Feb 24, 2010 · Ospho is a water-based solution and the water can hide in nooks and crannies causing adhesion failure of the primer. Old car frames are particularly susceptible to this because of the …

Mar 30, 2010 · This is the start of a thread dedicated to successful rust removal using ospho,a water based phosphric acid product I've been using professionally for many years. Ospho has some …

Oct 10, 2015 · I just completed a crude rust removal experiment and wanted to share my results with everyone. 3 products were tested: - Ospho ($32/gal) - Eastwood’s Gel Rust Dissolver ($38/gal) - …

Nov 21, 2023 · Meaning after you have treated it with Ospho which will take a while to get all the surface rust off and etch a tooth into the metal. Re-wet it with Ospho and keep it wet with Ospho for 10-15 …

May 15, 2015 · Ospho, is a great product for automotive if used right, we give scare warnings because we want people to call so we can make sure they know how to neutralize it, so no problems will arise.

Sep 8, 2024 · At this point I would do as texasking suggested, but for anyone else using ospho, I use ZEP industrial degreaser to wash the thoroughly wet acid off, then rinse with water.

Sep 9, 2022 · My understanding is that Ospho will convert surface rust, but if the rust layer isn't very superficial, I would assume that under the ospho treatment there is still deep rust. Is that just …

Dec 5, 2023 · Flash rust is OK. Stuff that happens in the moments after treating it with Ospho then rinsing. If you have any black pits of rust, you need to remove them or it will fail in that spot. Try …

Jul 18, 2025 · I have read and understand Barry’s recommended procedure for neutralizing Ospho prior to spraying epoxy primer. I have also read that Ospho is SPI’s only (and begrudgingly) …

Mar 23, 2017 · Ospho (product name) is Phosphoric acid which has the ability to turn iron oxide (rust) into iron phosphate state. This leaves a rust incapsulated with a dull black coating which is …