Repairing hole in refrigerator pipe..?

[DanFungus]

I've been slowly working on a project to retrofit a compact refrigerator's guts into a Red Bull ice cooler. Today when I was pushing down on a steel/zinc piece I have to disperse the heat, it punctured one of the pipes. Luckily it was a small hole and not much gas escaped because I patched it with some epoxy and duct tape.

What I don't know is if this solution will last, or if there's a better way to patch it? What kind of pressure is there in the pipes when the fridge is turned on? Is it possible to get these units refilled with refrigerant if I need to do that?

Refrigerator - Kenmore 2.7 ft^3 Model #92779

Red Bull Cooler with some of the fridge parts in it (yes.. I have a tire in my room.. who doesn't?)

Gutted cooler and the refrigeration components

The duct tape is where I poked a hole in the pipe

Another view

The metal part that did the damage. It does fit in flush when pushed all the way down, and the holes are for red and blue LEDs that will be controlled by a microcontroller so they fade in/out when the lid is opened/closed.

Also will have red LEDs in the eyes

Similar epoxy I used to patch. The one I used is the black one - 1500lbs/in^2 and sets in 5 minutes

Any advice/comments are appreciated!

 

[jagec]

Does it still get cold? It's on the low-pressure side, so if you did a GOOD job with the epoxy it ought to hold. I'd have probably used JB Weld or a similar, stronger epoxy, though.

Yes, you can get them refilled if need be.

 

[imported_weadjust]

To refill the freon you would need to add a tap valve and have a vacum pump.

 

[DanFungus]

Originally posted by: jagec
Does it still get cold? It's on the low-pressure side, so if you did a GOOD job with the epoxy it ought to hold. I'd have probably used JB Weld or a similar, stronger epoxy, though.

Yes, you can get them refilled if need be.

Haven't plugged it in at all. Figured it was a better idea to find out if I'd fill my room with gas before I did that

I put on a good amount so that there was about 1/16" - 1/8" thickness all over it then put the duct tape over it for it to set.

Originally posted by: weadjustTo refill the freon you would need to add a tap valve and have a vacum pump.

This is one pipe coming off the compressor (copper). I'm guessing the best way to add a valve would be to cut part of that off to open it up, add the valve after the pressure is released, then refill? Do refrigeration repair shops have something to remove freon so it doesn't just vent to the atmosphere?

 

[grrl]

I doubt very much this will work. You say only a little gas escaped, but gas will continue to fill the evaporator and thus create pressure until all the freon is gone from the system. I don't see how you could create a perfect seal that way. Once the gas is gone, you might be able to braze over the hole, but you'll scorch/burn the hell out of the evaporator plate doing it. Then you'll have to install a pierce valve to evacuate and recharge the system. I'd say just buy a new one unless you have the tools and experience to fix this.

 

[Eli]

Originally posted by: grrl
I doubt very much this will work. You say only a little gas escaped, but gas will continue to fill the evaporator and thus create pressure until all the freon is gone from the system. You might be able to braze over the hole, but you'll scorch/burn the hell out of the evaporator plate doing it.

I concur. Your closed system is now open - and empty.

If you could braze the hole closed, maybe an a HVAC place could refill it for cheap. Otherwise, you need a new one.

 

[imported_weadjust]

a/c repair link

http://www.biopatent.com/ac.html

 

[DanFungus]

Thanks guys. I'll head to an HVAC shop in the morning to see if they can do anything that won't cost more than the project is worth.

 

[OrganizedChaos]

If its a modern fridge it it probably uses r-134a, many older ones used r-22,r-12, or something even harder to find.

If its a puncture in the low side theres probably 20-30 PSI in the pipe when the compressor is running. 100+ when its off. High side pressure you can expect to be well over 160 when running, again 100+ when its not and the condensor has cooled off.

1. 5 min epoxy will not hold that kind of pressure
2. Refrigerant molecules are very small, they'll likely pass through the epoxy even if it could hold the pressure. Much like air escaping from a balloon.
3. Modern Refrigerators don't use nearly as much refridgerant as previous models. So any loss is likely to be significant.

To repair you will need to cut out the damaged section, and solder in a new piece. Your going to need to install a service port, most fridges come from the factory without them. Then you can evacuate the system,you'll need a good vacuum pump and gauge for this. Then refill by weight to the manufacturer specs. You'll need a charging scale for this.

 

[imported_weadjust]

Originally posted by: DanFungus
Thanks guys. I'll head to an HVAC shop in the morning to see if they can do anything that won't cost more than the project is worth.

It would probably be cheaper to find a used mini fridge and start over.

 

[jagec]

Originally posted by: OrganizedChaos
1. 5 min epoxy will not hold that kind of pressure

You can't make that sort of general statement. If the epoxy is sealing a small hole, partially intruding into the pipe, and smeared over a relatively broad area around the hole, it can hold a shocking amount of pressure. If you're trying to make a thin epoxy "sheet" to seal a larger hole...not so much.

2. Refrigerant molecules are very small, they'll likely pass through the epoxy even if it could hold the pressure. Much like air escaping from a balloon.

Smaller than N2? A thick layer of epoxy resin is much less permeable than the thin rubber of a balloon. Brazing would certainly be better, of course.

 

[Rubycon]

Looking at a PT chart for 134a shows 100 psi at 86.6 degrees F. That is quite warm.

So let me get this right-

You ruptured the condenser plate then repaired it with epoxy? It's definitely not going to work. That plate is most likely aluminum which requires a special rig to repair. You cannot repair a hole with a turbo torch and a stick of silphos! :laugh:

But seriously in any damaged system you have to repair/replace the damaged part, then install a proper service valve. A clamp saddle valve will work but brazing a Schraeder valve in the suction line is more reliable.

The system will need to be evacuated with a good vacuum pump to 1 microns and breaking the vacuum at least once with refrigerant and then a deep vacuum for 12 hours to remove moisture since the system charge has been blown. That looks like a very inexpensive system and proper repair by a qualified shop can be costly.

Additionally, the removal of refrigerant from a system is known as recovery and since 1994 in the United States the EPA has required technicians that work on these systems hold certification levels for the system they are working on. Unauthorized discharge of refrigerant into the atmosphere is illegal.

 

[DanFungus]

For all intents and purposes, yes it was the condenser plate. The part that got pierced is where the copper pipe meets the plate so it was much softer than the actual plate. Sounds like I now have a big useless piece of metal. Bummer.

 

[Rubycon]

Originally posted by: DanFungus
For all intents and purposes, yes it was the condenser plate. The part that got pierced is where the copper pipe meets the plate so it was much softer than the actual plate. Sounds like I now have a big useless piece of metal. Bummer.

Oops I just read your post and realized it was my mistake above. The piece you have pictured is clearly the evaporator not the condenser.

EDIT: There are epoxy compounds designed to repair aluminum components. I'm not sure if the epoxy you used would be suitable. In any case the system would still require evacuation and recharging.

 

[DanFungus]

Originally posted by: Rubycon

Originally posted by: DanFungus
For all intents and purposes, yes it was the condenser plate. The part that got pierced is where the copper pipe meets the plate so it was much softer than the actual plate. Sounds like I now have a big useless piece of metal. Bummer.

Oops I just read your post and realized it was my mistake above. The piece you have pictured is clearly the evaporator not the condenser.

EDIT: There are epoxy compounds designed to repair aluminum components. I'm not sure if the epoxy you used would be suitable. In any case the system would still require evacuation and recharging.

Gotcha. Shows what I know about refrigeration systems :laugh: At least it was better for the environment I had the epoxy I did than letting it leak out entirely.