Question: Why do people make moulds and casts of 3D prints?


New Member

Hopefully I'm posting this in the correct section, apologies if I'm not.

I have been a long time amateur 3D modeller and recently I have been getting into the whole, turning your virtual 3D models into physical 3D models world, and I must say I'm enjoying it!

I have printed 2 3D models so far via SLS (below are examples) and they tend to be small as I'm generally on a budget.

Tron Light cycle
Shapeways | Forum: It arrived! => Tron LightCycle

Dead Space Helmet
Shapeways | Forum: It arrived! => USB powered Helmet light

Getting past my intro spiel and onto my question

This forum has some great threads I've been reading and one thing I have noticed, is out of those who don't scratch build and 3D print, they tend to make moulds of their 3D prints and re-cast (hope I'm using the right terminology there; sorry, I'm new to all of this :behave).

Apart from producing multiple copies of their models/replicas, can I ask what benefits they get from doing this?


For instance, is it to convert the material type to something that easier to work with or produces smoother & better results? Or is it the case it's just generally done in case something goes wrong and you don;t have to start from scratch again?

Thanks in advance to anyone who takes the time to even read this post.
Re: Question: Why do people re-cast 3D prints?

I would say it's generally to have something made with a miniscule amount of error that can be worked to make an nearly perfect piece. Then that "master" would be molded and cast to make copies. 3D printing something is very pricey, so you only get one, master it and mold it, the casts are then done in something which is a lot cheaper therefore there will be more profit. At least that's how I would do it.
Re: Question: Why do people re-cast 3D prints?

Oh man, you definitely did not choose the right term :lol

You simply make a cast or a copy of an item, re-casting is only used when an item is copied from a source that is not your own.

I made a cast of an item that I needed in resin, so I could continue working on it.

Molds will allow you to make copies of an item at a lower cost and quicker than SLA would allow you to do.

RPF staff
Re: Question: Why do people re-cast 3D prints?

Cheers for the quick replies!

Also learned the difference between cast and re-cast. Joined this forum one day ago and already learned something!
Re: Question: Why do people re-cast 3D prints?

Shapeways prints don't always turn out the way you want, so you might clean it up by hand afterwards and then you'd want to make a cast. Also it allows you to make it into pretty much any material you want. The printing material isn't bad, but there's better materials you can cast it into.
Re: Question: Why do people re-cast 3D prints?

That Dead Space helmet has my curiosity piqued.
What scale (in relation to "real world" items) is it?
Re: Question: Why do people re-cast 3D prints?

@Darthviper107: Quite right, it would most likely need some cleaning up before making any casts from their prints, although their polished WSF material is pretty good at getting rid a lot for the sugary texture from the material (though it doesn't eliminate the "laser print lines" completely).

Even though this chap ( didn't make his at shapeways he gave me a very cool tip of using filler putty to hopefully smooth any printed parts before making casts so I'm definitely trying that out on the next project! Good point about the material conversion, I'll have to look into that next and see what materials I may want to try :)

@d_jedi1: The fact that it has your curiosity piqued is a compliment in itself, thanks! There should be a picture I posted with it next to my phone to give a rough idea of scale. As this was a present I gave a friend and don't actually have any more, I can't be exact but it was roughly:

10 cm high, 7 cm wide, 9 cm deep excluding the USB cable coming out the back.

So as you can see it wasn't very big as I was on a budget for this, but something I may consider in the future is print the piece larger, in a less polished material and cheaper material. Then clean it up, make a mould and then cast it into a better material. Not sure if that in the long run would make it cheaper than printing something large in a good material at shapeways but it's something I'll be considering.

Thanks all, I didn't think I would be getting responses this quickly :)
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Re: Question: Why do people re-cast 3D prints?

The polished white is fine, but if you're doing something small and detailed you'd need the Frosted Ultra Detail and it often has issues, but it's the only one that can get thicknesses down to 0.3mm and details of 0.1mm (like rivets).
Re: Question: Why do people re-cast 3D prints?

Perhaps I should clarify... I have a thread on here somewhere (buried) where I'm working on a 1:6th scale Isaac Clarke. A more accurate helmet (much like yours) would REALLY set the figure off so to speak. :D
Based on the pic you posted it looks close to the scale I need/want but I just wanted clarification for overall scaling. ;)

No matter what the scale, it's a beautiful piece. :thumbsup
Re: Question: Why do people re-cast 3D prints?

Hi Guys,
I am a garage kit builder and producer and for me the introduction of 3D printing opened up a whole new world of possibilities for kits I knew would never be made available through the regular commercial market.
3D takes away most of the time you need sculpting and re cutting parts and test fitting. I get others to make my 3D mesh...that part I haven't mastered yet....then I have to take the mesh apart to get it into parts that can be cast easily....casting has its parameters also.
The idea behind the casting for me is to off set the high cost of the master and to get the model out there to others that have the same interest.You will never make a fortune doing it but it covers costs and keeps the hobby interesting for me.
These are some of mine ...hope you enjoy them

The Serenity ImageShack Album - 15 images
Silent Runnings Valley Forge ImageShack Album - 27 images
Paul Atreides from DUNE ImageShack Album - 16 images
Atreides Transport DUNE ImageShack Album - 5 images
Talyn from Farscape ImageShack Album - 2 images
this one is coming....
Moyas Shuttle ImageShack Album - 18 images
Since seeing this thread on the first page of the modeling forum made me jump in my chair for the second time (reading "recasting" does that to me) I took the liberty to change the thread title.

RPF staff
Similar experience, and I worked on a TRON 1 lightcycle too. All to have the pieces printed and stuff.

Why would I mold those pieces ? Well, 3D prints have their laser marks on them, and that could require some sanding, bondoing, etc. I could also add elements on the piece, or doing some operations on it, that would transform it. Those times, it can be better to remold it to have a whole new, solid piece.

In case of symmetrical pieces, you can print only one and save some bucks, then mold it and make all the copies you need.

There's also the material choice : Making the base material, some nylon plastic, into another ( clear resin for instance ).

Here you go, that's a bunch of good reasons I guess. :)
Since seeing this thread on the first page of the modeling forum made me jump in my chair for the second time (reading "recasting" does that to me) I took the liberty to change the thread title.

RPF staff

Cheers, that's probably for the best. Damn noobs not using the correct terminology(!)
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