[79transam79]

I've been repairing my t top channel where the gasket lays, seems that some moisture got in there and caused some problems. I've welded up any holes and structurally it is strong, But I can't get all the rust out of the pitted areas I've tried naval jelly, also por 15 acid, and sandblasted it. But in the deep pitted areas it still has a dark area instead of the shinny metal looks. I was planning on using a product over the pits called "all metal made by USC" ( it's a aluminum base waterproof body filler ) over the pits. Am I being too fussy or does all this darker area need to be removed. I don't want to cut the area out because it two layers of metal with panel adhesive holding it together and if I try to separate the two it will probably turn into a mess. So do I need to remove this darker area on the metal? and is this product that I already bought the right stuff to use for this repair? I have about ten hours of work trying to remove this dark area.
Thanks for any help
Bob

[400 4spd.]

Is it possible that the grains of sand are too large to get the deepest rust out? If that's the case, try one of these 2 options. These are what work for me.
1. Get some DuPont 5717S acid and use it full strength on the stubborn spots. Lay a cloth or paper towel over the spot and saturate it with the acid. Let it soak 15-30 minutes and then scrub with a wire brush or scrape with a very fine pick. I even use the corner of a razor down in the pit to break it up after it has soaked. Repeat the steps as often as needed until it dissolves the rust spot clean.
2. Use an extra fine grade of sand, mixed with 50% bead blasting media (any type or grade) in your blaster. Even worn out media will do the job. At work I save all of the old media from the bead blaster just for this purpose. I run it through my portable sand blaster for stubborn deep rust or spots on large panels that may warp from the heat of sand. Just don't use any that has been used on greasy parts because it is contaminated.

Once the rust is gone, it won't matter what filler is used, but the All Metal should be fine.

[79transam79]

Do you need to get all the black spots out?and is the dupont brand better than the por 15 acid, and the naval jelly? I,ve used a die grind but to many small pits, also tried wire brushing it in while it was wet. I'm using a cheap sandblaster tried a few different grits. Pisses me off because I have a large industrial sandblast cabinet right next to it, and it doesn' t do me any good on this project.

[400 4spd.]

You do need to get the black spots out if you want all of the rust gone. I've not used the POR-15 acid or naval jelly because the 5717S has always worked well enough. PPG has a product just as good. I can't remember the part#, but it is purple. The green they (PPG) sell is too weak.