Mud-club

Vehicle & Technical => Discovery => Topic started by: wizard on April 03, 2009, 10:24:48

Title: Welding a chassis
Post by: wizard on April 03, 2009, 10:24:48

A good friend of mine has asked me to repair his Disco that failed the MOT mainly on rust issues.
There are several holes in the chassis, the biggist being roughly 60mm x 60mm.
Which is the better option,

1 cut the rust out and weld a bigger plate over the top of the hole.

2 cut the rust out and make a plate up that fits in the hole then weld it flush.

Would am mot  tester view these two repairs differently? I think option two would be the better looking repair of the two.

Regards
wizard :twisted:

Title: Re: Welding a chassis
Post by: Banjo on April 03, 2009, 10:35:14

Go for 2 , 1 ends up looking like a  " patch ".

Title: Re: Welding a chassis
Post by: wizard on April 03, 2009, 11:04:16

I was thinking along the same lines.

wizard :twisted:

Title: Re: Welding a chassis
Post by: Dr Neil on April 03, 2009, 19:38:19

not trying to teach "granny how to suck eggs" but whichever way you do it it will need to be seam welded all the way around the repair.

hope this helps

Neil...

Title: Re: Welding a chassis
Post by: clbarclay on April 03, 2009, 23:31:58

Patch over the top is easier, though set in and with the welds ground fluch (dressed) should be structurally better.

The workshop manuals says that all repairs should be as per your option 2.

Title: Re: Welding a chassis
Post by: wizard on April 04, 2009, 11:31:50

Thanks guys, I was leaning towards the set in option. I just wanted to know what every thought.
Once its done i didnt want it to look like a patched up job.

Regards
wizard :twisted:

Title: Re: Welding a chassis
Post by: biggerlandy on April 04, 2009, 12:26:14

what ever you do cut out all the rusty bits ive been welding for 20 years it is crazy when you see peps just put good metal over the rusty bits

Title: Re: Welding a chassis
Post by: Range Rover Blues on April 06, 2009, 00:09:32

Either way, done properly, will look ok.  If you are a damn good welder then option 2, but the advantage with option 1 is that if you burn through a little at the edges then you won't blow a hole in the joint.  Also a "lap" joint is easier to verify that it's been welded properly whereas a "butt" joint is not so, plus you have the rough edge on the inside going rusty again.

Horses for courses, depends how good you are and how much time you have.

Title: Re: Welding a chassis
Post by: Les Henson on April 07, 2009, 01:28:45

There are several reinforcing brackets inside the chassis (where the shocks are and other stress points), so it may not be a simple matter of cutting a square and expecting the cut to just fall out. If there's reinforcing inside where you need to do the repair, then you may be at it with an angle grinder for ages. You can do a perfectly acceptable repair by cleaning up and plating over the top - once cleaned-up with a flap wheel and undersealed it'll be barely noticeable.


Les.

Title: Re: Welding a chassis
Post by: wizard on April 07, 2009, 19:17:14

Thanks for the heads up Les.
I didn't realise there were re-enforcing brackets inside the chassis. I hope to start it early next week once my cold has cleared up. :sad:

wizard

Title: Re: Welding a chassis
Post by: Range Rover Blues on April 08, 2009, 16:44:54

If there are any brackets inside (which could have caused the rust) then you really need to make sure your patch is fastened to them.