Tuesday, December 2, 2008
A second attempt
I had this terrible image, driving back from our Thanksgiving trip to Ohio, of a picture like this one posted to the blog each day as I tried for yet another usable rubber master. Hopefully this second attempt - poured this morning - will be all that's needed.
And here is the first attempt sitting inside the gusset piece. The speckles on the gusset are air bubbles trapped inside the translucent rubber. My little foal, however, is almost entirely bubble-free, so my experimental trick worked perfectly.
I'm going to have to describe the trick in words. I really didn't have enough hands to make it work and I had to work quickly, so taking pictures as I went wasn't possible.
I started with the mold opened, and mixed my rubber. Then I dabbed a little bit of rubber onto the face and furry sides - places where air bubbles tend to get trapped. Once I had enough rubber to coat the face and the body, I lightly sprayed the surface with the airbrush to remove any bubbles. (The first time I sprayed too hard and sent rubber flying outside the mold cavity, but it wiped off the mold easily enough.)
With a thin layer across my potential trouble spots, I then reassembled the mold and poured the rubber as usual. (The first picture in this post was taken right after that was done.)
The tricky part is that you have to work really fast, because the rubber is setting up and it still needs to flow through the whole design area. Rapidly managing the mold, tools for dabbing, the airbrush, the rubber bands, and the rubber mix can make you wish for six hands. Or for employees! But if the end result is fewer air pockets in the master, the scramble is certainly worthwhile.
With a little luck this second pour will have all his parts, and I can show how the rubber master translates into a plaster mold.
at 9:25 AM