2-part mold help
How easy is it to do a 2-part mold for some of the weapons?
I've looked at videos on another site, but they're mostly if something has a flat end to be able to pour the casting resin into.
The handles on the weapons don't really have enough at the end to make a big enough hole to pour the resin into.
Would I have to use a sprue or something?
Go look at Smooth-On's tutorial videos. They have a raft of casting and molding videos on their site or you can find their channel on youtube.
I was never successful with doing 2 part molds and gave up the idea after several attempts. the instructions/websites make them look like a breeze but they arent
Originally Posted by Shadow-Ra
You can cut vent holes in the mold to pour the resin or plastic into it. basically you make a Y shape cut to the weapon. This also means you have this Y piece of resin that has to be cut from the weapon, but its one of the best ways I have found.
Im casting some weapons right now but here's basically what I do for a 2 part mold of a sword.
SIDE____----------0000000000000000000_____BOTTOM OF MOLD
the dashes are toothpicks
the zeros are a sword
So this means that in the clay base for the first half, lay toothpicks (or similar) leading from the bottom of the handle, and any edges (an axes blade or a sword's hilt). All tips have a line leading straight to the surface.
Once both parts of the mold are set, take the toothpicks out and you should have 3 ducts to allow air to flow to the extreme points. The middle duct may need slicing with an x-acto so you can pour more in. As long as you only cut where the toothpick was and not the original toy - it should be fine.
If you're not pressure casting, I recommend putting wire from the tip of the sword blade, round to the hilts, in the clay base, along with the toothpicks.
*AT LEAST 1 CM of space between ducts and outside edge! (or you'll leak)
* You should see 3 holes where you pour in at the top, only pour into one of them
*When all else fails, put an eraser into the middle of the mold to hold it open, pour in resin, when it's nearly at the top, take out the eraser and avoid resin splashing in your eyes!
Here is a (ancient, cant believe that was 2009 :hmshift:) old thread of when I started out making simple 2sided molds.
I think this is what you want to do:
What helps is squesing the 2 parts open , rounding it out so that resin gets every where.
Then press it together again. The resin that gets stuck between the mold parts will be very tin and can be cut away easily. This way you make sure air sockets are filled.
It is a lot of trail and error though. Especially if you dont want to or cant invest in pressure and vacuum chambers. A lot of new resins are very thin/ pourable nowadays though and dont need degassing.
Thats just my 2 cents ;)