Post by tyskkvinna on May 31, 2016 11:33:04 GMT -5
I've been using alumilite for a long time and suddenly I am getting bubbles, bubbles everywhere. I am using the water clear and the original white, and both are resulting in it. The white in particular, which is a product I've never had issue with.
I used the neon alumilite dye and you can see it also had some issues, but the orange dyed pretty good and is still bubbly like crazy. I also had this problem with keeping it white but I don't have any of those handy.
Post by carol - Alumilite Corp on Jun 1, 2016 14:45:49 GMT -5
Good Afternoon to you both,
There are a lot of different reasons for bubbles in resin...
Moisture is often time the big one, and sometimes don't have a happy ending if the whole bottles are contaminated by moisture. Important to keep/store and use in a controlled area for temperature and humidity. It is also important to stay with in the shelf life, each resin has it's own shelf life ranging from 3 months to a year. The longer the pot life, the more care has to be taken that it is used in less than 30% humidity settings. Using stir sticks or mixing vessels that have moisture, fillers or dyes that have moisture or water based (even if they aren't sometimes if they sit around in open containers they too can acquire moisture and hold it) then when you use them it introduces it to the resin. Constantly open and closing containers in humidity or a non air conditioned room, there are products like our Bloxegen if you are planning on storing, caps still need to be on tight at all times.
The others would be air bubbles trapping in a complex mold where you may need to put a vent/sprue to help that part of the mold fill, pushing the air out through the sprue making way for the resin fill. In some the recesses are so tiny that it may be impossible to do with out assistance of a pressure pot to get into these areas.
Also make sure there are no bubbles in the silicone mold, as it will transfer to the replica if it was on the original/master you used to make the mold. Silicone picks up everything that is on the original.
I think from what I am seeing here it looks like it may be some moisture ... how old is your resin, perhaps the green dye has some moisture contamination.
I've been having some bubble trouble with Alumilite Water Clear. It's my first time using it (though I've used Alumilite White a fair amount) and it is a fairly fresh bottle (just opened but purchased 3 months ago). The actual quantity of bubbles is not very severe but it leaves some very bizarre defects on the surface of the cast around what I think are the nucleation sites. Basically you are left with a pit where the bubble formed but didn't release and then some ripples/wrinkles on the cast's surface around said pit.
I think I can rule out the resin itself being contaminated with moisture because the resin left in my pour cup does not bubble as far as I can tell. However I don't think it is in the mold either because I keep my molds in a sealed contained with desiccant and because I do not have this issue with Alumilite White at all. I was thinking it might be due to some contracting of the mold/resin before the resin is cured but I really don't know.
I can tell you I use High Strength rubber for my molds and that I usually preheat the mold in a microwave (though I have tried this with a kitchen oven as well and had the same issue, but even worse.)
An example of this is seen below as well as an Alumilite White cast for comparison. The cloudiness is due to the surface texture, not off ratio mixing. I'll appreciate any help you can provide on this, and thank you very much!
Pour another Alumilite White casting and then go back and pour the Water Clear. Sometimes ... with a brand new mold, the excess tin that hasn't fully crosslinked in the silicone can effect the tin we use to cure the Water Clear. By pouring a few pieces with the White first, it can clean and crosslink any unused silicone raw materials to allow the more sensitive Water Clear to pour and cure perfectly.
Thank you for your insight to removing bubbles in resin. I was wondering if you had any recommendations for removing bubbles in the mold? I believe my issue is that the cast is emulating the bubbles of the mold. Would the same process of placing the form in a vent work? Additionally, do you have a specific dye/colorant that you would recommend to minimize the bubbles in the final cast?
Most people do not have the luxury of using a vacuum chamber and pump. If you do, simply measure, mix, degas, and pour.
But since you are writing this ... I'm assuming you don't. Therefore, measure, mix, brush on an initial thin layer of the mixed rubber onto your original and once you've wet out the entire piece, then go ahead and pour the rest of your mixed silicone slowly from one corner. This does not allow the bubbles to hold on to the master and forces to float up and away from the mold surface before the rubber cures. Even if the air bubbles is trapped in the middle of the silicone rubber, it will not be visible as it was when it on the surface and will not show in your cast resin pieces.
We have a complete line of dyes, metallic powders, and pearlescent powders you can add to the resins. They will not remove the air bubbles you may have mixed in but they do sometimes help to conceal air bubbles.
Something I found recently is the temperature of the mold makes a big difference. I didnt warm up my Vac 50 mold and had a horrible pour that was full of surface bubbles. I assumed it was because the resin is kinda old, turns out that wasn't the case at all. I needed to cast a bunch of pieces and to speed things up I heated the mold. I used new resin and of course it poured great. I really didnt want to give up on a gallons worth of the older stuff just yet so I tried it in the warm mold and much to my surprise it came out perfect. Been using what I thought was moisture tainted resin for a a couple weeks now. So if you get surface bubbles try heating your mold up just to make sure.