What blasting media to use?

[mike sampsel]

So I'm looking at my rear fenders, forward part where oil lines are on pass side. Thinking of blasting out the corner to apply a rust stop, rust inhibit paint in the area. There is no rust which is obvious.

What type of media to use? Aluminum oxide, sand walnut shells. Paint on the outside is only 5 years old and is in great shape. Want to keep stuff from sitting in the nooks to trap water where I am thinking of blasting.

Maybe not blast?

[mepstein]

Blasting in the open makes a mess. Especially on a running car.

[mike sampsel]

Originally Posted by mepstein

Blasting in the open makes a mess. Especially on a running car.

Good to know, what I should have known, thanks

[ChrisHamilton]

If you do end up blasting something, crushed glass is always my first choice. Coal slag next. Both are very affordable and somewhat easy to find. Northern Tool carries both. Tractor Supply has coal slag IIRC. Sand is never a good choice due to the amount of free silica in it which is not good for you to inhale.

Best thing you can use to inhibit rust is a quality epoxy primer. SPI (Southern Polyurethanes) makes one of the best available. Stay away from POR-15 and other "rust encapsulating" products, they don't truly inhibit rust and moisture can continue to wick in between the POR15 and the metal. Which leads to more rust. I've had clients who applied POR-15 at some point before bringing me their vehicle and where shocked at what the metal looked like after I removed the POR-15. A good quality epoxy primer like SPI's is the best thing you can use on bare metal and will provide many, many years of protection.

[mike sampsel]

Originally Posted by ChrisHamilton

If you do end up blasting something, crushed glass is always my first choice. Coal slag next. Both are very affordable and somewhat easy to find. Northern Tool carries both. Tractor Supply has coal slag IIRC. Sand is never a good choice due to the amount of free silica in it which is not good for you to inhale.

Best thing you can use to inhibit rust is a quality epoxy primer. SPI (Southern Polyurethanes) makes one of the best available. Stay away from POR-15 and other "rust encapsulating" products, they don't truly inhibit rust and moisture can continue to wick in between the POR15 and the metal. Which leads to more rust. I've had clients who applied POR-15 at some point before bringing me their vehicle and where shocked at what the metal looked like after I removed the POR-15. A good quality epoxy primer like SPI's is the best thing you can use on bare metal and will provide many, many years of protection.

Like the knowledge, it might be a challenge to get everthing to bare metal in the recess of the rear fender by the doors. As such, I'm thinking maybe a rust attacking-inhibiting paint might be okay. Or are these just snake oil? Hum, I guess the paint I ordered is fortified with epoxies, so it might suit me well.

Thanks for sharing your wisdom, knowledge is always appreciated.

[Bill Douglas]

Mike, this Brunox may be what you are looking for. It's an epoxy but with (I guess) phosphoric acid in it. I've had quite good success with the stuff https://www.brunoxswiss.com/brunox-epoxy

[mike sampsel]

Originally Posted by Bill Douglas

Mike, this Brunox may be what you are looking for. It's an epoxy but with (I guess) phosphoric acid in it. I've had quite good success with the stuff https://www.brunoxswiss.com/brunox-epoxy

Thanks Bill.

Might need a translator, I think I have something similar. The link is interesting, I can only get the Czechoslovakian language version.

[Bill Douglas]

Try this Mike. We sort of speak English around here. https://www.pacer.co.nz/category/301-brunox

[ChrisHamilton]

Originally Posted by Bill Douglas

Mike, this Brunox may be what you are looking for. It's an epoxy but with (I guess) phosphoric acid in it. I've had quite good success with the stuff https://www.brunoxswiss.com/brunox-epoxy

That stuff looks like it would be good on the backside of panels and other similar areas. Slightly confusing as to what it is because acids and epoxies don't really mix.

For overall protection though nothing beats a proper two part (activated) epoxy. Wise old guy I learned a lot from used to tell me in regards to refinishing that "nothing good ever comes out of an aerosol can." Stuff I use will pass the aviation Skydrol test. Skydrol is a highly corrosive hydraulic fluid and if a paint passes that test it's a good indicator of it's quality. Paint is so expensive and the amount of labor required is such that you want to do it right the first time. Having a quality two part activated epoxy as your base over bare metal is a good start.

[Bill Douglas]

Yeah totally agree. A good epoxy is not porous so therefore shouldn't let air and moisture in to allow rust to occur. In theory LOL

The Brunox stuff I used was in the half litre container and I used a paintbrush to put it on. It's been about a year and I put it on the rusty bit bottom left corner of the 911 back window area. No rust bumps yet. Who knows. It seemed quite happy with a regular PPG automotive primer/base/clear coat over the top.

I also used some on a rusty car trailer too with some success.

[Dpmulvan]

Originally Posted by mike sampsel

Like the knowledge, it might be a challenge to get everthing to bare metal in the recess of the rear fender by the doors. As such, I'm thinking maybe a rust attacking-inhibiting paint might be okay. Or are these just snake oil? Hum, I guess the paint I ordered is fortified with epoxies, so it might suit me well.

Thanks for sharing your wisdom, knowledge is always appreciated.

Just did this last year on a rotisserie and it was still a pain. Try a knotted wire wheel to remove chip guard( be careful they are dangerous don’t catch an edge) or a little pneumatic chisel, sandblasting would take forever. Get it down to metal apply ppg metal cleaner then the conditioner or similiar then epoxy let it flash then new chipgaurd.

[mike sampsel]

Hey, my exterior body is fine and great. However it appears there may be some rust going on between the rear fenders and the body. (As evidenced by couple of bubbles on the door jam with the striker plate). Not super serious but I’m trying to slow any progression as best I can. Does the black tarry stuff need to come off? I’m sure I can get some of it off, but not all especially in the crevices. Thinking if I hit it with a good rust inhibitor it won’t hurt. (After I do the best prep I can do in SITU). Probably best to remove as much of the black goo as I can.

It’s a Dallas/Arizona car so no salt. But it appears to have something going on here.

Your thoughts are appreciated. Is there a commercial black goo I could use to fill in after the rust inhibitor is used? Or is this a no no?





I guess it was answered above, get it down to bare metal as best you can:

Originally Posted by Dpmulvan

Just did this last year on a rotisserie and it was still a pain. Try a knotted wire wheel to remove chip guard( be careful they are dangerous don’t catch an edge) or a little pneumatic chisel, sandblasting would take forever. Get it down to metal apply ppg metal cleaner then the conditioner or similiar then epoxy let it flash then new chipgaurd.