Register now to get rid of these ads!

MIG welding sheetmetal that's been brazed

Discussion in 'The Hokey Ass Message Board' started by b-body-bob, Jan 8, 2012.

  1. b-body-bob
    Joined: Apr 23, 2011
    Posts: 515

    b-body-bob
    Member

    I've got a situation where the door striker on my OT car cracked behind the door striker and at some point it was fixed it by brazing it up. Now it's cracked again, and it's got brass gobbed everywhere. I was wondering if I have to get all that brass off before using my MiG to re-weld the crack, or if I can just file it down to good enough and have at it?

    Thanks in advance!
     
  2. i tired to do a bit of mig work on the fiat....hit some brazing fill and it went to hell....had to grind it all out...maybe i missed some trick, i'm no welding expert by any means....
     
  3. All of the brass has to go. You might want to make a patch to replace the area since it is probably stressed.
     
  4. rdscotty
    Joined: Sep 24, 2008
    Posts: 206

    rdscotty
    Member
    from red deer

    I agree
     

  5. Ole don
    Joined: Dec 16, 2005
    Posts: 2,915

    Ole don
    Member

    Readhead is right. The brass and steel have such different melting points, they are totally uncompatible. Re-braze, or do like it says above and replace a chunk of metal. I say that because it may be imposible to get the brass on the back and in the seams. It could blow back and burn you. If it has cracked twice, look for the cause.
     
  6. Blue One
    Joined: Feb 6, 2010
    Posts: 11,191

    Blue One
    ALLIANCE MEMBER
    from Alberta

    Yes, the brass has to go. No way to MIG around or near or even on it. As suggested cut the whole area out and fab a new piece to MIG in place.

    Re- brazing will only last a short time as there are stresses in the area that the brass is just not up to handling.
     
  7. b-body-bob
    Joined: Apr 23, 2011
    Posts: 515

    b-body-bob
    Member

    Thanks for the info, it's greatly appreciated.

    Reason for the crack is likely a misadjusted door banging into the striker for years. I know it was doing that when I got the car but at this point it's a chicken and egg scenario.

    It doesn't look like they really got the part flat before brazing it in and that probably kept the problem alive even after it was fixed the first time.
     
  8. that's what i am doing...cutting out the brazed area and fabbin new tin to replace it....pain as it is on the windsheild post...on both sides...where they brazed in the old traficator box holes..........they beat it all in to braze......common i guess back in the day...
     
  9. carcrazyjohn
    Joined: Apr 16, 2008
    Posts: 4,844

    carcrazyjohn
    Member
    from trevose pa

    Youll have no luck welding where the brazing is ,It all has to come out,I had quarters once that were peiced at the sail.And I grouund what I could out,It worked but popped when I hit the brass and I ended up with a bubble when painted over,,,,
     
  10. b-body-bob
    Joined: Apr 23, 2011
    Posts: 515

    b-body-bob
    Member

    This is what it looks like now, pretty much cracked all the way around

    I think my best bet is to grind out the humpy brass, bash it flat like it should be, and re-braze it. I haven't figured out a sure way to piece it in and be sure I put the holes where they should be for the striker and door to line up.
     

    Attached Files:

  11. Blue One
    Joined: Feb 6, 2010
    Posts: 11,191

    Blue One
    ALLIANCE MEMBER
    from Alberta

    A sure way to do it is to mark it out then cut the area out with a thin zip cut blade.

    Make some reference marks on the piece you cut out and on the material you leave, then use the cut out piece as a template for the new piece.

    When the new piece is made, weld it back in using the reference marks.

    Pretty easy.
     

    Attached Files:

  12. If it was mine, I'd replace the whole piece and mig/tig it back in . . . so you have some strength. Brazing is not the way to go with a stressed piece like this. Truth be told, it would probably be faster to cut/replace than screw around with the mess you currently have.

    Best of luck!
     
  13. Blue one has the right idea. Lay it out and make the new piece first. Lay it on top to check it. When it is right cut out the old stuff. Everybody is telling you to cut it out. If you don't you will be dealing with this again soon!!!
     
  14. 49ratfink
    Joined: Feb 8, 2004
    Posts: 18,125

    49ratfink
    Member
    from California

    do what blue one said or plan on "fixing" it again down the line.
     
  15. Do the job the right way, remove all the brass or the the piece out. I've learned being on the planet 66 yrs that doing a job that appears to be the long way, in reality is the short way. My .02
     
  16. Flop
    Joined: Jun 8, 2006
    Posts: 3,886

    Flop
    Member

    nothing but a pain in the ass is what brass is !!! cut out and replace!!
     
  17. Clark
    Joined: Jan 14, 2001
    Posts: 5,123

    Clark
    Member

    If you want to use the existing peice....heat the brass out. Use a torch and wire brush to get rid og the brass. Grinding it out will leave the metal thin and you won't get it out of the cracks and low spots.

    I hate brazed metal!!!!!
    Clark
     
  18. carcrazyjohn
    Joined: Apr 16, 2008
    Posts: 4,844

    carcrazyjohn
    Member
    from trevose pa

    brazing is bad ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
     
  19. b-body-bob
    Joined: Apr 23, 2011
    Posts: 515

    b-body-bob
    Member

    Yeah, too many people saying to cut it out to make me think re-doing the braze job is the way to go.

    Thanks for the tip on the layout lines, I'll see what kind of plan I can come up with to lay things out. I don't have to make a new piece, I've got a parts car I can cut it out of. It's putting it back in the right place that worries me.
     
  20. Blue One
    Joined: Feb 6, 2010
    Posts: 11,191

    Blue One
    ALLIANCE MEMBER
    from Alberta

    You will have no worries at all if you lay out reference lines like I said and use them to get the new piece exactly where it should be.
     
  21. Sounds like the real issue here is cutting, welding and sanding. This is a very basic repair. Especially since you have the new piece and the other side to compare. The cutting and welding is pretty straight forward. Where I see the most wrecks are at the sanding stage. Sand the welds flush with the base metal and then STOP. Bring up the low spots from the back or fill them with weld and sand flush again. I use 60 grit for all my rough work. 80 grit goes away to fast. If the metal is turning blue the disc is used up.
     
  22. 50dodge4x4
    Joined: Aug 7, 2004
    Posts: 3,535

    50dodge4x4
    Member

    After you cut out all that mess and weld in a nice new piece, fix the door hinges and adjust them correctly. If you don't do the followup hinge repair & alignment. you will be doing it again anyway. That area is not strong enough to be used as a door alignment and centering tool. It is only meant as a location to mount the parts to hold the door closed. Gene
     
  23. b-body-bob
    Joined: Apr 23, 2011
    Posts: 515

    b-body-bob
    Member

    Thanks again for all the input. The only good thing about the fix is I can get to both sides easily so I should be able to tack, grind those dots, planish, repeat.

    I'll heed the advice and will post back as I work on it or when when I run into trouble.
     
  24. joel
    Joined: Oct 10, 2009
    Posts: 2,040

    joel
    ALLIANCE MEMBER

    Ditto, about 2 hours work
     

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2021 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.