[Private_collector]

Nathan,

I always prepare new or clean (as should be with blasting) metal with an etch primer. You should make your selection of etch based on compatability to your primer, and primer type to suit your finish or top coat.

You will notice I said clean should be the case with blasting! If it is you doing the work I would wager that you will probably take extra care, but professional blasters wont spend the same time to get it perfect. I bet you find a number of areas not quite so clean, usually in tight or out of the way places. It is difficult to get things 100% in a dusty blast helmet. Any spots that you suspect may still have any surface corrosion must either be treated with a rust neutraliser or removed entirely by mechanical means.

Most sandblasting companies apply a coat of etch primer once the blasting has been done. Be sure to enquire if the coating is standard primer or etch! It is widely believed that an approprite etch prime coat will give better adhesion to the bare metal. I even reapply a light coat of etch to any areas of bare metal after final sanding, just before top coat spraying starts.

Etch does not offer much in the way of filling, so several coats of primer (compatable with your type of top coat) is best after the etch. If you have areas of body filler or place where heavy filling is desired, spray putty is the product you will need. As always, spray putty MUST be compatable with your other paint layers.

The following is my process:

Bare metal - etch primer.
Rust scale or flakes - must be entirely removed.
Surface staining or light rust on surface - rust neutraliser or mechanical removal, then etch.

Primer surfacer - minimum of one coat if not sanding, or if you are going to do repairs to the area and will be taking that coat off for that. I do three good coats, followed by a mist of black, because when you sand you will know everything is flat when all the black dots are gone. I will always wet sand, but thats just my personal preference.

If repairs have left deep scratches or if body filler applied - 1 or 2 coats primer then several coats of spray putty. Can use a wiping putty instead of spray, if area is small enough. Apply the black (or other contrasting color) guide coat, as per primer. Once sanded flat, return to the primer step above, for that area. The other areas should have already been primed.

One of the most important things to be aware of is that no primers or puttys are waterproof. Neither are they intended to remain without top coat for an extended period. If you are planning to do heavy repair work, etch alone will be OK until then, provided the repair work involves sanding and re-etching etc.. Exactly how long is too long to wait with exposed etch, primer, or putty.........well thats a point of great debate, and will also depend on what conditions your vehicle is stored in.

Adhesion to any surface, bare metal or not, can be improved with light abrasion of the area. Emphasis on light, 180 to 240 grit sandpaper will be adequate. After blasting this will not be needed. The tiny pitting does that job!

Hope this helps. Excuse if I have written about steps you are already knowlegable about.