Deep Pour and vacuum

[BobbyD]

I am wanting to try to make some hybrid blanks with old irregular weathered worm holed wood and Alumilite Amazing Deep Pour.

I have a vacuum chamber, but not a pressure pot. Apparently a pressure pot is not necessary with ADP as it has a 7 day cure time and very thin viscosity. I'm not concerned about the length of cure time, I'm not into high production numbers. I will be stabilizing the blanks with Cactus Juice first, then fitting into molds that I'll be making, then pouring in the ADP. Since this is very low production, I will try to cut the blanks to length first, and probably initially be making disposable molds. Commercially made molds coming later....

Any thoughts on using a vacuum chamber with ADP? My purpose isn't in eliminating bubbles... I know that's what a pressure pot is for, but isn't required because of the thinness and long cure time. What I'm wondering about is filling any voids or pockets in the wood that may not be expelled during the natural settling of the liquid.

It doesn't sound like premature hardening / activation would be an issue with ADP in a vacuum according to everything I've read about it so far.

Should the vacuum be run for hours as in stabilization? Should it be run just until the main bubbles quit? (I'm assuming since it's already stabilized, this wouldn't be long.) Is it worth vacuuming at all?

Thanks in advance....

 

[MRDucks2]

Not yet worked with the ADP, but when you apply vacuum you with get foaming/bubbles so keep that in mind to be able to contain your resin during the "expansion" phase.

The next thing to consider will be how long the viscosity remains thin under vacuum. By stabilizing first, it will help a lot because you will only be dealing with the bubbles/foaming from the resin itself. Just like when stabilizing, once the foaming is done,

I would think you would then release vacuum to let atmospheric pressure for the resin into your holes, nooks and crannies. If it takes 2 hours to stop foaming you will probably be OK, but if it takes a day, will the resin still be thin enough to move?

If you are like me, you have also found that cactus juice sometimes gathers or webs across some internal voids which could block resin access.

Cool idea though and certainly worth trying. Keep us posted of the results.

 

[JohnU]

You should be fine. I do this with other resin and have no problems only I use a pressure tank afterwards because the resin cures faster. Your probably not going to need it to run long. Since the wood will already be stabilized, your only going to pull what air is around the wood filling the cracks and voids. I only pull a vacuum for a couple minutes, opening and closing the valve a few times during the process, and the bubbles you see under vacuum disappear once you release the valve. Just be sure to watch the resin so it doesn't get in your air line (and pump) as it bubbles up. I place my resin and object in a plastic container and set that in my chamber so I don't have to clean resin out of it when I'm done. Good Luck!

 

[BobbyD]

You should be fine. I do this with other resin and have no problems only I use a pressure tank afterwards because the resin cures faster. Your probably not going to need it to run long. Since the wood will already be stabilized, your only going to pull what air is around the wood filling the cracks and voids. I only pull a vacuum for a couple minutes, opening and closing the valve a few times during the process, and the bubbles you see under vacuum disappear once you release the valve. Just be sure to watch the resin so it doesn't get in your air line (and pump) as it bubbles up. I place my resin and object in a plastic container and set that in my chamber so I don't have to clean resin out of it when I'm done. Good Luck!

That's pretty much what I thought I'd be looking at, although I thought it may take more than a few minutes to do, but since I'm not pulling air out of the wood again I guess I really shouldn't have to let it sit in a vacuum for any real length of time. Thanks for the idea of the plastic container... those little cheap "Tupperware" type bowls from the Dollar Store should work okay...

Since I'll be trying to make some "disposable" molds (plastic corrugated "for sale" signs or foam board lined with Tuc Tape), maybe I should make them much higher than the finished blank... say, 1 1/2 inch high and mark a 3/4 inch line inside to fill up to...

Think I'll experiment with colors... dye for CJ or clear... opaque or translucent for ADP... anyone found any combinations thereof that was disappointing? Favorable?

 

[JohnU]

I would make the mold as high as possible to fit the chamber. That way you won't have to worry as much about the resin bubbling over.

 

[MRDucks2]

You should be fine. I do this with other resin and have no problems only I use a pressure tank afterwards because the resin cures faster. Your probably not going to need it to run long. Since the wood will already be stabilized, your only going to pull what air is around the wood filling the cracks and voids. I only pull a vacuum for a couple minutes, opening and closing the valve a few times during the process, and the bubbles you see under vacuum disappear once you release the valve. Just be sure to watch the resin so it doesn't get in your air line (and pump) as it bubbles up. I place my resin and object in a plastic container and set that in my chamber so I don't have to clean resin out of it when I'm done. Good Luck!

John - so do you pull vacuum and release a few times then finish the cast or do you pull vacuum until the bubbles stop?

 

[JohnU]

Yes, I pull vac for 20-30 seconds and release a few times. After about 2 minutes I put it in the pressure tank. I want to make sure the resin is still thin enough for the air to escape or compress under pressure. I don't do it for everything but it works well for porous items or things with cracks and voids.

 

[MRDucks2]

Yes, I pull vac for 20-30 seconds and release a few times. After about 2 minutes I put it in the pressure tank. I want to make sure the resin is still thin enough for the air to escape or compress under pressure. I don't do it for everything but it works well for porous items or things with cracks and voids.

Thanks for the clarification. I just began to experiment with vacuum applied to resin and did the same thing, but was sure if I was gaining anything or not.