Help with paint prep, Need help with Ospho use Options

[sixaddict]

Have a glass blasted car in for paint. Needed to apply Ospho for surface light rust that developed. We are trying to determine how to neutralize before epoxy primer goes on.
Instructions say brush off dry powder then wipe with mineral spirits. In another section it says to etch wet with Ospho for 30 minutes then wash down with water.
That seems risky due to flash rust.
Anyone have experience to recommend which way to go.
TIA
Terry

[Montreal914]

Ospho website says apply thin coat and let dry 24h before applying paint. (IMG:style_emoticons/default/confused24.gif)

http://www.ospho.com/directions.htm

[Superhawk996]

Ospho website says apply thin coat and let dry 24h before applying paint. (IMG:style_emoticons/default/confused24.gif)

http://www.ospho.com/directions.htm

Personally, I belieive it needs to be neutralized. Go look at the various technical literature for your specific paint - don't belive me. Don't belive others opinions.

Ospho is not really designed for use under automotive finishes, especially 2K which doesn't like an acidic base metal that will be left by Ospho. I've never found it referenced by name in paint technical info. Ospho is basically designed for industrial and/or structural use with an acrylic enamel topcoat - I belive that is where their instruction to let it dry come from.

All I can tell you with certainty is that base surface prep is critical to paint success. Read and understand your paints technical literature. Failure to do so can lead to complete delamination of the paint.

Having said that, guys have been using vinegar and light acids to clear rust on project cars for decades including as prep for 2K. However, it was always advisable to neutralize the acid before paint.

The way you prevent flash rust is to work a small area to neutralize it and then IMMEDIATELY blow the water off with compressed air. This will prevent the flash rust. Brent's methold above of only working small areas with damp rag and scothbrite will achive the same result. Get it on, get it off and dried before the yellow flash rust develops.

SPI is not PPG, DuPont, or BASF but they do support the hobby more than the big guys. As stated previously -- read YOUR tech info but thought I'd post this link from SPI regarding Ospho.
http://www.spiuserforum.com/index.php?thre...ize-ospho.3973/

[sixaddict]

Great info

Thanks !


quote name='Superhawk996' date='Oct 6 2021, 04:03 AM' post='2950645']
[quote name='Montreal914' post='2950598' date='Oct 5 2021, 11:03 PM']
Ospho website says apply thin coat and let dry 24h before applying paint. (IMG:style_emoticons/default/confused24.gif)

http://www.ospho.com/directions.htm
[/quote]

Personally, I belieive it needs to be neutralized. Go look at the various technical literature for your specific paint - don't belive me. Don't belive others opinions.

Ospho is not really designed for use under automotive finishes, especially 2K which doesn't like an acidic base metal that will be left by Ospho. I've never found it referenced by name in paint technical info. Ospho is basically designed for industrial and/or structural use with an acrylic enamel topcoat - I belive that is where their instruction to let it dry come from.

All I can tell you with certainty is that base surface prep is critical to paint success. Read and understand your paints technical literature. Failure to do so can lead to complete delamination of the paint.

Having said that, guys have been using vinegar and light acids to clear rust on project cars for decades including as prep for 2K. However, it was always advisable to neutralize the acid before paint.

The way you prevent flash rust is to work a small area to neutralize it and then IMMEDIATELY blow the water off with compressed air. This will prevent the flash rust. Brent's methold above of only working small areas with damp rag and scothbrite will achive the same result. Get it on, get it off and dried before the yellow flash rust develops.

SPI is not PPG, DuPont, or BASF but they do support the hobby more than the big guys. As stated previously -- read YOUR tech info but thought I'd post this link from SPI regarding Ospho.
http://www.spiuserforum.com/index.php?thre...ize-ospho.3973/
[/quote]