Molds and casting fun - Printable Version

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Molds and casting fun - AF350 - 12-11-2011

Here are some pics of One and Two part molds for On30 roofs for rolling stock, a flat car and a small log. I am scratch building in 2 scales at moment On30 and S standard gauge.

So far I have Kitbashed 5 box cars(On30) and scratch built 3 cars 2 in S and one in On30(the On30 has had a mold and I have cast hald a dozen of them so far.

   

   

   

Re: Molds and casting fun - e-paw - 12-12-2011

Nice, great work Cheers

Re: Molds and casting fun - dave1905 - 12-14-2011

If you put the molds in a pressure tank when you make a casting, you will eliminate or minimize the bubbles in the castings. Many people use a paint sprayer bucket.

Re: Molds and casting fun - AF350 - 12-14-2011

dave1905 Wrote:If you put the molds in a pressure tank when you make a casting, you will eliminate or minimize the bubbles in the castings. Many people use a paint sprayer bucket.


I have also heard that de airing in a vaccume jar does the same thing, they also say a light dusting of talc in the mold also helps bubbles come to the surface and pop.

I am collecting stuff ro make a spincasting machine to help avoid any voids by useing centrifugal force to draw material in to the molds.

I noticed that now several suppliers are selling powders to coat molds with to give the look of metal to the detail surfaces of a casting.

Re: Molds and casting fun - nkp_174 - 01-14-2012

Practice and low viscosity resin help.

Here's a flatcar I cast:

[Image: IMG_8146.jpg]

The deck is a separate part from the frame, and is made up of scale 2"x6" boards...which are correct for this car. Some minor air bubbles were present, but I filled them with the trusty super glue and baking soda combination. You can't see them now.

Michael

Re: Molds and casting fun - AF350 - 01-15-2012

NKP_174,

Nice work it will be a while to I am that good at it.

What is the mix ratio of super glue to baking soda?

Re: Molds and casting fun - nachoman - 01-15-2012

I need to try this... someday!

I've got about 4-6 flat cars I want to make. But I am told for that few it's easier to just scratch them all in an assembly line.

Re: Molds and casting fun - nkp_174 - 01-16-2012

Kevin, I agree with that recommendation. That's not enough to justify the cost and learning curve of resin.

There isn't really a super glue to baking soda ratio. Just fill the void with superglue and then add baking soda to it. Usually, an air bubble leaves at least a thin layer on the surface. I recommend filing flat car decks from the bottom before removing them from the molds to protect the thin surface as the void is filled.

Keep up the good work!

Re: Molds and casting fun - AF350 - 04-30-2012

dave1905 Wrote:If you put the molds in a pressure tank when you make a casting, you will eliminate or minimize the bubbles in the castings. Many people use a paint sprayer bucket.


I have heard this a few times now and went looking for a pressure pot and they were kinda expensive however Harbor Freight has a 2 1/2 gallon one on sale for $79.99. At that price I am willing to try it. It beats trying to make a spincasting setup. If I get one will post the results in this thread. Thumbsup

Re: Molds and casting fun - AF350 - 05-02-2012

Well I got the pressure tank/paint bucket today and will test it out soon as I can get to it as I am in the middle of a job hunt and have slowed down my hobby pace a bit.

Re: Molds and casting fun - AF350 - 05-05-2012

Well here is the lattest casting and molding I have done, still have not setup pressure chamber due to a bad gauge waiting for replacement as the face of gauge was bent up and a loose screw as well rattling around(can you say mfg. defect?). 35 Anyway here is what I have been up to today.