Rusty roof repair

[Murray_Calavera]

12 minutes ago, PranK said:

If I spray enough converter and seal it all up with glass and bog will it likely keep getting worse or will that do enough to stop it spreading?

I know you'd like to believe that it won't spread, but it will. 

Just pretend that it wont. Give the roof a little pat and say she'll be right.... She'll be right  

[PranK]

Ok. 

Ok... 

Last question... Do you think it's worth fixing this again properly at a later date if I work on my welding skills? Maybe the entire roof? Or is that just nuts for anybody? 

 

[PranK]

Maybe I'm just making a bigger deal of this than it is.

[Murray_Calavera]

10 minutes ago, PranK said:

Do you think it's worth fixing this again properly at a later date if I work on my welding skills? Maybe the entire roof? Or is that just nuts for anybody? 

Do I think this is worth fixing properly? Nope. I'd use this project car to practice skills you want to learn. Once you're happy with your new skill set, I'd move the car on to the next owner. 

However if you think it is worth fixing, there is only one scenario I can think of that it makes sense....

I don't know this platform so I can only guess, lets assume the roof attaches like this - 

Where the red lines are, that is the frame/body of the car. When the car was manufactured, we'll assume they spot welded it to those points on the body. 

If this is the case, you could drill out the spot welds, then weld on a replacement roof. It is reasonable to assume that with enough practice, you could spot weld the roof back on. 

If the roof doesn't attach like this, say its all one piece... your back to the original plan of a cut and paste job. I wouldn't attempt it. 

12 minutes ago, PranK said:

Maybe I'm just making a bigger deal of this than it is.

Only you can answer that one. We already know what the previous owner thought lol. You'll have to decide how important it is to you. 

[PranK]

Thanks Murray I really appreciate the help.

[niZmO_Man]

Good time for a carbon roof  

[Duncan]

Shit thing to find eh? I guess the big issue is that whatever "fix" you do now, it might slow the rust down but won't fix it.

I just wanted to add that in no way is fixing sheet metal in 3 dimensions the place to start with welding....that is a pro only job because its too hard to work out where things should be, let alone doing a clean enough job that it can look OK and still be strong too.  I needed to get a new rear quarter panel on the GTR and it took a pro weeks to get the old one off cleanly, new one on in the right place and looking somewhat like it should have with most of the previous connecting panels in place.

Gluing a couple of bits of metal together with a welder in the garage is doable, but that is totally different to doing panel  replacement

[GTSBoy]

A realistic expectattion of how long it has to last also comes down to.... when do you think you will be banned from registering and driving old petrol powered shitters? It's 27 years since that thing was built. It probably rusted out 15 years ago. It was probably repaired and looked OK for another 10. If you do a similarish bodge job now, or perhaps slightly better with some actual rust conversion and glassing, then.... get another 10-15 years out of it, after which you'll only be permitted by the CCP to drive electric cars manufactured in their Shenzen zone anyway. 

[MBS206]

13 hours ago, PranK said:

Ok. 

Ok... 

Last question... Do you think it's worth fixing this again properly at a later date if I work on my welding skills? Maybe the entire roof? Or is that just nuts for anybody? 

 

If the roof is dual skinned the whole way, IE, there's a "top" metal piece, and a "bottom" metal piece, to slow it down as much as you practically can, you should be able to get an attachment for a spray can/your spray gun, where it is a long, thin flexible hose, and when you're "spraying" it is spraying it in every direction possible. The I'd get that, and feed it through the roof as much and as far as you can. It's basically like fish oiling the car, but you're soaking it in rust converter.

Then do the fix like Murray has described having cleaned up the existing metal as much as you humanly can. I'd also throw as much rust converter on that exposed metal before putting the fibreglass/metal filler over everything.

 

As for welding a replacement in. I've owned my own MIG welder for about 10 years. I've also worked in an industry doing MIG welding for a job for about 3 months dead straight, and we were doing 11.5 hour work days 5 days a week, plus a Saturday 6 hour day. (I then moved over to running the massive CNC plasma as I could understand the technology, and work with the main guy out there).
I also f**k around with my welders a bit at home. So what I'm saying here is, I've probably got more hours on a MIG gun than you'll manage to get under your sleeve doing home sorts of jobs over the next 5 years. I also have an ACDC TIG that I got myself a year or two back. I've got a short amount of experience on the TIG only.
My home MIG is also presently setup for doing thin sheet metal.

Unless I didn't care about how that roof looked, and I just wanted a functional metal roof, and it being out of alignment, warped, and bowed, I would NOT attempt a roof replacement UNLESS I could do it as a whole panel like Murray described where the spot welds were. 

Welding has this REALLY annoying thing, where if you want something to be perfectly square, unless you can clamp that thing to damn perfection (Welding fixture table), it is NOT going to be square, so you start to learn, the type of metal you're working with, how thick it is etc, and weld in VERY specific ways, and by knowing how YOU are as a welder, so that as the welds cool, the metal work pulls itself into place.

If you want to see some cool tricky shit done, Bennets Customs is an Aussie guy, and he mentions a guy a lot call "Kyle", who is from "Make It Kustom". Watch some of their welding videos, especially on sheet metal. You can use the welder to shrink the steel in, and you can also use the welder to stretch the panel out. When you have the skill level that I have, you can shrink the metal in and out... But never on purpose like those two guys do. You just manage to f**k it all up. Then I smack it around with a hammer till it sits lower than I will want it too, then I shove filler on top and then pray to deitys that I can sand it into some form of sane shape that doesn't look like a dog has taken a shit, after eating a tonne of pumice stone...

