Sunday, October 10, 2010
Bubblefest 2010! (molds work..now to learn how to cast proper)
Ok, so I've mastered the art of measuring. I kid you not I've eyeballed out the 2 pt mix resin volume for both castings with zero to spare. This is what remains of my drinking-games days. I used to want to bartend and would pour perfect shots every time into any type of cup. I guess this helped in the lab too.. except for when I spilled acid all over my benchtops. Yes, not the field for me to work in. Here you see how I spill all over the counter. Got the right amount inside of the cup... but a little over here and there too. (This is also why bartending never worked out for me either). ;)
My fiance did the other pouring... here's what happens when I try to pour gooey liquids.. this isn't the half of it actually. Somehow it got ALL over all the bottles. Wasteful wasteful tsk tsk -sighs-
First we did white resin;
The mold is full of clear liquid - this is really hard to show of course. Then when the reaction starts to happen this cloud of opacity spreads out. It's quite cool to see. I am wearing a mask & there's a big fan going on over here btw.
So I could see in the white resin that there were bazillions of little surface bubbles. So I decided to just give the black stuff a test again too. Yesterday's test of the 2 colors (normal white or with black dye added) showed interesting results for how the bubbles broke up differently in the black dyed one. Could've been temperature, stirring, our own mixing ratio differences. Lord only knows, seriously! THIS is why I don't have the slightest interest in casting my own en mass. I see these small armies of castings my fellow sculptors turn out and my hat goes off to them. We'll see.
Air bubble fest - this is NOT a surprise, I knew this was the main issue to begin with (the 2nd issue being consistently mixing things properly. Some swear by this or that, my own casters use baby powder and swear it's the reason they don't get surface bubbles. But they don't use much release agent as a result. Anyhow, so I wasn't sure they could mix - twas digging around online just as Becky Turner's comment off of my last post came in & she described to me how the baby powder can go WITH the resin release (and to tap it around like cake pan coating) so we'll see. I'll wait until the casting is done in another 20min before I post this!
My first castings in pure white (also helped to clean off clay from the mold - interesting!) were ok for a first try! I'm trying to fill in the grass on the standing boy & the mane more on the head so that these will be thicker for production castings. Thin on any kind of casting lead to bubbles and uncast spots. Anyhow, though, I got little eartip missing holes and nostril bubbles, the bigger kind... and millions of wee ones that hadn't quite broken the surface so they look like a small disease coating the surface? Soooooooo we went with a different pouring/mixing style and black dye to confirm that we stink at this! :D No seriously, you have GOT to enlarge these to understand just HOW MANY bubbles there are. These are nearly impossible to salvage;
I'll admit too that I'm a little sad the detail isn't as crisp as I thought it would be in some spots, although the above photo is out of focus on the horse and focused more on my finger prints -wow! This though is precisely why I wouldn't have sent clay to be cast finally & left off the facial vein there too.
Btw, the mane flashing excess is intentional - I sculpted the mane tips pretty thin so we leveled these where this area is (if not100% level) going to be the planar low point.. thus it'll be the thickest point of the casting. And all I have to do is trim around it and carefully cut out the loops & whirls.
I still wuvs the nosie nose though! :D (If you enlarge this you'll see the air bubbles at their most shocking!!!) (:-o Ok, I think I've figured out what this is... it's Falcor from the Never Ending Story isn't it... I'm SO unoriginal I really am! UGH!
Anyhow, this one isn't as bad as the next one WITH baby powder - believe it or not!
I'm gonna run for now and go look up some things about this. The lowest/deepest spots where it catalyzes first are the spots where the most bubbles form up. And we're pouring slow, thinly, and doing it all as they tell us to. With and without dye too. Time to watch some online vids & find a trouble shooting section.
Well truth is, if I have to I can work with the one in my hand here. The black (which is blue to purple in reality unless a LOT is used)... is nice at least for showing every little flaw very well. I would have all my resins cast in black except I know it's more work for the casters and surprisingly few people want it because many people start painting with white primer (verses reds or greys).
Ok, off to research during this next half hour. I'm very pessimistic about the one we just poured given how the bubbles coalesced in the same way as the worst one before it. Hrmm... ;)
Edit 20min later to add this in;
Hmmm castings get worse as day rolls on...
http://www.smooth-on.com/faq_display.php?faq_id=3&cID=2 (so many possible things to rule out!)
Humidity has gone DOWN today here but maybe not in the work building I'm using?
Release agent here sounds like the # 1 likely suspect from what they're saying.. it's time for me to demold the next batch so we'll see..
Edit ~1hr later to add this in;
Seems like the bubbles continue to come from the most creased parts of the mold. Trapped moisture? Release agent still?
White castings came out ok.. possibly the least pin-holed (no release agent used, just powder - thinking there may be some release agent still trapped inside however). Now black (with less dye) is curing up as I type.
My fiance officially finds this to be NO fun. I asked him if he's enjoying being surrounded by horsies and he said "no"... :-/ My hand-steady skills will have to improve here for this.
This stuff is expensive to be experimenting with like this. This is why I'm watching, taking notes all over the place (the flashing on these castings is covered in notes). :-P
It's almost like science again. Except unlike microbiology I can really see this stuff sprout to life before my eyes! (The child in me is gratified). ;)