Another resin casting question

[leadsleadolds]

With how fast that smooth on stuff hardned I kept getting bubbles in about half of it. I busted out the glaze coat and took care of it, but is there anyway to get rid of them or use less of one solution I guess wich ever is the hardener to give it more time to debubble I belive that is the scientific term for it. Other than that they turned out bad ass.

[TINGLER]

Lets see some pics.

I don't know exactly...cause I have never done that sort of casting before...

I have however cast with plaster and I always shook the mold while it set up. Tap the sides, peck the bottom on the table, that sort of thing. That gets the air to rise to the top most of the time.

Now for a fast setting thing...I don't know. Maybe mix it so it doesn't set quite so fast. Is that possible?

[leadsleadolds]

I dont know about the mixing all it says is part A and part B I would figure one is the hardener I just have a fear it wont set or harden enough dosnt hurt to try.I'll try to get some pics But I can show you one of my originals I used before as a shift knob. Next I got to try to cast some of my hot rod monsters I'll get some pics of those I have no idea how I will cast those it going to have to be a two or three peice mold as far as I can tell. It would be nice if I could find someone around whos done it to show me.

[leadsleadolds]

heres a blury pic of some of the other crap

[mule]

If you warm the resin slightly(very slightly), it will reduce it's viscosity, don't mix it to vilently and gently tap the mould on the bench a few times, this tends to move the bubbles out of the places they get trapped.

[flt-blk]

1) put a skim coat in the mold before closing it, kinda like a gelcoat layer when making a boat.
2) draw a vacuum on the part to suck the bubbles out.

as said before mix carefully and try not to induce bubbles
in the first place
TZ

[Unkl Ian]

The Big Boys will have a Vacuum chamber to suck all the bubbles out of the resin before they pour it in the mold.
Or they spin the mold after the resin is added,since the resin is heavier than the bubbles,it is forced to the outside.

These groups are pretty serious,lots of info here:
http://groups.yahoo.com/group/casting/ http://groups.yahoo.com/group/MOLDMAKINGGROUP/

[Unkl Ian]

For doing your Monsters,try a thin one piece latex mold,
with a multipiece plaster Mother Mold on the outside.
If you plan it correctly,you can use elastics,or surgical tubing,to hold the Mother Mold together.
The Latex mold reproduces the necessary detail,
but is thin so it can stretch enough to release the undercuts.
The Mother Mold gives the basic shape and supports the Latex mold.

[Unkl Ian]

Check the menu on the left: http://www.alumilite.com/howto.cfm

[oldtin]

Like Ian said, the pros use vacume chambers. The poor boy trick is fill the mold and place it on the fridge or some other appliance or toy http://www.jalopyjournal.com/ubbthreads/images/graemlins/shocked.gif that causes a similer vibration. The vibration will help the bubbles rise to the top. If the cast part is going to be painted and your using a silicone mold you can rattle can prime the inside of the mold, this gives good detail and allows a little surface material for clean up. The primer is thin and flows into details better than the resin, it also releases from the silicone mold.

Oldtin (http://oldtin.50megs.com)

[gowjobs]

My buddy casts model car bodies as a side business, and I've learned some stuff helping him out. Go to the local hardware store and get an old-school painters' pot. It comes with an air-fitting and a pressure gauge already. Pour the resin into the mold, and as suggested above, start out by painting the resin into the areas where you get the worst bubbles before you pour in the rest of the resin. Also, if you have a real problem spot, put a hole into the mold at that point that leads to the outside... you can trim off the thin "flash" later, but it'll let air escape.

Pressuruzing the resin helps to cause the air to come out of solution more quickly so that not onlw will the air escape, but pressurizing a silicone rubber mold will compress it slightly, pushing air and excess rubber out through the parting seam.

Here's a resin cast body:



Dave