maartenromijn
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| posted on 19/2/10 at 12:17 PM |
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How to repair spot welds on galvanised chassis?
I have bought a damaged Volvo V40. For the repairs, I had to cut out some spot welds. The chassis is fully galvanised.
I have tried to plug weld the removed spot welds, but without success. I expect the zinc to be the problem. Due to limited access I have cleaned the
area with a screw driver. Anyone some tips & tricks??
[Edited on 19/2/10 by maartenromijn]
BLOG: http://thunderroad-super7.blogspot.com/
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mad4x4
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| posted on 19/2/10 at 12:18 PM |
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What about brazing with a gas and brazing rods.
Scot's do it better in Kilts.
MK INDY's Don't Self Centre Regardless of MK Setting !
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scootz
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| posted on 19/2/10 at 12:30 PM |
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Lol... I read the title all wrong - thought it was "how to SPOT REPAIR welds on galvanised chassis"!
It's Evolution Baby!
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jambojeef
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| posted on 19/2/10 at 12:41 PM |
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Get one of them flap wheel sanding discs and clean the area of all the zinc coating before trying to weld.
Also clean a patch for your earth electrode too.
Try not to breathe in the zinc dust when sanding and if any white zinc oxide residue appears when welding you need to sand it more / a wider area
around the intended weld.
Geoff
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r1_pete
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| posted on 19/2/10 at 01:12 PM |
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You need to clean the zinc off to weld or braze, and don't breeth the fumes.....
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maartenromijn
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| posted on 19/2/10 at 01:30 PM |
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quote:
Originally posted by r1_pete
You need to clean the zinc off to weld or braze, and don't breeth the fumes.....
I have limited access with angle grinder, so I have tried scraping it off (no success).
Also, I do not want to remove all the paint/zinc in the engine bay.
Can I removoe the zinc ony in the area to be welded, or should I clean say 50mm around?
BLOG: http://thunderroad-super7.blogspot.com/
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Grimsdale
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| posted on 19/2/10 at 04:29 PM |
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get some hydrochloric acid in there, that should do the trick!
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bodger
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| posted on 19/2/10 at 04:59 PM |
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Local steel fabricators told me to be really careful with ventilation when welding galvanised metal. The fumes are very nasty/carcinogenic.
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iank
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| posted on 19/2/10 at 05:10 PM |
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If there isn't room for mr angry then a powerfile would be the best option.
You need to clear far enough that the galv doesn't vaporise in the heat of the weld.
Don't know if the fumes are carcinogenic or not, but they will certainly give you flu symptoms if you breath any.
Spray with weld through primer before welding and it should help prevent the tin worm in the future.
--
Never argue with an idiot. They drag you down to their level, then beat you with experience.
Anonymous
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bartonp
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| posted on 19/2/10 at 07:01 PM |
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Weld thru primer == zinc rich paint....
You can arc/mag (MAG - argon CO2 mix, slightly higher wire feed/current that's all) weld zinc coated steel, but must take serious precautions
with ventilation.
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Angel Acevedo
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| posted on 19/2/10 at 07:10 PM |
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Oxy Acetylene torch
Can you reach with Oxy Acetylene welding torch?
Play around your weld area just make sure you don´t breath the fumes.
No permanent damage AFAIK but real nasty headaches.
My 2 pence...
Beware of what you wish.. for it may come true....
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Peteff
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| posted on 19/2/10 at 07:34 PM |
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You will not get metal fume fever from spot welding a few holes in a chassis in well ventilated conditions. It should weld with no problems and earth
through it if it is still fairly clean but grinding it off is preferable.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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austin man
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| posted on 19/2/10 at 08:50 PM |
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use a dremmel or simmilar with a small grinding wheel
Life is like a bowl of fruit, funny how all the weird looking ones are left alone
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maartenromijn
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| posted on 19/2/10 at 10:04 PM |
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Well, I have used the angry grinder where possible, fake Dremel (rubbish) and sanding paper. Put up the current and wire speed a bit. Welds look very
crappy, but seem to be holding.
I have no quick access to brazing and gas/oxy equipment.
Wleding fum es: its mell sa bit funyy, but I haev n ohean ac he hr  
[Edited on 19/2/10 by maartenromijn]
BLOG: http://thunderroad-super7.blogspot.com/
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Grimsdale
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| posted on 21/2/10 at 09:42 AM |
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no, seriously, 25% hydrochloric acid! It'll fizz through the zinc and leave te steel alone. Just wash it off afterwards.
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