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NB

Molding compounds?

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I recently started a project I've held off on for a number of years thanks to most of the things needed for it becoming more affordable. Anyway last week I set up everything I needed for the mold and despite some small goofs(not making enough mix on the first batch, forgetting to shake it to remove air bubbles) the mold came out pretty good. Sadly I didn't have the resin yet as it wasn't in stock but I got a call last night saying my order was in. Filled with excitement about finishing this weekend I went about my evening but then I noticed the bottom section of the mold had turned up at the corners and something told me to look it over completely. It seemed okay at first, no cracks or serious deformities, but I tried to reinsert the ball I used and it stretched the mold.. putting the two halves 'together' left a half inch gap as the mold as a hold had shrunk significantly over the last week.

I still plan on picking up the items I ordered from the store today but now I either need to buy more molding compound, which this brand clearly isn't meant to be used more than once, or try to find a different brand I can reuse if I want. I'm leaning toward finding a new brand, but the hobby store only carries the one.

Does anyone out there play around with molding compounds and resin? Do you have suggestions for a brand that can be reused that hopefully isn't super pricey? I found a kit with rubber mold compound but it's $70 for the kit and the site didn't seem to have just the molding material.
Viewed: 30 times
Added: 5 years ago
 
FellDwarf
5 years ago
I am unable to contribute any useful information, but i am also unable to contain my interest in this project of yours. would you mind clarifying the nature of this project
NB
NB
5 years ago
Well this particular project was meant to be simple and I was just going to cast a resin ball, though once I had a good idea of what I was doing I was going to attempt to make a set of dragonballs.
FellDwarf
5 years ago
Oohh i wish you luck in your endeavor
Darkewulf
5 years ago
I'd suggest looking into a platinum-cure silicone rubber for your moldmaking. Smooth-On has a nice variety of silicones, urethane rubbers, and resins, all priced roughly the same (around US$35 on Amazon for their two-pound trial kit). I just got done trying it out today and so far everything seems nice.

Of course, I kind of did the inverse (poured/cast the silicone into a 3D-printed mold instead of having the silicone be the mold), but the principles are essentially the same. There are some nice videos available online that clearly demonstrate the two-part process for first making the mold out of silicone and then using the cured silicone mold for casting resin.
Darkewulf
5 years ago
And of course you can always just design and 3D-print your mold out of sturdy plastic like I did. Depending on which printing service you use (or if you have access to one locally), it might be a little bit on the expensive side, but you'll be able to re-use the mold as many times as you want. The only recurring expense would be a mold release agent, but even then a good sized bottle will last a very long time.
NB
NB
5 years ago
I didn't find the exact brand you mention at m local store but I did find rubber molding. However I can't seem to mat, or I'm forgetting my math lessons, but the box I have for pouring the mold into is 6x5x5(inches) and the instruction booklet says 1lb of compound makes 21 cubic inches by volume. I'm pretty sure this means I need more but I'm failing to get a consistent answer.
Darkewulf
5 years ago
My bad, I should have mentioned that Smooth-On products are rarely found outside of specialty stores, usually places like Reynold's Advanced Materials. That's why I mentioned Amazon, where I bought mine.

What molding material did you end up going with?
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