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914World.com _ 914World Garage _ Mixing metals in cooling systems

Posted by: Wilhelm Mar 22 2009, 11:08 AM

Question for the cooling gurus. I am using an aluminum block motor and an aluminum radiator. I will have some rubber hose connections but also would like to have some formed metal lines in the system. Do I need to figure out how to bend aluminum tubing or can I go with steel or stainless steel with out fear of electrolysis as long as I run the proper antifreeze? If I have to bend aluminum tube does anyone have hints for what type is best suited for this?

Posted by: r_towle Mar 22 2009, 12:07 PM

Stainless and aluminum dont mix...I would use aluminum tubing.
The electrolytes in the system will start reacting really fast.

If bending aluminum...no clue..there are so many types of aluminum.
Get Foley on the horn...hemay know.
Otherwise, find a mechanical engineer...my buddies know.
I do know that the tubing you need is NOT the type sold at the hardware store...that tubing breaks.

I think there is some chemical testing involved, but all the aluminum systems I have use plastic fittings...no other metals in the loop.

Rich

Posted by: sean_v8_914 Mar 22 2009, 12:14 PM

AL 5000 series can be formed

Posted by: Bruce Hinds Mar 22 2009, 12:33 PM

As far as the electrolysis is concerned this is not uncommon knowledge at radiator shops and even the auto parts stores. Any different metals in the system will react, alum and stainless being a really poor combination. You can monitor the PH to get a clue and even put in a sacrificial anode like they do in marine applications.
My car runs one inch hose front to back and I found some old lawn chairs that were made out of 1" tubing worked great.

Posted by: Wilhelm Mar 22 2009, 12:34 PM

Ouch!!!! Only $$$$76.91 for a 3' piece of 1.315 OD.

http://www.mcmaster.com/#4481t11/=1461kd

Ah!!!!
Just found this as well, More betta for my cheapness:

http://www.mcmaster.com/#catalog/115/132/=146q1a

Interesting they call this bendable though it is a 6061 alloy.

Posted by: Dr. Roger Mar 22 2009, 12:55 PM

the boating industry has been making that mistake for years using aluminum heat exchangers and iron blocks.

sacrificial magnesium anodes work very well on boat propellers when bolted directly on the inside of the prop.

then there's this...

http://cgi.ebay.com/ebaymotors/Sacrificial-Anode-Radiator-Cap-_W0QQitemZ130293592133QQcmdZViewItemQQimsxZ20090314?IMSfp=TL090314127003r30116