A question for the bodyshop guy's

Wed Jan 28, 2009 4:53 pm

I've decided it's time to sort some surface rust on my car, the thing I need to know is should I use zinc primer or self etching primer on the bare metal?

I've been looking at loads of restoration threads on here and other forums and while you get lots of people saying they used zinc primer to stop the rust coming back there are also those that say you should always use an etch primer on bare metal as it is more flexible and creates a better bond between paint and metal so it will provide better protection.

Is one better than the other or is this one of those things that is a personal preference.

Any advice appreciated.

Paul

Wed Jan 28, 2009 7:29 pm

etch primer is better than zinc primer imo.

Fri Jan 30, 2009 2:40 pm

I was hoping for a few more responses but thanks.

Fri Jan 30, 2009 2:48 pm

Im just undergoing a restoration on one of my cars and im using zinc primer all the way. This was advised from a guy that owns a bodyshop.

Fri Jan 30, 2009 2:52 pm

O oh, you've triggered my curiousity and Ive started browsing and so far its advised to yous zinc primer on welds and etch primer on bare shell, as etch primer sticks to the shell of the car where as the zinc primer lays ontop of it.

Fri Jan 30, 2009 6:56 pm

Anyone have anything to say about this?

Fri Jan 30, 2009 7:08 pm

zinc primer is only meant for seams where two layers of metal are on top of each other such as where the inner and outer arches form the wheel arch lip, the idea is that these areas need to be bare metal in order for you to weld them but leaving them untreated will lead to the return of rust in double time. zinc primer has a very high metal content and as such will conduct electricity and therefore enable you to spot or migweld the area.

do not mistake this product for some kind of galvanising as it really is not all that durable and doesnt adhere to the metal anywhere near as good as etch primer or any primer for that matter.

Fri Jan 30, 2009 7:21 pm

beardymat wrote:zinc primer is only meant for seams where two layers of metal are on top of each other such as where the inner and outer arches form the wheel arch lip, the idea is that these areas need to be bare metal in order for you to weld them but leaving them untreated will lead to the return of rust in double time. zinc primer has a very high metal content and as such will conduct electricity and therefore enable you to spot or migweld the area.

do not mistake this product for some kind of galvanising as it really is not all that durable and doesnt adhere to the metal anywhere near as good as etch primer or any primer for that matter.

Good post, I've learnt something today. Thanks.

Fri Jan 30, 2009 7:26 pm

beardymat wrote:zinc primer is only meant for seams where two layers of metal are on top of each other such as where the inner and outer arches form the wheel arch lip, the idea is that these areas need to be bare metal in order for you to weld them but leaving them untreated will lead to the return of rust in double time. zinc primer has a very high metal content and as such will conduct electricity and therefore enable you to spot or migweld the area.

do not mistake this product for some kind of galvanising as it really is not all that durable and doesnt adhere to the metal anywhere near as good as etch primer or any primer for that matter.

Ok well that sure answered my question

Fri Jan 30, 2009 7:31 pm

madaboutthe30 wrote:
beardymat wrote:zinc primer is only meant for seams where two layers of metal are on top of each other such as where the inner and outer arches form the wheel arch lip, the idea is that these areas need to be bare metal in order for you to weld them but leaving them untreated will lead to the return of rust in double time. zinc primer has a very high metal content and as such will conduct electricity and therefore enable you to spot or migweld the area.

do not mistake this product for some kind of galvanising as it really is not all that durable and doesnt adhere to the metal anywhere near as good as etch primer or any primer for that matter.
Ok well that sure answered my question

im here to help

its a good job you caught me early on a friday though as i soon start to no sense all make at the due booze to

Sat Jan 31, 2009 12:01 am

Beardy mat, with that zinc primer I sprayed onto areas of bare shell, do you think it would start rusting away again?

Is it worthwhile I sand it down to bare shell again and spray etch primer onto it, or will I get away with leaving it how it is??

Hope your not too out of it

Sat Jan 31, 2009 2:24 pm

madaboutthe30 wrote:O oh, you've triggered my curiousity and Ive started browsing and so far its advised to yous zinc primer on welds and etch primer on bare shell, as etch primer sticks to the shell of the car where as the zinc primer lays ontop of it.

Like you I was going to use zinc primer but then I started reading through some restoration threads and started doubting if that was right.

beardymat wrote:zinc primer is only meant for seams where two layers of metal are on top of each other such as where the inner and outer arches form the wheel arch lip, the idea is that these areas need to be bare metal in order for you to weld them but leaving them untreated will lead to the return of rust in double time. zinc primer has a very high metal content and as such will conduct electricity and therefore enable you to spot or migweld the area.

do not mistake this product for some kind of galvanising as it really is not all that durable and doesnt adhere to the metal anywhere near as good as etch primer or any primer for that matter.

Thanks beardymat, that's what I wanted to hear as the bits and pieces of information I'd found seamed to indicate that but with it all coming from different places I wasn't too sure. It's good to have it all come from one person who knows what they are talking about.