Sandblasting

[amashinga]

I am busy cleaning old paint and rust off a restoration project, a struck mini dozer. I bought myself a cheap-ish sandblasting setup to do it. I am pretty happy with the results, but I was wondering. Once you are down to that ash grey matt finish of bare metal, what is the process from there ?. Do you have to clean it with anything prior to priming ?. If so, what would you suggest ?

Thanks
Bruce.

 

[Runner]

Not sure if this is the "right" way or not, but on the old tractor I've been working on, after the part is sandblasted, I hit it with a wire brush wheel on a grinder to blow the last of the junk off the metal, then, I use a rag with some paint thinner on it to wipe the piece down to get the dust off of it before priming.

 

[Wombat125]

I've been doing mostly smaller motorcycle parts, but when done I just spray it off with brake cleaner. Then off to prime and paint.

Don't use paper towels to wipe down. You will leave paper lint all over the piece.

 

[AL_Josh]

I blasted and painted at a shipyard for 6 years. I paid my way through trade school doing it. After you blast and get to bare metal we would spray a zinc primer after blowing the dust off. Then we would apply a normal primer then a finish coat.

 

[john_bud]

I use an oil removing solvent to get the dirt off. There will be a LOT of dirt left. Then I use a rust converting chemical (Must for Rust is the name). They are fairly generic and contain a weak phosphoric acid solution. Dry then prime and paint.

 

[T_HedMF1533]

If you want the primer to last use Acetone or Laquer Thinner after blowing off the sandblasted metal. Paint thinner contains oils that might compromise
proper adhesion. Use the best primer you can afford.
I have used Kem Kromik primer from Sherwin Williams for years with fantastic results.
Data sheet for Kem Kromikｮ Universal Metal Primer from Sherwin-Williams on GlobalSpec
Hope this helps and good luck .


J

 

[SPIKER]

one thing is it depends on the SAND material that you used to blast with. some stuff (silica sand) is bad due to the material left behind as well as the dust in the lungs. if play sand or silica sand is used then you need to clean better than if a granite sand or steel shot was used. granite (black beauty trade name)
silca sand can/does leave a material that will prevent paint from sticking well and also leaves moisture locked in the sand pours in the metal which will let it re-rust and or have paint adhesion issues. Granted the blasted surface is probably one of the best surfaces for paint to STICK to is does still require cleaning and a good "phosphate" treating will also make a great surface to stop rust and stick paint... there are Primers that have a Phosphate material included but a better is a Phosphate wash prior to primer will help adhesion and stop rust better...

Mark M

 

[amashinga]

Thanks for the responses guys