Pressure Casting Equipment

[Magnetic Duckling]

[Deadmeat30]

CFM means cubic feet per minute, it's basically the air displacement the pump can remove within that time. Around 6-9cfm is good to look for.

[Magnetic Duckling]

[Deadmeat30]

depends on the size of your vacuum chamber and how quickly you need to get it to a vacuum (faster the better )

[mangozac]

Isn't Duckling talking about pressure casting only? In that case the CFM isn't all that important - it will only change the amount of time it takes the compressor to fill its own tank (how long it makes a noise for). I would want the compressor tank to be at least double the size of the pressure pot - the larger it is the quicker your pressure pot fill time will be (as the compressor tank empties the flow rate drops).

Either way I think you're really going to have to find a slower curing resin - you want at least 3 minutes of work time to get it mixed, poured, in the pot and up to pressure. I prefer 5 minutes!

[Magnetic Duckling]

Yup Duckling talks about pressure only.

Well the resin I use is cool, I like it (and I don't know any other one... oops), it starts to harden fast but has a texture close to silicon (high viscosity ?) for a long while after it starts so I should be fine.

So basically mangozac, between those two 8 bar machines :
2.15cfm / 24 ltr
4.5cfm / 25 ltr
both would do the job ?... I'd rather buy the cheaper, if you see what I mean =p
I thought cfm was the time it took to transfer the air from 1 tank to the other ?

A pressure pot company told me 3 cfm would take a few minutes to get the pressure pot under pressure but maybe the person considered the time to fill the compressor tank in the equation... how could I guess that though ><;
So I put my trust in you guys (because people who likes miniatures has to be good people ).

[Deadmeat30]

Ok, i mis-understood, Ignore everything to do wtih CFM's if your only needing to pressure, for pressure you want PSI (pound per square inch). Aslong as you have a good size tank attached to the compressor, your dont really have to worry about how quickly it'll transfer to the pressure pot. The compressor will have a regulator on it, just set this to the PSI required and then open the valve. The 2 tanks will equalise to the regulators setting.

that any clearer?

regards,

Alan

[mangozac]

[Magnetic Duckling]

deadmeat (that is the most peculiar nickname xD), it IS clearer thanks!

mangozac, you assume correctly!
Thanks for making a calculation too.

I just registered myself, ask for help and you all help me, that is really sweet so you see, I am right about people who likes miniatures =p
I hope I can be of help in return. If anyone here wants information about 3D prints that is more my area of expertise.

I guess it is set then, I'll most likely get the 2.15cfm / 24 ltr compressor and this baby http://www.axminster.co.uk/axminster-10 ... prod21334/
The dual hose kinda confuse me though. Can I close one valve and use only the other or something ?
(Once I got those I'll probably whine around while batting my eyelashes to get them to work ><; ).

[blind pig]

[mangozac]

Hey Duckling, Fleafa some fantastic drawings showing how he set up his pressure pot, along with some alternative configurations . Have a read of that and hopefully it will give you a good understanding of how you need to modify the pressure pot.

One other thing too: the pressure pot will come with an emergency release valve. It's to protect you in case you decide to stick a million PSI (well maybe not quite that much...) into the pot - the valve will "pop" open and release all of the air in a very loud manner. Generally these pots are rated to operate at well over 100PSI, however they are fitted with pressure relief valves set much lower - around 40PSI. Ideally you want to be casting at 60+ PSI so you will need to replace the relief valve with one rated at say 70 PSI. Air tool stores should sell them - I would expect to pay around 10-15 pounds.

Oh and also, you need to make sure that you use either some or some kind of thread sealant compound from a tube (like thick glue) on the fittings when you screw them together. They are not designed to be airtight without some kind of sealing technique.

One day we should all get together and compile a exhaustive tutorial on the best way to convert a pressure pot and all of the parts needed...

[Magnetic Duckling]

[blind pig]

A diverter is someting that goes over the inlet pipe under the lid of the pressure pot that stops the high pressure air from blowing down onto your resin and making it splash out of the mould.

A good hardware store should be able to help you with the fittings. Take your pressure pot and the hose that fits the aircompresser you are going to buy into the hardware store and say you want valves and connectors to fit it.

Batter your eyelases and wear something with a bit of boob showing and ask if someone would mind unscrewing the pipe inside the lid when you are in the hardware store (worked for me!)

@Zac: I can't believe there is a wiki about Teflon tape!!!

[Magnetic Duckling]

[mangozac]