Rusty roof channels

[BarneyB]

G'day Navheads,

Has anyone else seen rust in their roof channels?
(See photos)

I'm about to fit a permanent flat tray roof rack, but I think I should fix/treat the rust first...

Bodywork is not my strong suite.

Anyone got advice for a straight forward method?
How much do I sand back?
Rust converter and paint brush?

 

[Old.Tony]

I had a small amount of rust there. Wire brush to remove the filler and rust, then filler and paint on top. Use slow-setting filler or do it in several passes. If you use the normal 5-minute stuff you won't get it smooth before it starts to set.

 

[BarneyB]

I had a small amount of rust there. Wire brush to remove the filler and rust, then filler and paint on top. Use slow-setting filler or do it in several passes. If you use the normal 5-minute stuff you won't get it smooth before it starts to set.

Thanks Tony.
So it is indeed body filler in the channel? (we thought so...)

I went down to my local auto paint wholesaler (Spectrum) and worked out a game plan with a very helpful bloke.
He made up a 2 pac single can that is a one-off use base+clear.

Basically he told me the steps he reckoned...without getting too complicated...

1. Solvent wipe down
2. Hand sand all the rusty areas back to clean metal....but don't sand the whole channel. Just scuff it up where the paint is still good/no rust
3. Clean/wipe down
4. Spray primer - 2 coats, wait 24 hrs
5. Light sand the primer
6. Single part filler/adhesive (3M 227 I think) back into the seam
7. Optional single coat primer over filler (?)
8. Top coat both channels completely- 2-3 coats

I think that's what he said anyway
Now I've just gotta get 2 clear days with no weather, no kids, no wife..... no other bullshit going on!

And I might add a couple of small patches to respray at the forward bottom area of my rear wheel arch guards. The stone carnage there is brutal. And once I release the hardener into the can the clock is ticking

EDIT: He sold me a single part filler in a small tube. I'll see how I go with it on one side and if it's going off too fast I'll get some 2 part stuff. I'm only expecting to re-fill a very thin bead, not the whole channel (fingers crossed)

 

[Old.Tony]

Thanks Tony.
So it is indeed body filler in the channel? (we thought so...)

I went down to my local auto paint wholesaler (Spectrum) and worked out a game plan with a very helpful bloke.
He made up a 2 pac single can that is a one-off use base+clear.

Basically he told me the steps he reckoned...without getting too complicated...

1. Solvent wipe down
2. Hand sand all the rusty areas back to clean metal....but don't sand the whole channel. Just scuff it up where the paint is still good/no rust
3. Clean/wipe down
4. Spray primer - 2 coats, wait 24 hrs
5. Light sand the primer
6. Single part filler/adhesive (3M 227 I think) back into the seam
7. Optional single coat primer over filler (?)
8. Top coat both channels completely- 2-3 coats

I think that's what he said anyway
Now I've just gotta get 2 clear days with no weather, no kids, no wife..... no other bullshit going on!

And I might add a couple of small patches to respray at the forward bottom area of my rear wheel arch guards. The stone carnage there is brutal. And once I release the hardener into the can the clock is ticking

EDIT: He sold me a single part filler in a small tube. I'll see how I go with it on one side and if it's going off too fast I'll get some 2 part stuff. I'm only expecting to re-fill a very thin bead, not the whole channel (fingers crossed)

Sounds like good advice. Fingers crossed those two days come soon! Don't spray when the weather's really hot, or spray in direct sunlight because it will affect how the paint bonds to the car.

 

[BarneyB]

A big week pretending to be a panel beater & spray painter. Just gotta take the tape off tomorrow to see how good / bad it looks.

 

[BarneyB]

Couple more.
I prepped & sprayed the lower fwd section of the rear guards just to use up the expensive one-off paint can.