Bare metal prep

[rsrguy]

Fellow paint sniffers...
I'm currently working on a non porsche project.... Acres of bare steel, I've used the ppg one choice cleaner and conditioner. It's been done for several weeks now, and im almost ready to epoxy prime the bulk of the exterior..

I followed the tech to the letter rinsing until the water sheeting was apearant, and no, It's in a dry temp controled environment.

I intend to perform multiple wipe downs with acetone and w&g remover until the prep towels come away clean.

I've read some prefer a final scratch down of 80-100 before epoxy. I've also read some wash with soap and water to neutralize any remaining acid.

I paint every day... Aircraft both fabric and aluminum, I know my craft, however it's been 20+ years since I've shot bare steel..

So what's my best next move?

[rsrguy]

[962porsche]

I'm not a PPG user so with out looking up the TDS on that I'm not sure about the uses of it.
you state you did follow the TDS so you should be fine with that.
for the epoxy primers I use it's a 180 to prep the panels for the one wet coat of epoxy primer.
when we/I use epoxy just for metal protection and not as any type of a filler primer it's mixed as a sealer/ surfacer and not as a filler or build type primer.
with it as a thin mil sealer you can do your body work over it and not have to worry about feathering out a filler build primer around your body work areas.
once we are done with the body work and have bare metal areas I will again spray the epoxy mixed as a sealer just around the body worked areas where there is bare metal. I let it flash and go right to a fill / build primer over the hole panel/s to give a good surface to block.
if your looking to spray a filler primer over the hole panel/s I would sand the entire panel/s with 180 or 220 then spray the entire panel with one more coat of epoxy sealer and going wet on wet let the sealer flash and spray your filler primer right over it.
but read your TDS for your filler primer to be sure 180 or 220 is the proper grit to have the proper tooth for it to bit into.

[Dpmulvan]

Don’t use acetone to wipe down use denatured alcohol.

[962porsche]

acetone is not that bad of a cleaner for bare metal uses only. it shouldn't be use as a cleaner for porous substrate like primers or paints.
I use acetone on every roll cage I build to clean off the sharpie marker marks with no problems at all.
when and if your going to use it on bare metal you have to just like with all cleaning products have to wipe a small area and before the product dries wipe it back off clean and dry.
you most likely will have a problem with acetone if you just wipe it on the surface and not wipe it back off. by not wiping it off when it's wet you will leave a residue of the acetone on the surface that could easily give you adhesion problems later on with other products.

needless to say in many cases ( if your not dealing with sharpie marker marks ) to just use a metal cleaner product. many metal cleaning products you use the same way as you do with a pre body work grease and wax remover and a pre paint cleaner.

if your going to use an alcohol you would want to use Isopropyl alcohol .
this makes for a very good cleaner . I use it often as my go to cleaner because it low cost and readily available.
for a pre body work cleaner I mix it in a spray bottle 75% alcohol to 25 distilled water.
for a pre paint cleaner I tend to mix it 50% to 50%.

[rsrguy]

I'm not worried about cleaning the metal. My question is, after having used an acid based prep and conditioner.... Before applying cre epoxy to the metal have you or would you done a final scratch with a da...
The tech sheet says I'm good to go.

Even though, I'm apprehensive about shooting the cre on the product, as I've always shot epoxy dtm without any conditioner.

It's taken a while to get to this stage, so I went with the ppg conditioner because I wanted to address any potential microscopic rust(even though its inside a temp controlled hangar in a high desert environment).

My idea was that the conditioner addresses the low (microscopic) and scuffing the top would give fresh steel/tooth for epoxy to bond to.

[rsrguy]

Here's the tech sheet

[962porsche]

it looks to be you would only really need to scuff the panel/s with a scuff pad if it's a galvanized substrate. would it hurt anything if you still did it with a none galvanized panel? my guess would be NO you would be just fine.

[rsrguy]

Basically that's the finish after the conditioner (looks galvanized) zinc conversion surface coating.. This is before

[rsrguy]

Yesterday, That's ppg cre epoxy primer, it's tintable, I wouldn't call it color matched though, just close. I spoke with the ppg tech rep, he said the high end shops aren't using high build poly primer, just lots of this stuff to build and block... It's pricy, but, according to him there's hardly any shrinkage. I didn't even know blocking epoxy was a thing! I paint aircraft almost every day... it's been years since I've shot bare steel... much less acres of it.

I used the one choice metal prep system a while back, for 2 reasons, one to protect it from any atmospheric rust causing moisture until I could set aside a full day to get it into primer... Second because I wanted to convert any no-see-em teeny rust. It's been about 2 months from the time of treetment.

The ppg tech rep said the sx treatment and conditioner are meant to be shot within a short time frame, so I needed to sand it before priming. That was yesterday, 6:30 am to 5 pm... long day.

A seriously long day.... probably why it took so long to get to this point, mainly because, once you start, you* can't stop until it's all sealed up. Any way, yesterday was the first full day I could devote to it in a while, and that didn't include commute time. Now I'm free to chase dings and block at will daily, (search & destroy) I estimate 2 weeks to paint.

Any way, lots of good music.*

Gordon Lightfoot, Beatles, doobies, heart, Taylor, rush, Boston, Fleetwood, wilbury's, Petty (did you know he od'd on fentnyl? dip****) Beach boys, def Leppard, Zep, yes, elo, elp, Asia, Ramones, queen, acdc, derek&dominoes, bad co, the church, romantics, who, Kansas, vh, I'm sure a bunch of others I'm forgetting, I forgot daft punk.... there good for a driving beat when you get bogged... What a great day... just long.*