Post by DavidP on Aug 6, 2020 13:26:12 GMT -5
Hi folks,
I just started casting with Alumilte Clear Slow. I'm using a 5-gallon pressure pot from California Air.
I've done only 2 pen blanks using a Lizard 1x1x6 mold, and I'm getting bubbles in them. Really small ones but enough to leave little pin holes. The castings look great otherwise.
The first one was just using some blue Alumilite dye plus a bit of black mica powder. When I pulled it out of the pot, I could see some air bubbles at the top of the blank, all along the length. I have not cut the blank yet to see what's going on inside. I thought that perhaps there was dust in the pot and the bubbles are actually dust specks, so I cleaned it up well before the second casting. This one used some white dye and 2 separate colors of mica powder in separate little pots for accents. Poured the white into the mold, then the colors. When I took it out of the pot, it also had a bunch of small bubbles on top, some of them leaving little craters.
I actually cut and turned this blank and there are bubbles throughout. Not a crazy amount, and they are small, but they are there and leaving little holes. The blank polished up really well otherwise after turning.
Any ideas on what could be causing these bubbles to remain?
I pressurized the pot at almost 60 PSI, although the safety valve took it down to 50 (I'll see if I can tweak that to allow 60) and then a very slow leak seems to take it down to between 45-50 over 2 or 3 hours. (I waited that long on the second one). It seems that this amount or pressure should be enough, or do I need to work to get it to hold at least 50+?
I also thought that maybe the air could be spraying a bit of moisture to create bubbles at the top, but that doesn't explain the ones inside.
Could it be related to the mica powder? It's not from Alumilite or a known brand, just little baggies from Amazon. Or maybe the quantity of it? I did use more on the second blank and it seems to have more/larger bubbles. Since the main color is white, it's hard to see on the final turning if the bubbles are in the white part as well or just in the colors.
Also, I'm in Tucson, AZ. It's over 100 degrees out there these days and very hot in my garage. Could it be that the mixing time is shortened and I need to get it under pressure much quicker? It still seems liquid enough when I get it in there and well under 12 minutes, although it takes time to tighten down and pressurize the pot. I keep the resin inside my house at around 73 and only take it to the garage to do the casting.
I'd like to figure this out before I try some more.
I just started casting with Alumilte Clear Slow. I'm using a 5-gallon pressure pot from California Air.
I've done only 2 pen blanks using a Lizard 1x1x6 mold, and I'm getting bubbles in them. Really small ones but enough to leave little pin holes. The castings look great otherwise.
The first one was just using some blue Alumilite dye plus a bit of black mica powder. When I pulled it out of the pot, I could see some air bubbles at the top of the blank, all along the length. I have not cut the blank yet to see what's going on inside. I thought that perhaps there was dust in the pot and the bubbles are actually dust specks, so I cleaned it up well before the second casting. This one used some white dye and 2 separate colors of mica powder in separate little pots for accents. Poured the white into the mold, then the colors. When I took it out of the pot, it also had a bunch of small bubbles on top, some of them leaving little craters.
I actually cut and turned this blank and there are bubbles throughout. Not a crazy amount, and they are small, but they are there and leaving little holes. The blank polished up really well otherwise after turning.
Any ideas on what could be causing these bubbles to remain?
I pressurized the pot at almost 60 PSI, although the safety valve took it down to 50 (I'll see if I can tweak that to allow 60) and then a very slow leak seems to take it down to between 45-50 over 2 or 3 hours. (I waited that long on the second one). It seems that this amount or pressure should be enough, or do I need to work to get it to hold at least 50+?
I also thought that maybe the air could be spraying a bit of moisture to create bubbles at the top, but that doesn't explain the ones inside.
Could it be related to the mica powder? It's not from Alumilite or a known brand, just little baggies from Amazon. Or maybe the quantity of it? I did use more on the second blank and it seems to have more/larger bubbles. Since the main color is white, it's hard to see on the final turning if the bubbles are in the white part as well or just in the colors.
Also, I'm in Tucson, AZ. It's over 100 degrees out there these days and very hot in my garage. Could it be that the mixing time is shortened and I need to get it under pressure much quicker? It still seems liquid enough when I get it in there and well under 12 minutes, although it takes time to tighten down and pressurize the pot. I keep the resin inside my house at around 73 and only take it to the garage to do the casting.
I'd like to figure this out before I try some more.
