DIY stuff

3dprinteddoll · Post by **3dprinteddoll** » Sun Aug 22, 2021 5:15 am

Here is what I did yesterday in silicone(using 3d printer for mold printing):

Not outstanding, but not bad as for the first try. This is a body part scaled down to 60% of target size, to not waste silicone and to speed up the mold printing.

As you can spot there are some issues (like visible layers/steps) to solve. This doesn't look so bad on the foot, as it would look on the head or face, but I have some ideas how to tackle this.

I will probably try the whole doll too once I perfect the body parts making, but it will take some months, if not years.

I don't target for-profit doll making anytime soon, if ever, but in future, as I perfect the process I would like to share my progress, what I learned or maybe even collaborate on some cool projects.
I want to encourage others to do their own experiments.

gogodolls · Post by **gogodolls** » Sun Aug 22, 2021 7:40 am

Wow! Very impressive and interesting your first try!

According to your expertise, could we make 2 doll halves in order to insert a **skeleton between these halves and glue them afterwards?
(**...providing the necessary cavity inside the doll!

)

Is your printer capable of making the full body of a 1:6 scale doll? (12 inches long approx or less)
This could revolutionize the world of miniature dolls!

There are a lot of amateurs here!

Congratulations on this first try, I will follow your thread with great interest!

Cheers!

Lambymar · Post by **Lambymar** » Sun Aug 22, 2021 7:59 am

Very good!

3dprinteddoll · Post by **3dprinteddoll** » Sun Aug 22, 2021 8:21 am

gogodolls wrote:could we make 2 doll halves in order to insert a **skeleton between these halves and glue them afterwards?
(**...providing the necessary cavity inside the doll! )

I think that the typical process is that there can be two halves of the mold. Then you precisely place the skeleton into the mold, then seal the mold (both sides) before pouring into it liquid silicone, of course there has to be some hole through which you pour silicone. I think that most doll manufacturers do it pretty much that way. Then you wait and the doll is "baked" with a skeleton inside.

My printer can handle up to 15 inches, it is this model: https://www.anycubic.com/products/anycu ... 3d-printer

gogodolls · Post by **gogodolls** » Sun Aug 22, 2021 11:55 am

3dprinteddoll wrote:My printer can handle up to 15 inches, it is this model: https://www.anycubic.com/products/anycu ... 3d-printer

Thank you for the link.

As I learn 3D modeling in Blender in my spare time, it can be fun to buy this type of printer.

(They are more affordable than I would have thought.)

I will follow your tests or future projects with interest!

Cheers!

NotTheMessiah85 · Post by **NotTheMessiah85** » Mon Aug 23, 2021 4:21 am

That's damn impressive! Maybe a slight oversizing is required so you can trim / smooth out the more obvious print banding?

3dprinteddoll · Post by **3dprinteddoll** » Wed Aug 25, 2021 2:01 pm

NotTheMessiah85 wrote:That's damn impressive! Maybe a slight oversizing is required so you can trim / smooth out the more obvious print banding?

I am now working on this. But silicone is hardly trimmable or smoothable once cured, It's like smoothing out jelly or rubber. So I will only work on smoothing out the mold, before casting.

I have a dozen methods to try out, that include covering the mold interior with something (wax, Mr. Surfacer primer/filler, lacquer spray, various diy filler pastes on my list, I might even try hair styling spray and different powders), or printing the mold using different material than PLA or printing PLA with tiny 0.1mm nozzle, currently working on first: using hot wax to fill the whole interior of the mold. I will report later on results, and which of the methods tested gave best results, with least effort.

rubherkitty · Post by **rubherkitty** » Wed Aug 25, 2021 10:13 pm

Why not just print the object you want to make. Smooth and detail it, then make a mold of it to cast the silicone object?

3dprinteddoll · Post by **3dprinteddoll** » Thu Aug 26, 2021 4:44 am

rubherkitty wrote:Why not just print the object you want to make. Smooth and detail it, then make a mold of it to cast the silicone object?

I was thinkng about that too. And I see that making the mold out of object, instead of printing it indeed has some benefits:
1) smoothing out the object exterior is easier, than smoothing the mold interior, at least you see what you are doing

2) you have preview what you'll get and possibly more control on tiny details, after printing.

Some issues that I see with this approach:
1) it adds another time-consuming and error-prone step, you need to make the perfect mold out of the 3d printed object, and the object needs to be assembled and post-processed too, before making the mold.
2) you need to pull the object out of the mold. It could be troubling in case of pulling hard PLA doll out of let's say hard gypsum, is difficult to do that without causing cracks and detroying the mold. I would probably have to coat the object with something that would allow to pull it out of the mold smoothly.
3) gypsum is 2.96 gram per cubic centimeter, so it won't be lightweight mold, in case of entire doll. In comparision 3d printed mold is usually 80% or more empty inside (you can set infill density to whatever you need).

