified till they close. A trash bag and a container with a damp sponge can be used as a temporary humidor.
Author:  Corky Long [ Wed Dec 23, 2009 2:18 pm ]
Post subject:  Re: Advice please - unfinished back - cracked - low humidity
Padma, Todd, Michael,

Thanks all for your quick responses.

As to the acclimation of the Koa - actually, yes, it has been in my shop for two years, so it should have been pretty well acclimated. My shop has about 40 - 50% humidity in the summer, and I'm in New York, so the humidity has dropped suddenly, with the steam heat kicking in in earnest over the past 30 days or so. I've just bought a more aggressive humidifier, so that should help. It's always been a problem once winter is really underway, but clearly what I'v been doing hasn't been sufficient.

I won't do anything until I've brought the humidity back up to 40% for a week or so.

Sounds like both CA and HHG are good options.

Thanks again, all, for your help.


Regards,
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