- PLA as a material is at least food safe (though food safe and body safe aren't the same). But! The material passes through nozzles which probably have lead in them etc. even if that's of negligible consequence though the main issue with making something body safe is the layer lines, which retain moisture and breed bacteria.
- yes, concave surfaces are dang near impossible to smooth.
- plenty of household release agents don't work in a silicone to silicone mould, or impede the cure of platinum cure silicone (the body safe kind), and if you bugger it up you're just wasted the mould and the dildo's worth of silicone which is $$$.
- I just used PLA. the beeswax doesn't touch it for long, you literally pour it in and immediately back out. Because the print is hollow on the inside and because beeswax has such a low specific heat capacity it cools instantly, and this all works, my pics are proof.
- silicone doesn't bond to PLA, no, but you need to smooth the layer lines, which brings us back to point 1....
I've been orbiting this array of technologies lately - 3d printing + silicone, and also epoxy resin - so this is all really useful info for me. Your comment about having to figure out working processes by trial and error rings true. I'll be sure to bear beeswax in mind - maybe it'll work some magic on epoxy as well.
In the spirit of reciprocal knowledge sharing, I've been using filler primer spray or smoothing prints. You're probably aware of it already, but it seems very underrated in the 3d printing community. Sands to a mirror finish amazingly quickly and easily, especially under running water. Obviously that's not a body safe surface, and I don't know what effect it would have on silicone curing, but still - one worth keeping in the toolbox.
Which comment about trial and error sorry? I honestly rarely do the same thing twice... ADHD and all. lol
Yes, filler primer is great and I recommend it often. I think I actually mention it in the article? It's just a LOT more work than pouring some wax in and out of a mould.
>And there's so little info out there about the topic! What materials are safe/work? So many processes to master to get a good result, such expensive supplies to be dabbling with! Urgh! Not worth it, right?
Ah, it seems I projected the "trial and error" part. I certainly don't often get it right first try! I would never have guessed about dish soap preventing curing, for instance. So easy for a project to end prematurely in a sticky mess...
- yes, concave surfaces are dang near impossible to smooth.
- plenty of household release agents don't work in a silicone to silicone mould, or impede the cure of platinum cure silicone (the body safe kind), and if you bugger it up you're just wasted the mould and the dildo's worth of silicone which is $$$.
- I just used PLA. the beeswax doesn't touch it for long, you literally pour it in and immediately back out. Because the print is hollow on the inside and because beeswax has such a low specific heat capacity it cools instantly, and this all works, my pics are proof.
- silicone doesn't bond to PLA, no, but you need to smooth the layer lines, which brings us back to point 1....