Just Carbs
Well-Known Member
Good option. Except the Bondo will be subject to moister after the solder job and the fiberglass and resin after the solder job would not.
Holy Roof Rust, Batman!
- Thread starter ArnieJr
- Start date
azblackhemi
Old Man with a Hat
I've been making a living doing paint and bodywork since 1972. I've repaired a lot of rust especially working in NY for years, but the best rust preventative by far was moving to Arizona and avoiding rust at all cost! At least on my own cars.
57fury440
Well-Known Member
One of the problems with vinyl roofs was the lack of maintenance. The vinyl would dry out and become porous. Once that happened there was no hope for the roof. My friend bought a 68 GTO back in 1976. He always used a good dressing on it and 40 years later it is still good. I still think that roof is too far gone to repair. It needs a new shin from a donor car.
you might want to watch weird beard's vids on how he dealt with the rusty roof on a 72 fury.
it turned out alot better than i was expecting
it turned out alot better than i was expecting
Just Carbs
Well-Known Member
So beautiful, so terrible!
fury fan
Senior Member
If I was going to use fiberglass, it would be the mat, not cloth. Cloth works nice for wrapping around corners and edges. In your mind, you just add layer after layer and build it up.
In reality, I've found that whatever you are using to lay down the next layer will stick to the layer below and causes it to move around. You get air bubbles and all kinds of flaws.
Sure, you could do 1 layer at a time, curing in between, but who has time for that?
So I would use mat, as it is thicker and won't move around as much. If you wanted to do mat 1 layer at a time, at least you don't need to do as many layers.
BUT -
I think it boils down to how much time you want to spend, how good (or bad) you want it to look, and how often the roof will get wet in the future.
You mentioned small budget and not much experience. Small budget has been my M.O. for most of my life, but experience follows from that.
For the trim:
If you remove all of the trim at the front and rear glass to do this 'band aid' the 'right' way, you will find more damage, you'll find clips that are rusted beyond re-use (the glass must come out to replace them) and you'll likely bend some of the trim getting it off. That trim is a monster to get off when there's rust involved, even with the right tools, as each clip seems to want a different technique. And even after the clip is released, the rust and crud still hold the trim in place sometimes. It will snowball.
The side trim along the roofrail is a crimp-type fit, with no clips, and is much easier - I would remove that if you're up to it. Once you get a starting point, you just kinda walk it off the whole length.
Use a stiff rotary brush in a drill to clean the gutter area as much as possible.
For the holes:
If it were my car, I would use a die grinder with a carbide burr and go around the perimeter of each hole as surgically as possible, going 1/8"-1/4" outward into clean metal. If you don't have enough shop air, a decent Makita electric model is ~$100. I have the one shown, and for some jobs it is invaluable. The smaller the diameter of the carbide burr, the more surgical you can be. I would use a pointed-tip burr for this work.
Be careful around the trim, put layers of duct tape on to protect it. If the die grinder grabs and you nick a piece - that's unavoidable. (again, the smaller dia burr helps here)
Keep the shopvac hose nearby and such up as much debris as you can, as you go. Metal shards from a carbide burr are nasty, and you don't want them raining thru the headliner for the next year.
Use a nice sharp-edged scraper around the trim, to get as much of the old vinyl and rustflakes off. The hook on the one shown would be useful, dragging it toward you. As would a heavy-duty curved pick.
For areas that aren't yet perforated, and maybe around the trim - use the rust converter of your choice. Don't be afraid to make a few tiny holes in any questionable areas. Soak the rust converter in around the trim with a small paintbrush. Got to kill as much rust as possible.
After all the holes are hogged out, I would sand the whole roof with a DA sander, with maybe 150 grit. Wouldn't hurt to carefully put a phosphoric metal prep on that - make sure it doesn't run onto your paint. If you don't have shop air, the Porter Cable 6" electric DA is a great tool, I have one with many years of DIY use on it.
