Molding/Casting Starter Kits?

[SGluedMyFingers]

I think that I am going to have to take the plunge. But before I ask for recommendations, please consider the following:

1. I want to avoid vacuum molding /pressure casting, if at all possible.
2. I want to eventually make clear parts and Smooth-on only seems to sell clear resin in 1 gallon containers.

So... I am looking at three starter kits to familiarize myself with the process. Can anyone make any recommendations? Things to consider or avoid? Or just share your thoughts?

Micro-Mark, probably my last choice.
Allumilite seems to have cheaper possibilities for clear castings.
Smooth-on seems to come highly recommended. I would need to get some clay and the clear resin is crazy expensive in the 1 gal container, but it's the cheapest of the starter kits.

What do you guys think for the beginner?? Is there a better starter kit that I should consider?

[Joseph Osborn]

I use Smooth-on products daily and I wholeheartedly recommend them, but you're only getting a very small amount of materials to play with in the starter kit. I'd recommend getting the trial-sizes of the Oomoo 30 and Smooth-Cast 305 or 320. You can get some good non-sulfur clay at any decent crafts store and measuring cups and stir sticks are easy to get locally, too.

The Micro-Mark kit is a decent value and I think they sell re-labeled Smooth-on stuff.

The Alumilite kit is okay to learn with, but I'm not wild about the super-fast resin and the rubber in that set is stiff! Plus they both stink to high heaven.

If you want to make clear parts at some point, you'll almost have to use pressure to get good results. A cheap way to experiment with clear is to get some of the Castin' Craft clear epoxy casting resin from the crafts store or some epoxy resin from the RC airplane section of the hobby shop. Hope this helps!

p.s. The reason the clear Smooth-on is so expensive is because it's not meant for the casual user so they don't sell it in a trial size.

[Shinnentai]

I only have experience with the Alumilite stuff, but I'd echo what Joseph Osborn says about it. Usable, but less than ideal. The utra-fast resin will be particularly unforgiving to a beginner. Upshot is it'll teach you a lot about proper mold engineering, downshot is the learning will come mostly through failure analysis with accompanying wastage.

Between the other two I'd say Smooth-On over MicroMark. Getting it straight from the manufacturer = it's spent less time sitting on the shelf before you got it. Plus MicroMark repackadges it in their own containers, so it's already been exposed to air and possible contamination once already.

[macfrank]

Smooth-on products are great, and pretty inexpensive. Their fast cure resin is basically the same as the Alumilite tan resin. The Smooth-on Oomoo rubber is pretty nice, mainly because it's a 1:1 mix.

The Alumilite RTV is outstanding. It's a little harder to use than the Ooomoo (1:10 mixing ratio vs 1:1) but it's more flexible and pours much easier than the Oomoo. It also takes a little longer to set. The combination of low viscosity and slow setting times means that most of the bubbles will rise to the surface long before the RTV sets. Not so much with the Ooomo, which requires - at the very least - more care in pouring so you don't trap bubbles in or under the part.

Frank

[novahobbies]

I too would recommend the smooth-on, but be warned about Oomoo! It's great stuff -- especially for beginners -- but don't expect to pull many castings out of this stuff. Because of its easy mix ratio and the thin viscosity, the rubber doesn't hold up well in the long run. Expect to be able to pull maybe a dozen castings from it, max. Heat from the resin that's curing inside the mold also speeds the breakdown time.
I use this stuff, but I don't consider it a true working rubber. I just use it for fast prototyping when I need multiples of a small part that will go on a finished master. Like I said, if you want to jump in the pool and learn molding/casting, then definitely cut your teeth with this stuff, but expect to graduate to one of the tin-based 10:1 ratio rubbers pretty soon, and for that you'll need to build a vac chamber.

[cygaramond]

Allumilite seems to have cheaper possibilities for clear castings.

I got started with an Alumilite kit I picked up at Hobby Lobby with one of the every other week 40% off internet cupons. Yeah, it can be a bit difficult to work with, but if you snag it on sale like that you get a lot for your money to play around with. As far as I was concerned, the starter kit was just to figure out how this stuff worked and I had no desire to spend anymore than that on it. Now that I have gone through it, I have a fair idea of what I'm doing and can now spend a bit more on matierials and don't feel like I'm wasteing them with my incompotence.

-Chad

[sci-fi-bldr]

I too just got the Allumilite trial kit...(and used the 40% discount... )

I pour alot of resin at work....but was a little leary about trying it at home.....so I picked a few cool greeblie parts a gave it a try....I have to admit...much easier than I thought.....

Im sure with more complicated parts the more problems could arise....but I do see where this will come in handy

[Woody]

I've had good luck with the MicroMark kit and I second what Joseph said about epoxy for the clear casting.

. . .If you want to make clear parts at some point, you'll almost have to use pressure to get good results. A cheap way to experiment with clear is to get some of the Castin' Craft clear epoxy casting resin from the crafts store or some epoxy resin from the RC airplane section of the hobby shop. Hope this helps! . . .

[SGluedMyFingers]

Well this has been informative. But I feel kinda where I started. Everyone likes various apsects of various kits. LOL. Some like the RTV but don't like the resin or vice versa. That's really what I was afraid of.

I think that probably my best bet is to go with the cheapest and work my way into experimentation with other products.

And ACK! Pressure pots and vac chambers. Exactly what I want to avoid - more expensive modeling tools that I don't have room for. Oh well. It has to happen sometime.

For any further advice: I am not interested in molding/casting for distribution, so slight imperfections that could be fixed with a dab of putty or Mr. Surfacer 500 aren't a problem. Multiple castings are likely not going to happen either, so mold wear isn't that big of an issue. And finally, any clear parts will probably be used for lighting, not canopies or anything like that. So a few imperfections there are acceptable as well.

Thanks for the advice so far. I'm getting closer to a decision.