Metal Casting
 

This is my first attempt at metal casting, and it actually went pretty good. This is a hobbiest technique and there is far too much work involved to ever make these wheels commercially viable. So rather then start making these and selling them, I will show you how you can make them.

The master was taken from a 1/18 scale Sherman. I sanded away almost all the molded on tires except enough to bring the diameter of the wheel out to 1/16 scale.

I backfilled the void with plastercine.

Normally I use Smooth on products, but I ran out and the nearest supply is in Edmonton. I found a two part silicone molding paste locally and being desperate I thought I would give it a try. It worked, but is a poor imitation of what could have been cast using the smooth on product.

The metal is a low temp alloy that melts at 158 F. You guys in Arizona might want the 170 stuff.:D

It is melted in a regular candle wax hot plate. I sanded in a pour spout to help control the pour of the molten alloy.

Each wheel is made from two castings. The rough casting are sanded smooth on both sides. The two halves are then glued together. Half way through boring the axle hole I use my drill to get the casting rotating and then sand the rim smooth.

I use Tamiya Sherman rubber tires. 1.5 tires for each rim. I plan on running this wheel through black silcone caulking to hide the seem. Once dry it should look ok.

Not much to it. Micro mark sells the Low temp alloy.

Again each wheel takes a lot of work, and I am afraid I would never want to make these for a commercial endeavour. So no I won't be selling these.!!!!!

This method though can allow a hobbiest to do something a little different and fill a void until some commercial offerings are made.

I have no idea how they will hold up. I sleeved them all with brass and I am hoping they last. I'll let you know if I have a failure.

RE: Metal Casting
 

WOW!!! Very nice!

RE: Metal Casting
 

That is a really good job you got done on the wheel. Where did you get the alloy from?:D

RE: Metal Casting
 

Micro Mark sells low temp metal .

RE: Metal Casting
 

Now that is just awesome.

Is there an odor problem with the melted metal?

Don

RE: Metal Casting
 

Thanks YHR. I always wondered what metal to use for the low temp molds. One would think that with this process down it wouldn't be that much of a stretch to try to mold some silicone tires.
Perry

RE: Metal Casting
 

Actually I used to dabble in vintage RC 1/24 scale slot cars. Cox Lotus, BRM, Ferrari, GT40. I have a whole set of molds for making tires for them so I know that process well.

Don

There is no offensive odour with this. Spray painting is much worse.

RE: Metal Casting
 

Hey, neat stuff YHR! I always wanted to get into metal casting and have looked at the low-temp alloys (fields metal, woods metal, cerrobend), but it always seems to require a lot of prep work and tricky mold prep. You make it look doable.

But, just an FYI for those thinking of trying this...a lot of the really low temp alloys include lead and/or cadmium, and as such are toxic. I would recommend taking precautions against breathing or ingesting particles or fumes, and watch that you don't track little particles(e.g. filings or sanding dust) into the house where kids might ingest them.
Looks like Micromark's 160 metal (160F melt point) contains both lead and cadmium and is most like Wood's Metal. http://en.wikipedia.org/wiki/Wood%27s_metal
The 280 doesn't, but melts at 280F instead. :P

D.

RE: Metal Casting
 

This is definately a bookmarked post! Thanks YHR!






The Blitz















RCTankWars.com

RE: Metal Casting
 

Yes all these low temp metals contain lead. So keep away from Children. Good point Darkith. I wear gloves when working with this stuff, and it will be painted in short order, but a person must be aware of this. We have a whole old generation who grew up and old playing wth lead soldiers, but still, lead is known to cause learning learning disabilites for Children who are exposed to it at a young age.

RE: Metal Casting
 

Maybe I should get that pencil tip that's been in my finger for 30 years removed? :D Nahh!!!

Great work Dan, you make it look so easy that I'm even tempted to try it!

RE: Metal Casting
 

Those wheels look killer - nice job!! And it's sort of inspring me to go metal wheels on my latest project, and not resin.

So... was the female mold silicone then? I had assumed that the hot metal would have melted it.

Nice

Shep

RE: Metal Casting
 

Nice Job. I had bought months ago a nugget of metal from the train store made by Walthers. Until now wasn't to eager to try it. To comfortable with resin. Now I have done a few things with it and it is a lot easier than I thought and a lot stronger. Thanks for waken me up to it.

Richard

RE: Metal Casting
 

I have quite a bit of experience with this as well.....but mostly with urethane resins. I was once very involved with bronze casting....which is a whole other level. I was a 3D modeler for video games since 1996.....having worked on games like Coolboarders and Auto Assault. The fun aspect was I was able to take models I had in 3D and transfer them to physical models. Here's my old web site on one.....it really needs to be updated......so bear that in mind.

http://sites.google.com/site/corvairmodelkitproject/

Best

Skitt. (Shawn)

RE: Metal Casting
 

Maybe worth a try ,guys ,walking stick rubbers ,they come different sizes and i know that Grompix did this on his sherman to good effect, checkout his you tube films.........
Fleshy...............

RE: Metal Casting
 

Excellent - thanks for sharing. I've casted in RESIN for scale models but never in metal as RESIN would be too "soft" for wheels I suspect.

RE: Metal Casting
 

Most rubber can handle the heat that these low temps alloys carry with them. Remember they are using silicone for cooking utensiles and oven mitts now.

RE: Metal Casting
 

I have an idea that might work. Could you reinforce the castings with carbon fiber strands? That might help the durability. I used the strands when casting sub props. Just don't know if the fibers could handle the heat. They should though. Just a thought.

Don

RE: Metal Casting
 

There are pattern making resins that 1) don't shrink much 2) are hard as any low temp metal. But many of these compounds
have very toxic bases. The low temp metals I would be careful of; use them outside if possible. I use one of these for the occasional
chamber cast.

Consider traditional foundry or investment casting. If several of you are in close proximity you can pool your resources. Making the models I do, a foundry is integral to my work. Foundry work need not be super expensive nor complicated. You can scrounge
raw materials and make a setup for next to nothing if you really want to. I built my own furnace with a capacity of a #16 crucible
for not a lot of money. I can use a #2 crucible in it as well. I can melt that #16 full of aluminum in 10 -15 minutes. If you want to do
bronze as it flows better you can do that also. You'd be surprised how easy it is. Safety is key however as with any molten metal- it is not a toy. It can and will hurt you ( or worse) if you are not careful.

jerry

http://tanks.linite.com/casting/Cast_lot_50P.jpg