Making plastic parts

Hi, i've been searching around for the cheapest way to make plastic parts from molds. I've looked at alumilite/alumalite. The stuff is expensive. What is the cheapest way to make plastic parts from a mold?

They don't have to be exceptionally strong or tough or anything, just cheap.

Is epoxy any cheaper or some other kind of resin perhaps? Have you rocket, railroad or scale model guys found anything economical.

Thank you to whoever replies.

Reply to
Loading thread data ...

I don't know how cheap epoxy out of a tube is, but I do know I used to use it and it worked for me.

I also made my molds from silicon bathroom caulk and that worked, too.

Reply to
Gerry Leone

It depends on how accurate you need the parts to be, the cheaper materials are more prone to shrinkage and the mold durability. I have used Dow Corning RTV for molds and melted styrene crystals in the oven in them for small parts where the shrinkage factor is not noticeable. Works fine for things like mirrors and other small parts. Sam

Reply to

Polyester casting resin is cheaper than urethane, though it does not make as finely detailed parts.

Also, you can make molds from Plaster of Paris, which is cheap compared to RTV mold materials.

However, with plaster molds they are rigid and fragile, so you absolutely cannot undercut mold angles. >

Reply to
Don Stauffer

formatting link
Click on 'mold making'. Haven't tried it myself yet but it's on the big list.

Ted Novak TRA#5512

zalz> Hi,

Reply to

Try the mold making materials and resin from Micro-Mark. These are the most forgiving for starters. After you get the hang of it try some of the resins and mold materials such as Quantum Silicones especially QSIL 40 RTV.

Reply to
Keith Ehley

For what it's worth, I make all my molds and castings at "Moldin' Oldies" using 2-part silicone RTV and 2-part polyurethane resin from a company called Smooth-On.

formatting link
The 2-part materials all mix 1:1, so it's extremely easy to measure them out. There is no vacuum de-gassing required. There is no bubbling. Shrinkage is virtually non-existant. Both the molds and castings reproduce even tiny details. The RTV material becomes fully cured and ready for use in about 6 hours. The castings resin flows like water and starts to set in 3 minutes, is fully cured in 10 minutes and rigid in less than

30 minutes. They have a starter package that gives you everything you need, including a detailed instruction book for around $25-$30. If you ever want to try making your own molds or castings, this is the set I'd recommend. Mike
Reply to
Mike Schmidt

Reply to

Like the other poster who mentioned a starter kit, I got a lot of use out teh starter kit from Ace Resin in Arizona. I'm not sure if they're in the latest FSM or not, but I like the stuff I got from them.

Mike please remove "diespam" to reply

If you can keep your head when all about you are losing theirs, perhaps you've misunderstood the situation.

Reply to

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.