Why make molds from 3d printing?

[Frenzy1971]

I am a relative newbie. I just got my Creality CR-10 yesterday. I am reading tons of info on here, watching tutorials, and trying to get the best game plan before I try to do anything, so I don't waste time and material. One thing I see, is people printing a costume, a helmet, etc, then making the silicone mold for resin casting.
Is this done so they can replicate copies, or to make a version without print lines?
Since they bondo and sand it to get that perfect finish, why then mold and cast?
Is it a strength and durability thing, or primarily to replicate and make money?
I did search before posting, so forgive me if I'm duplicating something.

 

[venommaggot619]

Hi there,
From my experience, you make a mold of your finished print (filled and sanded smooth) to make copy of the item you want to save yourself time and effort. Many pieces take a ton of time/effort to smooth so why not make a mold to cut down on that time and effort. It can also be preference but I would rather have a resin piece the a pla or abs one.

 

[Frenzy1971]

Oh man that's something I had not thought of! So like if doing iron man- the arms, legs, forearms and feet? That sounds like a HUGE time saver! Thanks!

 

[JPH]

I made some goggles out of clay and metal, then made a 3d model. The 3d model is not transparent, but cut and pasted the halves so it is perfectly symmetrical. I used it to make a mold then cast out of epoxy resin. The goggles are concave left right and top bottom, so, trying to vacuform left me with goggles that didn't want to come loose!

You can rough and dirty prototype using 3d models by just setting the machine and going to sleep. Much easier than trying to tweak a prototype.

Making a 3d print nice and pretty, and then creating a silicone mold and casting lets you make multiple perfect copies. A lot of work up front, but then you can make multiple copies for friends or yourself. I do not condone making cast of other people's work! I made a dragon scale mold, then slush cast several scales. I can modify them as I want, so they aren't all boringly the same. I made a PEP Judge Dredd helmet, then made a mold, that way I can make several copies in midnight blue, to my liking, but I could make a flaming pink helmet if I wanted as well in an hour with the mold and the resin.


Also, my printer can't make a full sized helmets.

When ever you make a master prototype, I'd recommend creating molds for it and pulling from those. If the mold goes bad, just repeat the mold-creation process on the master mold.

 

[mdb]

I have found printing in ABS to be my best of both worlds solution for costuming.

Most resin winds up a health hazard as it's heavy and brittle. All the armour I have made has been from epoxy fibreglass to at least be safe and light, and chemically bonded from inner to even paint if I want.

PLA is good for a fast print but requires smoothing with a filler- and usually one that doesn't chemically bond to the plastic in the same way you can use an epoxy filler on epoxy resin.

ABS on the other hand can be fumed with acetone to fuse all the print lines. And as the print is comprised of solid walls and lower density infill it winds up with a high degree of strength. I find then I have more room to cut back and also fill with thin layers of ABS dissolved in acetone.

It also allows for mirrored pieces- in the Iron man costume mentioned you can't just make two molds of the same cast as a body is mirrored each side.

But yes for multiple copies of scales, or anything that is faster to cast than print that would be the best way to go. And really good for rapid prototyping for later casting in different materials.

I may be attempting to digitally sculpt some 16thC jewelry as I don't trust my ability to sculpt some of the basic shapes- rings, 8 shapes and split rings etc. I will mold them in silicone, then cast in wax, add the sculpts I am happy to do (petals leaves etc.) tidy , cast again in a silicone that will cope with metal and cast them that way.

 

[Frenzy1971]

Thanks for the answers. This place is amazing for a newcomer to this wacky world of building.

 

[Birdie]

Resin casts also have a decent weight to them.