Now we're ready to fill.
For holes - peck the edges inward a bit and use fiberglass mat cut to shape, overlaying the hole by 1/4-1/2". It may sag into larger holes, like the one on that C-pillar. Maybe tape it into place to hold the edges, it should peel off after it's all cured? Do a few layers on the larger holes as needed. I would recommend 1/8" thickness. If the hole wraps behind the trim - do the best you can.
For the smaller holes - cut a small plug of fiberglass, roll it into a cork shape, and put it in all the holes. Mix up some resin, and carefully dribble it on/in the plugs. Don't go nuts, to prevent the resin from dripping thru and hitting the headliner. After cured, cut them flush with a hacksaw blade. Or you could use a fiberglass-reinforced bondo on small holes - just pack it in.
Take the DA and do a rough feather-edge at the holes, making sure to not weaken where the fiberglass is adhering to the metal. Do NOT try to make this be like good bodywork. You want the fiberglass to have integrity at the edges.
And maybe let the whole business cook in the sun for a few days to dry any moisture or rust converter left behind.
Spray the whole top with a metal-etching primer. Rustoleum has that in spray-can form at home stores now, 3 cans should do it?
Coating it.
FYI with Flex-Seal - it is great stuff, but it has a waxy surface and paint will NOT stick. I recently repaired some of the bottom edge of my shed's wall sheathing and learned that the hard way. The can warns of this, too, BTW. So use black or white to emulate a VT, I guess?
I would coat the whole top with roll-on pickup bed liner. I would do 2 coats to hide the sins, and I would pay particular attention to get it right in the interface between the roof and the stainless trim for the front and rear glass. Edge it in with a paintbrush if necessary. The side trim is not involved in any water-sealing, so I would put that trim on afterward. (don't coat the lip it attaches to, gotta make sure it will still snap on)
If some of the repaired areas are too noticeable - roll more bedliner onto those areas to thicken it up a little?
Some folks might say it heresy to put the bedliner onto the edge of the trim, but the goal is to keep water from seeping back in those areas. This is not meant to be a pretty repair, but a waterproof one. Around the trim is where the rust is hardest to remove, and therefore needs the most waterproofing. And - it can still breathe from where the trim lays on the glass. So you're not really waterproofing at the trim, you're just making an umbrella for it. Rust tends to be stable if it stays dry.
Overall:
Based on the pics and some similar VT rust repairs I've had to do, I would expect to spend a full weekend doing all of this, perhaps +1 day more.
Depending on what tools you need to buy, and the primer, fiberglass, bedliner, etc - it still might cost $200-500 to do this repair. (but IMO that's a reasonable cost for the benefit)
And after that, I would NOT get that roof wet unless washing the car, and I would not rinse the roof, I would damp-cloth it.
I believe, if you get as much of the rust out as possible, and metal-prep what is still there, that this repair could last for years if you keep the roof dry.
In reality, I've found that whatever you are using to lay down the next layer will stick to the layer below and causes it to move around. You get air bubbles and all kinds of flaws.
Sure, you could do 1 layer at a time, curing in between, but who has time for that?
So I would use mat, as it is thicker and won't move around as much. If you wanted to do mat 1 layer at a time, at least you don't need to do as many layers.
BUT -
I think it boils down to how much time you want to spend, how good (or bad) you want it to look, and how often the roof will get wet in the future.
You mentioned small budget and not much experience. Small budget has been my M.O. for most of my life, but experience follows from that.
For the trim:
If you remove all of the trim at the front and rear glass to do this 'band aid' the 'right' way, you will find more damage, you'll find clips that are rusted beyond re-use (the glass must come out to replace them) and you'll likely bend some of the trim getting it off. That trim is a monster to get off when there's rust involved, even with the right tools, as each clip seems to want a different technique. And even after the clip is released, the rust and crud still hold the trim in place sometimes. It will snowball.
