Making Miniatures

Gettin' the lead and makin' it pretty
thedugan
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Making Miniatures

Postby thedugan » Tue Sep 09, 2008 1:40 am

I mentioned that I've investigated making my own miniatures, and at least one person has inquired into the results of that investigation. Rather than merely respond to his email over on the MJ12 yahoo list, I figured I'd post it here, which would end up there.....


First - you need a mold, to get the mold, you need a model. I made some out of sculpey, and they well and truly suxored...but they worked for learning how to cast things.

I made all my molds out of 100% GE Silicone caulk, straight from Walmart (I wish I was paid for each time I mention them to someone).

There's a method mentioned here:
http://forums2.gardenweb.com/forums/loa ... 22593.html

...basically, it involves mixing glycerin and latex paint to get the caulk to cure no matter how thick it's applied.

Do a Google search...
http://www.google.com/search?hl=en&ie=U ... caulk+mold

..and you get a lot more hits...
http://www.myheap.com/book/chapter-07/s ... kmolds.php
.. is also pretty thorough.



I used water, soap, and mineral spirits (you should use some other solvent, trust me!) with some kitty litter in it. I used it because of my rather circuitous route to getting information. Seems that you have to do (had to, now I know the magic phrases to plug into Google) a lot of reading to get an idea as to how it cures, and I couldn't find glycerine ANYWHERE until I'd already done all this...

You can use something called Xylene to thin the caulk, it works better from what I'm told.

It did work, and I've got a brick of silicone caulk with some rather crappy little ship molds on one side to show for it. yeah me... "Proper" moldmaking Silicones can cost up to 100$ a gallon.


As to making ships:

I've actually tried a plaster mix, a cement mix, 'PVA Goop' (hey, I had a gallon of Elmer's and some unused "20 mule team Borax" sitting around sitting around...) and straight polyester resin.

The winner was polyester resin.

Dan, Jim, and a couple of other folks on this forum can attest to the crappy-ness of gypsum-cement mixes I used (and to my general lack of sculpting ability at this point). I understand that there are 'dental cements' that I could have used, but considering their cost, I saw that as a non-starter.

Polyester Resin is cheap (I can get a pint of it at Walmart for about 12 bucks), easy to find (eh..Walmart vs mail order), and is certainly strong enough unless you plan on using your little space ships at actual scale speeds.

Another neat thing I've not yet investigated is the use of fillers in Polyester resins. I'll try that at some future point, but I'm still shy a decent place to work and haven't the time at present. Once things settle down, I'll try to dork with it some.

I would suggest (and I'm planning on) investigating kitty litter (yes, KITTY LITTER) ground in a beat up old blender (certainly never use food in it again!) with a solvent compatible with the resin. Another thing that would be cheap is paper pulp in solvent. I don't know just how much fillers would weaken the miniature beyond use, but OTHER fillers are used in commercial products - so I'd have to play with it to see if it was workable. It may be more work than it's worth. Fillers only purpose is to extend your resin so that the miniature costs less in terms of resin.

Here's some more info on resin...
http://users.lmi.net/drewid/resin_faq.html

This guy is using 'proper casting silicone':
http://www.hirstarts.com/moldmake/moldmaking.html

You can use Styrene Monomer to thin resin, but it's pretty hazardous:
http://www.fiberglasssupply.com/Product ... esins.html

..hope this helps, and I'd LOVE to hear if anyone else has tried casting there own...
Becuz I'm da friggin' ART FAIRY - dats why!

Big Bang = Let there be LIGHT!

jimbeau
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Postby jimbeau » Tue Sep 09, 2008 2:45 am

my experience with molds is limited, but why not just get the real stuff and use real plaster or dental plaster?

Just wondering

OldnGrey
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Postby OldnGrey » Wed Sep 10, 2008 2:05 am

I can remember when, if we needed an extra small part for a kit or figure, we used cuttlefish bones. Intended for the birds cage but made a real simple mould.
Usually took two and flattened the soft sides, then put the piece in between and squeezed. Removed the original and held the two halves together with rubber bands using pieces of matches to align them.

