I was at my local Michael’s store and saw some clear casting resin for $9 for a 16 ounce bottle. You have to buy the catalyst separatly, I couldn’t find the price. The rubber for molds is latex rubber, $12, and is cured by heat. (Such as a hair dryer.) I wondered if the resin would be usable for model RRing. It says it is a mix of polyester and styrene.
There are modelers casting their own resin parts. I use a products from
http://www.ares-server.com/Ares/Ares.asp?MerchantID=RET01229&Action=Catalog&Type=Department&ID=63
http://www.alumilite.com/index.php?page=home
One persons examples. http://www.housatonicrr.com/coal_gondola.htm
Using Google, search for resin casting, model train resin casting, etc. There is a lot of resin casting info on the 'Net.
Rich
I just found this message near yours.
The 2 part RTV is a much better choice for making your own molds. Yes, latex will work, but it is shortlived and needs many applied cured coats to the master before removal. RTV is almost indestructable. You can place the master on a smooth flat surface, glass or plastic, dam the perimeter and pour the RTV. Once cured, you will have a mold that can replicate almost a hundred versions of the origional. Latex on the other hand, if you are lucky to capture the origional master on the first attempt. Even if you do so, the latex will break down after a dozen or so castings. Latex molds once inverted for a pour need serious support as to not distort the casting of the pour. The RTV done as a solid slab will always produce a casting as flat or in the same plane as the origional master. I got so tired of proping up a latex mold to salvage the Hydrocal casting from being misshapen or distorted in some way, rendering it basically useless.
A good tip, lightly coat the glass or smooth surface (ceramic Tile) with a release Pam or grease.
As a follow up, read and follow instructions until you understand the process. You are working with chemicals that can be toxic under cenrtain conditions. Much of what I and others do is without heat. We might use a microwave ot heat up the cured rubber mold so the resin will flow more readily, and only for 20 or so seconds. That has to be carefully controlled. I found a rubber two part product to make molds started to breakdown in a microwave after only five seconds. I went to a better two part rubber product that was suggested on a Yahoo Casting Group. If you have never done casting before, I strongly suggest searching and reading before starting.
Rich
Stay away from the “casting Supplies” you find in most craft shops. it sounds like what yours has is the resin used in fiberglass work. This is what is commonly sold in most shops. while it can be used to cast parts from it is not the best option. The casting kits that you can get from some shops also, in most likelyhood, have been sitting around for a while and this stuff does have a shelf life. The casting resins that micromark sells are better suited for what you want to do. The material they sell is repackaged Smooth-on product. It is not bad to buy, but it can be had cheaper from Smooth-on and the quality is better. What was said about the latex mold compounds is true. If you are looking to make 1 or 2 copies it will work OK but, it is better to use one of the better grade RTV silicone based rubbers to make your molds from.
Dan Pikulski
I personally prefer Hobby Silicones or Alumilite products.
I didn’t have good luck with Smooth-on resin, but that was several years ago, they may have improved their quality control.
Alumilite resin is very good, but they don’t sell their “slow set” resin in small quantities. The Dow HS2 RTV is some of the best I’ve used. The regular Alumilite RTV is OK for quick flat molds but isn’t as good for large castings or undercuts.
The Hobby Silicone has a good set time and their RTV is good also. Plus very reasonalbe in price.
Expect to make a couple tries at molds to get them right, especially when starting. Don’t bother casting unless you want a bunch of what you are making. If you want 6 or 60 parts, casting is the way to go. If you want 2, then maybe not.
I have found that warming the mold after you have poured the resin really helps complete the curing and insured a good product.
Dave H.
As I have never used either of those products I could not report on them. From what I have heard though over the years though, the alumilite is a good product.
Dan
I too keep hearing aluminite is nice stuff , I don’t use it though. I use the rubber mold and resins from Micro-Mark.
Micro Mark is repackaged Smooth-On products. They manufacture the RTV and resins for Micro Mark.
Dave H.
I know the Alumilite is what they say to use, but I just wondered if this would work because it is cheaper.
I’ve used the polyester resin before. My advice here is DON’T.
That stuff stinks to high heaven while it’s curing, and is quite brittle afterwards. You also have to be very careful about the timing of removing it from the mold…too soon, and the outer surface will be tacky. Too late and you’ll have problems getting it out of the mold (it can fuse itself to latex/RTV). You’re much better off going with the Alumilite or Micro-Mark resins. I’m partial to the water-thin resin from Micro-Mark, myself.
Just my $.02, take it for what it’s worth. [:)]
You get what you pay for. I certainly would not recommend the polyester resin for beginners, as it is finiky to use and you will also need mold release, Pam won’t do it.
The starter package from Micromark is a good way to go, (about $50-60), it comes with everything you need to start making molds and castings and some basic instructions. You’ll be able to make quite a lot and it’ll give you the practice and experience, after that you can try other products.
I did some casting of mrr parts but it was not cost effective, though I got what I wanted. I dupicated some frames for the Mantua General and duplicated some four wheel ore jimmy parts. I used Alumilite products and Micro Mark products. It is not plug & play. It takes a little practice. Here are some links that I used when I did some casting.
http://www.hirstarts.com/casting/plastic.html
http://groups.yahoo.com/group/resin-casters/?v=1&t=search&ch=web&pub=groups&sec=group&slk=45
http://groups.yahoo.com/group/casting/?v=1&t=search&ch=web&pub=groups&sec=group&slk=1
Rich