After a bit of trial and error I have now welded most of my chassis but some of the welds are still a bit "lumpy".

I need to dress back the welds where the side panels will fix and also underneath where the floor fixes which I was going to do with an angle grinder + flap disk.

Whilst doing this I was considering dressing all the accessible welds simply to make them look better before I get the chassis painted.

My only concern is whether this would adversly affect the strength although if it's OK where the panels will fit then I guess it will be OK elswhere.

Any comments?

John.

I understand that if you are building a MSA roll cage, then scrutineers would not accept dressed welds - presumably because doing this affects the strength.

So I would only dress them where neccessary to make panels fit etc.

HTH

Cheers
Mark

I believe ground down welds are not acceptable at MOT for patch repairs, so presumably there is a strength issue.

If you welding has good penetration you should be able to dress them back.

Trouble is how can you tell how much penetration you have without destructive testing on the tubes...

As far as I know any material above the surfaces to be joined should add little strength to the weld as the penetration adds the strength...

But I'm not a welder....

Dan

Many of the welds on my MK chassis had been dressed.

It hasn't broken yet.


Stu

Only requirement for MoT is that patches are seam welded there is no requirement for weld quality other than that the patch is attached & certainly no mention of dressing welds. Removing a lump from an ugly weld will not affect its strength, removing good weld that is properly attached & has penetrated obviously will - bit of common sense is all that's required.

My SVA tester said that he was always suspicious of dressed welds as it suggested poor quality welding in the first place. Unless they are really shocking I would only dress the ones necessary for panel fit and leave the rest. It all adds to the character of the car anyway and once the thing is ciomplete noone will see most of them.

Cheers

Gary

Good welds that are dressed are less likely to fail than undressed welds --- all to do with fracture mechanics.

However a good weld shouldn't need dressed to improve the appearance.

If dressing a weld on a locast chassis use a flap-wheel not a grinding wheel.

I would suggest that if the weld looks lumpy and not very nice to look at that it is probably not a good weld ?
what about grinding back with a flap disc and re-weld, only my opinion as a welder by trade