DurocShark
Member
I'm curious... Is this from too much dye? I used Alumilite black dye and Alumilite white:
Alumilite Voids?
- Thread starter DurocShark
- Start date
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thewishman
Member
I had some special order (solid color alumilite) blanks done and they also had voids.
MesquiteMan
Retired Head Moderator
Were they cast under pressure? Is there anything in the resin? I cast solid resin and get absolutely no voids. Now in cactus, I do get some tiny bubbles on occasion due to the complexity of the cactus.
workinforwood
Member
Hope those blanks weren't from me Chris! I rarely find voids casting alumilite. Once in a while if casting something complex where there's places for air to really get trapped like in a scrolling it can happen, but otherwise, I never saw one.
DurocShark
Member
No pressure was used. I've seen tiny bubbles in my castings but nothing like this.
ed4copies
Local Chapter Manager
A long shot!!!:
Your signature says "a mile high". Don't suppose your reduced air pressure could have a bearing on this, do you??
Your signature says "a mile high". Don't suppose your reduced air pressure could have a bearing on this, do you??
DurocShark
Member
Yeah, I'm in Colorado. It's always possible that could have a bearing, but I've cast other blanks including a few coffee bean blanks with no problem.
MesquiteMan
Retired Head Moderator
Alumilite needs pressure. If you are using Alumilite regular or white, you can get away with no pressure but if it is clear, you must use pressure, even with just plain old resin with nothing in it. The amount of dye you used would not cause voids. If you got too much dye, it would cause problems with cure. If you are using Alumilite dye and did not get it mixed in completely, you could end up with spots that ooze.
hughbie
Member
if you violently mixed the colorant in the alumilite then you could have mixed a lot of air bubbles in and with it setting so quickly, the air bubbles don't always have time to rise to the top
DurocShark
Member
Thanks all. None of these things feel right. If you look, the voids look like swirl marks. That's why I was thinking the dye. I'll probably never know. especially since I probably won't buy any more. I didn't know the clear needed pressure. There's no way I can get that pressure since I have no pot or compressor. Yuck. PR. Stinky-never-cures-for-me PR.
thewishman
Member
Alumilite
Member
Hey guys,
Best process I've used for casting bubble free parts with Regular, Black, or White (including with dye) ...
Pour the A side into your mix cup and add dye if need be. Mix the in dye thoroughly and allow to sit for 5 minutes to allow the air mixed in to come up and evacuate itself. Drag any remaining bubbles to the side of the cup and crush them with your stir stick. Then slowly add the equivalent amount of B side by pouring it down the side of the cup as you would pour a beer into a tall glass. Once all the material is in, I typically take it one step further and drag any of the bubbles that were created when pouring the two together to the side of the cup and pop them by dragging them up the side of the cup. When pressure casting, you typically stir it vigorously to mix it quickly so you have plenty of time to pressure cast HOWEVER when you don't have the means to pressure cast ... take extra time to mix since you don't need to pressure cast by slowly mixing the material (keeping your stir stick in contact with the bottom of the cup) for 1 full minute. Keeping the stir stick in contact with the bottom will eliminate the chance of sucking air down into your resin. Slowly mix for a 45 seconds then be sure to scrape the sides and bottom well and then mix for another few seconds until you get to the minute point. Make sure there are no swirls present in the mixture and pour the resin into your mold cavity if you were once again pouring a beer into a tall glass. Try to pour it down the side wall on flat angle (by tilting your mold) to slow the flow of the material entering your mold. This will dramatically decrease the cavitation at the bottom of the mold and reduce the amount of air you create during pouring.
Be aware of the heat the material is generating while holding the cup. The warmer the material gets the closer you are to the material kicking off. If it gets pretty warm, you better start hurrying a little more or risk losing the batch of resin.
The last trick of the trade is to baby powder your mold surface prior to pouring. Baby powder releases surface tension and will eliminate a lot of air bubbles from the surface. Knock and or blow out all of the excess baby powder before pouring. And do NOT use this method with the clear as it can leave a cloudy haze in the resin as it pulls the powder off the surface.
If you can't vacuum or pressure cast, give this process a try and hopefully you will have much better results.
Oh, and I also use this with our clear resins with great success although the castings will not be 100% bubble free, I think you will be impressed with the results. I use this technique every time I demo the material outside of the shop where I have the ability to vacuum or pressure the material.
Mike
Alumilite
800 447-9344
Best process I've used for casting bubble free parts with Regular, Black, or White (including with dye) ...
Pour the A side into your mix cup and add dye if need be. Mix the in dye thoroughly and allow to sit for 5 minutes to allow the air mixed in to come up and evacuate itself. Drag any remaining bubbles to the side of the cup and crush them with your stir stick. Then slowly add the equivalent amount of B side by pouring it down the side of the cup as you would pour a beer into a tall glass. Once all the material is in, I typically take it one step further and drag any of the bubbles that were created when pouring the two together to the side of the cup and pop them by dragging them up the side of the cup. When pressure casting, you typically stir it vigorously to mix it quickly so you have plenty of time to pressure cast HOWEVER when you don't have the means to pressure cast ... take extra time to mix since you don't need to pressure cast by slowly mixing the material (keeping your stir stick in contact with the bottom of the cup) for 1 full minute. Keeping the stir stick in contact with the bottom will eliminate the chance of sucking air down into your resin. Slowly mix for a 45 seconds then be sure to scrape the sides and bottom well and then mix for another few seconds until you get to the minute point. Make sure there are no swirls present in the mixture and pour the resin into your mold cavity if you were once again pouring a beer into a tall glass. Try to pour it down the side wall on flat angle (by tilting your mold) to slow the flow of the material entering your mold. This will dramatically decrease the cavitation at the bottom of the mold and reduce the amount of air you create during pouring.
Be aware of the heat the material is generating while holding the cup. The warmer the material gets the closer you are to the material kicking off. If it gets pretty warm, you better start hurrying a little more or risk losing the batch of resin.
The last trick of the trade is to baby powder your mold surface prior to pouring. Baby powder releases surface tension and will eliminate a lot of air bubbles from the surface. Knock and or blow out all of the excess baby powder before pouring. And do NOT use this method with the clear as it can leave a cloudy haze in the resin as it pulls the powder off the surface.
If you can't vacuum or pressure cast, give this process a try and hopefully you will have much better results.
Oh, and I also use this with our clear resins with great success although the castings will not be 100% bubble free, I think you will be impressed with the results. I use this technique every time I demo the material outside of the shop where I have the ability to vacuum or pressure the material.
Mike
Alumilite
800 447-9344
Jim15
Member
Thanks Mike.
DurocShark
Member
Yes, thanks Mike.
I found the voids WERE dye. I stopped mixing when the part A was an even black. But apparently I used enough dye that there were still pockets of pure dye that caused the voids. Hence the swirl pattern to the voids.
I found the voids WERE dye. I stopped mixing when the part A was an even black. But apparently I used enough dye that there were still pockets of pure dye that caused the voids. Hence the swirl pattern to the voids.
JayDevin
Member
mike you are the best....