SRMW Threadwell Textile on the S&S RR

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Here are our three mold boxes - going through the curing process.  I usually wait overnight before I remove the mold boxes but in this case I got away with waiting about four hours with this material.

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While I was waiting for the molds to cure - I took inventory of the castings that I had already made and poured another batch of casting from the first set of molds that I made for this build.

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Here is a picture of the resin in the mold cavities that I needed.

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While I was waiting for the resin to cure.  This is much faster about 30 min. to and hour. I started to remove the mold boxes from our second batch of molds. I always start in one corner by cutting a pealing the artist foam away from the mold and castings.

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I cut the artist foam with a single edge razor blade and then peal it back away from the mold and castings.  Keep the casting flat on the workbench and don't put any pressure on them as you peal the artist board away.
You need to do as much cutting as is necessary to keep from breaking the castings.

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I use the razor blade to cut along the edge of the mold to remove any of the rubber that seeped under the casting. I simple cut this flash away and then peal the mold off the plaster casting. Once I start this process I put the tools away and don't use anything sharper than my finger. to remove the mold from the plaster.

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Here is a picture with the first casting removed from the mold.

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You will notice that I place the castings in the mold box so the corners do not line up.  When you removing castings from the mold this is the first place they like to tear. My plan is to make two sets of castings from these molds and then store them away, just in case I find a need for more castings on a future project. I have a picture of each mold in a file so I can reference them.  A numbering system is going to be implemented the next time I need to go looking through the 4 or 5 boxes full of molds stored under the layout.

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Here is the first of the three molds ready for some resin.

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The resin is mixed using the same method that I use for the mold materials. Part A and B are poured into two different clear plastic cups and then mixed together in a third cup. Equal volume of A and B. If you want to save a cup the resin can be mixed by just adding part A to B. Again you need to stir throughly without whipping bumbles into the mixture. You need to move fast with this - you will feel the cup start getting warm as the two components start to react. Once I'm satisfied that I have the components mixed, you can tell by the color change, I simply pour it into the molds, on these castings I use the window openings as a fill gauge. I read in Bob's instructions that he has 0.030 of an inch in the windows. Mine are between .003 and .01 of an inch depending on how quick I can cut off the flow. Pouring them to thick just causes problems when you have to clear them out.

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Finally, we have resin in the mold starting to cure. It takes less than an hour. It turns white as it cures. You will also notice that the curing reaction produces heat. If the castings are cool to the touch your castings are ready for your build project. I have tried to capture the process here, as requested. Please let me know if you have any questions and / or comments. I should point out that these molds will work just as well for hydrocal castings. In fact, I have only switched over to resin in the last couple of years. In the past, I didn't like the finished look of resin castings as well as I did with hydrocal castings.  The issue was perfecting my techniques so they look the same with both materials.

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The first batch of castings - just out of the mold.

[vinceg]

Pure gold, John - thanks for posting all of this!

[fsmcollector67]

John,
a priceless post. Some really great info here. I have done small objects using Amazing Mold, this opens up a whole new horizon for my scratch building.  Thanks....

Loren...

[S&S RR]

Pure gold, John - thanks for posting all of this!

Vince


Thank you for following along.  I'm glad you found the information of value. I'm looking forward to meeting you at the Narrow Gauge Convention.