pressure pot idea, maybe very bad idea

[Rifleman1776]

The thought occurred to me that many folks would like to get into stabilization but simply cannot afford a good pump or pressure pot. I have been looking for a used paint pot for months without success and will probably have to spend the bucks for something like the $80.00 HF one that is so popular.
But, I have seen many pressure cookers available cheap and am wondering (prepare to tell me I'm nuts) if it would be practical to put blanks and stable solution into a pressure cooker and apply heat to achieve needed pressure inside.
Of course, the heat would have to be fairly low and safety precautions observed as the solution inside is flammable. Personally, I would want to know the boiling point and flash point for the solution. e.g. acetone
OK, what say the jury?

 

[rjwolfe3]

What kind of pressure can you get with a pressure cooker?

 

[maxwell_smart007]

I think you only get 10 or 15 psi, and that's generated by steam. Without any water in there, you'll get NO pressure, and just burn the resin...which I'm assuming is flammable?

Considering a good pressure cooker costs more than the pressure pot, you're better off getting the HF one, I think...

 

[Daniel]

This has been tried and there was some issue with the seal. Not sure if it was under vacuum that the problem occured but something about it getting sucked out of place or pushed out of place. in any event from what I have heard pressure cookers do not work, at least not well.

 

[leehljp]

I considered a pressure cooker for a while but nowhere in my mind could I establish that it would be safe as a pressure pot itself. With age, I find I take less chances.

Problems that I "saw":
1. Pressure cookers have one or two relief valves. They would need to be fixed. It is possible to drill and attach fittings to those holes.

2. Does the rubber gaskets on pressure cookers hold as well as the ones on a pressure pot at 40 to 60 psi.

3. I am not sure that pressure cookers can stand a vac like pressure pots can.

4. The locking lid of a pressure cooker is pre-set - and that in itself is limiting.

I worked these over in my mind numerous times and never felt comfortable in trying, so I gave up until I was back in the States and got one at HF (Little Rock) and mailed it back here.

 

[Glass Scratcher]

Frank, check your email.

 

[DozerMite]

...

 

[Rifleman1776]

I think you only get 10 or 15 psi, and that's generated by steam. Without any water in there, you'll get NO pressure, and just burn the resin...which I'm assuming is flammable?

Considering a good pressure cooker costs more than the pressure pot, you're better off getting the HF one, I think...

Any sealed container when heated will develop pressure inside. Used pressure cookers can be bought for $5.00.

 

[woodman928]

Ill still give you the 2 pressure pots that I have for free if you want them Frank they might need new seals but you should be able to get them from Spray Equipment here in Springfield for less than $10.
Jay

 

[wdcav1952]

There is a dental version of the pressure cooker that has an air valve to pressurize the container for some acrylic repairs. They are expensive, though. Before I could afford one of them, I used a Walmart pressure cooker and put an air valve and a pressure gauge on it. It worked decently up to about 25 psi.

Frank, FWIW, I don't think I would heat a pressure cooker with acetone in it. Now if my ex BIL needed a job.............

 

[Roy99664]

I made a pressure "pot" out of a 12" long piece of 4" iron pipe I salvaged. Had the plumbing shop thread the ends for caps, drilled and tapped one of the caps to accept a 3/8" air hose fitting, and ripped an 1/8" plywood shelf to fit inside. Set the regulator on your compressor to (what ever you use) and you're good to go. I just leave the hose hooked up till I'm done. You can weld something to it to make it sit still but I just clamp mine in the vise. Whole shebang cost me under $20 including threading. With just one shelf in it I can do 6 at a time which is plenty for me. I don't do enough casting to invest in a full fledged pressure system. It's an inexpensive alternative.

 

[nava1uni]

I wouldn't heat the acetone and it might combust due to the flammable nature of the substance. Be careful with a pressure cooker, I have treated several people who blew them up just cooking food.

 

[MesquiteMan]

Go to the casting group at Yahoo groups and ask them about pressure cookers as pressure pots. There is a fellow there that will chime in and tell you all about his major injuries using a pressure cooker as a pressure pot. It is worth it to save a couple bucks??

Besides, real pressure pots can also be had used for $5-10 if you just look. There was a Binks on Craigslist Austin just a few days ago. Binks is a helluva lot better than the Horrid Freight ones too. I know, I have both.

