Repairs in stainless steel?

[Dic Doretti]

To the technical minded amongst us is there a downside to repairing a bodyshell with stainless steel. My Doretti is on the spit waiting for the frilly areas to be cut off and replaced with new metal but should that new metal be stainless steel to avoid future problems or is it unsuitable for car bodywork. I have a couple of square metres of 19 gauge stainless going spare. Any advice welcome.

Cheers

Richard

[RogerH]

Hi Richard,

there is stainless and there is stainless. Some works reasonably well others are utter pigs.

You can anneal it to help it to work and you can get it in various harnesses - 1/4 hard, 1/2 hard.  Escutcheon plates on building doors are hard. This helps them not to get scratched and is a pig to work.

You would do well to investigate the best SS for bending, drilling etc.

The harder SS's are not good for structural as they are prone to cracking.

So you want an annealed (soft) SS that is easily worked.  Perhaps 304 may be in this area.

There are a great many aerospace SS's that work well but are wickedly expensive.

What grade have you got.?

I made a repair section for my 4A front wing lower rear section out of SS and welded it direct to the mild steel body using a butt weld.

If you are welding TRy not to use lap welds - you could end up with Galvanic corrosion

It is heavier than mild steel if that is a concern.

If you could make the body from SS and then polish it you would have 100% BLING

DeLorean here we come

PS - this is what I have been using since retiring from BA  https://www.smithmetal.com/s525.htm   it works well but is not cheap.

Roger

Edited February 8, 2021 by RogerH

[Waldi]

Hi Richard,

if you weld a more noble material to normal carbon steel, galvanic corrosion may occur. 300 series stainless steels, like 304, are work-hardening, and difficult to bend, drill. Also, shrinkage during welding can be an issue.

I would only use the same grade and thickness of steel. Butt-welding is preferred and is fairly easy on the thicker metal chassis. Best with a small pre-opening for better penetration. If you do make a couple of test plates first, you can adjust speeds, current. Intermittent welding will reduce risk of burning holes.
Regards,

Waldi

[Lebro]

In around 2000 I was running a Stag, & although pretty good corrosion wise, It did need some work.

On a recommendation I took it o a classic repairer in Dorking - Foundry Classics (no longer there).

He always used stainless when repairing panels. I had the car for around 6 years after that & no sign of any problem.

I don't know what gauge or grade of stainless he used.

Bob.

[ed_h]

Before you commit to using the stainless, try welding it.  In my experience (which isn't that extensive in stainless), it can be harder to weld.

Ed

Edited February 9, 2021 by ed_h

[Lebro]

I had to completely re model my rear Stainless silencer piping in order to clear the newly fitted rear antiroll bar.  I used stainless welding wire & MIG welder, it presented no problems, & has remained solid.

Bob.

Edited February 9, 2021 by Lebro

[RogerH]

8 hours ago, ed_h said:

Before you commit to using the stainless, try welding it.  In my experience (which isn't that extensive in stainless), it can be harder to weld.

Ed

Hi Ed,

joining SS with mild steel can done and mild steel filler wire is recommended. 

You probably will not get a perfect weld bead, but on body panels it would probably be ground flat.

When I did my 4A front OFS wing rear lower corner I welded both sides. Ground the puter face flat but left the inner face with a decent weld bead to give support.

Using a butt joint removes galvanic corrosion form the equation. The weld bead on the inner face needs to be very well protected.

Roger

[Dic Doretti]

Thank you for the advice. I do not know what grade the stainless steel is, it may be good, Faslane submarine base is only over the water. I have used it to make templates of the Dorettis's floors so I have cut and drilled it without any problems and could weld stiffeners in to form real floors but first I need to try folding it to test for fatigue and do some test welding. It is a good match for the Doretti bodywork which is a flimsy 20 gauge, although the A posts are 16 gauge.

          Cheers

          Richard

[ed_h]

8 hours ago, RogerH said:

Hi Ed,

joining SS with mild steel can done and mild steel filler wire is recommended. 

You probably will not get a perfect weld bead, but on body panels it would probably be ground flat.

When I did my 4A front OFS wing rear lower corner I welded both sides. Ground the puter face flat but left the inner face with a decent weld bead to give support.

Using a butt joint removes galvanic corrosion form the equation. The weld bead on the inner face needs to be very well protected.

Roger

Yeah, I was using SS wire, which may have been part of the problem.  Thank providence for grinders.

Ed

[Ian Vincent]

As I have said before, since the invention of the angle grinder there is no such thing as a bad weld. 

Rgds Ian