Air bubbles

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keithbyrd

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I’m casting some “worthless” wood with alumilite and after curing I have lots of bubbles where the wood and acrylic meet. Is this because the wood is not stabilized or is there something else going on?
 
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Dieseldoc

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My experience from casting is.
Number 1 Moister, number two not mixing product completly. Lastly not getting alum complexly around , leaving little pockets of air between piweces.
 

its_virgil

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This is very old wood - very old! certain there is no moisture.
This is a common misconception. The wood will be in equilibrium with the ambient relative humidity. Wood taken from the desert southwest to an area with higher humidity will take on moisture until it is in equilibrium with the area's relative humidity. The humidity in Mount Wolf PA is currently 49%.

Also, you did not identify which Alumilite you are using. Alumilite is a brand and not a product. Alumilite makes and sells several different resins.

Alumilite clear and Clear Slow are both urethane resing and and are very sensitive to 3 things: moisture, ratio of the two parts, and how well the two parts are mixed together. The curing produces carbon dioxide and thus the need of using pressure. Also, you did not say what pressure you used to cast.

Lots of variables.
Do a good turn daily!
Don
 

1080Wayne

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In my experience , wood needs to be at 5% MC or lower to minimize interaction with Alumilite clear . However , if you didn`t see any whitening of the resin around the bubbles , moisture isn`t likely the problem . If the resin layer over the wood where the bubbles are was thin , it might also be caused by air from within the blank being forced out by resin . As screwy as that sounds , I`ve never been able to come up with a better explanation for what I sometimes see . A photo of what you have would help .
 

djrljr

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My experience would also lead me to believe it's moisture. If it is as old as you say a couple of hours in a toaster oven should fix your problem.
 

Kenny Durrant

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Sachse Tx. 75048
Moisture can be tricky. Like mentioned before humidity has a lot to do with it. Some won't even try to cast when it's above a certain point to avoid problems. I use Alumilite Slow and cast inside the house. If I'm casting several pieces I'll put all of them in the oven for about 45 min while getting every thing else ready to go. Then when I get the wood in the mold I'll put the wood and mold back in the oven for 40 min to make sure there's no moisture and to get everything warm. I think warming up the mold also helps with the resin flowing into the cracks.
 

MRDucks2

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Franklin, IN
I have seen what you describe on a couple of mine, bubbles next to the wood (or even other embedded items) without streaking.

Normally if moisture is an issue for me, it is accompanied by white streaking or haze. If I have enough moisture for bubbles it is rampant, not just a few.

For a few bubbles that seem to emanate from around the wood of cast items, I have found that warming the blanks in the mold for 10-15 minutes between 150-190 degrees Fahrenheit before casting solves the problem.
 

Silverman

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I’m casting some “worthless” wood with alumilite and after curing I have lots of bubbles where the wood and acrylic meet. Is this because the wood is not stabilized or is there something else going on?
When i work with non stab. wood - at the first i threat the wood surface, that will contact resin, with small amount of resin with help of brush. It soaking and sealing the surface. After curing that layer (at least for 50-70%) - make the main cast, as usual. Also a good idea to dry your wood, as were suggested many times earlier. You can control the dry process by scales. Measure weight of you wood before drying process - write the value on paper. And make weighing with some interval - 1 hour for example. Write value for each measurement and compare with previous, until the weigh stop decline, or decline just a bit - the wood is almost dry. Let it cool down and go further.
 

keithbyrd

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Mount Wolf, PA
Thank you Folks! I appreciate your taking the time to provide feedback .Lot of good tips that I think are totally reasonable - will use the heating processes and try another batch - will let you know how it goes.
I am using alumilite clear - again Thanks!
 

keithbyrd

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Folks - I followed eat wood and paint a light coat of clear on the wood - let cure overnight
2.Heat wood and mold - up to about 175
3. Mix and pour 3 colors of alumilite into mold with manzanita.
4. NO bubbles and beautiful bond between wood and acrylic!
5. picture will be forth coming!

thank you all very much!
Keith
 

keithbyrd

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Mount Wolf, PA
I just reread my last post! I did not "eat wood..."! Should say I followed the "heat wood and paint a light coat ..."
Gotta start proof reading my comments!!
 
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