 

[workinforwood]

Once in a while I find glass jars at garage sales, big thick glass jars, as big as a pressure pot and usually larger in diameter with a large rubber seal and handles that push down and lock the glass lid. I bet those can take some pressure. I wouldn't pump 80 lbs, but I bet it can handle 40 lbs which should be plenty of pressure for casting. Tough part is drilling the glass, but not impossible. I would personally hunt for a certified pressure pot, but having a thick glass one would sure be nice and useful.

 

[MobilMan]

Check Ebay. "Paint pressure pots". There were a few on there last night.

 

[MobilMan]

"Paint pressure tank" I mean

 

[MesquiteMan]

Jeff,

PLEASE DO NOT USE GLASS! It MAY hold but if it doesn't, you will most likely be hurt VERY badly. It is just not worth it! The price of a real pressure pot is cheap compared to the potential ER bills and long term effects of exploded glass.

 

[Mudder]

I agree with Curtis.

If the glass in the pressure pot fractures you have pretty much created an Improvised Explosive devise.

The glass pressure vessels that we use at work are made from Chemically inert borosilicate glass and they are flame tempered, which means that if they do fracture it will break into cubes (very much like the side windows in a car). I just went and looked at one of the vessels and they are rated for 5 PSI max!

 

[workinforwood]

Don't worry, I use a pressure tank, not glass. Love the glass idea, but not interested in performing the experiment. Seems to me someone around here not long ago created a window in their pot and it exploded or imploded. Heck, my train of thought is that maybe even if it works the first time, when will it not work and what then?

 

[Mudder]

Don't worry, I use a pressure tank, not glass. Love the glass idea, but not interested in performing the experiment. Seems to me someone around here not long ago created a window in their pot and it exploded or imploded. Heck, my train of thought is that maybe even if it works the first time, when will it not work and what then?

I think something like that happened to Don Ward (Its_virgil)?


matter of fact he talks about it in his snakeskin tutorial posted here:

http://content.penturners.org/articles/2006/snakeskinblanks.pdf

 

[Darley]

The thought occurred to me that many folks would like to get into stabilization but simply cannot afford a good pump or pressure pot. I have been looking for a used paint pot for months without success and will probably have to spend the bucks for something like the $80.00 HF one that is so popular.
But, I have seen many pressure cookers available cheap and am wondering (prepare to tell me I'm nuts) if it would be practical to put blanks and stable solution into a pressure cooker and apply heat to achieve needed pressure inside.
Of course, the heat would have to be fairly low and safety precautions observed as the solution inside is flammable. Personally, I would want to know the boiling point and flash point for the solution. e.g. acetone
OK, what say the jury?

Why would you add heat you add only pressure and I would not recomended for vaccuming

This is a pot I did in December 2005 for my first pressure casting as you can see the pressure cooker is incased in a wood frame the hold as is ballon up when under pressure but hold well a 25 PSI one nigth I left it connect to the compressor and the pressure went up to 60 PSI I was very luky he didn't explode I still using it only in 1 test blank casting, I use the HF most of the time more secure and you cast more blanks

edit: as poeple say better off to buy an HF paint pot you will be able to cast more blanks

 

[Smokey7385]

Another source for the pressure pot is Grizzly Tools. http://www.grizzly.com/products/2-1-4-gal-Paint-Tank/H6330

 

[Vince_Hoffmann]

What I'm reading here is that it is inadvisable to use a pressure cooker for anything other than its intended use (food preparation) and that a paint pot is the best thing to use because it is purpose built for higher, long duration air pressure.

 

[NewLondon88]

What I'm reading here is that it is inadvisable to use a pressure cooker for anything other than its intended use (food preparation) and that a paint pot is the best thing to use because it is purpose built for higher, long duration air pressure.

I think so. I hope so. I picked up the HF pot yesterday for $64 and change.
It's a 2.5 gallon pot, so that should be fine.
Now all I have to do is seal all the leaks..

My understanding of Harbor Freight is that it is good for things with no
moving parts..

 

[amosfella]

Well, I have a unique thing then. It's an all in one computer controlled vacuum/pressure pot with a 3/4 inch walled vessel, 18 inches in diameter and 2 feet high. It has about 20 bolts with 3/4 inch shafts. It's rated for 2000 PSI. Oh, it's also needs 3 phase 440v or 460v power.
I bet I could do some interesting casting or stabilization in that.
Picked it up out of a paper manufacturing plant that went broke. Total cost was the diesel to get it out the the plant and to my house.