If you play with oogoo, the fantastic low-cost silicone , presented in the great oogoo instructable of mikey77, you might have noticed that if you use it to make for instance molds of large objects, (say > 10 x10 x 10 cm), then you still need to buy quite a lot of the acetic type silicone and so even though the acetic type silicone in itself is quite cheap in the end its no more so cheap , even though still much cheaper than using commercial mold making silicone.
But you can save even more money if you recycle your oogoo scraps from old or unsatisfactory oogoo molds that you don't need any more. Also you can recycle all the oogoo "waste" that builds up on your table, spoons and cups when you mix silicone with cornstarch to make oogoo.
Step 1: Collect and Prepare Oogoo Scraps
- First you need to cut your old oogoo molds or other oogoo objects to small pieces , smaller than about 3-6 mm in size (about the size fo coffee beans). This is necessary for the following grinding step with a coffee grinder.
- Do the same with all the oogoo residues from your tools that you used to mix oogoo.
- Add some cornstarch to your oogoo scraps. I use about 2 or 3 part scraps and 1 part cornstarch, but actually you can choose this in a wide range, depending on how much silicone you want to add later. Adding more cornstach means you will need to add more silicone later. The cornstarch and silicone that you add later act as "glue" to stick your scraps together to give a sticky /grainy silicone paste.
Step 2: Grind Oogoo Scraps and Mix With Silicone
- grind the so prepared scraps in an old coffee grinder, that you won't use any more for coffee of course.
If you feel the grinder is struggling to grind your oogoo scraps it's probably because there are some larger/longer than "allowed" pieces of oogoo in your mix that tend to entangle around the rotation axis of the knife blocking it. In this case stop immediately before your grinder overheats and free any scraps eventually entangled onto the knife/rotation axis. Be careful with your fingers !
- add acetic type silicone as in mikey77's instructable to the ground oogoo+cornstarch powder. The amount depends on the amount of cornstarch that you added in the previous steps and you can again vary it in a wide range, but I suggest you to add at least as much silicone as cornstach, better more. Mix the "paste". Now its ready to apply it to make new molds and oogoo objects.
Step 3: Use Your Recycled Oogoo , E.g. to Reinforce Larger Molds
- Since the recycled oogoo has a grainy texture, depending on how fine you ground your scraps, you cannot use it to replicate fine details, but you can make good use of it to reinforce normal oogoo molds since fresh recycled oogoo will stick to any old/cured oogoo or other silicone. I use to first coat my object which I want to replicate with a sufficiently thick "shell" of normal fresh oogoo and then to add an outer reinforcing shell of recycled oogoo. I also use it to add protrusions for fixing the mold to a rigid frame for roto-casting (I use a LEGO frame for that purpose).
- If you compress your recycled oogoo paste you can increase the replicated detail. You can then try to directly make new molds using only recycled oogoo. The quality of surface finish of the molds will depend on how much silicone you added in the previous step and on how well you do the compression molding and of course on how fine you ground your recycled oogoo. A oogoo mold for LEGO casting turns out sufficiently well to cast new LEGOs but in my case with a modest quality of surface finish.
- finally you can use recycled oogoo just to have fun. Since normally your oogoo scraps will have all different colors (if you colored oogoo), recycled oogoo has a nice multi-color apperance, sometimes resembling "flesh". So it's easy for instance to make mock-up "oogoo-salami"
Long live oogoo !