I’ve had to repair a paint defect, a 4 inch long horizontal split/crack over the wheel arch.

Initially, this was supposedly a 10 minute repair; flat down split to bare metal, feather painted edge into metal. etch primer, build up to existing paint with high build primer, flat and apply top coat; all from Rattle cans.

However, whilst reposition masking tape around the area to be primed (back masking) the original paint peeled off with the tape; so that area had to flatted too; now, there’s so many areas which I’ve had to flat to a bare metal and feather; I’m wondering whether I should skim the flatted areas with filler; to prevent a fried egg effect from occurring once painted.

As this was initially a temporary repair, to prevent corrosion and to make it look more presentable, I was happy to just build up the bare metal area with primer and paint.

Searching YouTube, all results relating to bare metal repairs and paint feathering, appear to demonstrate just the feathering of the paint edge and no mention of the possibility of the fried egg effect.

It’s my belief, that when paint is flatted back to bare metal, even with a feathered edge, the bare metal area is much lower than the original paint; therefore, the bare metal area has to be built up to the same level as existing/surrounding paint; thus, a light skim of filler is applied and once cured, it’s flatted and feathered into the feathered bare metal paint edge, so there’s a smooth transition between the two feathered edges; or does the use of high build primer negate this ?

If you feather it out far enough it's usually not a problem.
For really thick paint or a problem area you can always add a little
spot putty, then prime and sand smooth.

BTW. Most rattle can primers are lacquer based and
not for bare metal. They soak up moisture like a sponge
and will rust underneath. They also shrink a lot for a long time
so anywhere you build up more than a coat or two needs
days to dry and shrink.

Thanks for your reply.

I’m at the limit with how far I can extend the repair to feather out; any additional feathering and I’ll end up removing all the paint. Also, I’m attempting to keep the repair within the middle section of the wing/fender and within a lower contour line.

Although the paint and primer I intent to use is from Rattle cans, it’s actually 1k and mixed by a bodyshop supplier; would that be lacquer based ?

I’ve never heard of lacquer based primers.

The etch primer, which I intended to apply over the bare metal, although it’s off the shelf, it’s supposedly marketed to the trade.

If I skim filler/bondo over the bare metal, I won’t use the acid etch primer.

Good results and rattle cans rarely get mentioned in that same sentence when it comes to external repairs, especially when it is necessary to blend in with existing paints.

1k means it has no activator or hardener. Generally that is what lacquer based paint is called.

2k means it has two components, a base and an activator or hardener.

Most of the today's automotive paints are 2k from epoxy primer, build primer, single stage, base coats and clear coats. The thing is 1k and 2k products are not often compatible.

A good auto body and paint shop should be able to mix 2k spray can style products for you.

The problem soon becomes the cost, hence most body shops and painter's by quantity, mix and spray it themselves, using a proper spray gun set up.

1968 Coronet R/T......Thanks for your very thorough reply

I’ve repaired and painted bodywork for many years, I actually trained to be a paint sprayer but never took it up professionally.

I’d just never heard of lacquer primers

Yeah, professional paint spray equipment can’t be beaten and for my current repair, I should be using my DeVilbiss Spot Repair gun.

However, as a teenager, when purchasing a compressor and spray gun was way beyond what I could ever afford; I had no choice but use rattle cans, and eventually, I developed a flair, this was when the paint quality was poor and the nozzles and fan patterns was terrible; nothing like the “ Professional “ style nozzles of today; eventually I graduated to the use of an air brush with air canisters, then replaced the air canisters when I could finally afford a mini compressor.

Over the years, mainly on my own vehicles, I’ve actually achieved some fantastic results from rattle cans, good colour blends and paint match; although the colour match is due to the level of tint added during the mixing and my rattle can suppliers use of spray out cards; also, I normally apply primer that’s the same colour as the base coat.

I don’t use 2k paint, especially those which still contain isocyanates; also, I don’t have an air fed mask and my compressor isn’t powerful enough to feed a mask and spray gun at the same time.

I’ve never had the need to use epoxy primer, as my repairs are normally painted once primer has flashed off and dried.

So if you have all of this experience and success with rattle cans, why post the question?

Keep in mind,
etch primers and body fillers are not compatible.
If you use a etch primer for bare metal it needs to be covered
with a regular primer before any filler is added.

1968 Coronet R/T.......I’m sorry if I’ve offended you and I appreciated your explanation and initial response.

However, my question was in regard to feathering paint, preventing the “fried egg” effect and what I’ve recently seen on YouTube.

YouTube footage, demonstrates the feathering of the paint around the repair but non I’ve found, mention or demonstrate the application of a body filler/bondo or glaze to bring the bare metal up to the same level as existing/surrounding paintwork and I wondered, whether the application of high build primers has negated this process.

I didn’t actually asked for advice in regard to using a rattle can and I only included “ Rattle Can” in the subject title; so that anyone who was good enough to reply, knew where I was at.

JCCLARK wrote:Keep in mind,
etch primers and body fillers are not compatible.
If you use a etch primer for bare metal it needs to be covered
with a regular primer before any filler is added.

Yeah, I only planned on using Etch primer when it was a quick repair and building up with the high build.

I’ve decided to skim with filler now, so wont be using the Etch and once the filler has been flatted, I don’t expect any bare metal areas to occur.
Thanks.