Attachment of copper to mild steel-Electrolysis bad!

[alpha chimera]

Well hello again welding weberinos!!!!!! I finally got my shop going. I have been designing a job for the past couple of months. Finally got the design finalized and materials are on the way. The part of the job that I have a question on is on doing these copper inlays on these curved steel post that are for the porch. The post are 39.5" tall. Have a 3 inch curve to them. taper from 2" to 1" over 3". The copper is inlaid into two 16" carved steel diamonds that are stacked on top of each other on the 1" side of the post. I was not aware of the electrolysis problem. I am thinking of forming stainless steel diamonds to go under the copper diamonds and then silver soldering the copper in. I think that this should solve the problem. Is there a certain kind of stainless that I should use as the buffer. Could I use aluminum? Would be much easier to form. Also, would the electrolysis transfer through the copper, through the silver solder the surrounding mild steel?

Any and all help would be greatly appreciated. I am really excited about this project. The customers love the design and I am looking forward to executing it. Also going to get a tube bender for this one I just ordered a 40 cubic foot 9010 gold gas for my 350p. Can hardly wait to at last open up the pulse capability!!!!!!!!!!!!!!!

[Robert Hall]

I can tell you you'll have electrolysis with copper and aluminum.

[MikeGyver]

I can tell you you'll have electrolysis with copper and aluminum.

You mean galvanic corrosion, not electrolysis.

[wade23454]

Look up silicon bronze filler if you don't know about it already. I had some given to me recently, and it is made to join copper and mild steel among other things. They make it in tig filler and mig spools.

http://www.stoodyind.com/Catalogs/FISC/05catpg391.pdf

Should have no problem with corrosion.

[Silicon-based]

The main problem you will have is visible rust stains. There is a strong galvanic action between copper and steel, and copper always wins. How bad it will be depends on how much rain you get where you are, and how exposed the posts are to the weather.

Coating the posts with a good clear sealer will help a lot but any coating requires maintenance.

Silicon bronze is indeed the right filler for joining copper to steel (A2 aluminum bronze is good too) but you will have the same galvanic corrosion issues between the filler metal and the steel.

John

[alpha chimera]

Ultra thanks to all of you. I will check into the silicon bronze. Might call up Tm technologies. They are close by. I was worried about the entire copper plate being in contact with the post. Would the copper rot away the part of the post that is underneath it? I think that I can paint where the copper is welded/brazed/soldered to the post. I really appreciate all the help that I have gotten here. I will try to get some pictures of the 1/4 scale model that i made of this thing. Hopefully that might help the all of you advice people out their. Thank you for the correction mikegyver, galvanic corrosion is what I was going for. Also I was wondering if putting stainless behind the copper would be an acceptable barrier to prevent the galvanic corrosion?