Assembled the pressure pot

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penmaker134

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Well I assembled my first pressure pot and getting ready to walk into new territory with casting it looks like alot of fun also.

Testing the pot with my compressor for the first time that gave me a kinda a scary feeling but also very intriguing fun. I have been reading on here and other places of how bad these things can go but its been something I have been wanting to try since the beginning.
 
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If you are using the Harbor Freight paint pot, keep it at or below 50 PSI and you should not have any problems. They are rated to 60 PSI, but from my research you can do okay with 50 PSI, just let your cast sit in the pot a little longer.
 
I plan on making my own blanks and maybe I will do the next contest for casting but this casting is new to me so maybe next time
 
Pressure has no impact on cure time...just saying. Happy and safe casting.
Do a good turn daily!
Don

i
eharri446 said:
If you are using the Harbor Freight paint pot, keep it at or below 50 PSI and you should not have any problems. They are rated to 60 PSI, but from my research you can do okay with 50 PSI, just let your cast sit in the pot a little longer.
Click to expand...
 
What exactly do you mean pressure has no impact dont you just need pressure to have the air pockets come out
But after you have had it pressurized for so long.

How long do you let the pot sit. For me I am just gonna use 1x1x5.25 molds for the blanks till i get better at it
 
Just started with this myself... Grabbed a Grizzly pot and fired it up for the first time just 2 nights ago. There's certainly a bit of a learning curve in timing your pour so you get a good mix of colors. The rest of it is pretty straight forward.

My wife actually did 3 blanks and I did 1 in our first attempt. Mine was... ok... She did a white/purple one on her first try that was amazing. My son actually helped me pour one last night that came out pretty good. I can certainly see why folks say this is addicting.

As for the pressure bit... What folks are saying is that the resin is going to harden at the same rate regardless of how much pressure it is under. Once it is hard, you're not squeezing any more bubbles out. Keeping it in the pot past the point where it's cured doesn't accomplish anything. Keeping in mind I'm a newbie at this too... I take that to mean you're better off getting the max pressure you can safely run for the time before it cures.

Interestingly enough, the lid on my Grizzly says max operating pressure 90psi and the tank itself says 45. I've been running 50 and there are a few stray bubbles up at the top of the blank on occasion but nothing in the core of it.
 
Cure time can vary depending on the temperature. During our hot desert summers I can demold Silmar 41 in 4 hours and probably less, but I leave it overnight during the "cold" months. Also, it doesn't hurt to replace the blowoff valve with one you know will work. I read where a guy pumped his up to 90psi and blew the lid 12 feet from the pot because the safety valve didn't open. There's a thread here on replacing the parts with ones bought on Amazon if you haven't already read it, but that's probably not necessary. Still, it buys some peace of mind for $40.
Just so you feel safe, my pot has been at 60psi for hours without any problem, but I prefer to keep it at 50. I forgot I turned the pressure up on my compressor when I was inflating my bike tires and accidentally tried to blow the pot apart. Just be sure you get the lid cranked down real tight. If not you can have anything from a minor leak to one or more of the clamps popping off, both have happened to me. I made a wrench from a 2" dowel with a slot cut halfway through and give each clamp an extra turn after hand tightening now, and have never had a problem since.
 
I had to replace my relief valve since I broke the original tightening it down too much.

It's set for 60 and it means it.
 
"With a 2-1/4 gallon capacity, this Paint Tank features a smooth-walled galvanized-steel tank for easy cleanup, double output regulator and pressure relief/safety valve. Lid gasket and clamps stay attached during lid removal. Works with any pressure feed HVLP or conventional spray gun. Maximum pressure is 45 PSI."

If the people that make the pot say 45 psi max - why do so many people take the chance to use higher pressure?

My car owners manual says oil capacity 5 quarts, but I put in 6 - haven't had a problem yet...
 
Not really a valid comparison. Motor needs a certain amount of oil to operate, lawyers put a pressure rating on a pot. I doubt very seriously these Chinese pots go through any kind of rigorous testing and they just pick a nice safe pressure to stamp on there. Funny thing, the lid on my Grizzly pot actually says 90psi and the body says 45.
 
Yes, there are safety concerns using these. If they stamp 60 lbs max on it and put a 60lbs blow off valve you can be sure they test much higher than that. in 20+ years of working in a shop with a lot of these used for spraying laminate glue I do not remember one failure. Use common sense and safety precautions and there's little to worry about.
 
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