10 replies to this topic

[WillBriggs]

Hello All,

 

I've recently picked up a '95 SPI Cooper in BRG. I've noticed a few areas of rust which I want to address as soon as possible before it becomes a bigger issue. 

 

I managed to poke (with very little pressure at all) a small hole through the rust. What are my best options here? I was thinking of stripping back the paint and rust in this area, then building the metal back up with a MIG welder on low power, then grinding flat and repainting. 

Ideally I want a permanent repair - I'm guessing fibreglass/filler would be classed as a botch and would come back to bite me in future? 

 

Many thanks for your advice in advance 

 

I've attached a couple of pictures:

 

 

 

 

[sonscar]

Are the holes in the roof?or the flat gutter?Welding to build up will probably result in explosions as the rusty metal layers burst.Easy enough to repair but the headlining and glass will cause potential problems and are best removed from the area.
One of those small problems which quickly escalates.Steve..

[WillBriggs]

Are the holes in the roof?or the flat gutter?Welding to build up will probably result in explosions as the rusty metal layers burst.Easy enough to repair but the headlining and glass will cause potential problems and are best removed from the area.
One of those small problems which quickly escalates.Steve..

 

Hey Steve,

 

Thanks for the advice. Looks like in the flat gutter rather than the roof - what would you recommend? Would it still burst if I was to strip all of the rust out? 

 

Thanks, Will

[stuart bowes]

Yeah you'll more than likely blow out the corners and edges and then you end up chasing a hole halfway across the roof, it's because the metal is thin from rust, pressed to shape as well so not full thickness to start with, and also near an edge where heat can't spread

You can't even get a copper heat sink on the back because of internal structure

Obviously the right answer involves welding, one way or another, but to do it properly you'll end up cutting out around it and then fabricating pieces with curves and bends, which isn't easy to get right.

Also welding and tidying up an internal corner isn't the easiest thing to get right..

And then there's the paint after

I think in this instance unless a substantial rebuild is on the cards I'd wire brush it, kurust or deox it, fibreglass filler and touch up pending proper repairs some time in the future. That's just my 2 cents though others may disagree

Edited by stuart bowes, 15 July 2024 - 01:09 PM.

[WillBriggs]

Yeah you'll more than likely blow out the corners and edges and then you end up chasing a hole halfway across the roof, it's because the metal is thin from rust and also near an edge where heat can't spread

You can't even get a copper heat sink on the back because of internal structure

Obviously the right answer involves welding, one way or another, but to do it properly you'll end up cutting out around it and then fabricating pieces with curves and bends, which isn't easy to get right.

Also welding and tidying up an internal corner isn't the easiest thing to get right..

And then there's the paint after

I think in this instance unless a substantial rebuild is on the cards I'd wire brush it, kurust or deox it, fibreglass filler and touch up pending proper repairs some time in the future. That's just my 2 cents though others may disagree

 

Thanks for the advice. Been chatting to a colleague about this and he advised the copper heat sink, but I was dubious about how I'd manage to get one behind that... I was kind of hoping that somewhere sold replacement gutter sections, so I could cut it out and weld new in. 

 

A full/drastic restoration isn't quite on the cards just yet, maybe I'll wire brush, fibreglass and filler for now - might buy me a few years?

[stuart bowes]

as long as you're only calling it a 'temporary' repair I can't see any problems with it, it's certainly better than letting it get worse over time in that same time frame isn't it

 

I may be wrong but im not aware of repair sections for the gutter / roof, anyway, it's still not an easy job then because you're welding a piece into the roof which will no doubt warp slightly due to heat unless you weld intermittantly from both sides and even then it's not ideal, the weld cools and contracts and the metal bows inwards, I've had these exact same issues modifying my door skins recently, you'll end up with a few mm of filler being required

 

all that stuff is way better with the shell stripped down, access from both sides, and nothing flammable within reach

 

also your first picture is annoying me I want to flick that fly away lol

Edited by stuart bowes, 15 July 2024 - 01:20 PM.

[WillBriggs]

as long as you're only calling it a 'temporary' repair I can't see any problems with it, it's certainly better than letting it get worse over time in that same time frame isn't it

 

I may be wrong but im not aware of repair sections for the gutter / roof, anyway, it's still not an easy job then because you're welding a piece into the roof which will no doubt warp slightly due to heat unless you weld intermittantly from both sides and even then it's not ideal, the weld cools and contracts and the metal bows inwards, I've had these exact same issues modifying my door skins recently, you'll end up with a few mm of filler being required

 

all that stuff is way better with the shell stripped down, access from both sides, and nothing flammable within reach

 

also your first picture is annoying me I want to flick that fly away lol

 

Yeah, definitely think I'm better sorting it than leaving it to get worse.

 

I noticed that fly when I uploaded it, so annoying haha - nearly didn't upload it

[Designer]

Hi WillBriggs

 

Put Stuart out of his misery delete the photo, Photoshop it too get rid of the fly and repost it. Or perhaps add a few more      

I have got to do similar repairs to the Moop, fortunately just surface rust no holes.

 

Paddy

[WillBriggs]

Hi WillBriggs

 

Put Stuart out of his misery delete the photo, Photoshop it too get rid of the fly and repost it. Or perhaps add a few more      

I have got to do similar repairs to the Moop, fortunately just surface rust no holes.

 

Paddy

 

Fixed - spider ate the fly 

 

If only rust repairs were as easy as photoshop

 

Edited by WillBriggs, 15 July 2024 - 09:48 PM.

[Designer]

Brilliant

[MiNiKiN]

Yuck and screech! I thought about not helping you out, for triggering my phobia posting a spider   

But anyway, I would try brazing it with either oxy-acetylen and a brass solder. Or as I have recently started doing: by MIG brazing with CuSi-wire in the MIG welder.
Expert tip: use a PTFE-linered cable-hose-assy. Ask me why I know
MIG brazing uses less heat, rust is still an issue, but not as bad as in welding.