Friday, December 9, 2011

DIY Pressure Pot: Part 1

WARNING:  Use the information listed in this post at your own risk.  You can purchase a pressure pot specifically made for casting resin if you worry about safety.  Safety is very important, so make sure you research before attempting to do your own conversion.  What I have done is gathered information from various sources and documented how I did the conversion.  If you happen to know more about this then I do and feel a step or procedure done is potentially dangers, please let me know.  Regardless, objects under lots of pressure can be dangerous.

A while ago I searched for various websites that had information about converting a paint pot into a casting pressure out and made a post containing the links.  Please check those links out for additional information.

A few components of a pressure pot...
1.  Safety Relief Valve - Helps vent air when rating is exceeded.  Additional safety measure.  Should not be used to manually vent pot.  Is more likely to fail over time than the pressure gauge.  (Rating at 60 psi?)
2.  Pressure Gauge - I think this is straight forward.  It lets you gauge the pressure in the tank.
3.  Air Hose Connector - Well, you have to connect the air hose from the compressor some how.  Better if it is quick and easy to remove the air compressor hose.
4.  Ball Valve - Use between Air Hose Connector and tank.  Allows you to open and close opening to allow air out or keep it in.  Slowly open valve to bring tank pressure up and close when pressure is reached so the air compressor hose can be removed.  Open valve to release pressure slowly when venting pot instead of using the Safety Relief Valve.
5.  Regulator - Some conversions include this component while others do not.  The purpose of the regulator is to help maintain a pressure you have set it to keep.  It seems most useful if you plan to keep the air compressor connected to the pressure pot to maintain pressure, but I don't see the need to do that.  If anything leaving the air compressor on and attached to the pressure pot may be disastrous should the regulator fail to maintain pressure.

Additional items needed
1.  Teflon Tape
2.  Wrench

The 2.5 gallon paint pot is $99.99 from the Harbor Freight website.  I purchased the paint pot from a local Harbor Freights store on sale for under $70 (after sales, coupon discount, and taxes).

Above you can see what what came in the box.  **Note that I already removed the paint tube that was attached to the lid, which is why the lid is laying flat.

The first thing I did was remove the paint tube.  It did not take a lot of muscle to get it off with the old wrench I used.  I didn't care that it was leaving marks in the pipe since it is being discarded.  The open hole is where the paint tube was and the one that seems solid is actually not.

As you can see above what looked like a solid covering of one hole is actually not.  It has 2 holes, one on each side.  This will help keep the air coming into the pot from blowing directly downward onto whatever is below.  If this part was not present, an L or T piece will help divert the air flow from going straight down and blasting resin below.

Above you can see several views of the top of the lid.  They are also labeled well.

When I break everything down to essentials, it is easier for me to see that the conversion doesn't have to be so complicated.  There seems to be 2 common ways to do the conversion, which seem to be dependent on whether you use a regulator or not.

With regulator...


Without a regulator...


Very good illustrations from a Fleafa's Photobucket Gallery.

I need to decide whether I plan to use a regulator or not.  On one hand, going without will allow me to either reuse the pressure gauge that came with the paint pot or buy a better quality one.  Without the regulator things won't be sticking out so much especially if I planned to use the pressure pot on its side vertically instead of on its bottom horizontally.  The extra weight hanging off the lid may not matter though, but seems cumbersome.  Some thought will be required before I decided which way to go.  But these two methods seem to be the two basic choices on doing a paint pot to pressure pot conversion.

DIY Pressure Pot: Part 2
DIY Pressure Pot: Part 3


  1. Muy interesante tu proyecto, me contruire una, has tenido algún problema con el esquema que muestra tu pagina?

  2. Very interesting your project, I contruire one, you have a problem with the diagram showing your page?

  3. How do you like this product for pressure casting acrylic? I'm looking to buy one and I cannot really tell online which product is of better quality.

  4. How did you remove the paint tube? I bought one and the tube seems to be stuck on there no matter how hard I try to remove it. Any help you can give me would be great.