Bare metal parts - prep

toddu · 05-14-2007, 10:51 AM

So I've got parts back from the blaster. Was told to clean with prep solvent, wash and dry WELL. However, I envision wash + bare metal = instant haze of rust????

Porsche_monkey · 05-14-2007, 10:57 AM

POR-15 Metal Prep shouldn't cause rust. If you do use water, just dry it with a heat gun right away.

When will you be painting them? If they sit around like that they will rust fast.

toddu · 05-14-2007, 11:15 AM

PRep I have( forget brand) says to rinse right away.

I'll primer same day. What if I do get a light haze? Sand?

Porsche_monkey · 05-14-2007, 11:36 AM

Mike O'Meara · Mike O'Meara's Garage

The metal prep is usually phosphoric acid which cleans really well and also leaves a protective coating on bare metal. Dry it well, and if you ever should get a haze of rust, wipe it with the metal prep, it will take it off very quickly and easily.

shbop · 05-14-2007, 03:23 PM

Ospho or Rust-Mort. Quick and easy

Zeke · 05-14-2007, 03:35 PM

Quote:

Originally posted by Mike O'Meara
The metal prep is usually phosphoric acid which cleans really well and also leaves a protective coating on bare metal. Dry it well, and if you ever should get a haze of rust, wipe it with the metal prep, it will take it off very quickly and easily.

The POR stuff leaves a goo. You HAVE to rinse it. Most of the top shops are using "The Must for Rust," which can be left to dry without rinsing.

However, you don't need any of these products if your parts are blasted and clean. But, your parts are rough from the blasting. You need to sand them at least to an 80 grit and I go further to 120. Then, you can blow them off, wipe them down dry and then use a painter's prep, which is a highly volatile solvent. Prime ASAP with self etching primer and don't sand through that in subsequent primes and sands. Or, you can prime with epoxy primer which is very expensive, but will hold the metal for months, if not longer.

We have some good threads here about this.

911SCfanatic · 911SCfanatic's Garage

I found that out with Eastwood OxiSolv the other night. Left it on a little tool long and it dried into a sticky goo. I'm prepping parts fasteners for replating. I sandblasted, ran them through the vibratory tumbler w/ Eastwood Metal wash. That worked for most of them, but a few of the brake parts and some washers got some flash rust. Used the OxySolv, but it was kind of a mess to work with...you have to babysit the parts for 30 minutes. Would the Must/Rust work for this application (as well as body panels)?

toddu · 05-15-2007, 07:08 AM

I'm a little confused now with all the replies (which I do appreciate). So, the "Must for Rust" stuff can be used as a paint prep for the bare blasted parts? I picked up a bottle, but it seems geared towards rusty metal. My parts are bare (and nice and smooth), I just want to make sure I prep it good to get the best possible end results.

Tim Hancock · 05-15-2007, 07:21 AM

Todd, if you have fresh sandblasted parts, you would be plenty fine to just prime with epoxy primer or a selfetching primer. I have used metal treatment products myself on some jobs prior to priming, but when I have fresh sandblasted parts, I typically just skip the metal prep solutions and have had great long lasting results. There are plenty of ways to do this job and everyone will have their favorites. The fresh sandblasted surface pretty much insures that you will not have any problems no matter which technique you use.