Monday, December 19, 2011

DIY Pressure Pot: Part 3

Here are my previous posts:
DIY Pressure Pot:  Part 1
DIY Pressure Pot:  Part 2

I have made some changes since part 2, which was to add a regulator.  I also added something to help remove moisture from the air going into the pressure pot.

Here are the updated pictures of my pressure pot.

NOTE:  I had problems with the safety relief valve that came with the pressure pot.  The safety relief valve kept popping out at 40 psi and would also leak air.  I temporarily replaced it with a 1/4" NPT Brass Drain Cock until my 60 psi safety relief valve arrives.  I in no way intend to do without the safety relief valve, but for testing purposes I use something else to plug the leak.  Keep in mind, my pot's maximum pressure is 80 psi with its working pressure range of 30-60 psi according to the specification.  So I am in no way adding more pressure than is specified for this pot.  I do not recommend using a pressure pot past its recommended pressure specification.

Now to list what parts I used for the conversion.

Click the images to zoom in more.  Sorry I did not take pictures with the parts still in the packaging, but I wasn't sure what parts I would be using until I put the pressure pot together.  The packaging themselves should have enough description to know what parts they are.  These two parts were used to add the pressure gauge to the paint pot.  The Central Pneumatic parts were from Harbor Freights and the Kobalt part was from Lowes.  You should be able to find both at Harbor Freights.  I had to go else where for the part because although they had said item in stock according to their computers, they couldn't find it in the store.

Above are the remainder parts for the pressure pot conversion.  The connects go as the following:

1/4" to 1/4" male coupling  --  air compressor regulator  --  1/4" ball valve  --  1/4" male steel industrial plug  (picture below)

As mentioned earlier, all Centra Pneumatic parts were purchased from Harbor Freights.  Their prices were almost half then what Home Depot was charging.

Instead of using the air regulator that came with the paint pot, I bought an air compressor regulator.  It took me a while to get it set, but it does work.  Just make sure if you plan to use a different regulator that you get one that regulates the pressure NOT air flow.  An air flow regulator is more like a ball valve.  It doesn't regulate air pressure.  An air pressure regulator helps regulate the air pressure.  I have mine set at 50 psi for now.  I may up it to 55 psi once I have my 60 psi safety relief valve installed.

Above you can see the parts used.  The gray parts came with the paint pot.

What did the parts cost?

160 psi pressure gauge (J): $5.99
1/4" female x 3/8" male NPT adapter (I): $2.28

1/4" male steel industrial plug (H): $0.99
1/4" full port ball valve (G): $3.99
1/4" air compressor regulator with gauge (N): $ 4.99
1/4" male to 1/4" male coupling (O): $1.29

Cost of Parts: $19.53 +tax

I did buy a few additional parts.  For one thing, I bought a new safety relief valve for $7.98 from ebay.

I also added an inline dessicant dryer/filter for $7.99 from HB and 2 additional connectors.  I needed a 1/4" female steel industrial plug for $0.99 and a 1/4" male steel industrial coupler for $2.99.  Above you can see the picture of the parts put together.  The reason I made it removable is so that I can keep it in a tightly sealed plastic bag when not in use so it does not absorb moisture from the air while not in use.  Below you can see what it looks like attached.

So if you include the additional parts I got, the total now comes to $39.48 + tax (and minus 3 20% coupons used on the more expensive parts from HB).  Still not bad.  I will probably have to replace the inline desiccant dryer later for something better, but for now I wanted something to help remove moisture from the air line.

The air compressor I chose is the Ryobi 3 gallon oil-free air compressor from for $119.00 + tax. Shipping was free.  Overall I like this air compressor, but that opinion is coming from a person who has no clue about these types of things.  The reason I like it is how portable it is, the cost, and the fact it isn't too loud.

I did have one major problem with my set-up I think I should say.  If you notice the bulk of the air regulator (N).  To connect it I had to remove the base T (B) attached to the pot and attach the regulator to the T (N-O-B connection) before putting it back on the pot.  The regulator also had to be angled in such a way that it can pass over the bump sticking out that the handle bar attaches to.  That also means that the handle bar can not be attached and even the pressure gauge (J) in the other opening can not be attached during this process.  What is worse is if you have a leak where the regulator connects around the T because you have to keep taking everything off and back on.  I was lucky that I had to do this soooooo many times.  **end sarcasm**  But I did want to mention this part since it may be tricky for some.


  1. Thank you soooo much for all of the detailed work that you put into this! I am going to attempt to make your final design.

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  4. This was very helpful, I made nearly the same decisions.

    Unfortunately, my pot came from harbor freight, but unfortunately, it seems like they used some sort of adhesive to attach the parts. I ripped one bolt almost into a circle attempting to remove them with very, very long wrenches. Did you break the adhesive somehow, or did you not have this issue? I don't know what it is, but the little bit I can see is greenish and extremely hard. Maybe I'll see if I can get some acetone in there.