Ok, so I decided to smooth the firewall on my '58 Apache. Just a bit mind you, fill in the unnecessary holes in the fire wall etc. I've got most of it sanded down to bare metal now and will fill in the holes tomorrow. Afterwards do I etch prime the bare metal or can I use a high fill poly like PCL? When is it necessary to use an etch prime? Also are there any decent primers in a can or am I better off shooting it with a gun? Any advice would be appreciated.
In the panel shop I worked in we would etch prime anything over 5-6 inches in area. Either way it cant hurt, the better you set up the basis for paint the better and longer it will last. The smaller areas were primed with a rattle can (Wurth? from memory?) Doc.
Just speeking from my experience, etch is a base for the High Solid primer (or whatever you are using) basically it is just something for the primer to stick to. i never use rattlecan primer cause i found most of it you can scratch off with your nail, if your willing to spend the money Glasurit EP is awesome. Although it does seal the metal and prevent rust it isn't meant to be left unprimed for a long period of time or it will rust (eventually), get that! ha ha
Hey Matt, I used to live in Pelican Waters not too far from you! Too bad Im in ****ty Aspley now. The Wurth etch primer stuck pretty well, never had a problem with it. I do agree though, if you have the means go with a real primer though! Doc.
Hey doc, cool to see other aussies into it, not really much of a scene. We use that wurth stuff at work for priming behind rust patches or in between panels that are getting plug welded, because it melts in to the weld(apparently). By the way i am a third year apprentice at Cl***is Ridz, dunno if youve heard of it?
I've been using the duplicolor self etch, got it originally because i was driving a project and wanted to protect the bare steel between work, stuff has worked way better then i ever expected, not exactly "cheap" for a rattle can,but great stuff.
Always etch. I have used the spraybomb Duplicolor for small areas, and it works great. Sometimes you waste more by mixing up a batch for the small spots. Not to mention the equipment cleaning, etc
Matt, I'm guessing in thats the shop in Caloundra? If so, yeah dropped in there a few times for a sticky beak. I would be deferring to you on the technical aspects, I was just a general dogs body and did minor repairs at Knox Panels in Vic. Hell man, I'm ex Army and a Paramedic!! I only remember doing small patches and like you mention. Cheers, Doc.
There's always a variety of ways to go about it. Ask 10 bodymen, you'll get 10 answers. You could etch primer, then use a hi-build urethane primer. You could use an adhesion epoxy, then hi-build, or use an epoxy that IS an adhesion primer plus hi-build, like HOK's KP-2 epoxy. Old school...lacquer primer (though not nearly as durable as today's products.)
You should almost knock that whole firewall/bulkhead area down and spray the whole piece, or maybe thats what you're doing already?!? Whats up with the disc brakes, tubular a-arms, rack & pinion and TPI motor in the background? Don't let any of the HAMB hard-***es tell you you're doing it all wrong, your truck is gonna kick ***! Especially with that TPI motor if thats what your using! Bryan
Actually, Im using that 5.3L LS1 in the back ground. The TPI is a stoutly built 383 that will just sit till I either sell it or find a project for it. As far priming goes I am sanding the whole firewall/bulkhead. It sounds like using an etch primer is the way to go before using the poly primer.
OK since Doc is probably asleep right now, I'll step up and answer this one. "Sticky Beak" is Australian slang for "having a look at" or "check out". It's usually used in a slightly negative way like a nosey neighbor taking a sticky beak over the fence. As for the origin of the phrase, I'm really not sure but I hope this makes a little more sense now!
I'm proibably a little more old fashioed than others but the way I see it you have two options. Use self etching primer, if you're using a rattle can I've always had good luck with Duplicolor as has been mentioned. Yoyu're other option is to wipe it down with muratic acid then go with whatever promer you want to use. The muratic acid etches the metal which allows the pait/primer to adhere to it. The muratic acid aproach is way old school, but it works well.
i would use etching primer, even with primers that have etch built in. etch in a spray bomb is cool also, id stay away from the poly primers.......i see that alot of guys like the stuff here, but i think its junk, and doesn't last. every job that was cracked up like a dry lake bed that iv'e seen , had poly on it. dry sanded, and with the right top coats it can last, but still not my cup of tea, no offense to the guys who like it skull
A little more explanation in this thread on etch primers. http://www.jalopyjournal.com/forum/showthread.php?t=297587&showall=1
I always use either an etch primer or manual acid etch on bare metal before anything else. Then lay your high build on top of that. Obviously try to avoid mixing lacquer and urethane products, it can be done either way but I personally don't like doing it even in a pinch. Any time you're doing paintwork yourself in less than ideal conditions you have enough to contend with/worry about, you don't need to add any factors that increase chances of trouble. ps- speaking of pinches, I've had good luck spot etching with naval jelly (phosphoric acid)
The Jalopy Journal
