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Discussion Starter · #1 ·
Hey all. First time poster.

I've got a 14" x 12" x 3" box that I'm making out of Padauk. Put the Padauk on the CNC and it milled great. But I've noticed that it is warping more and more each day (see the image attached). I live in dry desert-ish Colorado, so moisture is very low. I purchased the wood at a specialty lumber company which sells wood ready to be used for these types of projects, but perhaps the wood wasn't properly dried or hadn't dried for long enough?

In any case, I think I'm going to make a custom-sized vacuum chamber and try to stabilize the remaining Padauk with Pentacryl or Cactus Juice. Is that a good solution? Is one product better for this purpose than the other?
 

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David
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Welcome to the forum, Gordie! Did you mill just one side of the CNC? I wonder if that's causing an imbalance of moisture and will stabilize in a couple of days - possibly?

If you have a CNC I would encourage you to join our sister site Router Forums where dozens of us have CNC machines. You can probably use your same member name there and participate in both forums.
 

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Discussion Starter · #3 ·
Thanks David. So, it was milled on both sides; one side got the deep pocket cut and the other was just milled flat and shaped.

Thanks for the invite to Router Forums. I'll check it out.
 

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I doubt stabilization will help for several reasons

First reason is that resin stabilization doesn't really take well on sense or oily woods. Dense woods don't allow for much penetration, and the natural oils interfere with the resins cure. I seem to recall paduak being fairly dense and oily, pretty poor candidate

The other problem is part of the stabilization process is to completely dry the wood by baking it at 250f for a few hours/days to get the internal moisture content down to 0%. Since drying is what's causing your warping issue to begin with, you'd probably just make the problem worse
 

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Discussion Starter · #5 ·
I doubt stabilization will help for several reasons

First reason is that resin stabilization doesn't really take well on sense or oily woods. Dense woods don't allow for much penetration, and the natural oils interfere with the resins cure. I seem to recall paduak being fairly dense and oily, pretty poor candidate

The other problem is part of the stabilization process is to completely dry the wood by baking it at 250f for a few hours/days to get the internal moisture content down to 0%. Since drying is what's causing your warping issue to begin with, you'd probably just make the problem worse
Thank you for the notes! I do think the Padauk is dense and has a decent amount of oils. So, what do you think I should do?
 

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Thank you for the notes! I do think the Padauk is dense and has a decent amount of oils. So, what do you think I should do?
Well, unfortunately i dont know of any good fixes, just preventative stuff. My guess to what happened lines up pretty well with what David already suggested, im guessing the wood wasnt completely dry, or dried improperly, and milling it out either exposed the wood to uneven drying OR released some built-up stresses in the wood. Someone else might have a fix, personally i got nothing since when my projects hit that point they become firewood

Preventative in the future though, that i have a few ideas on. First option is the most obvious one, let the wood hang out for a while. If its not completely dry, best fix is time. Next idea that works particularly well for CNC applications, do the machining in 2 steps. First, rough to general shape, but leave a decent amount of wood to cut to get to finished dimensions. Let the piece acclimate for a few days, then finish the machining process. Idea here is that any warping happens after the first round of cutting and gets taken out by the second round.

Finally, stabilizing is still an option, just not an easy one or one i particularly recommend, owing to the difficulty, extra expense, and chance of failure. Making stabilization work on exotics requires getting rid of the internal oils to start with, best bet for that is a good long soak in acetone. A lot of acetone actually, since you need to soak the piece long enough to penetrate the wood fully, then repeat with fresh acetone until the acetone remains clear after a soaking. After that, you continue the stabilization process like normal, just be prepared to need to keep the piece under vacuum for several days, then keep it soaking in the resin for upwards of a week.

Got some past experience stabilizing ebony, not a fun process. Honestly, id avoid it unless you absolutely have to
 

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Is it possible to apply thin shallow grooves on the inner surface? I saw such a way against bending wood in one of the discussions of the great work done on CNC
 
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