Pressure Casting Equipment

[mangozac]

Good tip with the vaseline sealing the Lego mould box - I just don't like the idea of having to clean it up afterwards! The small amount of seepage hasn't been enough to bother me, but I figure if it does reach that stage I would just run some packing tape down the inside of the mould.

[Fleafa]

I sometimes use a hot glue gun. Recently, I rolled out some plasticine nice and thin and pressed the mould box onto it.

[mangozac]

[Lane]

Depending on the mold I either:

Press the mold block into the base layer for a two part mold. This mostly seals the clay to the box preventing bottom leakage. A quick pass with the tail end of a brush seals the edges.

or

Use poster adhesive to seal the bottom of the box if making a single sided or cut mold.

[Hiflt4@juno.com]

[Eltnot]

Just a heads up for those in Australia, Super Cheap has 10L pressure paint pots on sale for $99 at the moment.

[blind pig]

Thanks for that!

Hmmmmm....Do I need a third one......

[Magnetic Duckling]

I see there is already this topic about pressure casting stuff so I figured I could use it instead of opening a new one.
I have noob questions about which machines I need because it is still confusing right now, too many figures...
Can I post my inquiries here ?

[Anvils Hammer]

yep, go for it.

AH

[Magnetic Duckling]

Soooo I wanna cast bubble free resin with bubble free silicon mold. Nothing new so far. I already know how to cast stuff but I still have annoying bubbles.
I read that you need 70/80 psi for silicon and 60 for resin, no idea but I tend to believe people who knows how it works.

I found the following machines :
http://www.abac-support.co.uk/individua ... 30_7_S.htm
http://www.spraydirect.co.uk/acatalog/1 ... tator.html
but it is still unclear. I vaguely understand that when it comes to transferring the air contained in the compressor tank into the pressure pot, the relevant information is the 3 cfm but I don't know what to do of it. Can you tell me how long it would take to fill the 10ltr pressure pot depending on the psi I want (granted I already let the compressor get filled beforehand) ?

Please don't tell me things involving gallons because I have no idea what it is, I only know the metric system ^^;
Also English is not my first language so please disregard mistakes as a lack of attention at school xD
Thanks \o/

[mangozac]

OK well for starters you don't need any higher pressure for the silicone than you need for the resin, since during casting the silicone will only be compressed tot he resin pressure anyway. That said, even for resin the higher the better.

Here's a good number for you: 28.3. To convert CFM to litres per minute just multiply the number by 28.3

The CFM of the compressor isn't all that important as you want a compressor with an air storage tank. The transfer rate between the tank and your pressure pot will be much higher. For the compressor you will want a tank size of at least double that of your pressure pot.

The compressor and pot you linked to are far, far overpriced! The compressor should be just a cheap one from an auto or hardware store, no more than 120 euros. The pressure pot should be a similar price (eBay?).

Here in Oz we are Metric too, but unfortunately many measurements involving pressure and air are still imperial. You just have to get used to it

[Magnetic Duckling]

Thanks for your answer!
I know right, they are so expensive! I can't find anything significantly cheaper.. I did a lot of browsing and it seems getting this kind of product in the UK just plain sucks. I was thinking of going to browse around my neighborhood for compressors as those are more common in store than pressure pot.
Thing is I am in an apartment so I need a quiet one. We got thin walls ><;

Isn't silicon harder to get bubble-free because of its higher viscosity ? Anyway it doesn't matter much at this point. I know I need a high psi to do the job.

More noob questions :
Is the air transferring from compressor tank into the pressure pot or is it like, sharing the pressurized air between the two (I suck at explaining that in English). I hope that makes sense.

So ok 3 cfm => 85 ltr/min. I have a 10 ltr pot... but I assume it depends on the psi I am choosing to use so I still don't understand how to know how long the filling of the pot would take. I honestly try though ^^;

Or maybe girls should just stop playing with men machines xD
Please make me clever

[Fleafa]

I don't have much time to respond right now (& I'm shattered) but these are what I bought:
http://www.axminster.co.uk/axminster-10 ... prod21334/
http://www.amazon.co.uk/Wolf-Sioux-9-5c ... B004CRF9I0
Though I seem to remember getting the compressor cheaper than that...

As for quiet compressors... I think you'll end up paying considerably more. Mine is very noisy.

[blind pig]

[Anvils Hammer]

Any 25L compressor will have no trouble at all filling a paint pot, timings are only important when you start messing with vacuum!

the equipment listed by fleafa will do just fine, but you can get a cheaper compressor on ebay-

http://www.ebay.co.uk/itm/25L-Direct-Dr ... 3f11730ec2

cant find the one I bought anymore but I paid £90 including postage.

Pressure of 3 Bar (45PSI on the dial) will be good enough for both silicone and resin, and its highly unlikely you will get a pressure pot rated for more than that!

You wont find a quite compressor.. talk to your neighbours and find out when they are at work!

AH