FIXED -- Help fix pressure pot


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This sucks. I finally got my rig all ready and go. I'd been testing the last couple of days to make sure I could hold pressure, it was working great. I mixed and vac'ed the rtv, poured it in the mold and sealed it in the pressure pot.

I had a leak on my air in valve. Dang it! I hoped I could crank it down a little and seal it up. See the picture for what happened. :cry

Can anyone offer any ideas on how to get the broken part out of the threaded hole in the lid? Preferably a quick/easy/cheap DIY method...yeah I know. Thanks.

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Re: Help fix pressure pot

Not sure if it would work for this but I've used it in the past on other things. Take a piece of aluminum or copper pipe that fits into the hole ( solid bar even better ) with a little extra room. mix up some weld bond and weldbond the pipe into the hole. You should then be able to use a vice grips and unscrew the broken piece. Best of luck.
Re: Help fix pressure pot

Looking at it here is what I thought.

Drill out the center of the stuck part. Run a threaded rod though the hole and then lock the rod in place with either two nuts or some good lock washer on the top and bottom. Once the rod is locked in place I would then attempt to just remove the part. it should be obvious but make sure you use nuts and washers that are small enough to fit though the opening without harming the threads.


PS. To seal the leak use either teflon tape or gas pipe dope. You'll want the stuff rated for gas since that tends to stay flexible and is designed for pressure situations.
Re: Help fix pressure pot

I'm pretty sure Home depot sells a kit for this! It's a reverse type bit, it fits into the inside of the broken piece, and as you turn it, counter clock wise, the bit screws onto the inside of the broken piece and as you keep turning it, counter clock wise, it unscrews the broken piece out. it's called a reverse drill and screw Extractor. Here a link of what it looks like.
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Re: Help fix pressure pot

You can try taking a large lag bolt and from the INSIDE (aka the opposite side you screwed that pipe into) screw the lag bolt into that pipe, because you are coming form the other side the thread rotation is reversed or mirrored ;) Simply screw the lag bolt in and with some luck it 'might' back out the broken pipe out the top...

Or just get the proper tool and be done with it, as stated above most hardware stores will have left hand threaded extractors...

Spiral Screw Extractor Set No. 1 - No. 5-21822.0 at The Home Depot

And as stated get the 'yellow' gas pipe goop and use that vs the tape, IMO it seals better it's just messy to use, nothing a paper towel can't handle though...
Re: Help fix pressure pot

If nothing else works for you I would use a fine toother junior hacksaw blade & cut into the side of the brass untill you can just see the tips of the steel thread. I'd cut two slots about 1/8" or 3mm appart, then pick the 3mm slither out with a sharp tool. Then you can use a small chissel or punch to close the diameter of the brass part thats left & it should pretty much fall out without any damage to the treads in the steel. This method will work if its a straight or taper thread. Then you just need a new union & fit it with a bit of ptfe tape wrapped in the oposite direction to tightening.

HTH :)

Edit: If all that fails I'd just drill it out to the next thread size up & re-tap it, the boss looks thick enough to take the next size up. :)
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Re: Help fix pressure pot

Thanks everyone who has chimed in so far with ideas! I'm considering all of them.

A bit more information, I had used Teflon tape. It was working great. I could hold 50 psi for 24 hours.

I didn't think much of it at the time, but when I was setting up I slipped and set the lid down roughly. It couldn't have fallen more than 3-6 inches, but it did land upside down. I was more concerned about breaking my pressure gauge. It must have landed just right to stress the brass and cause the leak. It still seems a stretch, but that is the only thing I can think of.

Thanks again.
Re: Help fix pressure pot

I took my lid to a Westlake Ace Hardware just down the street from me. One of the guys took a look at it and said 'Follow me.' He went to his own toolbox and pulled out a flute extractor. He tapped it in the hole and used a pipe wrench to twist it and the broken brass came right out. No charge. Woohoo.
Re: Help fix pressure pot

I took my lid to a Westlake Ace Hardware just down the street from me. One of the guys took a look at it and said 'Follow me.' He went to his own toolbox and pulled out a flute extractor. He tapped it in the hole and used a pipe wrench to twist it and the broken brass came right out. No charge. Woohoo.

One of those 'perks' that we are losing due to the big box stores... All my life I have LOVED the service and selection of parts at the local ACE's when all my searching fails they seem to always have what I need... My location helped a lot as most of the ACE's by me are owned by the previous many year standing CEO of ACE and being the CEO he had to have all his personal stores shine above all and lead by example so they where (and still are) a treasure of goodness... But, I hate stomaching the price they charge for comparable items... Those prices where high even before the big box stores came to town, even as a kid I would joke about going to ACE and paying twice the price for even a pack of gum...

