Filaments dissolves in what ?

[Nueiba 0]

HI and thanks for your appreciated help.

I am a hobbyist and I wonder what will happen to my 3D print when I'll try to make a mold with it.

For example; If I use my PLA printed part and immerge it in a urethane based product, or an epoxy resin. Will it melt ? 

 

To turn around the question.  

What filament will not melt with urethane, epoxy resins and silicone ?

That is what I'd really want to know.

 

Regards !

[geert_2 560]

Maybe you need to make a distinction between "chemically melt" (dissolve) and thermally melt (high temp)?

 

Most epoxies I have used are very exothermic reactions: they get extremely hot. So, these will melt a PLA mould for sure. I don't know about PU, but I believe it is also exothermic? So you need to search for slow-curing, low-exothermic versions (usually they do exist). Added benefit is that these shrink less than fast-curing

 

But PU and epoxies may also bond very strongly to PLA, so you need a good separator: multiple layers of silicone or PTFE-separator spray, or other. And even then... Try it on small test pieces first. As far as I know, PU or epoxies will not chemically dissolve PLA.

 

Silicone depends: there are sticky silicones like the sanitary versions. And there are non-stick versions for mould-making. None of those that I used caused real warm-up, so I guess these should be temp-safe. Also, silicones are chemically quite inert, so they should not dissolve anything.

 

Another option would be to use the PLA to make a positive model, and then use silicone to make the mould from that PLA-model. And maybe make a hard shell in PLA too around the mould, to keep the silicone in place, so it does not deform (may happen if you use very flexible silicone). In Youtube, search for: mould making and casting. There are lots of good tutorials.

 

[Nueiba 0]

Thank you for your 'articulate' answer. 

I'll make small tests has you mentioned. Your answer gives me orientation in the material I can print with. (PLA)

 

I've also discover the Smooth-on answer to my question.

They recommend the coatings of XTC-3D, to protect the model. 

 

I realize that in the modeling world, everyone wants to sell you something that you may not need... Or worse, inappropriate material.