"How Miniatures are Born" Topic

A little how-to, or at least a how-to from ZombieSmith:

YouTube link

Facinating. I'm still not clear on the vulcanization step- what precisely happens, how you place the figures, what keeps the halves from sticking, etc. Definitely different than the two part RTV molds I make.

Thanks for posting the video.

EDIT: I was hoping you'd show yourself casting 15mm Quar Royalists, including cavalry. Alas!

I will probably make a how-to video when I make my next mold.

Kick ass! A sequel.

Cool!

Now I know how you do your casting (as well as what your setup looks like – kinda like I imagined it to be).

Mike… I don't know how to take that parenthetical statement! ;-)

Joshua.., Not a bad thing – It is just how I pictured it, 'ok' maybe you have a bit more duct-tape :)

No casting shop is complete without a roll or two of duct-tape…

:-P

Really interesting – thanks for posting it

Great video! I love the duct tape.

How do you keep the slag out of the pots? They look pretty clean.

Steve

No casting shop is complete without a roll or two of duct-tape…

And if I remeber a can or two of talc

Fantastic stuff:

How would you like to walk us through the tricks of laying out the original sculpts or masters on the mold rubber. I assume there is a lot of cutting and gouging to make little cavities for the objects to be molded. Also, what is the trick is separating the two mold halves for the first time after the vulcanization?

I can do that in the next video. (The trick though, is talc!)

@nycjadie -- Flux and then I skim the top after it heats up.

Zombie, how much do you think it would cost to have that equipment made for someone who doesn't have a machine shop in the family?

Very nicely done!

@psyckosama – Less than a $1000? If you really go after it let me know and I am more than happy to provide measurements.

There are also good used models out there. I have two spincasters. My Contenti was $800, but there are cheaper ones available. I spent a bit more so I could handle 12" molds, if I wanted.

I have the New Venture model as well. Looking to sell it. I never even used it.

Steve

That's a good deal! See if you can buy nycjadie's machine and get another company to make your molds to begin with. My $1,000 USD is just a guess, and is inclusive of the vulcanizer, I spent around $200 USD so I am really just guessing!

@headzombie: I am, I really am. Not quite at the moment as I'm still learning how to build 3d models (intend to digitally print my models) but once I'm there I sure as hell intend to really go after it. This is something I've been wishing I could do for the better part of a decade, and the combo of 3d cheap printing and your rig has made me see that it's not just a pipe dream… I gotta thank you. I mean it. Thanks for the inspiration.

@headzombie: I'm with Psyckosama on this one. I've been kicking the idea around with my wife & friends. I'm already a decent 3D guy (though low-poly modeling is a bear for me).I've got a sculptor lined up (provided he can work in 28mm). I've casted up my own stuff with RTV & resin in the past and got pretty good at it.

I've been watching the rise of the "boutique" mini companies and have decided I want to give it a go. If I can do it on the cheap (but effective), then I'm only out a couple grand, if I fail. Will it replace my day job? Probably not. But it's worth the try.

It's really been fascinating to watch the changes in the past decade. If you've ever read the book
Tipping Point, this seems were the industry is heading. The convergence of multiple technologies & hard work, catalyzed with internet commerce has created a new business model for the mini producer.

I also thank you for the inspiration. I also placed an order..hehe..

The original purpose of this post was to also ask you for the measurements.

Thanks again,
Don

Measurements -- Oops, I meant to take those and forgot. I will get back to you.

Do you have the measurements yet?

Ack, sorry! There is an inch of mold space and 1.25 inches of total space. The top has an inset circle that is .24" thick so it settles down inside the can.

thanks Zombie! :D

how wide is the disc both with and without the side walls?

9" and 9 1/2" I take it?

Yes.

@headzombie

Is the top inset .24" or .25"?

Not sure that difference would be meaningful. Did you mean two ask about to dissimilar numbers?

Above you say the inset is .24".

The local machine shops here, "Don't got no .24, but got .25"

I didn't think the .01" would make much of a difference, just wanted to be sure.

Did I? Ah, I mistyped.

Don, how much are they charging you for it?

found these. Very interesting…

granthams.com/Spincast

Probably thinking about this too much for someone who doesn't actually need it – but in order to hold your top plate in place you are currently using wing nuts. Relatively fast to put on and off.

Another option though are Speed Nuts:

link

You can see how the nut works on this page:

link

Will allow you to tighten it down with only a few twists, but provide more pressure than something like a quarter turn fastener.

Again, if you are looking at production…saving a few seconds off from each spin adds up over the course of a day or two of casting.

great idea that! Didn't know about speed nuts!

@Psycho

One shop gave me $30.00 for just the inset piece. Another $50.00 USD. All added up about $300 for raw mats.

Still shopping around. More than likely I'll take the plans to a true CNC shop and let then do the cutting & welding. I'll cost me more but I know it'll be accurate.

Most of our local "machine shops" are mostly concerned with car parts/engines.

A vac can I banged out in Sketch Up this afternoon.

Comments/Suggestions are welcomed.

link

Most of our local "machine shops" are mostly concerned with car parts/engines.

There are machine shops – and then there are machine shops. Most the ones that deal mainly cars wouldn't even have the capability to do this work (at least not without hand cutting with something like a plasma cutter).

Hit the yellow pages and look up Welding Services or Metal Fabrication shops. There was a shop that I used when I was stationed in Panama City that was located in Pensacola that cut mounting plates for me. I think they specialized in decorative fencing – but they had the tools back then to do CNC plasma cutting, so I am sure they probably upgraded to a water jet by now (was several years ago).

