After Sandblastig...What have you found...

Steve Plucker

Steve Plucker

BANNED
After sandblasting a part, what have you found best to treat the part with before painting if left for a period of time?

Thanks.

Pluck
 
Last edited:
I agree with Brent, phosphoric acid. I have kept parts for almost a year after treating with phosphoric acid. You can spray or brush it on. I use a foam brush for small parts, and usually treat everything I do.
 
I like "picklex20", I have stuff hanging around that was treated over 5 years ago, the treated metal welds nicer too, on modern cars that live outside I have stopped repeating reoccurring rust bubbles from ordinary body shops with sandblasting, picklex20, epoxy primer--- more than 10 years with no signs of any rust
 
+2 Brent. Phosphoric acid works great. It stops the rust and gives the paint (primer) a good base. I use a product called Ospho, But there are others. Be careful some metal preps are mostly water with a little acid mixed in.
 
Pluck,


In 1979 I used lacquer primer and a Rustoleum gloss black enamel top coat (fish oil base), and to date there are not paint failures or rust on those parts.


From 1998 to 2016 I used Krylon epoxy primer and Krylon gloss black enamel on parts that were absolutely rust free. I also used POR-15 Chassis Black epoxy on bare metal with a top coat of Krylon gloss black on parts that had some residual rust, and parts I wire brushed clean.


POR-15 adheres tenaciously to bare metal, clean or rusty but it fades when exposed to the ultraviolet rays in sun light. The Krylon top coat is cosmetic, to avoid fading.



Most importantly, all of my parts were cleaned with lacquer thinner before any painting.


When using POR-15 or other epoxy primers, you need to consider that these paints are very strong thread lockers. Also, epoxy paints adhere very well to human skin.


With POR-15, a little goes a long way. I did my the frame and most of the running gear of my 190A with just two half-quart cans applied by cheap throwaway brushes. Each part was given 2 light brush coats of POR-15. POR-15 flows so well that there are no residual brush marks.
 
Spraying it with a very heavy epoxy primer that I use. If you drop it in water for a while it doesn't rust. It also can sit around for years.
 
After blasting my fenders I found lead filler.
Old school repairs...no bondo
Side question: When did they start using bondo?
 
burner31 said:
After blasting my fenders I found lead filler.
Old school repairs...no bondo
Side question: When did they start using bondo?
Click to expand...

Bondo was introduced in 1955, though a few products similar to it were around in the late 40's. It was originally meant to fill in small imperfections in metal but people got lazy and started filling dents with it that we see on our antique vehicles after they have been sandblasted today.
 
Oldbluoval said:
Brent-
Do you treat as such if priming within hours of the blasting?
Click to expand...

No Bill, since there are many DTM primers ( -such as SelectPrime ) or even epoxies that can be applied first and then filler added to the top. Generally we use the Phosphoric to give us some 'hold time' between blasting and metal repair. Once finished we wash the metal with Wax & Grease remover to remove the Phosphoric from the pores.
 
Do you have to remove the phospho before painting? I thought it can be used as an etch and can be painted over ?
 
Gibbs brand lubricant is another option and they state that it is safe for painting over it later. It is sold on Ebay and great as a rust preventative on guns and any metal. I have used it to prevent rust on metal sandblasted and cannot get to right away and clean later with mineral spirits or lacquer thinner than use the acid others have mentioned for adhesion. I think Gibbs is paint friendly cause of no silicones.
 
You must log in or register to reply here.
Back
Top