need some help with a sandblasting project

[SPYDERLK]

It's important if your goal is get rid of rust.

You may not have seen metal rust from the moisture sprayed on by the sand blaster. But, I did this for a living, and I sure have.

A system like this, under the right conditions, can spray almost as much water as sand.

Yes, with the proper knowledge and products it can be treated. But, its not the best way to start out your new finish.

I never had one spray that much water. Even if it did it would dry almost immediately. A patina of surface rust on the bare metal will wipe of with a scotchbrite hand pad. Even that is too much trouble for something that will make no detectable difference in the result of his refinishing project.
larry

 

[ray66v]

I never had one spray that much water. Even if it did it would dry almost immediately. A patina of surface rust on the bare metal will wipe of with a scotchbrite hand pad. Even that is too much trouble for something that will make no detectable difference in the result of his refinishing project.
larry

Yes, a scotch brite will remove a light coat of rust from a nice smooth piece of metal. However, rusted metal is NOT smooth. It is usually pitted and rough. Sometimes very pitted and rough. and a scotch brite would have NO effect on that, it would simply skip over the top of the pits.
As I said I actually did this for a living, (30 years). I have actually experienced the water, (even on some days, using a 10 hp compressor), and actually seen the corrosion form on the freshly sand blasted parts. The moisture is a problem, and the rust can be an issue. That is why today where is is done professionally, and properly, there is big money spent for a good size compressor and big money spent on the equipment to remove the moisture from the air.
I wrote that check many years ago, because it was an issue.

 

[RonMar]

Well the shipyards I have been in over the past few years are getting away from sand and using high pressure water to strip hulls...

 

[ray66v]

Well the shipyards I have been in over the past few years are getting away from sand and using high pressure water to strip hulls...

Probably for the same reasons we got away from sand blasting. OSHA has gotten involved because of the silicosis issue, and banned the #2 silica which was widely used. The products that replaced it are more expensive and not as efficient.

Ships are made of higher grades of steel that is expected to be exposed to moisture during construction.

Water can be used on steel, (it often is at the mill), if the proper treatments are known and applied to counter the effects. There are up and down sides to these products. They generally are not for sale to the public.

The automotive paint companies we dealt with, do not recommend the use of any water based products or treatments on bare steel in their warranty programs. Following their guidelines I could do the job, and never have it come back due to failure.

 

[bjcsc]

You fellows realize this thread is about repainting a piece of ag equipment, a $40 planter at that, right? In my experience (and location) the moisture in the air is enough to surface rust a freshly blasted surface regardless of what comes out of the blaster. When I blast stuff, I seldom blast it into the white anyway. I just get all the surface stuff off, use a good primer and good paint and I'm done. Don't forget that rust requires oxygen - primer and paint quality/coverage is the key...