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Rust - weld in new plate or grind out rust?

Paul 290T

PCGB Member
Member
Hello,

I'ts your advice and experience I need on rust around the edge of the front wheel arch, where the arch turns under and into the wheel well at the leading bottom corner.

The rust does not seem to be right through the edge. So it seems I can either have the steel ground until its back to bare steel. Or have the edge cut out and a new repair peice welded in place. Then primed and sprayed in either case.

On the one hand all of the rust may not ground out. On the other hand I don't know if welding will cause the steels properties to be altered leading to rust.

What in your experience is most likely to give the longest lasting repair?

Thanks

Paul
 
If it's not holed or wafer thin, I would be inclined to remove as much corrosion a possible. Careful spot blasting would be preferable to grinding on a small area so as not to make the metal any thinner, treat it, then repaint.

 
the big thing with welding or grinding on such a small edge like the return on a wheel arch edge is that it will get hot very very quickly and distort,

the best answer is as white944 has suggested, clean off all the rust with a rotary wire brush then use some converter like Bilt Hamber Hydrate 80, or POR15

then Primer and repaint, abusing thin metal especially on rolled edges is not a good idea, unless the man or woman fixing it is very skilled

 
As Waylander has said it's all down to the person doing the welding. I used to be a fabricator welder, and I've seen plenty pictures of rubbish welding on car forums. it comes down to cost, a good repair panel fitted by someone that knows what they're doing is almost as good as new, balance that against filling and painting every few years maybe.

 
Hi Paul, I have just done some body work on my seal and front lower arch. The metal was too thin to weld as I would rather weld the entire new seal in , so I grinder all rust away, sanded the inside also. Treated with rust treatment and I made plates up and resined them it place then fiber messhed it all then filler, primer , chipstone , then paint .

just put it up on the what did you do to your 944 thread ,with pictures.

atb

daniel

 
Gents, thank you. I gather now its at least as much down to the repairer skills as it is the method. I need more than ever to find someone who is skilled and trust worthy.

Bonding in the new repair plate sounds interesting. No heat affected zone, which i think promotes corrosion. Any thoughts on my theory?

 
Hi Paul,

i used to weld plates and seals on cars for about 3 years in my younger days as a Macanic sand although I would have liked to weld mine small plates when I found a few rusty bits on my seals I know from experience that it coukd have caused warping becuase the area was quite thin. If i was. Start welding I would have wanted to cut allot more out even though i did cut the rusted area out , becuase I would have wanted to find a thicker area to weld to, so. Knew that if I were to bother welding it I may as well buy or make some new seals and do a thorough job which wasnt worth it as it’s in pretty nice condition in there and I could see what looked like the galvanised colour with the bore scope so the resin fix is perminant as I’ve done it on a few friends classics and 20 years later that area is still going strong.

as long as it’s a thorough prepped fix and not just a bit of filler thrown on there it will last.

peopke are always going to say it needs welding but it’s one of those cases that if you know what your doing and have a bit of experience you can access it. The ideal solution is always going to be cut the offending area off and weld in a new piece or change the Pannel, but his is not always possible for some becuase of time or cost . Me personally I can weld a seal in on the weekend becuase I can so with my fix I’m very confid by it will last a long time but if it doesn’t I’m prepared to go all out on it as it will just cost me a bit of time and material.

if you can do it yourself have a go, ing not find someone that seems like it’s a piece of cake becuase it should be for a pro.

ive seen redicukous repairs in my macanic days that the owners told me lasted 10 years withought rusting out so as long as it’s prepped properly it should last.

atb

Daniel

 
Astons / lotus / maclaren etc are glued together so well bonded sills could work well as a structural element. Pretty sure both inner and outer sill are structural and create a box section.

Tony

 
A long time ago when I worked at Lola, amongst other things I used to bond and rivet the carbon fibre tubs together, AFAIK the rivets were there to hold everything together until the adhesive set. Never fitted sills on a 944 so I don't know if the mating surfaces are suitable.

 
Exactly right

people sometimes look past some things in some situations.

i personally went down the resin route in my own personal sercumstance for a good reason, not becuase I couldnt weld the small plates in but becuase I acessed the area and the entire seal with a bore scope, and the best thing for me was to do what I did as the area was thin, and in doing the resin plates it’s acually 10 times stronger than it was before and if the MOT tester was to try punching a Blunt nail with the same force through my seals or anybody else’s 32 year old seals I know for fact it would eventually go right through when a certain force is achieved but the areas that I just repaired with a oversized plate on the inside with resin , then stainless steel fiber mesh and glass fiber filler over that then followed by fine filling filler , it would be very difficult to penetrate hence was my reason for not welding my perticular holes I made to cut some rust out.

Patching rusty holey area just by grinding away the area and treating with rust products will not hold up without further reinforcement but every situation has to be treated separate as some Car seals look ok but are rotten on the inside but just so happens mine are in real nice shape inside.

Mthe way I did mine is just my own way through my own experience and knowledge of materials ect.

atb

daniel

 
944Turbo said:
And with rivets you cant use them for an MOT but you can hold a 747 together with them ;)
:) I used to drill, tap, screw and glue the bulkheads into the tubs though.

 
horses for courses i guess,

if the MOT tester spots any filler or glass fibre or resin he will fail it as structurally unsafe, because that is not original material.

the MOT rules changed a lot back in may

 
I don’t deny some laws might have changed but really can’t see a MOT tester failing the seal I just repaired as there is the same plate in place and there’s no resin that is visible as it’s on the inside bonding the new plate which blends into the original seal, and the stainles mesh is just another hard layer of metal which makes that repared area twice the thickness in metal material with only a slither of filler to smooth the surface, these combined is way way stronger than the original bar non. unless there’s a law that states if the seal repair area is stronger than the original material that was used 32 years ago which I can’t see ?

i can understand if someone cuts a rust hole out then puts a bit of mesh over it then squashes through some glass fiber filler through the mesh then yes it’s not enough solidity there and would be a bodge job, but in this case it’s actually over strengthened.

i am still yet to book my MOT in as the cars been off the road for 3 years due to the full engine rebuild I’ve just finished , so what I don’t mind doing is to show the MOT tester the photos of my repair and then we will all know. If he says it needs welding in I have no problem doing that I woukd however do the complete seal if that’s the case, which would unfortunately lead me to spraying that entire side of the car as there’s a few bits I don’t like, but really can’t see him saying that it’s not expectable.

I will comment back once i MOT her 👍

atb

Daniel

 
I think I’m gonna have to now Martin otherwise it’s gonna be playing on my mind.

Theres no no real rush anymore to get her back on the road seeing that the summer seems over. I wouldn’t actually mind welding a new seal in to be honest. Once I have something in my head I get it done how ever long it takes me.

The way it’s going I need to take it off the ramps as it’s just costing me a fortune as I keep seeing things and renuing them! 😩😊

 
It really is mate. And what I find is you can spend a fortune and seem like you still have 70% of things you’d still like to renew and always seems to me anyway that I havnt done much but spent loads and loads of my personal time !

 

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