Plastics

[I D Miller]

does anyone know of a good strong mold plastic? I would like to make some clay models and be able to pour some compound into them and have it harden to take it's shape any suggestions?

[I D Miller]

thats a little bit pricy.... looking for something thats going to be in a liquid form that can be poured into a mold or casting.... i was wondering about fiberglass but i've never worked with it. I would perfer something that would be pourable that would harden like plastic but needs to be pretty cheap easy to get and moderatly ok to work with. kinda like a beginners plastic.

hehe thanks thought

[wrighthobbies]

Take a look at Alumilite at www.alumilite.com. Pretty easy to work with if you take a moment to read the instructions.

I've been casting some parts using a single piece silicone mold. Works great for me...

[I D Miller]

looks like some good stuff. but is it really like 80$ for a starter kit? Gonna see if my local hobby lobby which just opened a few months ago is carrying it i noticed that they are a dealer in the area.

[wrighthobbies]

I think I paid $69 for a starter kit at hobby lobby. It's a good place to start and get an idea of how it works and if it suits your need.

Here's a couple of pointers -

The mold needs to be warmed so it doesn't act like a heatsink and pull the heat out of the resin while it is curing. They recommend about 150 degrees but as long as it's pretty warm to the touch, it should work. I use a cheap electric griddle that cost $20.

Stir the resin thoroughly, scraping the bottom and sides. The resin that comes with the starter kit starts to cure in 60 - 90 seconds, so you have to work fast. If you find that the last bit of resin you pour isn't mix well (what's in the very bottom of the cup), then try mixing a little more than you need and leave the dredges in the cup.

Let the plastic cool down before pulling it out of the mold. I find it easier to demold if I wait 10 minutes or so. It cures in 5 but its still a little flexible at that point.

Use the universal demold spray. This will make your molds last longer, assuming you want to make a large number of parts. For me, most of the cost is in the molds, not the resin so I want to protect the mold.

Have fun!

[I D Miller]

here is my idea. I have a vex kit but i'm wanting to make some custom parts like say Linear gear. I've built a small rig that will be filled with clay or putty so that i can dip my gear in some vegie oil ( excess will be removed ) so that i can take a gear and roll it down into the clay and make like a 2 , 3, 4, 6, 12, 18, and 24 inch track. for a gear to roll on. so it would be something like this from a side view
_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_
It would have a nice even spot at the end for bolting i might even do it off the sides instead of at the ends so i can just put them all together for one long track if i need to. So would the aluminite be a good choice for that?
it's going to be about 3/8 to 1/2 inch thick and about 3/8 to 1/2 inch wide need to get some tighter measurements. thanks alot for this help

[wrighthobbies]

I think Alumilite could work for that. Do you know how much force you'll be applying? I don't know for sure, but I bet Alumilite would be as strong as the original Vex gears.

I've made several casting and the plastic seems very strong...

[TheDuck]

I've sent a message to willettfx who works on this project: http://www.botmag.com/forum/showthread.php?t=189

He may have a few ideas as he seems to work with a few different materials.

[willettfx]

Sorry took so long for reply
http://www.smoothonsecure.com/store/index.php?cPath=50&osCsid=505965d86a5b6550bdfd083e28b1e57b

http://www.smoothonsecure.com/store/index.php?cPath=278
If you are going to mold something use silicone and cast it in poly
http://www.smoothonsecure.com/store/index.php?cPath=291_1&osCsid=505965d86a5b6550bdfd083e28b1e57b
Gary

[I D Miller]

now thats not as pricy but it's still up there but your getting 2 gallons for 77 bucks 17 .lbs so that like 8.5 pounds of plastic i do believe thats completly doable. thanks alot for that info.