Molding and casting your own found items in resin
After playing around with the Composimold reusable molding material last week for molding chocolate, I was pretty eager to try it for casting resin items. I decided to make resin Legos and used the same molding techniques as I did when experimenting with the material last week. I used the meltable molding material to create two new molds for casting resin. I cast two Lego pieces into two separate cups. I let them sit overnight before I demolded them from their cups. (In case you want to see pictures, I used the same techniques as I did in this blog post on expermenting with new resin molding products.)
Not shown: Before pouring the resin into the mold, I sprayed it with a light coating of the Petrolease non silicone food grade mold release.
I poured resin into the mold cavities. Note: This molding material cannot withstand extreme heat. (Otherwise, it melts!). It is suitable for casting epoxy resin, but not polyurethane resin. Because polyurethane resin heats up very quickly, it will produce too much heat for the mold and cause it to melt.
After pouring in some of the resin, I picked the mold up and flexed it a bit. I did this to allow resin to shift and allow bubbles to rise. This would also be important if it was a very intricate design, say flower petals for example.
I covered the molds and allowed them to cure overnight. Note: once you use this molding material to create resin castings, do not use it for making food items again.
Once the resin had cured, I demolded it the same way I demold castings from silicone: flex the mold, grab the edge of the casting and pull from the mold. Everything had seemed the same until this part. The mold gripped my casting much firmer than silicone does. In fact, I was worried that the resin had stuck to the mold.
I continued to gently pull at the casting and was relieved to be able to demold it. I’m also betting using the Petrolease mold release was a big help as well.
Overall, I was quite impressed with the finished castings. After my chocolate ones turned out ‘just okay’, I wasn’t sure what to expect when using the molds to make resin castings.
Here’s how they compare to the originals. The detail is the same!
I was even pleasantly surprised to see that the word LEGO came through onto the resin castings.
So what are my overall impressions with this molding material?
1. I think if I only need to cast a non complicated item once or twice, this material would be ideal. Being able to remelt it means I can continue to use it for new projects.
2. If I want a food safe mold, I think this will do the trick. The only problem is that it’s not heat safe. If I needed a food safe, heat safe mold, I would use the Alumilite Amazing mold putty to create a mold.
3. If I were going to create an intricate mold, two part mold, or a mold I wanted to make multiple castings from, I would make a silicone casting. I think it would hold up to demolding over time better than this material.
What other questions do you have?
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