Standard of welding

[The Buddah]

Hello

Is there an MOT tester on here that can help me as I would like to do the job correctly and make my car safe.

When replacing a floor panel drilling out and using original spot weld holes would it be acceptable to use these for welding the new floor pan or does there need to be any extra welds to meet MOT standards.

Appreciate any help you can give.

Thank you very much

 

[seanc]

would be fine to replace with the same method that it was put in with originallyif your replacing a whole floor panel !

 

[The Buddah]

would be fine to replace with the same method that it was put in with originallyif your replacing a whole floor panel !

Thank you for reply Seanc,

Are you a M.O.T tester ?
I want to weld my car and take it for a M.O.T before the paint work is done, so I want to do it right.
I was thinking of putting some extra inch runs in on the edge of the overlap.

Cheers.

 

[richiegallon]

I`m not an MOT tester but this has always been a confusing one for me, I put one car in for MOT that I had welded a skin sill on, that is a repair panel, I seam welded the top joint that you can see when you open the door and plug welded the bottom flange as per factory but was told that the bottom flange also required seam welding as it was a repair panel I had welded in. The next time i did the same job on another car I bought a complete sill as I thought it would probably be easier and make a neater job plug welding as per factory, but..was told the bottom flange required seam welding as I was fitting a reapir panel! Sorry if this doesn`t help but if I were you I would either ask the tester how he wants it done or plug then seam weld to save doing the job twice

 

[piman]

Hello Richie,

I think your MOT place has given you the wrong information, it's patches that need to be fully seam welded, any join that was originally spot welded can have the new panel also spot welded. I have done exactly the same sill replacement as you and not had it fail.

Alec

 

[The Buddah]

Thank you Piman,

This is what i need ti do,.

Do i butt weld the floor?
If i find original spot welds i will drill them out and spot weld the new floor.
Once spot welded should i weld along the edge of the overlap?

I'm nervous about making costly mistakes and want to do a good job as intend to keep the car for some time.

Cheers.
Mike.

 

[Lawnmowerboy]

You don't want to weld to MOT "standard". If you did the patches would be barely hanging on!!! If you're joining new panel to old then you need to fully seam weld it. If you're joining the edge of a new panel to the original body if ti was originally spot welded it's fine.

 

[richiegallon]

Hello Richie,

I think your MOT place has given you the wrong information, it's patches that need to be fully seam welded, any join that was originally spot welded can have the new panel also spot welded. I have done exactly the same sill replacement as you and not had it fail.

Alec

Yeah I think you`re right Alec, that is my understanding of the MOT rules too but he failed it anyway and I had to seam weld the bottom flange, needless to say I don`t use that tester anymore!

 

[Chickenjohn]

Richie, yes, I would go to another MOT garage as that garage has got it wrong! Plug welding where spot welding was originally is perfectly fine for MOT and safety!

 

[Wozzaaah]

Richie, did you remove ALL of the damaged panel including the bottom spot-welded flange or did you cut the majority of it off, leave the bottom flange in place then spot the replacement panel to that flange?

 

[the snooper]

Thank you Piman,

This is what i need ti do,.

Do i butt weld the floor?
If i find original spot welds i will drill them out and spot weld the new floor.
Once spot welded should i weld along the edge of the overlap?

I'm nervous about making costly mistakes and want to do a good job as intend to keep the car for some time.

Cheers.
Mike.

if you remove a full panel lets say its square and drill out spot welds on all four sides to remove it, then you can replace that panel by spot welding all four sides again

but

if you remove a square section with three sides spot welded and have to cut through the fourth side with a grinder to remove it then the fourth side would have to be seam welded while you could still spot the other three.

its all simple common sense it has to be like for like.

 

[richiegallon]

Richie, did you remove ALL of the damaged panel including the bottom spot-welded flange or did you cut the majority of it off, leave the bottom flange in place then spot the replacement panel to that flange?

Hi Woz, I cut all of the old sill off and used the angle grinder to remove the rest from the bottom flange, leaving the existing flange from the inner sill ( I think ) to plug weld the new sill to

 

[The Buddah]

if you remove a full panel lets say its square and drill out spot welds on all four sides to remove it, then you can replace that panel by spot welding all four sides again

but

if you remove a square section with three sides spot welded and have to cut through the fourth side with a grinder to remove it then the fourth side would have to be seam welded while you could still spot the other three.

its all simple common sense it has to be like for like.

Hi Snooper,

In this instance of seam weld, could you elaborate please as i don't quite understand (my fault not yours...lol)
This is my understanding of weld joins but i am willing to be corrected.

My understanding =
Butt weld,
Two pieces joined end to end with the weld bridging both pieces.

Overlap,
Two pieces joined with one piece sitting on top the other piece by about half an inch and where the top piece edge rests on the bottom piece the surfaces are welded together.

seam weld,
Two pieces with a small lip that returns 90 degrees to the main surface by about a quarter of an inch, each return or lip is butted together then welded along the seam with spot weld.

As you can see i have cut away the the corner piece here leaving a section to weld to, how should i repair the corner?

Thank you.

 

[Wozzaaah]

Hi Woz, I cut all of the old sill off and used the angle grinder to remove the rest from the bottom flange, leaving the existing flange from the inner sill ( I think ) to plug weld the new sill to

In which case the MOT tester in question needs to familiarise himself with the relevant section of the tester's manual as he was wrong to insist you seam welded it.

