Resin Presure Cast Pot

OdysseySlipways · Post by **OdysseySlipways** » Wed Nov 22, 2006 10:45 pm

oh and when i get a tank:

I always replace the Pop Valve

for used tanks, it's a must.

for new tanks (such as from HF) the new valves i put in seem to release better

i have been running my tanks at about 45 - 50 psi. i use smooth-On smooth cast 321 resin and have noted that sometimes 30 just didn't seem to work, that and i have sometimes up to 15 small molds int he tank and i need to crush them bubbles good and fast as the resin is sometimes starting to kick off

Sparky · Post by **Sparky** » Thu Nov 23, 2006 2:02 am

OdysseySlipways wrote:okay, first off, why do you need a clear lid on you tank when you vaccum?

I just put the batch of mixed rubber into th tank, set the timer for 7 - 8 minutes and walk away.
-snip-
?

Murrphy's Law, a watched bucket of RTV deairs fine, an un watched bucket spontaneously upchucks its contents all over the inside of the pot.

After 2 batches out of 3 blew up insde the tank I started using a clear lid. Also you can get a away with not having a big enough bucket for the expanding RTV, as you use the relief valve to work out the initail expansion without letting it boild over. Then after it settles you can leave the vacuum to reach the full deep vac.

If you're mixinig 800-900 grams of RTV at a shot. a bucket big enough for that is very large and then you'll be scraping the sides of it to get all that rtv out (which will then really require another degassing in the modl box). There is a safe way to rig it so you can do it blindly but if the mold leaks or the bucket boils over, you have to scrap and slop to recover the RTV or right it off.

Also if you vac cast, you want to watch as you work out the air in the mold. Vacuum till you see a few big air bubbles perk through the reservoir, then let the vacuum out, continue until you see only small bubbles perculating. Resin foams up even more than RTV, and it will continue to boil leaving lots of air bubbles if you try to cast it under vacuum.

OdysseySlipways · Post by **OdysseySlipways** » Thu Nov 23, 2006 8:31 am

I think i mix 1 - 1.5 pounds at a time

Antenociti · Post by **Antenociti** » Tue Nov 28, 2006 11:36 pm

Just as way of a little update - use this thing quite literally every day now and casting commercially with it. Response from customers is pretty fabulous.... failure rate in casting 1 item out of about 700 (my fault as i let a bit of resin flash drop into a mould which blocked off a tiny section!).

Other than that - zero mistakes, no wastage. Chuffed to bits. Got a Hoooge pot now also (5 gallon and a 10 gallon)!!!

Thanks Sparky again for all the help - owe you one!

OdysseySlipways · Post by **OdysseySlipways** » Tue Nov 28, 2006 11:46 pm

I wouldn't mind a 10 of 15 gallon tank to add to my stock

Antenociti · Post by **Antenociti** » Wed Nov 29, 2006 5:56 am

keep an eye on ebay - there seem to be quite a few come up in the USA, had to wait for donkeys for some in the UK.

Sparky · Post by **Sparky** » Wed Nov 29, 2006 1:32 pm

Antenociti wrote:Just as way of a little update - use this thing quite literally every day now and casting commercially with it. Response from customers is pretty fabulous.... failure rate in casting 1 item out of about 700 (my fault as i let a bit of resin flash drop into a mould which blocked off a tiny section!).

Other than that - zero mistakes, no wastage. Chuffed to bits. Got a Hoooge pot now also (5 gallon and a 10 gallon)!!!

Thanks Sparky again for all the help - owe you one!

You could spill the secret of where you found a 5 gallon and 10 gallon pot. . . (Were ethey expensive?)

Antenociti · Post by **Antenociti** » Thu Nov 30, 2006 9:22 am

just on ebay - simply couldnt find them anywhere else in the UK but they keep popping up on ebay from companies that sell off liquidated assets.

I got the 5 gallon for Â£37 and the 10 gallon for Â£69.. also ended up with another 5 gallon one (Â£29 - i got the 2 5-gallon pots together in a bundle)) that turned out to be unusable but at that price i didnt really mind too much as a new 5-gallon would have set me back Â£500 (and more).

But it just meant checking ebay literally everyday over a month or two until some came up.