The side trim along the roofrail is a crimp-type fit, with no clips, and is much easier - I would remove that if you're up to it. Once you get a starting point, you just kinda walk it off the whole length.
Use a stiff rotary brush in a drill to clean the gutter area as much as possible.
For the holes:
If it were my car, I would use a die grinder with a carbide burr and go around the perimeter of each hole as surgically as possible, going 1/8"-1/4" outward into clean metal. If you don't have enough shop air, a decent Makita electric model is ~$100. I have the one shown, and for some jobs it is invaluable. The smaller the diameter of the carbide burr, the more surgical you can be. I would use a pointed-tip burr for this work.
Be careful around the trim, put layers of duct tape on to protect it. If the die grinder grabs and you nick a piece - that's unavoidable. (again, the smaller dia burr helps here)
Keep the shopvac hose nearby and such up as much debris as you can, as you go. Metal shards from a carbide burr are nasty, and you don't want them raining thru the headliner for the next year.
Use a nice sharp-edged scraper around the trim, to get as much of the old vinyl and rustflakes off. The hook on the one shown would be useful, dragging it toward you. As would a heavy-duty curved pick.
For areas that aren't yet perforated, and maybe around the trim - use the rust converter of your choice. Don't be afraid to make a few tiny holes in any questionable areas. Soak the rust converter in around the trim with a small paintbrush. Got to kill as much rust as possible.
After all the holes are hogged out, I would sand the whole roof with a DA sander, with maybe 150 grit. Wouldn't hurt to carefully put a phosphoric metal prep on that - make sure it doesn't run onto your paint. If you don't have shop air, the Porter Cable 6" electric DA is a great tool, I have one with many years of DIY use on it.
Now we're ready to fill.
For holes - peck the edges inward a bit and use fiberglass mat cut to shape, overlaying the hole by 1/4-1/2". It may sag into larger holes, like the one on that C-pillar. Maybe tape it into place to hold the edges, it should peel off after it's all cured? Do a few layers on the larger holes as needed. I would recommend 1/8" thickness. If the hole wraps behind the trim - do the best you can.
For the smaller holes - cut a small plug of fiberglass, roll it into a cork shape, and put it in all the holes. Mix up some resin, and carefully dribble it on/in the plugs. Don't go nuts, to prevent the resin from dripping thru and hitting the headliner. After cured, cut them flush with a hacksaw blade. Or you could use a fiberglass-reinforced bondo on small holes - just pack it in.
Take the DA and do a rough feather-edge at the holes, making sure to not weaken where the fiberglass is adhering to the metal. Do NOT try to make this be like good bodywork. You want the fiberglass to have integrity at the edges.
And maybe let the whole business cook in the sun for a few days to dry any moisture or rust converter left behind.
Spray the whole top with a metal-etching primer. Rustoleum has that in spray-can form at home stores now, 3 cans should do it?
Coating it.
FYI with Flex-Seal - it is great stuff, but it has a waxy surface and paint will NOT stick. I recently repaired some of the bottom edge of my shed's wall sheathing and learned that the hard way. The can warns of this, too, BTW. So use black or white to emulate a VT, I guess?
I would coat the whole top with roll-on pickup bed liner. I would do 2 coats to hide the sins, and I would pay particular attention to get it right in the interface between the roof and the stainless trim for the front and rear glass. Edge it in with a paintbrush if necessary. The side trim is not involved in any water-sealing, so I would put that trim on afterward. (don't coat the lip it attaches to, gotta make sure it will still snap on)
If some of the repaired areas are too noticeable - roll more bedliner onto those areas to thicken it up a little?
Some folks might say it heresy to put the bedliner onto the edge of the trim, but the goal is to keep water from seeping back in those areas. This is not meant to be a pretty repair, but a waterproof one. Around the trim is where the rust is hardest to remove, and therefore needs the most waterproofing. And - it can still breathe from where the trim lays on the glass. So you're not really waterproofing at the trim, you're just making an umbrella for it. Rust tends to be stable if it stays dry.
