Rust: Stopgap Measures?

I'm still looking for a replacement for my '98 'burb whose roof is rusting through: http://tinyurl.com/3dzzrql
I'm hoping to find something within a year - especially if/when
we see $5.00/gallon gas.
Besides covering up the hole so rainwater won't pour in, is there anything I should be doing to mitigate the damage?
Maybe some kind of expanding foam I can spray in there that will bond to the already-rusted metal and slow down the process?
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PeteCresswell

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Fiberglass resin and cloth on the outside and foam from the inside?
Ken
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Per NapalmHeart:

Any idea of what kind of foam? I Googled a little, but could not find anything.
Polyurethane insulating foam seems to adhere quite strongly to a lot of stuff. I'll try in on some rusted steel today - but would like to hear from somebody authoritative before I inflict it on the vehicle...
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PeteCresswell

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If you don't go the Cut and weld approach (best action) then I would use Epoxy fiberglass, as epoxy will bond better to a metal surface than fiberglass resin. You can pick the stuff up at West marine, or I use Raka in Florida. http://www.raka.com / Surfboards are made with Epoxy, since it is stronger than fiberglass resin. It bonds better to most materials. but you need to prep it properly for paint because of it's Amine Blush. Read the manual <http://www.raka.com/manual.html
You can shoot them an email and see what they say.
Cheers
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Hopefully, you haven't done anything yet. You need to change your thought process.. Foam... NO GOOD. It won't stick to rust. It has no strength. It will hold moisture which will accelerate the rusting. 1st thing you will need to do is remove the roof rack. Leave it off if you want to do a fudge and butter seal. No need to have it on there unless you plan to use it. WHAT? You want to USE IT? (OK, judging from the pics... you obviously want to use it.) You will need to at least rivet some decent pieces of steel over the damage, with holes for mounting the rack back onto. Don't ignore the fact that with any load on that rack, the wind resistance is trying to rip that rack off the top. One thing I find works well to slow down rusting steel is NAPA brand open gear lube. Nothing else quite like it. But your best bet is to cut away the rusted metal. You need to build your patch first. Have your holes all drilled and lined up with the old holes, and mark the patch position before cutting out the rotted metal. Then patch, seal, paint, and mount the rack back on. Obviously, it will looked repaired when done. You'll need a good body guy to prevent that, which is where the major expense would come in.
Plan B: Make some sort of dam all around each spot (the bigger, the stronger). Fill the holes with something thick (maybe some foam might work for that) and then pour epoxy resin such that it is large enough to grab a good solid footprint around the rack mount, and deep enough to encapsulate it. Then you have it glued down and sealed.
Plan C: Duct tape. Lots of it. At least that will add some strength.
Please update with what you end up doing!

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Red Green and the boys at the Possum Lodge would be proud.
John
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My thought exactly. Keep your stick on the ice, where all in this together!

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