New HF Pressure Pot Leaks and questions

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R

RHunter

Local Chapter Leader
Joined
Dec 17, 2008
Messages
118
Location
Mechanicsville, VA
I modified a HF Pressure Pot like tool-man did here:

http://www.penturners.org/forum/showthread.php?t=42075

Mine leaks like a sieve, but only around the rim- all my connections are soapy-water tight.


  • Do I need to do something to the sealing gasket? I've rotate the lid around the rim, and it does not leak in the same spot every time.
  • How tight do I need to secure the hold down clamps?
  • Just what REALLY is the pressure limit of this pot? It's stamped 80psi, but are those REAL numbers or the typical HF numbers?

TIA!

-Doug
 
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I'd guess you have an out of round lid, I'd also venture to say the warranty is void due to the alterations. I'm not the expert just an observation, hope I'm wrong.
 
I took the gasket off, turned it upside down, sprayed some silicone grease on it, clamped it down tight and let it sit for a day. Now I can hold 65psi for at least 30 minutes, probably longer but with alumilite, I never had the need to keep it pressurized longer.

Curtis (mesquitman) came up with the silicone spray idea.
 
Well I think I found the sweet spot. :redface:

I got the pressure up to about 75psi and I lost about 9psi overnight.

I marked the alignment with tape for now, but plan on making it permanent tonight.

Once I get (yet) another fitting (will get some silicone grease while I am at it) I will test with vacuum tonight!

Pix to follow once I finally remember to take my camera out to the shop.

Thanks folks!

-DD
 
I added clamps to mine. Found the clamps at a supply house. Cant remember what one. Then welded them on and no more leaks. 100psi and holds if the temp doesnt change.
 
neon007 said:
I added clamps to mine. Found the clamps at a supply house. Cant remember what one. Then welded them on and no more leaks. 100psi and holds if the temp doesnt change.
Click to expand...


Got any pictures Neon?

If I hand tighten my HF PP I get 50 PSI before the pressure starts to give.
If I use leverage (wrench) I get 70+ PSI. WOuld be nice if there was an easier way to fasten the thing down tightly.


Manny
 
we recently had a member on here who's PP exploded. don't know the problems he had but think about that before you disregarg a stamped warning. I had problems with rim leaks too but once I started using the same spot evrytime time and tightening the heck out of it, it seems to be resolved. I can leave my pot for a couple days and not loose more than 2lbs.
 
neon007 said:
I added clamps to mine. Found the clamps at a supply house. Cant remember what one. Then welded them on and no more leaks. 100psi and holds if the temp doesnt change.
Click to expand...
Keith, Not trying to be a smartass but.... why 100 psi? I'd hate to see a member put lots of clamps on their pot in order to get more pressure when half that 100 psi would suffice... then have the pot explode possibly causing harm.

A friend does a lot of "worthless wood" blanks where he forces resin into the tiniest of crevices in some very hard wood. This is done with alumalite at approx 70 psi.

I have cast my own "worthless wood" blanks where alumalite was pushed into the grain of desert iron wood and some pretty dense burls at 65 psi with ease.
 
Take the gasket out completely and rub plumber's grease on all surfaces. Make sure the channel's clean and put the gasket back in. That fixed my first pot's leaks.

I think it's important not to worry about losing 2-3 lbs. overnight. It won't effect your casting, and can drive you nuts for no good reason. DAMHIKT.

Dale

P.S. I would agree wholeheartedly with what George just posted about going beyond the pot's recommendation. The difference in effectiveness in the casting between 65 and 100 lbs. is likely zero. The difference between the pressures on the downside is a possible if not probable tragedy. I know someone has pumped these things up to 200 lbs., but to me, it's just not worth the risk. I have kids here that need me. All of me. Someone needs you all too. Don't go over what they rate the pot at. Period.
 
Last edited by a moderator:
I would add to the thread; I would definitely put the pot on the other side of a sturdy masonry wall when pressurizing it for the first time.

I was in a dive shop in the Caribbean when a scuba tank "let go". The sound was worthy of Mythbusters! Fortunately the pump station was fully shrouded.

Now scuba tanks contain a LOT more pressure than your paint pot, but be safe and not sorry.
 
Didn't find the silicone grease at the BORG, but I got my fitting and tried vacuum.

I get about 7" Hg then nothing else. :confused:

I can't tell if it's leaking or I just can't get enough air moving fast enough through the HF venturi (96677) to pull any more vacuum. I have a HF 40400 air compressor (hey it works fine for dusting, nailers, and some spraying), but is it enough? Specs on the compressor read 4 SCFM at 90psi (but like most HF Specs is probably over stated...)

Any one using vacuum, how big a compressor do you have?

Ultimately I'm looking to pull vacuum on Poly to stablize some blanks I have.

Thoughts?

-DD
 
RHunter said:
Didn't find the silicone grease at the BORG, but I got my fitting and tried vacuum.

I get about 7" Hg then nothing else. :confused:

I can't tell if it's leaking or I just can't get enough air moving fast enough through the HF venturi (96677) to pull any more vacuum. I have a HF 40400 air compressor (hey it works fine for dusting, nailers, and some spraying), but is it enough? Specs on the compressor read 4 SCFM at 90psi (but like most HF Specs is probably over stated...)
Click to expand...

And that sounds like about 1/3 of what you'd need to pull a good vacuum
with a venturi pump.. but I'm not positive. I haven't used the venturi pump,
since they had the vacuum pump on sale when I went there.

You might try taking the pressure pot (venturi attached) to a service
station and see if the mechanic will give it a blast of air for you. That will
tell you if it is your compressor or a problem with the pump.
 
I pull 23 lbs. with the same setup. You need a certain amount of "OOOMPH" with the compressor, although I'm not sure how much is enough. I had an 8 hp anyway that can pretty much keep up with anything so it wasn't an issue.

You may try to find a friend or neighbor with a full-size compressor and rule that out.

Dale

P.S. Yeah, what Charlie said! Would help if I could read...
 
Dale, you hit it on the head!

I pulled the gasket out, smothered the thing in silicone grease pumped it up- 75psi easy!

Moved the lid off my Registration Marks, 75psi and holding!!! :)

Between you and Charlie, I like the mechanic route.

Updates to follow!

Pix when I get the camera running (I brought it back with me to the shop to take some pix and post- but no batteries...:confused: )

Thanks folks!

-DD
 
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