casting small parts in resin?....feedback.

[mikebonellisr]

I model nyc 1950's era.many of the centrals engines had a shroud over the pop valves on the top of the boiler,right behind the steam dome.I can't seem to find this detail from cal-scale,psc,etc.I do have a trix mikado and a bli mike that have these shrouds.I think that micro-mark sells a system for making castings.I am thinking about using these engines to make a master.Will it in any way hurt the models, is it a involved process and what kind of results can i expect?
Is there a nother or better way?

[areibel]

Hi Mike,
The only hard part sounds like getting the area boxed in for pouring the mold itself- the rubber could be poured into a small built up box lined with tin foil, then the shroud area lowered in, upside down??
Anyway, Go to www.smoothon.com and order one of their "Super Sampler" kits. For $25 you'll get the mold rubber, the resin plus mold release and excellent instructions. The quality of the stuff is great and it's about a third of what Micromark charges . And Smooth On's tech support is great, that's what they do- castings!

[dehusman]

I would choose the Alumilite products. Micro-Mark stuff is Smooth-On re-labeled. I have had horrible luck with Smooth-on products. Alumilite has been pretty much foolproof. The key on small castings is to keep the molds warm or to warm the molds after pouring the resin. On small pours I have used a spotlight in a clamp-on fixture to warm up the resin. Alumilite sells a mini casting kit for $30.

For more advice join the Casting Yahoo group.

Dave H.

[pike-62]

I have "pulled" several molds from engines and cars over the years when I needed a small detail piece just like you want to do. I have never harmed any paint on the engines I made the mold on. However, you do need to use some sort of mold release to get the mold to release from the surface you pour it on. The best material to use to make these molds with is a type of mold rubber that has additives that keep it from running. These products are generaly refered to as Thixotropic rubbers. They basicaly stay where you put them instead of running off of the part. Not too long ago I had to make a large mold of an arcitextural detail on a building that was under an overhang. I was able to get a good mold on the first try without any material sagging off. Most good mold supply companies have this type of material in their product line.

Dan Pikulski
www.DansResinCasting.com

[mikebonellisr]

Thanks all
What if i use kleen klay?as the detail is on the top of the boiler,if a clay mold can be made,then it would be a lot easier than turning the engine upside down.If i can get a good master from the clay,would that hold the resin?