Pressure pot predicament

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Russknan

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Mar 13, 2012
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Location
Nanuet, NY
Now that we have the alliteration out of the way . . . Recently, I purchased a pressure pot from HF. Got around to buying the additional fittings and assembling it yesterday. Went for a "dry run" only to discover that the safety valve was letting go at 32-34 lb. pressure. The pot is rated for 80 max and I was anticipating using 60 or 70 lb. for Alumilite. Called HF and, after being on hold a LONG time for a tech support person, I got a recording that said I should leave my phone # and they'd call back in 24-48 hr.

This is my first foray into casting, so I don't know how to solve this. Have you experienced people had a problem with this, replaced the safety valve with something stronger, or eliminated it altogether? I don't mind having something for safety, but this doesn't seem to be a good setup at this point.
Russ
 
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I remove mine. Main reason is that you are the safety valve. You fill it and close the valve. The safety valve was put there to protect the tank in the event that the regulator failed while you are 25' away painting.
 
That would be quite common Russ and I would suggest 2 way to resolve it, if you compressor as a pressure gauge (most do) you will have no problems in fixing the problem and have a valve that will be set to activate at the 80 PSI or where ever you want it to activate.

Most safety valves are not sealed so you can dismantle them quite easy, replace the original spring with a stronger one but the way I done mine was to get a general purpose safety from the hardware store, they are normally rated for 150 PSI, in this case you get the spring out and replace with a light one or cut 1/3 of it and assemble. The cap the screws the spring in works as the adjustment and the further forward you tight it in, the more the spring get compressed therefore, requiring more pressure to let go and open the valve so, you start testing with the spring no ver much tensioned and get air in until the valve opens, read the pressure on the gauge, it will be low, so you turn that end cap a couple of turners and try it again, you stop when you get the valve opening at the maximum pressure you want, and that is it...!

Cheers
George
 
Thanks, Guys! 3 great replies in about 1 hour from experienced people, literally all around the world (George). Typical, but still amazing! One way or the other, I should have resolved the issue today and, perhaps, I'll try to make my first "waste wood" blank tomorrow. I hear there is a bit of a learning curve but, if the wood is truly "waste" . . . Never before have I had a hobby with so many new things to explore. Russ
 
Hi
Please do not remove the safety valve without replacing with a higher rated one that has been tested to that higher pressure, if that pressure pot explodes because you are relying on the cheap gauge to tell you the pressure where will I send the flowers a pressure pot is a dangerous peice of equipment if used improperly treat it with the utmost respect
Stay safe
willie
 
I got one from HF on Monday. I followed Curtis' advise. I set the air compressor gauge to a bit over 60 psi. Took everything off the pot and put on my own gauge and lever on/off.
Russ
 
I remove mine. Main reason is that you are the safety valve. You fill it and close the valve. The safety valve was put there to protect the tank in the event that the regulator failed while you are 25' away painting.

I removed my H.F. pressure relief valve also

BUT

I replaced it with one rated at 60psi from Northern Tool.

"YOU are the safety valve". In my opinion not a good idea most failures are do to HUMAN ERROR. Heat building up accidental overfill could certainly happen. You also need a pressure/vacuum gauge.

Another thing I through away was the H.F. pressure regulator. The threads on these I think are metric can be a little tricky when adapting new parts.

Good Luck
 
I remove mine. Main reason is that you are the safety valve. You fill it and close the valve. The safety valve was put there to protect the tank in the event that the regulator failed while you are 25' away painting.

I removed my H.F. pressure relief valve also

BUT

I replaced it with one rated at 60psi from Northern Tool.

"YOU are the safety valve". In my opinion not a good idea most failures are do to HUMAN ERROR. Heat building up accidental overfill could certainly happen. You also need a pressure/vacuum gauge.

Another thing I through away was the H.F. pressure regulator. The threads on these I think are metric can be a little tricky when adapting new parts.

Good Luck


With my Pressure pots I have a pressure gauge and a valve. One the hose it is double regulated. I have my compressor set at 80psi and a second regulator at 50psi which is where I typically cast. I understand where you are saying that there could be enough resin to raise the temp creating more pressure but I rarely have more than three mold at one time in my pot. Mainly due to the 7min pot life. So I was forced to buy 3 binks pots to be able to cast in the volume I wanted.
 
I had the same problem with my HF tank. I pulled mine off and replaced it with a coupler, not because I needed another on the tank, but because I had a spare in my parts drawer.

My compressor has two gauges, one measuring the tank's pressure and one measuring the output pressure. I set it to 60psi and let that meter the casting tank's pressure. My casting tank has a slow leak, so the 150psi starting point of the storage tank will keep the casting tank at 60psi (unpowered) for about 15 hours.
 
