Cleaning very rusty old pst 120's couple of questions..

[211ratsbud]

I am cleaning up a pair for pst 120. they are first hydro 93. been out of service over 10 years. I want to get them back- if I can into service . there is definitely some rust inside, which even with a good light is hard to get a firm grasp on the actual condition.

I have naval jelly and I have muriatic acid. I've heard that muriatic is hard to control and phosphoric acid is safer and gentler.

Given the amount of corrosion in here, I want to clean these up, retest them , clean again if needed, vip them. can I use an appropriate diluted mixture of the muriatic under supervision to get them in condition that the hydro shop will take them in? I tumbled them for a while but the media proved painstaking to remove and insert into the tiny 7/8 unf thread. ceramic/stone media.

Any advice on dilute is appreciated .

 

[Blakec1980]

Take them to a reputable hydro facility. Pay for a VIP and Hydro. during that process they will clean them and determine within tolerance if they are serviceable or condemned. Take into consideration that you are talking about using muratic acid and or phosphoric acid to clean metal. Then planning on breathing from those tanks at depth under pressure. If you were to miss just a tiny amount of anything in there after using that you would be breathing potentially dangerous air. Just my thoughts.

 

[zider]

Before trying a chemical treatment, make sure you can't tumble the rust out.

 

[grf88]

See post #4 in this thread
O2-Safe Rust Inhibitor for Steel Tanks

 

[runsongas]

call the hydro facilities in your area and find out if any of them can shot blast your tanks before hydro. it generally is pretty reasonably priced and does a better job than tumbling imo

 

[andrewy]

search this board i had whole writeup on it​

 

[211ratsbud]

Is there any shops that specialize in doing this ? I'd like to mail then out if I could ..

 

[tbone1004]

Is there any shops that specialize in doing this ? I'd like to mail then out if I could ..

some of the big hydro shops MAY sand blast the inside of the tanks, but you have to call around and find one. You will have to go directly to the hydro facilities, not the dive shops. May be easier off finding someone in the area with a tumbler and let them sit. If you have a treadmill you can DIY it. Not very graceful, but leave it on overnight with media and they should be good to go.

 

[211ratsbud]

I had to send them out 100 miles away for testing, and they said they would tumble them for free. Turns out they wouldn't test them because they were dirty. Well what happened to tumbling them? I dont know how far I'll have to go. But it's a gamble and I know the replacement cost for double hp 120's is near a grand.