Searching for Compounds

[Ric Murphy]

Good morning,
I'm working on a couple of prototype solar hot water heaters. I'm in need of a material to use between the copper tubing and the aluminum absorber plate. In addition to being able to withstand the heat and severe temp swings it also needs to act as an adhesive and an anticorrosive between the 2 dis-similar metals. The primary method of securing the coils is mechanical fasteners. Also looking for suggestions on what to use as a seal between the glass and the aluminum shell. Was thinking silicone would be adequate. Both items need to be readily available if possible.
Any suggestions?
Ric

[Paul Bailey]

Hi Rick : I think I would lean towards a good polyurethane Caulk . Its Inert when dry ,has extreme adheasion properties,lasts forever, is temperature and UV light stable. Yes its at almost all hardware stores and the Big orange box as well. Paul:)

[Ric Murphy]

Thanks Paul. I'll check it out
Ric

[Mark Parsons]

Hi Ric and Paul,

Ric, you need a compound with good thermal transfer characteristics, right? This compound will help to transfer the absorber heat into the copper pipe as well as providing adhesion.

Paul, does polyurethane caulk have this characteristic?

I was wondering if a silicone based adhesive might be found that has reasonably good heat transfer characterisitics. I know I used a high temp silicone to adhere the gasket around my wood stove. I'm not sure about the thermal charactersitics of the stuff.

Best regards,
Mark

[Paul Bailey]

Hi Guys: I had implied the caulking for the glass sealing only...I'm not sure what you could use for bonding the 2 dis-similar metals , other than making up some plates similar to those used in radiant staple up jobs. see the attached photo. .You can make these yourself with a homemade jig. Paul:)

[Ric Murphy]

Yes Mark you are correct. I forgot to include that requirement in the long list of things I need in the compound. Maybe I'm looking for a "magic" solution that doesn't exist. The seal between the box and the glass cannot be permanent in the event I have to get into it for service. I think a high temp silicone would work. I could always cut or pry it apart if I need to.
Paul, I started another thread with some pictures and a description of the design. That should help explain better.
Thanks to both for your input,
Ric