Pressure Pots for casting questions

[Kylash]

Alright, i know next to nothing about this, but I want to be able to get nearly bubble free urethane castings of fairly small items, is this the kind of pressure pot most use, and how does it work?

http://www.harborfreight.com/cpi/ctaf/disp...temnumber=93119

 

[GeneralMayhem]

Eeeeek.

No.

Do NOT buy the cheapie Harbor Freight Pressure Pot.

I belong ton a couple differrent casting groups on Yahoo, and there have been horror stories about the bolts failing on that pot. Very dangerous. The Alumilite Pressure Pot is the one you seek...

Alumilite

 

[exoray]

<div class='quotetop'>QUOTE(GeneralMayhem @ Mar 8 2007, 10:48 AM) [snapback]1434750[/snapback]</div>

Eeeeek.

No.

Do NOT buy the cheapie Harbor Freight Pressure Pot.

I belong ton a couple differrent casting groups on Yahoo, and there have been horror stories about the bolts failing on that pot. Very dangerous. The Alumilite Pressure Pot is the one you seek...

Alumilite
[/b]

$187 for the Alumilite pot, that is an Eeeeek in itself... You can purchase top quality pots all day for less then that on ebay

The Harbor Freight one is fine and many people use it without issues, just hit up the hardware store after you purchase it and purchase all new GRADE 5 bolts and nuts to replace the hardware and you sholuld be fine... Also get an inline regulator for you compressor and make sure you don't go over the 60psi rating...

Probably 90% of the pressure pot issues result from failer to tighten down the lid correctly and regulate the pressure...

And if you don't want to go the Harbor Freight one, because of some surrounding issues, I suggest you watch ebay just search "paint pot" and the sorts and you can usually get used ones for under $50 and new ones in the $100 range... I picked up a vintage Mongomery Wards one for $20 delivered on ebay and it has served me for many years, ugly but functional...

 

[Kylash]

so then you need an air compressor for it, what do those run?

 

[exoray]

<div class='quotetop'>QUOTE(Kylash327 @ Mar 8 2007, 11:47 PM) [snapback]1435458[/snapback]</div>

so then you need an air compressor for it, what do those run?
[/b]

Um, $100 for a cheapy small one...

 

[dstephan]

Sorry to resurrect an old thread, but I recently got this harbor freight pot and a bunch of ball valves to seal off all the extra outs on it. The release valve seems to leak and even when that's closed off I still lose all pressure in about 30 mins. That's okay for quick resin, but not for the silicon molds that I'm pressure casting as well.

Anyone solved the leaking problem on this pot?

 

[darth_myeek]

I have heard the same about the harbor freight pots. I purchased this dvd (Vol. 7 in the series.) which covers the basics on scratchbuilding and moldmaking & casting. He appears to be happy with his harborfreight pot, and gives a rundown on his setup. Worth the $17.95.

-DM

 

[exoray]

Anyone solved the leaking problem on this pot?

The release valve seems to leak

I would start there... Did you purchase good quality valves? Cheap valves might very well be an issue...

My tank will hold a vacuum for days, the vacuum's nature actually helps promote a better seal on the lid so that shouldn't be an issue... You need to figure out where it's leaking and I suspect it's in a valve or pipe fitting...

If you left the pressure relief valve that came on the tank in place remove it and replace it with a ball valve, its for "pressure" relief not vacuum relief... The vacuum inside the tank will actually suck that valve in by itself, so it's no wonder it would be leaking...

 

[SG Merc]

I've been thinking of one of these for a very long time! I also see the Harbor Freight model is also only $80.

Hey exoray, any estimates on about how much money worth of upgrade parts one would spend on the HF model? I speak mainly of the inline regulator + nuts/bolts that you've mentioned. I've already got a good air compressor.

Craigslist might be another good place for people to look for the paint pots :thumbsup

 

[exoray]

Hey exoray, any estimates on about how much money worth of upgrade parts one would spend on the HF model?

It really depends on how fancy you built it out... You could probably get one up and running for about $40, as long as you get a good deal on the gauges... Vacuum gauges are pretty expensive at the retail level, but you can find them on Ebay pretty cheap...