Later moved on to using plaster of paris, which was cheap at any chemist.
If you try this make sure that the plaster mould is dry right through. You do not want to pour metal into a damp mould!

Do you have to buy rtv silicones by the gallon? Smallest I have seen in the UK is a 500g tin. Or if it is a very small model you are making there are two part silicones that you kneed together and press the original into it. This can be used with the two part pourable plastic to make things like small fighters.

Whatever anyone decides to try, please take heed of the warning about damp plaster moulds and hot metal.

Paul
So let it be written, so let it be done.

Lsutehall
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Postby Lsutehall » Wed Sep 10, 2008 11:30 am

I've had a lot of success (for a complete novice) with casting my scratchbuilt homeworld ships in resin. I stocked up on silicone and PE resin from here:

http://www.tomps.com/

I found a good couple of tutorials online, and then went ahead and had a go. Its a real learning experience, but very worthwhile when you pull a copy of something you've just made. The most important things to remember are to think about your mold design, and not to forget the mold release!

I can post some pictures if anyone is interested?

tnjrp
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Postby tnjrp » Wed Sep 10, 2008 11:52 am

Well, making miniatures isn't my cuppa tea, but sure we want to see the pix!

thedugan
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Postby thedugan » Mon Oct 06, 2008 10:01 pm

jimbeau wrote:my experience with molds is limited, but why not just get the real stuff and use real plaster or dental plaster?

Just wondering


I only found out recently that the Forum had stopped sending mail to the Yahoo list, I thought the Forums had died! Didn't see your post, because I was using the list to keep up with anything interesting on the forum.

What do you mean by 'real stuff' - the mold making stuff that costs a hundred dollars a gallon?

Real plaster is pretty weak. Dental plaster isn't a common item, and costs as much or more than fiberglass resin. Fiberglass resin is in about every Walmart I've ever walked into, most Auto parts stores, and quite a few other places.

I just did some fiberglass castings from my crappy old 'kitty litter' mold, just to evaluate Fiberglass resins with fillers. It's likely not worth it. Makes the resin too thick to pour well, and it's thick as it is (well, my 20+ year old quart of resin was, anyway). I did come away with some idea of how tough the stuff was, and I'd be hard-pressed to say that any kind of plaster would be worth it for minis. YMMV, however....
Becuz I'm da friggin' ART FAIRY - dats why!

Big Bang = Let there be LIGHT!

thedugan
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Postby thedugan » Mon Oct 06, 2008 10:10 pm

OldnGrey wrote:Later moved on to using plaster of paris, which was cheap at any chemist. If you try this make sure that the plaster mould is dry right through. You do not want to pour metal into a damp mould!


OldnGrey wrote:Whatever anyone decides to try, please take heed of the warning about damp plaster moulds and hot metal.


That's what we ex-Navy guys call a no-Shi**er....

I'd go so far as saying to dry the molds in an oven for an hour or more after they set over night - bearin mind that any temperature over 212F could disassociate the plaster and give you a pile of soft powder.

Hot metal is something I avoid unless the item in question has to be welded or cast (in metal...)

Concrete and Plaster will EXPLODE if damp and hit with hot metal!


OldnGrey wrote:Do you have to buy rtv silicones by the gallon? Smallest I have seen in the UK is a 500g tin. Or if it is a very small model you are making there are two part silicones that you kneed together and press the original into it. This can be used with the two part pourable plastic to make things like small fighters.
Paul


The gallon price is the lowest price-per-unit, you don't have to buy a gallon. If I cast minis, I want to cast a BUNCH...
:)
Becuz I'm da friggin' ART FAIRY - dats why!

