Quote Originally Posted by Stewie007 View Post
He will have to run a somewhat dilute glycol solution. I would recommend Propylene Glycol just because of its low toxicity and better heat transfer capabilities than ethylene.

20% or higher glycol in water. 20% is still pretty close to water's Cp. Its a little better than ethylene. ~.96 vs ~.91 You can get it at Tractor Supply, but you'll need to use a corrosion inhibitor with it. If your loop uses all copper its probably not necessary; but it also retards the rate of the breakdown of the glycol. Not like it happens over night, but still....

As far as insulation goes, it depends on your temps and typical humidity inside. Given your temperatures, the water tubes will probably be fine with 3/8" wall insulation. Make sure you size it appropriately for the outside diameter of your tubing. For 0C and above applications with <50% RH, you don't need to use thick walls.

For socket insulation, I am less experienced. Although, eraser material is somewhat dense compared to insulation materials and will transmit heat moreso than the insulation. Though, its less messy than trying to use a foam insulation (polyurethane), I don't like the idea of using it for a 24/7 rig. I'm sure people have, I just don't like the idea.

Dielectric grease is what I would use for any gap coverage in your socket. Using any type of petroleum grease is not a good idea on silicone or plastics. Dielectric grease is designed to protect electrical connections from things like moisture; that is why you use it on your spark plug wire connections and coils in your car; not to mention battery connections. It prevents corrosion of the surfaces as well. Petroleum makes a snack out of it in the long term. There's no excuse not to use D.G. in my book.

I would personally favor the usage of foam insulation at the lowest level. Then I'd be using the Expanded Elastomeric insulation sheets to cover the rest. I'd use thicker wall for the pads just to be save and use a proper adhesive to join the layers. I would build a little "bowl of sorts and fill it well with the P.U. foam. There are different grades of the stuff. It has excellent insulation properties. You just have to make sure you fill all gaps.

That's just one way to do it though. I am sure others have different ideas.

However, I would consider Dielectric Grease MANDATORY. I would not use less than 3/8" wall insulation on the tubing. Finally, on the back side of the motherboard, an insulation pad with a low power pad heater just for safety. It isn't really necessary to use a heater if you have insulated well and don't get too cold, but its good insurance.
Stewie, awesome stuff thank you bro! This is exactly the information I was looking for.

As far as adding glycol to the water I was ahead of you. I actually went down to home depot and picked up a bottle of propylene glycol at was a to find by the way since nobody knew what the heck that was let alone where it was in the store.

Yeah I was thinking about 20% glycol myself, glad to hear I was on the right track.

Honestly I have no idea how low the temps will get. I'll try to provide more information as I work on it more that way more experienced members can shed some light.

What I'm working on is a old juicer type unit with a stainless steel water evaporator. Here is a picture the only one I have at the moment, but the evap is on the right there is very well constructed even though is an older machine. I ran everything before I started taking it apart and recovering the refrigerant before cutting the copper lines and everything was running well.



I know it looks dirty I'll be taking everything apart and cleaning it thoroughly before I start brazing anything back together.

The unit looked similar to this one before I started taking it apart.



Since I will be mixing copper with the stainless steel what corrosion inhibitor do you recommend I use?

The unit has a Danfoss 1/4 HP compressor based on my findings and calculations this compressor should be enough for 186 Watts right I'm not sure if I'm thinking about this in the right way since I'll be chilling the water in to a small reservoir and then running the chilled water loop in to the waterblock.

Now on the subject of insulating the actual motherboard. I picked up some liquid tape I was going to cover the motherboard socket area front and back with it and then use 10mm neoprene around the socket. Do you suggest I go with dielectric grease and neoprene instead on both front and back? have you ever used the liquid tape stuff? I would much rather go with what works best and since I have zero experience on the subject I'm really interested to hear what you have to say.

Thanks so much again for all the great info.