I don't know what other material to use for such mold, at first I was thinking about calcium sulfate(gypsum). I was thinking also about alginates(+gypsum), it sets faster, it is like jelly at first, so you have a chance to pull out hard PLA object (but unfortunately unlike silicone, alginate is prone to tearing, so it would had to be pulled out in very gentle and thoughtful manner). Alginate-gypsum mix also shrinks and cracks as it is drying out completely, usually after 1 day so mold is usable for short time.
I don't know what cost-effective material could perform better than alginate-gypsum for such mold. Maybe pure alginate, but it is like jelly, so probably not the best mold material either.

So for me this is backup-alternative approach, with it's own major issues to resolve, I will go this way only if mold printing and smoothing, will not give any good results.

gogodolls · Post by **gogodolls** » Thu Aug 26, 2021 5:21 am

I think this might interest you and maybe answer some of your questions.

Smooth-on offers a whole range of casting products and products to make any type of mold.

(In the other link, you can find other products like synthetic clay, plaster of paris and others ...)

https://www.youtube.com/channel/UCfaq-2 ... NbuzRvc5sg
https://www.sial-canada.com/en
Cheers!

3dprinteddoll · Post by **3dprinteddoll** » Thu Aug 26, 2021 7:21 am

gogodolls wrote:I think this might interest you and maybe answer some of your questions.

Smooth-on offers a whole range of casting products and products to make any type of mold.
(In the other link, you can find other products like synthetic clay, plaster of paris and others ...)

https://www.youtube.com/channel/UCfaq-2 ... NbuzRvc5sg
https://www.sial-canada.com/en
Cheers!

Yes, perhaps some putty/clay based thing, could do the trick, I've never tried this, but for now I'll be trying the most straightforward process first by printing mold parts and smoothing them, and l'll try the more complex one with making the mold by the print impression, only if first one will not deliver good results, or pherhaps if I will like to compare cons and pros of both approaches.

gogodolls · Post by **gogodolls** » Thu Aug 26, 2021 8:26 am

3dprinteddoll wrote:Yes, perhaps some putty/clay based thing, could do the trick, I've never tried this, but for now I'll be trying the most straightforward process first by printing mold parts and smoothing them, and l'll try the more complex one with making the mold by the print impression, only if first one will not deliver good results, or pherhaps if I will like to compare cons and pros of both approaches.

I totally agree with your way of thinking. (Look at the easiest and cheapest method first.)

Ideally, a technological improvement in the printer would be needed to make the last layer of silicone smoother and respecting the data of the 3D model.

But until then, people like you can find an innovative solution!

Cheers!

3dprinteddoll · Post by **3dprinteddoll** » Thu Aug 26, 2021 9:56 am

gogodolls wrote: Ideally, a technological improvement in the printer would be needed to make the last layer of silicone smoother and respecting the data of the 3D model.

Cheers!

There already is, it is called resin printer, unlike plastic deposition printers (FDM) which usually have 0.4mm to 0.1mm accuracy, resin printers use laser/lcd to solidify object (Stereolithography/SLA) and have 0,05 mm to 0,015mm accuracy. The cons is that these printers have usually smaller working field, 20x20cm x something is considered large, and they are slightly more expensive, also the resin itself is more expensive, than PLA plastic. But even those resin 3d prints are prone to edge-warping, so there is no perfect printer yet, that would not require 3d print postprocessing at all.
And also SLA printing is even slower than FDM, which is already slow (it can take 8-12 hours to print something size of 10x10x20 cm).
Perhaps the CNC machining in metal is most ideal method (smooth outcome, large parts, no warping), but it is also very expensive in comparision to 3d printing so I will not cover that, as this is just kind of a hobby project that almost anyone can start in their own basement, not an attempt to create some serious doll manufacturing line

rubherkitty · Post by **rubherkitty** » Thu Aug 26, 2021 1:36 pm

Many professional silicone doll molds are layed up over a model making a fiberglass shell mold with reinforcements. Generally a special resin hard coat or epoxy coat is applied to the model first followed up by the fiberglass cloth and resin. I don't know of anyone who uses a plaster type mold for a full size doll.

3dprinteddoll · Post by **3dprinteddoll** » Thu Aug 26, 2021 2:02 pm

First attempt of smoothing out (by pouring wax), is a failure, or more accurately a mess

:

Contact of wax and silicone seems to cause the surface of silicone to become messy. Also some wax droplets are reflected in the cast. Many nice details had been removed. I haven't expected that wax will give so poor results.

I am abadoning the liquid wax, and proceeding to the next diy approach on the list. I'm starting from the easiest, so now acrylic filler.