With all the info, think I'm getting closer. I just ordered a 70 lb. pressure release valve from Amazon (auto parts guys were clueless, something I've observed more than once in the past.) I have a pressure regulator and cleaner system in the line from my compressor. It's always been set to 80 lb. So the question remains, do I really need to replace the HF regulator and gauge, or can I be reasonably confident that I'm OK with that set-up? If you feel I should ditch them anyway, can you recommend replacements that hit the "sweet spot" between function/safety and cost? Russ
 
With all the info, think I'm getting closer. I just ordered a 70 lb. pressure release valve from Amazon (auto parts guys were clueless, something I've observed more than once in the past.) I have a pressure regulator and cleaner system in the line from my compressor. It's always been set to 80 lb. So the question remains, do I really need to replace the HF regulator and gauge, or can I be reasonably confident that I'm OK with that set-up? If you feel I should ditch them anyway, can you recommend replacements that hit the "sweet spot" between function/safety and cost? Russ

Russ, if you have found a safety valve at the correct pressure you want, that is the simplest way to get around, may not be the fastest way but, I also understand that, a lot of the "stuff" I do, when it comes to tools/equipment modifications, isn't something that everyone is either comfortable/confident or experience to do so, I accept that modifications can be dangerous if not done properly.

The problem with those cheap pots is that, you get what you paid for, they are able to do the job but aren't as safe and or reliable as the quality ones.

And while a medium quality pressure pot can be setup to function as efficiently as any Binks or other specialised pots, the mistake that many people make is to want to save money on the pot and buy a HF type pot, but then, they start to want all these modifications to match the better pots, not realising that, by the time they finished, they spend weeks trying to get stuff, spend the time trying to make the modifications but because they don't know really what they are doing or have the correct tools for the job, they get struck with things like, different threads, different size parts and a variety of situations that become real, as a result.

Frustration sets in, wasted time start to be annoying and all the initial excitement of trying to cast they first blanks, fall into the "too damn difficult" basket, and people move away from it.

Now, one would think that, this situation would suit me well, as I make cast blanks for sale on my eBay store, and if everyone is casting their own, I won't sell any, right...??? WRONG, I have always encouraged and help others to set up their casting gear, some the exact guys that have been buying my blanks however, I still invite them to my place to show them how everything is done, or showing/sharing it all, here on IAP.

There will be always new turners wanting to start, every single day, they will want to try the cast blanks when they start seeing them on pens, they may one day buy they own casting equipment but for some time, they will be struggling to set themselves to get going with the turning, they will require the supply of the blanks, even if for a short period of time so, I will always have some cast blanks ready for these occasions and I will be the first person to ask then if they want to learn how to make them, they may be able to learn how to cast what is available to them however, there will be always the "stuff" that George has, that they won't have to cast themselves so, if they want some, they will look me up, simple...!:biggrin:

Ones of the things Russ that you may have to consider to invest on, is to buy a quality gasket on eBay for that pot, they are notorious to leak, any gaskets provided by the pot seller will be the exact same ones as the one that came with the pot so, if you get sick and tired of the lid leaks, a good gasket should set you back about $30.00

Remove anything from the pot that you will not need and while you are working on it, any fitting that will stay, remove it, and put some thread tape or any other type of thread sealant, and put it back together, at least you will know that, any leaks are not from the parts you have sealed...!

Good luck and hang in there, a few setbacks are part of life, you will get lots of fun times with it, as soon as you have it all together...:wink::biggrin:!

Cheers
George
 
"And while a medium quality pressure pot can be setup to function as efficiently as any Binks or other specialised pots, the mistake that many people make is to want to save money on the pot and buy a HF type pot, but then, they start to want all these modifications to match the better pots, not realising that, by the time they finished, they spend weeks trying to get stuff, spend the time trying to make the modifications but because they don't know really what they are doing or have the correct tools for the job, they get struck with things like, different threads, different size parts and a variety of situations that become real, as a result."

I've actually tried to learn that lesson, George. Among the MANY other things I used to do (including bartender, musician, wedding photographer, etc. before I "settled" for becoming a psychologist) was I taught guitar lessons. Unfortunately, a lot of people would buy a cheap guitar "to see whether they liked it." The strings were too high, the neck was warped, and their fingers hurt so much from this set-up that they gave up. Also, couldn't sell the cheap guitar like they would have been able to do with a quality one.

I prefer to buy better quality tools ONCE, although I will probably never spring for Festool, etc. But this project has really stymied me. I read everything I could find on pressure pots here and, until your post above, didn't see discussions about maybe choosing a higher quality pot such as "----". And there were no musings about pressure relief valves, etc. I think that, although there truly is some great stuff here already, there is still room in the Library for another article or two on setting up and using a pressure pot, taking into account these extra things that experienced people already know. Please note that that is not in in any way to diminish my gratitude for all the help people have offered, just a suggestion for a "refinement".

I know from personal experience - and from the experience of my patients - that the things that one values the most and which provide the most self-esteem are the things that take time and effort to master. I'm guessing that casting will be the same. And, George, I agree about the continued potential for sales. I expect that I will continue to buy most of my cast blanks and wood that I can't get for myself. I'm just looking forward to learning how to turn some of my "waste wood" into attractive blanks of my own crafting. Thanks again to all. Russ
 
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