I'm all for DIY, and for learning, and please, feel free to give it a go, but be aware, you need to live with the consequences of how time consuming it is to do, AND that it's going to look no where near as good as what you can make it look with just some filler now. Oh AND, even once you replace it, it's like to still rust away again eventually, because you'll have missed putting primer and paint on some part of the newly welded in sheet metal, or against part of the existing metal you couldn't get to...

 

Oh, and to weld all that in, you will need to pull the window out, and strip at least the roof and A Pillars of interior trim and wiring. You'll then need things like the big fire proof/weld spatter proof mats to lay down, OR you'll end up needing to strip the ENTIRE interior to avoid sending it all up in a ball of flames.

If you want to see how annoying sheet metal is to weld, head to bunnings, buy there 600x600 1.6mm mild steel (Not GAL!) sheet, and cut a few pieces, and try and weld them together.
Then understand, 1.6mm sheet is nearly 50 to 100% THICKER than the cars sheet metal.

 

The photos I posted before, I'm replacing with 1.2mm thick mild sheet, and it's very easy to blow through both the original steel (Especially if I hit an area that should have probably been cut out a bit more) or straight through the new sheet metal. And I'm doing the floor, which can be hidden easily, and doesn't matter how pretty I make it, as long as it's damn strong! I'm also doing it in a 4WD, that has seen many off road trails, and doesn't need to look that pretty ever

[PranK]

Thanks guys, I really appreciate the help and experienced opinions. 

I have spent a lot of my life working on boats so I'm pretty good with fibreglass. I'll take everybody's advice in here; 

I'll cut a little more of the 2nd layer away as it's a bit crunchy rust and also it's sitting high now. Then I'll wire brush it all a bit to get off anything loose, then I'll soak the bejesus out of it all in rust converter. I'll make sure to get a little hose piece and feed it into all the holes and gaps between the roof layers. Then I'll fibreglass up the holes. 

Then I'll get a pallet of filler and mix it with 3 buckets of hardener and hope that is enough to build up the roof corner. 

Does that sound sane? Is one type of filler better than others for this?

[GTSBoy]

Sane enough. Remove the roof liner, because the acid will go everywhere.

[PranK]

@GTSBoyas luck would have it and it's legit the only part of this story that goes my way, I already had the liner out to retrim!

So much lucky!

[PranK]

Hey guys, what's the best type of filler to use for this? 

Thanks.

[GTSBoy]

11 minutes ago, PranK said:

Hey guys, what's the best type of filler to use for this? 

Thanks.

That depends. Are you going to glass it in first?

[PranK]

12 minutes ago, GTSBoy said:

That depends. Are you going to glass it in first?

Yep I'll patch the holes with glass first

[PranK]

Is this ok and then I don't need to patch the holes? Or is it not as good as separate fibreglass repair as well? 

https://www.supercheapauto.com.au/p/septone-septone-glass-fibre-filler---500g/3151.html#q=Filler&lang=en_AU&vid=itBd4yPRKxscpBbIMOhvMg%3D%3D&start=10

 

[PranK]

Also I cut away the top metal that was bent as there's no way I could have gotten it level and the rust stopped. I can also see clean metal under the windscreen. So it looks like this is the extent of it. The lower metal here is also strong. 

 

[GTSBoy]

51 minutes ago, PranK said:

Yep I'll patch the holes with glass first

 

43 minutes ago, PranK said:

Is this ok and then I don't need to patch the holes? Or is it not as good as separate fibreglass repair as well? 

https://www.supercheapauto.com.au/p/septone-septone-glass-fibre-filler---500g/3151.html#q=Filler&lang=en_AU&vid=itBd4yPRKxscpBbIMOhvMg%3D%3D&start=10

 

That was the reason I asked. If you were going to be fully bodge spec, then that type of filler is the extreme bodge way to fill a large gap. But seeing as you're going to use glass sheet, I would only use that fibre reinforced filler if there are places that need a "bit more" after you've finished laying in the sheet. Which, ideally, you wouldn't.

You might use a blob of it underneath the sheet, if you need to provide some support from under to keep the level of your sheet repair up as high as it needs to be, to minimise the amount of filler you need on top. Even though you're going bodge spec here, using glass instead of metal, the same rules apply wrt not having half inch deep filler on the top of the repair. Thick filler always ends up shitting the bed earlier than thin filler.

[PranK]

Thanks. Yeah I realised that there's no way I'd be able to cover the holes with the filler, it would just fall through.

Thanks again @GTSBoy!

[PranK]

So, I started this repair and got as far as "fixing" the holes with some fibreglass.

God all those years working on boats came back quickly.

I decided I'd reach out to some rust guys just to see what they would say about it. I came across a guy about 40 mins away and went to see him. He said the windscreen needs to come out, that there might be some more bits around the windscreen and he'd quote them at the time. But his quote was $300 to remove and replace windscreen and $3k for the damage he can see. He said he could respray the roof for $1200 and the bonnet for another $800 (somebody has previously rattle canned it, its horrendous). This is $5300 + any small additional bits.

It's a lot, I get that and the name of one of my fave youtube channels 'Not Economically Viable' comes to mind. 

I'm not being financially rational, but I've taken him up on the quote. He's opening a new shop in November with more room, so we're waiting for that. I'll leave the currently missing headliner out until then.

I'm looking forward to it being fixed and having the paint looking nice again (lots of clear coat issues on the roof too).

/ flame suit on.