On the banged out sketch up thing…link isn't working.

@DonLeg

Please, keep me up to date on your progress. I'd like to know how you go about it so when I make a vulcanizer can I won't have to do the same.

Though thanks for the model and I'm thinking I'm going to take ScoutII's advice and hit up a scrap metal place for steel and a steel pipe to keep costs down.

@ScoutII

Thanks for everything again. I also found most of the machine ships around here specialize in cars. I'll look into metal fab and welding services. Thanks.

Try this link. I thought I had made it public..

You'll notice I have two top covers in the graphic, only one would be required. Also the bolt hole is a place holder. I would use the largest bolt I could get away with, without compromising the rings sidewalls…

link

I have found a few that can do the work. Its just a matter of finding the time…

In order to make your life a bit easier – you might consider making the top and bottom larger than the OD of the ring and mounting your bolts on those plates as opposed to through the ring itself. This would allow you to use much larger bolts (possibly doing away with the C-clamps).

There really isn't a significant benefit to running them through the ring on this configuration and running 4 straight holes through 1 1/4" of steel is not fun. Even with a solid drill press, it takes a fair amount of time and is messy with metal shavings and lubricating oil. Going through just the top and bottom plates still isn't fun – but they are easier to handle and much, much thinner.

The other issue that I am not too sure about would be possibly reducing the height of the ring slightly. As opposed to an actual 1 1/4" tall – make it 1 7/32" or so. This would make sure you could apply pressure on everything you put in the can. If you were to go through and run a set of swords or shields (or swords and shields) there isn't much to them.

Not sure if headzombie's set up is actual or slightly undersized – so he might have a bit more to add in that regard. I know that would be my only concern given the dimensions.

ScoutII,
I see what you are saying. Use 10X10 plates for top & bottom. That would maybe be cheaper than having two rounds cut out. Also i could probably get away with a thinner ring OD.

I thought about the compression/pressure issue. Maybe an additional loose insert (1/16") to go in the can.

Square – round – octagons…all about the same. You want to make sure that you have the bolts close to the ring though – otherwise you will get a bulge in the middle as it flexes.

My setup is slightly undersized. I can measure exactly. I didn't realize people were hot on my heels actually building!
Don, can you e-mail me to remind me?

We're drooling for charts here.

Though I'm going to see if I can use 9" steel pipe instead of having a ring cut out. Should be easier.

link

Version 2 based on Scoutll's recommendations.

Looks to be workable, though I would change the cylinder height back to 1 1/4". I assume the thin disc is a removable shim that can be added if needed to create more pressure on thinner castings?

Oh – and the bolt hole diameter should be only slightly larger than your chosen bolts. While it might seem like a good idea to use the largest bolt you can get your hands on – this isn't necessarily the case.

When you apply torque to a bolt (tightening it down), the clamping pressure is related to that torque on in a linear manner. For example, if you apply 100 in-lbs of torque to a 1/4" bolt you will apply 2000 pounds of clamping pressure. When you apply that same 100 in-lbs of torque to a 1/2" bolt you will apply 1000 pounds of clamping pressure. When you apply that same torque to a 1" bolt you will apply 500 pounds of clamping pressure.

Finding the proper balance between a large bolt diameter (for the strength) and a small bolt diameter (for the ease of tightening and clamping pressure) will be your task. The 3/8" grade 8 bolt that I mentioned should have a torque rating of around 50 in-lbs of torque for the maximum clamping pressure (give or take 5 in-lbs or so). To get that same pressure on the 1" bolt, you would need to apply 1400 in-lbs of torque, well beyond what I can apply manually (at least without a very, very long breaker bar). As always, double check my math – it has been awhile since I have had to use those formula. The basic concept is correct though.

Yes. Thin disk is a shim.

The height should have been 1 1/4". I'll correct that.

And change the bolt holes to 3/8".

You think the 1/4" top & bottom plates are good to go?

Rough caster assembly

link

1/4" plate steel is pretty strong. I think it should be able to handle anything the rubber molds throw at it. The big thing is that the ring must be welded to it completely. On a situation like this, you will want to bevel the outside of the ring so that when it is sitting on the plate, it leaves a groove that goes around the ring on the outside. The inside should be sitting flush.

At that point, the ring is welded in place and the groove is filled with the welding wire/rod. That ensures that the welded contact point is equal to the whole thickness of the ring. If you were to simply attempt to weld the ring with a perpendicular cut to the plate – your contact points would be limited to the perimeter. The inside of the ring you want to keep clean to avoid interfering with the mold itself.

Anywho – on the caster, I would look for something that you can salvage as opposed to designing something from scratch. There are a lot of different options that will work from automotive to large appliances and shop tools. Designing your own, you will need to include a bearing assembly for the pulley shaft as well as other concerns.

If you are still intent on designing your own – use two shaft mounts (and a bearing in each) like you see in this picture:

With a single mount – you have undue stress applied pulling the shaft in the direction of the motor. With two mounts and the pulley between the two – the tension applied by the belt is dealt with. You should be able to get some ideas from looking at the drive assemblies used on homemade lathes – just skip anything with a direct drive…that should be reserved for grinders.

Whichever way you go – plan for maintenance and general construction on the way. I have seen a few homemade tools which are great, but impossible to do simple things like replacing a belt should it break. You might consider looking at linked belts to help deal with that (I use them in all of my machines and keep spares on hand just in case).