Alumilite foam?

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mywoodshopca

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Charlottetown, PEI Canada, Derby Kansas and Canyon
Any ideas what went horribly wrong here?

Blanks were very dry, no where near any moisture. CC alumilite was used, mixed well, some pearlex added then poured into the mold, then put into the pressure pot about 5-10 minutes. Took out of pot, slab looked ok, but was pretty warm (setting up), I then mixed up another slab of CC alumilite and cast it with no problem, the messed up slab had a few bubbles on top when I left the shop. Today.. this is what was I was faced with. Peeled off most and sanded off the rest, none of the alumilite setup inside any of the voids but all looked like the foam, even in the voids.

I use a digital scale and used the exact same amounts of both A & B.
 

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Looks to me like the Alumilite didn't have time to set up properly. My best guess would be that the air bubbles you 'crushed' under pressure had an opportunity to re-expand thus causing your bubbles.

I have found that the cooler winter temps create the need for slightly longer cure times while in the pressure pot. Either way, 5-10 minutes under pressure is probably insufficient even under the best of circumstances. 15-20 minutes is my minimum time, 30-60 minutes when my shop is cooler (65 degrees F).

Hope this is helpful.
 
Definately looks like moisture to me. Not leaving them in long enought will not cause that effect. Was all of your components completely dry? What about your pearlex? Just becasue a moiture meter says it is dry does not mean anything at all. Did you have the proper calibration adjustments for the particular wood for your meter? Best bet is to put the wood in a toaster oven for a number of hours before casting to ensure it is oven dry.
 
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I have played with some of the same wood you are using and have found that the wax/sealer inside it will also cause what you have. I have taken to boiling the wax/sealer out, but I do it 3 times now to assure it is all gone, then I microwave the blanks for 20 minutes at a time, several times over a few days, an oven will work as well. I don't know if the wax/sealer is holding moisture or if it just creates the same effect but it is important to get it all out. Feel free to use your wifes favorite pot for the boiling part.
 
I have played with some of the same wood you are using and have found that the wax/sealer inside it will also cause what you have. I have taken to boiling the wax/sealer out, but I do it 3 times now to assure it is all gone, then I microwave the blanks for 20 minutes at a time, several times over a few days, an oven will work as well. I don't know if the wax/sealer is holding moisture or if it just creates the same effect but it is important to get it all out. Feel free to use your wifes favorite pot for the boiling part.



Thanks for the info. Will try that.

Favorite pot?? Want me to leave the cdn money to you in my will?:biggrin::tongue:
 
Looks like the money blanks Neil tried to do a demo on and the October meeting. :)
He learn that money can absorb moisture from the air.
That was pretty funny, too bad the time I added water to make it foam it wouldn't. Paper money can definetly hold enough moisture to foam up.
I believe it was the July meeting, we didn't have one in October and July was real humid.
 
I knew it was before the November meeting that I didnt make it too. I was thinking September but typed October. Funny how the brain works. I really think that spit and water are totally different when it comes to Allumilite reactions.
That was pretty funny, too bad the time I added water to make it foam it wouldn't. Paper money can definetly hold enough moisture to foam up.
I believe it was the July meeting, we didn't have one in October and July was real humid.
 
I knew it was before the November meeting that I didnt make it too. I was thinking September but typed October. Funny how the brain works. I really think that spit and water are totally different when it comes to Allumilite reactions.
Just becareful if I offer you a drink of water....LOL
 
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