Re: Model brake component size comparison to prototype


Tim O'Connor
 



Thanks Drew for the clarification. I'd love to see this done. It seems to be an
almost forgotten art at least for HO models.


On 4/4/2020 11:35 AM, Drew wrote:
Tim,
   I worked in a prototype model during my high school years. We used lost wax a few times. First a master is made and a mold made off that master, the mold was usually RTV rubber. Wax was poured in to that mold to make a second master which did shrink a bit. That wax master was then placed in foundry sand and hot metal poured in to the sand mold. The wax melted/vaporized and metal took its place, hence the name lost wax. It's been 20 years since I last did that but I do recall there was a bit of shrinkage in each step.

Drew Marshall in Philly, PA

Modeling the pre-Depression years.

Sent from TypeApp
On Apr 4, 2020, at 09:15, Tim O'Connor <timboconnor@...> wrote:

As I recall, all Cal-Scale detail components were OVERSIZE because they were used
for lost wax casting! In that process the plastic parts are for the molds and are
destroyed in the casting process, and the shrinkage produces parts that are closer
to scale.

Or am I wrong? :-)

Tim O'Connor

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On 4/4/2020 9:00 AM, Lester Breuer wrote:

A comparison of several manufacturers’ model brake component measurements to Westinghouse prototype brake component measurements prepared by George Toman was sent to me for my use.  I asked George to share his measurements comparison on my blog.  If you are interested in the  comparison measurements, they are now available on my blog I have to share photos and writeup of projects on my Minneapolis & Northland Railroad Company. If would like to take a look please do at the following link:

 

http://mnrailroadcab100.blogspot.com/

 

Lester Breuer



--
Tim O'Connor
Sterling, Massachusetts

--
Tim O'Connor
Sterling, Massachusetts

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