Zinc Chromate tech......

[ryoken]

in light of recent posts (), and the numerous PM's I get pertaining to the product, I thought I'd throw out some of my findings, etc after using the product for decades...

as to prep.... gritty is good.... sometimes... here's why.....

if zinc chromate is going to be used strictly as an etching primer and have a filling primer on top of it, you wont need to worry about sandscratches showing thru, or even a heavy gritblast, as the fill prime will take care of anything...

the courser the cut, meaning the lower grit #, the better ANY autobody product will adhere... I usually prep raw steel with 80 grit on a DA for a zinc/fill application..

stupid small part you don't wanna bother with a fill prime? a little lighter on the grit and a couple extra coats of the zinc... paint right over the zinc...

this leads me to mil thickness and windows of application.......

generally, in a perfect world, your parts wont be green long.... you zinc em, come back in an hr once they've flashed off and overcoat them with your filling primer... a "wet on semi wet" app as I call it.. in this case, you want a minimum of mils, just a pisscoat is all thats needed... 2 thin coats...

now, for the rest of us in the not perfect world, parts may sit... if the zinc is going to be uncoated for more than a day, IT SHOULD/LIKES TO BE, SCUFFED OR SANDED before the next app, either paint or fill prime... doesn't have to, but likes it...

course scuff pads work the best.. 3M's are the maroon.... you can sand it in a pinch, but it's easy to go thru to raw steel...

this brings up the last point.. perfect world, the application should be thin enough that exposure to weather, etc will allow rust eventually....

sitting around for weeks and plan on having to scuff it? put double the primer on... it now holds up to any moisture VERY well, and gives you some material to scuff/sand when the time comes...

I wont bother with getting into 2-part washs, etc unless we need to.....

comments, questions, feel free... if I remember anything else thats pertinent, I'll post back up...

 

[scotsdale83]

numerous posts and pms you say? Never would have thought that would happen. lol

 

[ryoken]

I'm good for about 2 or 3 a week I'd say..

It is a nice procedure...


oh, just remembered another..

zinc doesn't like bondo, etc on top of it like an epoxy or urethane primer does... so do any bodywork, than spot in the zinc on the bare stuff, then fill prime everything...

 

[Greg72]

Subscribed.

I'm a recent convert and fan of what I now call "Ryoken Green"...

 

[ThaMule]

i was first introduced to zinc chromate when i was in the army. we used it to fill in spots on the tail rotor driveshafts where paint had peeled. We did this with as little as possible and did not paint over it either so as not to disrupt the balance of the driveshaft. vibration in the tailrotor cause lots of problems.

 

[BGKYK5]

Subscribed.

I'm a recent convert and fan of what I now call "Ryoken Green"...

Is that anything like Soylent Green?

 

[rdn2blazer]

I have never painted anything with a paint gun, only rattle canned stuff. Don't know a damn thing about painting. Wish I did. So is this good primer to use? What kind of primer should you coat over the Zink primer with? And do you have to paint over the second primer coat? If so or if you want to what should you use? Thanks for the recommendations.

 

[rufusbooth]

Thanks Ryoken! Great info. I would actualy be interested in the 2 part wash info as well if you manage to get the time to post up about it.

Cheers,

Rufus

 

[ryoken]

I have never painted anything with a paint gun, only rattle canned stuff. Don't know a damn thing about painting. Wish I did. So is this good primer to use? What kind of primer should you coat over the Zink primer with? And do you have to paint over the second primer coat? If so or if you want to what should you use? Thanks for the recommendations.

it's probably the best initial prime coat to raw steel you can do, better than epoxy, etc.. it can be overcoated with any primer... usually it'll be a fill primer, urethane or enamel.... urethanes are superior.. heck, you can put lacquer primer over it..

whether you have to paint over a second primer all depends on what primer you put on... zinc with an epoxy or urethane primer will hold up for a damn long time... it'd chalk at some point from oxidation, but wont rust... thats with no topcoat...

paint over the zinc, or the filler primer on top of it can be anything from rattlecan lacquer to base/clear urethanes...

i wouldn't do a whole vehicle in strictly zinc, then paint.. you could, but for that your better off adding the filller primer above the zinc...for bodywork/blocking/sanding reasons...

if your feeling lazy with smaller parts, say a dif cover, whatever, you can just paint right over the zinc... it's fine... not quite as tough as it would be with a zinc and filler primer, but FAR superior to just paint on raw steel....

anything comes up you wanna know bodywork/paint/fiberglass-wise Rob, just PM me, I'll hook ya up....