I sent a little more money then necessary because I put a bunch of quick connects on there to make things easier...

I really suggest watching Ebay for tanks, they usually go real cheap, then you can spend the money decking them out...

 

[SG Merc]

Awesome, I appreciate the information and advice!

 

[dstephan]

I would start there... Did you purchase good quality valves? Cheap valves might very well be an issue...

My tank will hold a vacuum for days, the vacuum's nature actually helps promote a better seal on the lid so that shouldn't be an issue... You need to figure out where it's leaking and I suspect it's in a valve or pipe fitting...

If you left the pressure relief valve that came on the tank in place remove it and replace it with a ball valve, its for "pressure" relief not vacuum relief... The vacuum inside the tank will actually suck that valve in by itself, so it's no wonder it would be leaking...

Thanks, I'll try replacing the relief valve. As far as I can tell, that's the only place it seems to be leaking.

 

[Docbudo]

I use a pressure cooker and just added a tire valve. works great

 

[belleauwood]

I use a pressure cooker and just added a tire valve. works great

I hope like hell thats just for vac, not pressure . . .


Ryan

 

[LordVdr]

So let me get this straight...you can use a pressure pot as a vacuum chamber as well? I'm only asking as I am interested in getting a vacuum chamber for silicone casting, but don't have the $500+ for the one listed on Smoothon's site. Would I need a vacuum pump hooked up to it?

Thanks in advance for any info....

 

[exoray]

So let me get this straight...you can use a pressure pot as a vacuum chamber as well?

Yes... As far as paint pressure pots... Personally I wouldn't use a pressure cooker pot as they are generally a MUCH weaker design, and I would NEVER use a pressure cooker pot as a pressure tank...

Would I need a vacuum pump hooked up to it?

Yes, you can get the cheapy venturi one from Harbor Freight if you have a decent air compressor, or you can look around for an electric one... I have lucked out since they outlawed unlicensed servicing of many freons there are a bunch of AC unit vacuum pumps out on the market from handymen that used to do it, and no longer can... They can be found at garage sales and even Ebay pretty reasonable...

but don't have the $500+ for the one listed on Smoothon's site.

I was at a Smoothon distributor last week and saw that tank in person, it's real nice, and the additional size would be welcomed, but like you it's a little too rich for me and my needs...

 

[judgedredd]

are there any online tutorials on how to set it all up?

 

[cheech9898]

So let me get this straight...you can use a pressure pot as a vacuum chamber as well? I'm only asking as I am interested in getting a vacuum chamber for silicone casting, but don't have the $500+ for the one listed on Smoothon's site. Would I need a vacuum pump hooked up to it?

Thanks in advance for any info....

are there any online tutorials on how to set it all up?

If your looking for info on your own vac chamber, there's one here that shows how to build the equivalent to Alumilite's here . Pipe can be gotten from evilbay, look up the store: ShortPile Plastics to get short sections of 8-24 inch pvc sewer pipe. You may want to check with a local builder/contractor or city water dept. for some throw-away type pieces you might have or pay a small fee/donation for also.

 

[judgedredd]

interesting thanks will see what vac pumps are around

If your looking for info on your own vac chamber, there's one here that shows how to build the equivalent to Alumilite's here . Pipe can be gotten from evilbay, look up the store: ShortPile Plastics to get short sections of 8-24 inch pvc sewer pipe. You may want to check with a local builder/contractor or city water dept. for some throw-away type pieces you might have or pay a small fee/donation for also.

 

[moff man]

Being the poor cheap dude that i am i have in the past used a 5 gallon pail , a shop vac and a piece of plexiglass before with fair results. That pail method did remove alot but not all of the air bubbles. The other method i use alot is the claying half casts.

this way you pour your silicone over your half clayed subject and all the air bubbles rise to the top and away from your subject. When it dries flip it over, remove clay, apply mold release and pour the second half.

Sorry to get off topic:lol I do need a pressure pot myself and am watching this thread with great interest.