Overall:
Based on the pics and some similar VT rust repairs I've had to do, I would expect to spend a full weekend doing all of this, perhaps +1 day more.
Depending on what tools you need to buy, and the primer, fiberglass, bedliner, etc - it still might cost $200-500 to do this repair. (but IMO that's a reasonable cost for the benefit)
And after that, I would NOT get that roof wet unless washing the car, and I would not rinse the roof, I would damp-cloth it.
I believe, if you get as much of the rust out as possible, and metal-prep what is still there, that this repair could last for years if you keep the roof dry.
Just Carbs
Well-Known Member
On old cars like this, I've been covering the whole top with fiberglass cloth because it makes a good solid consistent structural base. And it's easy to prep to refinish with paint.
Use non-waxed laminating resin. Then after that cures go over the tacky surface with a smooth coat of waxed finishing resin that leaves a tack free surface. Then remove the wax with a striper after it's cured so it can be sanded before the finishing routine starts.
I can't say that some rusting doesn't take place down the road, but it's never been an issue with a full fiberglass cap over the entire roof.
Of course, I am respecting the impracticality of replacing the entire metal roof here.
I do a lot of extensive boat repair and alterations. Have for decades. So that's what I'm handy with.
That old roof will make a very good mold for the new fiberglass roof.
Use non-waxed laminating resin. Then after that cures go over the tacky surface with a smooth coat of waxed finishing resin that leaves a tack free surface. Then remove the wax with a striper after it's cured so it can be sanded before the finishing routine starts.
I can't say that some rusting doesn't take place down the road, but it's never been an issue with a full fiberglass cap over the entire roof.
Of course, I am respecting the impracticality of replacing the entire metal roof here.
I do a lot of extensive boat repair and alterations. Have for decades. So that's what I'm handy with.
That old roof will make a very good mold for the new fiberglass roof.
thethee
Senior Member
This sounds like you are using too much resin. That way your previous layer can end up swimming and is easy to move around with consecutive layers. It should be just enough to cover each layer and don't forget to use the squeegee and/or roller in between layers.
Cut the roof off . Put another on, donezo.
Just Carbs
Well-Known Member
That's why we use laminating resin not finishing resin for the buildup and let it set between layers.
The next layer bonds to it as one layer.
Then finishing resin with no glass for the last smooth cover.
57fury440
Well-Known Member
I've replaced a few roofs over the years. The amount of work that has to be done with the resin and cloth, etc. is more than just replacing the skin with a good used one. The rusty roof will eventually return.
Just Carbs
Well-Known Member
Replacing the roof might be beyond the owners' capabilities.
fury fan
Senior Member
My memory was that it was tacky no matter what, and there was no way to have the next layer not interfere with the prior one.
Pulling fingers from layer #2 was a great way for it to happen.
It was 30+ years ago.
Just Carbs
Well-Known Member
Air inhibits the non-waxed surface of laminating resin from curing. Even after the subsurface has cured. The next layer will chemically bond to it as one. The sticky surface of non-waxed laminating resin can't be sanded. It will clog the paper, even 24 grit.
Waxed finishing resin has a wax in it that floats to the surface and prevents the air from stopping the surface cure. Waxed finishing resin with no glass in it goes over the non-waxed laminating resin for a smooth top surface ready for finishing products. It is self-leveling. As in glass smooth.
The wax must be chemically removed for paint products to stick. The surface under the wax is rock hard but sands very nicely. Epoxy primer loves it.
Waxed finishing resin has a wax in it that floats to the surface and prevents the air from stopping the surface cure. Waxed finishing resin with no glass in it goes over the non-waxed laminating resin for a smooth top surface ready for finishing products. It is self-leveling. As in glass smooth.
The wax must be chemically removed for paint products to stick. The surface under the wax is rock hard but sands very nicely. Epoxy primer loves it.
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