 

[ryoken]

Thanks Ryoken! Great info. I would actualy be interested in the 2 part wash info as well if you manage to get the time to post up about it.

Cheers,

Rufus

your quite welcome.... it always boils down to how much i feel like typing...

sure, i can do a post on 2-part products as well.. i'll do one later tonight, going to din-din now.....

i just kinda realized there are quite a few other related tidbits to write about in closely related subjects that i've touched on in here over the years.. but probably never had in one thread... metal conditioners, proper grit prep, sealers, compatibilty things, etc...

lets just say, I should probably be writing a book.... if i didn't write like a 6 yr old...

maybe i'll use this thread for autobody tech stuff...

 

[LUBA]

Thanks for the info. I'll be watching this thread.

 

[BoondocK5]

Hey Paul, how do you feel about self etching primers?
I bought the 2 part yellow, But I have some aqua green 2 part self etching primer also. I guess it really doesn't matter as long as paint or sealer sticks to it and its sand-able.

 

[ryoken]

Thanks for the info. I'll be watching this thread

no prob......

here's a few tidbits concerning 2-part washes.... This is a product thats becoming harder to come by every year... at one time, all the manufacturer's had one in their product line-up....

now with the push of "all in one, zincless, etching primers", they are becoming harder to come by... I do know the marine industry still has them available... Awlgrip has one... it is a vinyl phenolic resin based product.. it uses an acid reducer..

they are usually a 1 to 1 mix, primer (base) to acid (converter)....

you want it to be about 5 mils wet thickness.. in other words, thin... you want to keep it translucent a bit...

as with the rattle cans, the same overcoating windows, scuffing rules still apply...

I think Dupont is still making theirs too... but I have no idea if the other manufacturers have theirs out anymore.. PPG, Sikkens, etc....

 

[ryoken]

Hey Paul, how do you feel about self etching primers?
I bought the 2 part yellow, But I have some aqua green 2 part self etching primer also. I guess it really doesn't matter as long as paint or sealer sticks to it and its sand-able.

well, that term is a slippery slope these days... manufacturers have been abusing it for awhile now.. what TRULY is a self-etching is murky these days.. zinc wash, no question there...

zinc chromate, aka zinc washes are THE original, true self etching primers.. over the years as the gubment has tried to get the zinc out of the products, the manufacturers have moved to "all in one style, self -etching primers" with self-etching capabilities, without the zinc..

some are decent alternatives to zinc when it is unavailable.. down the road, it may be the only option.. a better option than many of course, but not as good as the oldschool zinc stuff imo..

 

[BoondocK5]

I use the real ZINC chromate on Aircraft parts because it sticks to aluminum like glue and creates a corrosion barrier. I was just wondering if it would work on steel, both regular, and Stainless as well.
Uncle sam keeps going back to the real stuff because the "fake Zinc Chromate" crap just does not provide as good of corrosion protection.

 

[ryoken]

yup, thats it's original purpose, alum and galvanized..

one of my pet peaves, people, and products that paint directly over alum, or galvanized.... it WILL fail, without the etch...

but yeah, zinc, is very beneficial on steel... not as vital as the other 2, but helps a ton....

 

[BoondocK5]

Also, I think I'm going to start using Alodine on everything I build anymore. steel or Aluminum. It bonds with the base material creating another layer of protection against the dreaded corrosion, and can have the self etching primer applied directly over it, then paint.
Any comments?

 

[ryoken]

I'd be VERY curious as to the Alodine process... I've known the term for years, understand what it is, but have never had the opportunity to use it..

any tech you could add on that process down the road would be awesome!

Alum is where I would think that process would really help... steel's, I've always just liked metal conditioners..

 

[BoondocK5]

ALODINE

Good stuff, if you leave it on too long it will "burn" the metal leaving it brown instead of gold tinted.
It chemically bonds with metal, creating a micro-thin layer of protective surface that stops rust and oxidation cold.

I paint metal with it that I'm going to leave outside for more than a day. rinse off after 10 minutes.

 

[ryoken]

yeah, i've used the #33 and #79, but never the alodine... I'll have to give it a try, thanks!