Copper, stainless.....& some bronze too

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Okay...... I'm repairing what are known as flight bars. These bars are made of stainless with a copper bus bar bolted to the flight bar. They are used in a plating process, so there is always exposure to chemical bathes as well as hot dipping and vibratory tanks.Here is one......As you can see here the joints have given way due to corrosion and electrical current as well as the chemicals used in the processes.Even missing a bronze horn. First thing is to remove the bus bar and clean it up a bit.... see all that corrosion on the copper and the flight bar, that's has to be removed and cleaned.Next we need to take the bar apart and clean the joints......Notice how the joint is all corroded and the lack of bonding between the 2 platesFirst I will repair the missing horn.... The horn is bronze which will be silver brazed to the copper bar. This pic is right after brazing..... It is still red in color from the amount of heat you need to get the material hot..... a dull cherry red. You also need to be careful when heating bronze.... it will not wet as it reaches its melting point and it will just start to deform.Brazing complete and the part has cooledThe trick to this is to make sure the braze flows under the brass horn and that there is as much bonding as possible. To do this I will heat the part up to temp and as I continue to maintain the temp I will feed the rod in from one side  letting to capillary action draw the filler to the other side of the block. When I see the filler emerge I will then add the filler from that side and just let it flow. I do this on all 4 sides. The joint is not only to hold the assembly together but it also has to conduct electricity as well so a sold bond is a must. I've have to post again to show more pics.I will clean up the copper bar again when I am completely through with the repair, there is no point in ding it now.Thanks for looking.........Last edited by lorenzo; 04-08-2007 at 01:08 AM._________________Chris
Reply:Looks great, I've never seen anything like that. It's awesome to see different processes!John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com
Reply:As part of the repair I correct some of the problematic issues like this one.....The addition of these spacer tubes to prevent the tubing from collapsingWeld the plate back on.... remove the gussets that were on either side of the down bar....Then off to separate the other joint on the bus bar.... same thing corroded.... lack of  any bond. _________________Chris
Reply:Those parts where you seperate the buss bars say "lack of any bond", were those previously silver soldered only not quite completely?? Great work and tutorial BTW.
Reply:Originally Posted by SandyThose parts where you seperate the buss bars say "lack of any bond", were those previously silver soldered only not quite completely?? Great work and tutorial BTW.
Reply:Cool stuff, Thanks for sharingIs there some way to shim the parts before brazing.  I know in bicycle frame building there is an optimal clearance between the lug and tubing.  Too tight and incomplete flow occurs. I just noticed you had a clamp on the parts and I would suspect that reduced clearance even more.Would placing fluxing the parts and placing flattened filler between the parts work the heating the assembly until the filler appeared.
Reply:Originally Posted by tapwelderCool stuff, Thanks for sharingIs there some way to shim the parts before brazing.  I know in bicycle frame building there is an optimal clearance between the lug and tubing.  Too tight and incomplete flow occurs. I just noticed you had a clamp on the parts and I would suspect that reduced clearance even more.Would placing fluxing the parts and placing flattened filler between the parts work the heating the assembly until the filler appeared.
Reply:nice fix Chris interesting job Creative metal Creative metal Facebook
Reply:Thats cool
Reply:You get all the fun jobs.. ...zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Good stuff -Graham-Mechanical EngineerAutosport Mechanic/Fabricator
Reply:Alright....... the bar is finished so I have some pics to post.After cleaning the old braze material out of the joints I reassemble the flightbar, this includes re-welding the stainless shim that is behind the copper bar as well as re-tapping all the mounting holes. As you can see in the pic there is quite a large gap between the bars, too large for the braze to take up. So...... it's off the the Bridgeport to make a shim.....Now I set-up to re-braze the joints. You can see the shim in placeAfter everything is clamped up TIGHT!, everything has to be unbolted so that the copper bas assembly can be removed from the flightbar for brazing..At this point the joints get brazed and cleaned up.....The bar is reassembled and a flap disc is run over the copper once more to buff it up a bit and out the door it goes.....The braze material I use for these joints is the phos/copper 0 by Harris.Yup shop is a disaster.......... I've been straight out so clean up has been a bit low on the priority list..... Thanks for looking!_________________Chris
Reply:You have the second most messy shop..We're #1!!  ...zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.