Sub 100$ single stage

[Mythicaltech]

I just want to start this by saying this probably won't be safe and definitely will not be a good unit. With that out of the way, let's get started. The united will be based on an old ac unit I got from a thrift store for 15$. It has a 1/3 hp rotary compressor and a decent sized condenser that I will be reusing for this build. Here is where the unit gets a little ghetto, the evaporator will be made out of a 2 inch offcut of 110 copper with a 2-inch diameter and the suction line is going to be made out of a manifold hose connected to a Schrader valve without the stem in it. I am going to use a cheap filter dryer off eBay and 0.031 cap tube. For gas, I am going to be using standard propane that will be run through a filter dryer as it is charged so it hopefully will get some of the moisture out

[makaka]

sound like not a bad unit . keep us posted with photos and good luck

[Mythicaltech]

I am hoping the unit will do at least -20C at 50W just so I can use it to cool 775 north bridges but I do not expect the unit to last long.

[makaka]

what compressor ? any photo of condenser

[Mythicaltech]

what compressor ? any photo of condenser

I am not currently at my place due to school being closed from covid but I will get pics when I get a chance to go back.

[Mythicaltech]

All the parts are on their way and should be here within a few weeks. Evap is going to be a normal heatsink that is stripped of all its coating and I am going to be making a housing for it in the coming weeks out of scrap 1/4 inch acrylic.

[aenigma]

That should work just fine, however the schrader valve will be a big restriction even without the core, and so will the small refrigeration hose. If you are doing it that way just to have a flexible hose then standard propane 3/8 flare rubber hose works good for that, so does that yellow painted flex steel that is I believe for water heaters, but you have to braze it with silver solder and a bunch of flux, but it works great. I have used it on my autocascades for years. The 3/8 rubber propane hose would be the easiest as all you would need is a braze on 3/8 flare on your compressor suction line and evaporator.

The evaporator with acrylic is probably not a good idea however. I tried thick lexan on a Maze 3 years ago just for the fun of it and it would start leaking at low temperatures, especially when turning the system off and equalizing. Acrylic might even break from the equalized pressure and low temperatures since it's much weaker than polycarbonate. I was using a similar a/c compressor as you back then and it was getting about -50c iirc. It did look really cool however haha

[Charles Wirth]

I will offer a few single stage carcasses soon for those who would like to build a custom cooler.

[Mythicaltech]

That should work just fine, however the schrader valve will be a big restriction even without the core, and so will the small refrigeration hose. If you are doing it that way just to have a flexible hose then standard propane 3/8 flare rubber hose works good for that, so does that yellow painted flex steel that is I believe for water heaters, but you have to braze it with silver solder and a bunch of flux, but it works great. I have used it on my autocascades for years. The 3/8 rubber propane hose would be the easiest as all you would need is a braze on 3/8 flare on your compressor suction line and evaporator.

The evaporator with acrylic is probably not a good idea however. I tried thick lexan on a Maze 3 years ago just for the fun of it and it would start leaking at low temperatures, especially when turning the system off and equalizing. Acrylic might even break from the equalized pressure and low temperatures since it's much weaker than polycarbonate. I was using a similar a/c compressor as you back then and it was getting about -50c iirc. It did look really cool however haha

I do not expect this unit to last long it is just a fun project.

[mike]

I do not expect this unit to last long it is just a fun project.

Don't see why it wouldn't last long. Just fired up a couple of my super simple single stages and was shocked to see them all still work after sitting in the garage collecting dust for a decade...

[Mythicaltech]

Don't see why it wouldn't last long. Just fired up a couple of my super simple single stages and was shocked to see them all still work after sitting in the garage collecting dust for a decade...

I do not expect the suction line to last very long.

[mike]

Gotcha on the suction line...just now noticed the 775 Northbridge cooling plan...hmm... someone going for big numbers...looking forward to see what you are up to!

[Mythicaltech]

Small update on the build. Just got 100ft of bronze flex line from ron so I will be using that and will be using a pipe cap as en evaporator. Total cost as of now is looking like it will be about 30$. I am thinking of doing r600a and r290 mix to keep the pressure down and prevent any cold bug on the northbridge.