Big Bang = Let there be LIGHT!

thedugan
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Postby thedugan » Mon Oct 06, 2008 10:26 pm

Lsutehall wrote:I've had a lot of success (for a complete novice) with casting my scratchbuilt homeworld ships in resin. I stocked up on silicone and PE resin from here:

http://www.tomps.com/

I found a good couple of tutorials online, and then went ahead and had a go. Its a real learning experience, but very worthwhile when you pull a copy of something you've just made. The most important things to remember are to think about your mold design, and not to forget the mold release!

I can post some pictures if anyone is interested?


Sure, post a link....

I checked their resin price, and it's 9.26 Pounds for a 1 kilogram tin that appears to be about a quart. For us here in the USA, the shipping would be more expensive than just taking a short drive (for most of us) to Walmart to grab a quart of 12$ auto-repair resin. That's what I used on my test figures recently, though it was 20+ years old - I'd had it that long!
:)

..worked fine. Didn't use a mold release, and the mold was the 100% silicone caulk I mentioned earlier.

One thing I've noted on all the casting and molding lists I'm on is that everyone has their preferences, and the vendors always think their stuff is the best. Got nothing against making a buck, but if my el-cheapo stuff works for me, then I'm sticking with that... Unless someone has a cheaper or better way.

If I were to gear up to make 'em for a living or a little extra cash, having an easier to use product might be worth it.
Becuz I'm da friggin' ART FAIRY - dats why!

Big Bang = Let there be LIGHT!

nathan
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Postby nathan » Sun Oct 12, 2008 10:03 am

Good morning all.

Thought this might be pertinent:

http://www.taxidermy.net/forum/index.ph ... 157.0.html

Apparently using cheap silicone and polyester resin to make castings is a common practice among taxidermists. Not a bad little guide.

Also on the "My Heap" link in the first post, there's a link to an experiment. Using a naphtha based lighter fluid to thin the silicone.

http://www.myheap.com/book/chapter-07/e ... ple-01.php

Given that this is effectively brush on mould making, I think the same principles apply. For example, after a coat of the thinned stuff (or two, I see no reason why you could switch to full thickness stuff with paint/glycerin. And then even make a mother mould.

One thing that naptha experiment doesn't say is how long it took to set. Some say days if you thin it too much. Also, it isn't using any catalyst. What happens if you add paint or glycerin to stuff thinned with naphtha? Will it work at all or tear apart?

Things to try. Also, while this is fine for making miniatures, I'm thinking it may have even more applications for terrain. Terrain is often suited for a single part mould with a flat bottom, whereas miniatures often need a 2 part mould. I'm thinking I might make some 6mm scale shipping containers and cast a bunch up to make a space port full of such containers. I think there might even be properly scaled textured plastic sheeting from plastruct or evergreen. Might be fairly simple.

nathan
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Postby nathan » Thu Oct 16, 2008 1:56 am

Well, I gave the process a test. I used it on some model kit sprue I had because they had some really fine pressure pin lines and I wanted to see if it would pick them up. I tried the method above (straight silicone for the first layer) but I didn't like the process. It was a major pain to work with.

So I tried the tinned method. Much better. But too slow to cure. The post on that Myheap site said that using glycerin or paint with the thinner would make it lumpy and that it was counter productive. But I tried it anyway. I thinned down some silicone caulk with some camp fuel (naphtha white gas) and added glycerin and paint. It didn't turn lumpy at all. I painted it on (and it went on easily when thinned) and set the sprue chunk aside. It cured fast and normally. It didn't lump up or shrink or anything. Naphtha as a thinner and glycerin and paint as a catalyst work together just fine.

My friend has some plaster blocks in which he carved a stone pattern that we wants to test it on, so I'm going to do that Saturday. Plaster is pretty porous, so I'm going to have to do some reading on how to properly seal it.

Oh, and the silicone replicated the detail just fine. It even picked up some pin indents that I couldn't see with my naked eye. I saw them when I looked through a magnifying lense and thought something was wrong with the mould and then grabbed the sprue and saw them on the sprue itself.

I've always not bothered doing much more than the occasional conversion because I thought replicating what I made wouldn't be economical. But now... now there's scratch building to be done.


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