stripping a patina Duster hood

[ESP47]

I guess I don't understand why there was a need for ospho if the hood was media blasted. One of the biggest perks of media blasting is that it gets the rust pits out that sandpaper and wire wheels can't touch.

 

[ir3333]

Google Eastwood "Fast Etch"

 

[mopowers]

Google Eastwood "Fast Etch"

I had to look this stuff up.

Correct me if I'm wrong, but at $55 a gallon and only 7.8% phosphoric acid (the other 92.2% is water), the Eastwood Fast Etch product is pretty pricey for a diluted acid solution. You can buy a 35%-45% phosphoric acid solution at the hardware store for $18 a gallon and have enough to make 5 gallons of the more diluted Eastwood stuff.

 

[mad dog]

Esp47, i didnt have the whole hood blasted because i was fearful of warping the metal, i only had the backside heavy hood bracing blasted, i still had to deal with the pits everywhere, Duster hoods are getting harder to find so i guess the effort will be worth it in the end.
finishing my coffee and then back to sanding and then seal it up with some SPI epoxy...

 

[ir3333]

Is Eastwood Fast Etch just diluted phosphoric acid.Their tech say you only need to wipe with paint prep before top coating and bare metal can be left nearly indefinitely without flash rusting.
Also leaves zinc film to promote paint adhesion.
If it's the same as hardware products diluting is a great idea but a gallon of Eastwood Fast Etch will do more than a whole car.

 

[340six]

I wouldn't even let it dry. It's much easier to clean up when it's still wet. Plus, if the metal's been DA'd and/or blasted, it shouldn't take that long for the phosphoric acid to clean up what little rust is left. Maybe it's just me, but letting it dry just results in more (and usually unnecessary) work. The "white powdery substance" isn't as easy to get off as they make it sound. From my experience, it's a pain in the *** to remove.

If it was me, I'd apply the acid, let it sit for 10 mins and wipe it off with a wet sponge and a bucket with lots of fresh water, then repeat as necessary.

That is what PPG DX579 is. Thet say do same but use Hot water and wipe with was grease remover, Wipe Down like normal. Then epoxy
DX579 metal conditioner is same stuff.

 

[mopowers]

Is Eastwood Fast Etch just diluted phosphoric acid.Their tech say you only need to wipe with paint prep before top coating and bare metal can be left nearly indefinitely without flash rusting.
Also leaves zinc film to promote paint adhesion.
If it's the same as hardware products diluting is a great idea but a gallon of Eastwood Fast Etch will do more than a whole car.

That's a good question. I looked up the MSDS for Fast Etch and it looks like it's just a much more diluted version of OSPHO or similar product. Maybe paint isn't as much of an issue because it's more diluted?

https://www.eastwood.com/images/library/19416Z.pdf

 

[ESP47]

Esp47, i didnt have the whole hood blasted because i was fearful of warping the metal, i only had the backside heavy hood bracing blasted, i still had to deal with the pits everywhere, Duster hoods are getting harder to find so i guess the effort will be worth it in the end.
finishing my coffee and then back to sanding and then seal it up with some SPI epoxy...

Makes sense.

In the future if you have the room and don't mind getting dirty, you can always fill up a bucket with this media

https://www.tractorsupply.com/tsc/product/black-diamond-medium-blasting-abrasives?cm_vc=-10005

and use a blast cabinet gun hooked up to your compressor and get all the rust pits out that way. Use your safety equipment of course....but this type of media has very low silica so it's one of the safer types to use.

I would not recommend trying to blast anything large with this method because it would be like trying to paint a hood with a fine tip sharpie. But it gets the rust pits out without worrying about warpage and it gets the nooks and crannies that you can't get with sandpaper.