Rust, here I come!

[VicVan]

Thanks. I should get to this next week or so.
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'90 Little Blue Truck, 2WD auto, FAS GenV 2.0 NA (AVH)

[VicVan]

What sort of primer should I get for that outside seam?
I have some standard self-etching primer.
I've seen some sandable primer, one for small cracks, one for deep cracks... What do you recommend?
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'90 Little Blue Truck, 2WD auto, FAS GenV 2.0 NA (AVH)

[ghianowbug]

self etching primer normally goes over bare metal. since you are going bare metal and the converted rust you can use the etch if you already have it and use a build primer to build and sand smooth when wet sanding . the etch primer gives more bite when going over bare metal. some quality rattle cans that are available in canada are Dominion Sure seal and SEM both are products that I have used. dominion products are available at canadian tire and they have the etch, primer in three colors and clear coat . make sure you buy compatible products. if you use any filler use a sealer coat to prevent bleed through.

buildable primer does not cover cracks rather you use it to build up thickness and then sand smooth to get straight surfaces you need to fill the crack first. what I would do is clean the crack removing the previous seam sealer and rust , seal the rust if not already done and then prime with your etch if that is what you have then apply seam sealer to the panel crack using masking tape on each side of the crack to keep it it in the crack nice and clean , use your fingertip to spread in one swipe , prime and paint . the seam sealer will remain flexible in the crack and is protected by the paint. use a glove to protect your fingertip

[VicVan]

Thanks ghia
What grit for the sanding? 800?
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'90 Little Blue Truck, 2WD auto, FAS GenV 2.0 NA (AVH)

[ghianowbug]

Use the wetsanding for the primer coats and dry on the bare metal to prep for paint dont go more that 120 on bare metal to allow the primer to get a good physical bond . Work progressively to the higher grits. if you have a relatively smooth surface then 120-150- then 220 then 320 then 400 maybe 600. dry sanding numbers have a different feel and I would stop at 320 or 400 . you are not going for show car just a repair that looks good? use a w or cross hatch pattern to keep a straight surface works well on a straight panel
I like wetsanding as it really shows the imperfections when the water is sheating. if wet sanding use a small drop of dawn dishsoap in the water bucket. make sure to rinse the surface and wipe with degreaser before paint.

dont need to go further than 400- 600 as the color coat needs bite

always work progressively in sanding for if you miss a step the scratches you are trying to remove are too large for the grit so going from 150 to 400 would leave scratches that show through the clear. if you use a sanding disc or the media blaster then sand the edge of the paint to the bare metal to a taper to avoid getting a hard edge . you should see the primer progressing to paint away from where both were removed aggressively. then prime over and sand again till recoat

oh and use a block makes it easier to sand .

by the way in the previous comment i assumed that you meant the seam between the panels when i referred to the crack not cracks in the paint . but primer is not a crack filler anyway . if the paint is cracked sand down the cracked paint area prime and repaint . if the seam sealer between the panels is cracked then remove and replace.