 

[hotrodder]

In this context for 'seam welding' read continuous weld as in no gaps. For distortion reasons on sheetmetal this'll typically be done in sections by skipping around doing short runs of weld. You skip around until there's no gaps left i.e. the weld continues around the entire patch

In this instance of seam weld, could you elaborate please as i don't quite understand (my fault not yours...lol)
This is my understanding of weld joins but i am willing to be corrected.

My understanding =
Butt weld,
Two pieces joined end to end with the weld bridging both pieces.

Overlap,
Two pieces joined with one piece sitting on top the other piece by about half an inch and where the top piece edge rests on the bottom piece the surfaces are welded together.

seam weld,
Two pieces with a small lip that returns 90 degrees to the main surface by about a quarter of an inch, each return or lip is butted together then welded along the seam with spot weld.

http://www.thefreedictionary.com/seam
All of the above are joint types which have a seam where the two pieces meet. What you described as a 'seam weld' is a flanged joint. It can be spot welded or it can be welded as an edge weld. The edge weld (as with butt, lap and fillet welds etc) could be an intermittent weld where you'd say weld for an inch, leave a once gap, one inch long weld etc or it could be a continuous weld

Appendix C of the MOT manual is here. While it's wording might suggest otherwise it's quite simple in principle... If/when you're replacing rot with fresh metal it needs to be done in a 'like for like' manner. In other words you can use spot (or plug) welds where they were used origionally. This is how complete panels are typically joined together. If you're cutting a hole in what was a single piece of steel then you need a continuous weld to effectively make the panel a single piece of steel again. They don't care if you use a lap joint or a (preferable imo) butt joint, only that the weld is continuous. As already said this means if you are replacing, say, the corner of a panel the repair can comprise both continuous welds (to replace the steel in the origional panel) and spot welds (if and where they were used to join an adajcent panel)

I can't be sure what's going in the pic as there's too much paint and rust going on still. It looks to me like you've cut through the floor inboard of the factory spot welds.

 

[The Buddah]

In this context for 'seam welding' read continuous weld as in no gaps. For distortion reasons on sheetmetal this'll typically be done in sections by skipping around doing short runs of weld. You skip around until there's no gaps left i.e. the weld continues around the entire patch

http://www.thefreedictionary.com/seam
All of the above are joint types which have a seam where the two pieces meet. What you described as a 'seam weld' is a flanged joint. It can be spot welded or it can be welded as an edge weld. The edge weld (as with butt, lap and fillet welds etc) could be an intermittent weld where you'd say weld for an inch, leave a once gap, one inch long weld etc or it could be a continuous weld

Appendix C of the MOT manual is here. While it's wording might suggest otherwise it's quite simple in principle... If/when you're replacing rot with fresh metal it needs to be done in a 'like for like' manner. In other words you can use spot (or plug) welds where they were used origionally. This is how complete panels are typically joined together. If you're cutting a hole in what was a single piece of steel then you need a continuous weld to effectively make the panel a single piece of steel again. They don't care if you use a lap joint or a (preferable imo) butt joint, only that the weld is continuous. As already said this means if you are replacing, say, the corner of a panel the repair can comprise both continuous welds (to replace the steel in the origional panel) and spot welds (if and where they were used to join an adajcent panel)

I can't be sure what's going in the pic as there's too much paint and rust going on still. It looks to me like you've cut through the floor inboard of the factory spot welds.

Thank you Hotrodder,

Very helpful.

Yes, what you can see is where i have cut away part of the panel on the right, it was in two sections that were joined two thirds towards the left but rust got the better of it and i cut it out. There was a flanged joint to the left of the picture were you can see whats left.

I left the lip on the right so i have something to weld to, the left hand side will replaced.

Appreciate your help.

Cheers.

 

[zx9]

In which case the MOT tester in question needs to familiarise himself with the relevant section of the tester's manual as he was wrong to insist you seam welded it.

It is frightening how some of them use the MOT bay as a sales office for the shoddy welding shop. One of the new testers at the MOT station I used to use failed my Rangie because the floor was bolted in, I went into a right one telling him how Landrover had built it that way but no use he would not pass it without them welding it up. It passed at another station within an hour and I never used them again. Driving past I notice the site is now a hand car wash, how or why they closed I know not but I suspect VOSA may have had something to do with it.

Sorry off topic rant over, feel better now.

 

[W.olly]

Lots of good info there, but after have done car repairs myself for many years ( and never had a comeback ) i have found it a whole easier to remove the bad area and weld in a new plate, even a new panel, for what it takes to do a seam weld will always be better than spot welds.

I agree though the MOT tester doesnt seem to know the correct regs on it.

 

[W.olly]

Just to add on MOT testers

I had a job on afew month back, i didnt take it on as it was that bad it was near unfixable.

A Transit van, rear inner arch and loer quarter had gone also the out rigger, i mean gone, the floor was holed/ rotten from left to right, it failed on them.

BUT

the other side rear quarter was also gone and out rigger was bad, enough to put your finger through. It DIDNT fail on that.

He got it done by some else, i did say not to go back to the MOT station he did the first time.

He eventulay took the van to a garage i said to go to, well it failed again on rust, the main chassis had a crack about 2 foot long which was rusted and holed.


Goes to show how dodgy some MOT testers are

 

[richiegallon]

In which case the MOT tester in question needs to familiarise himself with the relevant section of the tester's manual as he was wrong to insist you seam welded it.

Cheers Woz, that was my understanding!