But, like you they do have a tendency to go over and above, a few years back I was trying to get a copy of a vintage house key cut, no one had the blank... Turned to ACE and although they didn't have the blank either, the key cutter like your guy had his own toolbox and over the years when ACE had dropped key blanks he horded them in his toolbox just in case, he spend a good half hour going through the pile of blanks he had collected looking for the blank... Ended up going to the local ma/pa locksmith, he just chuckled and said he hasn't cut one of those blanks for about a decade but he knew exactly what it was and knew where the blank was on his wall...
I love ACE Hardware, they make good paint too.

I've used the same type of valve on my air tank and the lever always develops a leak. That may be what happened here, not a problem with the treads.
I always leave my tanks hooked up to the air compressor with an inline regulator, so even if they leak slightly pressure remains constant...
I love ACE Hardware, they make good paint too.

I've used the same type of valve on my air tank and the lever always develops a leak. That may be what happened here, not a problem with the treads.

Hmmm...maybe when it dropped it landed on the lever and caused it to leak. I couldn't really tell where the air was coming of, except from that general area.

I am a newbie at pressure casting. Is there a better type of valve to use? I've seen bigger valves, but they would then require a reducer to fit my lid. My goal was a few seams as possible.

I replaced it with the same type of valve and have the second half of my mold in the pot right now. Smooth-on tech support said since I had vac'ed the rubber it might still work for pressure casting. At this point I don't have much to loose if it doesn't.

Is there a better type of valve to use?

Yes, there are better valves and you can go hog wild and spend a fortune on top of the line medical or food grade ones that are top notch but WAY overkill... Just get an inline regulator and keep it hooked up to the air compressor if it has a small leak... Or hit up a local plumbing supply store (or Ebay) vs the local hardware or big box store and get a moderately better quality valve...

These are old pics and some changes have been done, but just the same you can still see the inline regulator off to the right in this pic... It fits into the quick connector on the tank and then to a quick connector on the hose attached to the air compressor, dial it up to the proper pressure and it holds steady... The quick connector also acts as a secondary valve on the tank, you need to put a fitting in the connector or else it's closed...


Also I do this when I pressure cast to avoid dust or other contaminants from getting into the resin, especially for clear...


Basically an upside down food storage container, and under the band-aid is a hole to allow the pressure inside to balance, the band-aid acts as a mini air filter and thus keeps dust out...
First off, that is cool with the food container/band aid. I'll use that!

Explain the in line regulator to me please. My compressor has a regulator. Is there a difference? My understanding is that it limits the pressure coming out of the compressor. I textured my bathroom walls with a texture gun and I had to limit it to 40 psi, I get the basics. If my regulator is set to 40 psi, does the pot top out at 40 psi?

I may be remembering wrong, but the time I tried to regulate at 40 psi, my pot pressure kept going up once it got to 40 psi. I freaked, because it is not what I was expecting. I had my blower attachment hooked up, so it was easy to relieve the pressure. Since then, I watch my gauge and shut things off manually. I really don't need the thing blowing up in my garage.

Most air compressors do have a built in limiter but I like the secondary ones just because... The air compressor will still max out but the pressure coming out should be regulated and thus you tank should max at that pressure as well...

As I said I have upgraded and use my 10 gallon pot pretty much exclusively for pressure now... But, I will set the air compressor limiter to 65psi the inline one to 60psi and I have a blow out valve on the tank at 100psi, my tank has a rated working pressure of 110psi...

I highly recommend the blow out valve as a safety feature they are cheap on Ebay... And you can use it to let the air out as well by pulling the ring...

Here is an example of a 60psi one...

1/4" Air Compressor SAFETY RELIEF POP OFF VALVE 60 psi | eBay
Hmm. I will have to try the regulator test again.

My pot is the cheapie Harbor Freight paint pot. All of the gauges and blow out valve it came with it was crap. It is max rated up to 80 psi. The 60 psi safety valve that came with it would pop at ~40 psi. :angry

I did buy a replacement 75 psi safety valve, but could not get the dang thing to not leak. That was trying to connect it with a T that came with the pot. I think I'll try a new T and see if that fixes it. It would be nice to have that bit of safety.

Awesome, glad to hear you were able to get it fixed with little trouble.

On a side note I had not seen the reverse extractors up to a size 5! I just walked though HD yesterday and they only had up to a #3 in sight.

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