Mould material

Looks like what I've been looking for. Will order some in the A.M. Thanks for finding this product. It's bound to keep me busy this winter. (My RR building has no heat, yet.)

Download

Go to  https://forum.mrhmag.com/magazine-feedback-was-ezines-891776 and use the "Other copy options" button. 

Some questions I didn't find answers too.

I have no interest in making hundreds of parts from the molds I have made so far, but I don't know when I will be using many of the molds I will be making, so how long will these molds last if stored at normal room temperature in a mold box? 

And what would you consider the upper limit as to the number of parts that one mold can produce? 

My previous supplier of RTV rubber compounds no longer sells it, and to go with a place like Alumilite and buy their rubber molding compounds is very expensive.  If this stuff is cheaper, it might be the solution to finding something that is very cost effective. 

Thanks.

Ken L.

Alumilite 40% off

A bit disappointed, but still optimistic

Excellent overview of Composimold.  I have been experimenting with it on a completely unrelated project (decorative cement tiles, a la Frank Lloyd Wright) and was also intending on using it to cast components from resin, using both original masters from Shapeways as well as from discontinued kits to make DPM-style wall modules for kitbashing as well as rolling stock components.

Observation:

I have used both plaster and cement and found that after setting, the surface of the casting was powdery and not very resistant to chipping and scratching.  Also, the surface of the mold appeared to have melted, either from the exothermic reaction of the plaster setting or the presence of water; Composimold dissolves in water, which except for clean up, is a bit of drawback when using water based materials.  

Unless I've been doing something wrong, this product has been disappointing in this application, but I'm still eager to try it for resin casting of model railroad related items.  That said...

Question:

Did you find that the hot Composimold melts or distorts plastic?  

Thanks.

Possible Alternative

Composimold looks like a great product for the occasional making and low number of castings as Ken mentioned in his post. And using Alumilite as Rick mentioned can be had for less. I personally am not fond of using Alumilite's resin. I tried casting the resin under pressure to minimize bubbles. The castings seemed to become more brittle and easily broke during assembly of multi parts.

In my search for a casting system I wound up using SmoothOn. http://www.smooth-on.com/ When Rail Yard shut down his company he thanked the many vendors that he had used. One of them was SmoothOn for his resin casting material. If any of you ever had or has one of his kits you know how nice the resin part of the kit is. So I ordered the started kit. http://www.smooth-on.com/Getting-Started-Po/c4_1217/index.html Yes it's more expensive but is very easy to use, plus they have many video's showing how to use their product. I've done some and I'm very satisfied with the out come. As with any process one needs to do several castings in order to become efficient at it.

This is just another alternative if you want to cast from your master or copy something else to make multiple copies. It is more expensive but is of a higher quality in my opinion. That and 25¢ (inflation?) will get you a cup of coffee.

Bernd

Where to Purchase Composimold

Who sells Composimold?

Jack Cutler

Haldmoon, NY

Micro Mark

Sells Composimold.

http://www.micromark.com/composimold-heat-and-pour-mold-rubber-10-oz,10894.html

Bernd

Ordered

the small container today. This is exactly what I need for single piece casting. And reusable!!

Would like a report

Let us know how it works. A few pics of the process would be neat to see.

Bernd

Composimold shelf life

You stated,"Composimold has no shelf life." I believe you mean it has a very long shelf life.

Well it won't work for what i need it for..

The casting material i use, Alumilite, can get up to 225 degrees or more, so that is too hot for this stuff.  However, now that I found out Hobby Lobby now carries ALumilite products including their silicone rubber material, using the 40% coupon i get every week, it makes it about the same cost as this stuff.  Still not super cheap, but it is afordable enough for what i need.  So thanks!

Ken L.

Plaster of Paris?

My Composimold arrived in the mail yesterday, and I started playing with it in the evening. I made a couple of test molds using a DPM wall and a hopper coal load as masters, and cooking spray (Pam) as a mold release (I've gotten modeling supplies from some pretty eclectic places before, but the kitchen pantry was definitely a first!).

The molds poured nicely, using a disposable aluminum baking pan for the mold box. I stuck it in the fridge for an hour or so to solidify the Composimold. The masters popped out easily. I then gave the mold a shot of cooking spray and poured in Plaster of Paris. Came back to it after a couple of hours. The castings popped out just as easily as the masters did, and look great. No evil bubbles that so many detractors complain of.

Here's the issue, though. After leaving the castings out to cure overnight, this morning they felt cold to the touch and still rather soft and clammy. Could that be due to the cooking spray mold release, or because I was pouring wet PoP into a refrigerated mold? For rock castings I always use wet water as my release agent, but didn't this time because I read that Composimold is water soluble and I didn't want to compromise the molds.

Anybody have experience with this stuff who might be able to shed some light on the subject? It has all sorts of potential and I'd really like to make it work.

Jim

Composimold

Seems a lot of people on modelling forums have had probs with using plaster.....

.Not sure why..maybe its the mold release used...cooking oil?

Certainly seems best to use the mold straight from the freezer to avoid melting.

Just bought some so will test to hair tearing stage!!

It won't work for me...

...Alumilite exceeds the max temp for Composimold when curing according to the manufacturer.  Disappointing since I was intrigued with this material.  The good news is someone posted the fact Hobby Lobby carries Alumilite and the Silicone Mold Making rubber, with a 40% coupon it is still more than what i was paying direct from the manufacturer, it sure is cheaper than the local hobby store or direct from Alumilite!  So the article/thread discussion has been very helpful!

Ken L.

ComposiMold problems with using plaster

Hi Folks,

This is just a guess, but it seems to me that the mould is leeching the water out of the skin of the casting before proper curing can take place.

Maybe an oil base or shellac (hair spray) primer on the mould could prevent this?

I'm looking forward to trying this stuff.

Trials & observations

I've found that if you spray the plaster casting with a coat of paint, the chalky layer gets sealed in and the casting is quite usable.

I got a small box of Easycast to see how the Composimold would work with casting resin. Made some test casts using metal castings from my one FSM kit as masters

I would classify the original metal castings as very finely detailed (actually exquisitely detailed when viewed very closely). Some of that extremely fine level of detail was lost in making the mold, though the resin castings are quite nice in their own right. From more that a few inches away, there's virtually no discernable difference. I give the test an overall thumbs-up.

I have some clear plastic vehicle kits from Williams Brothers that i'd love to try duplicating, but am fearful of what the hot Composimold might do to the plastic. Any thoughts on the melting point of Composimold versus the melting point of clear plastic?

Jim

Thanks for the great product intro

This is a product I never know existed and I'm glad to have the information. The fact that it is easy to clean up, relatively inexpensive, and reusable sounds like a winner in my book. I understand it doesn't make perfect castings, but with care, it looks like it makes some very good ones. I'll be giving this a try.

If I need better replication, I will probably try other, more expensive products, like the Alumilite or silicone, but I would be surprised if they were reusable at all. Right now I'm just getting stated, so I have to make my money go as far as I can. This seems like an excellent early investment.

Thanks!