Re-finishing a bad paint job - is 29107 the magic bullet?

[Misterg]

Firstly, apologies for another paint question.

I am contemplating how to tidy up the cumulative efforts of the previous owners of my MX5. (Note to self: Never EVER buy a car in the rain again.)

It has blistering (that looks like it has previously been over-painted):

Some colour variation (I think down to using grey vs white primer):

And some questionable clearcoat (don't think it's factory):

I'm taking it as given that I need to sand out all of the damage until I'm back to a sound surface (I don't have the appetite / ambition to take it back to bare metal , and it's not worth it, anyway) but am looking for some reassurance on how to proceed after that. I'm looking for something between a 3' and a 10' finish (i.e. you wouldn't recoil in horror when viewing it from 3 or 10 feet away). I have a 'normal' garage and a 100L / 3HP compressor with ~5m of copper pipe as a cooler and a water separator, and an LVLP spray gun that I've used exactly once.

From many posts on here, I've picked up that Lechler 29107 epoxy can be used as a bare metal primer, a sealer, and a surfacer (to some extent). Am I OK to sand everything back, maybe hitting bare metal in places. and then go over it all with 29107 until I have a consistent base? (Some of the paint comes off with thinners, so I assume it is rattle can of some description.)

My hope is to use Nisocoat 2 direct gloss as a topcoat, but not sure how well I can can match the colour, as the original was base/clear from the colours available. (Not a huge deal, as I intend to do the whole of the outside of the car, but want it to be somewhere close to the door shuts, etc.) I assume that this can go straight on top of 29107 (bearing in mind the overcoating times).

The bumpers are plastic of some sort - will the 29107 stick to them / the existing paint OK? Or do I need a plastic primer / adhesion promoter / whatever?

The bonnet is aluminium - If I hit bare metal, will the 29107 be OK?

All advice gratefully received.

 

[ajlelectronics]

Firstly, apologies for another paint question.

I am contemplating how to tidy up the cumulative efforts of the previous owners of my MX5. (Note to self: Never EVER buy a car in the rain again.)

It has blistering (that looks like it has previously been over-painted):

View attachment 496255

View attachment 496256

View attachment 496257

Some colour variation (I think down to using grey vs white primer):

View attachment 496258

And some questionable clearcoat (don't think it's factory):

View attachment 496260

View attachment 496261

I'm taking it as given that I need to sand out all of the damage until I'm back to a sound surface (I don't have the appetite / ambition to take it back to bare metal , and it's not worth it, anyway)

That would be correct, but I fear that the damage will take you to bare metal anyway. On a steel car it isn't much more trouble anyway.

but am looking for some reassurance on how to proceed after that. I'm looking for something between a 3' and a 10' finish (i.e. you wouldn't recoil in horror when viewing it from 3 or 10 feet away). I have a 'normal' garage and a 100L / 3HP compressor with ~5m of copper pipe as a cooler and a water separator, and an LVLP spray gun that I've used exactly once.

You can do an acceptable job with that, the quality of finish is in the preparation as the spraying is just 5% of a good job. You can also correct most spraying errors.

From many posts on here, I've picked up that Lechler 29107 epoxy can be used as a bare metal primer, a sealer, and a surfacer (to some extent). Am I OK to sand everything back, maybe hitting bare metal in places. and then go over it all with 29107 until I have a consistent base? (Some of the paint comes off with thinners, so I assume it is rattle can of some description.)

A good choice, but it is only as good as the substrate. I have to urge you to bare metal it. The main benefits of the epoxy will be lost if you put it over an unknown surface.

My hope is to use Nisocoat 2 direct gloss as a topcoat, but not sure how well I can can match the colour, as the original was base/clear from the colours available. (Not a huge deal, as I intend to do the whole of the outside of the car, but want it to be somewhere close to the door shuts, etc.) I assume that this can go straight on top of 29107 (bearing in mind the overcoating times).

If a good match is important, I would go with conventional solvent basecoat and then (I believe) that there is a Nisocoat lacquer which would be a good compromise from what I have read. Or you could just go with a 1k Upol lacquer etc.

Choose a warm, dry and windless day if spraying outside.

The bumpers are plastic of some sort - will the 29107 stick to them / the existing paint OK? Or do I need a plastic primer / adhesion promoter / whatever?

The bonnet is aluminium - If I hit bare metal, will the 29107 be OK?

All advice gratefully received.

Epoxy primer is excellent on difficult substrates like plastic, rubber and aluminium. It replaces all the old specialist primers.

 

[Misterg]

Thanks

On this:

The main benefits of the epoxy will be lost if you put it over an unknown surface.

I was thinking that it would act as a sealer / isolator coat over any existing, sound paint.

 

[ajlelectronics]

Thanks

On this:


I was thinking that it would act as a sealer / isolator coat over any existing, sound paint.

You would be correct. However the adhesion would be down to whatever you put it over.

 

[julianf]

As above, alloy is fine. Plastic too, although there may (or may not) be better options for that - I don't know.

If you spray over unknown paint you may get small blistering where the old paint is feathered. This will be reduced if you limit the epoxy thinner. If you flat off the blistering and keep going with the epoxy until it's resolved then your top coat will then not suffer in the same way.

 

[ajlelectronics]

Plastic too, although there may (or may not) be better options for that - I don't know.

I have yet to find anything as good. I have rubber bumpers on the GTC which were epoxied. Even in a minor collision, the epoxy did not let go.

 

[ajlelectronics]

If you spray over unknown paint you may get small blistering where the old paint is feathered

Unusual as the thinner content is no more than 10%. Add to that the "grab" coat that you spray first and it is unlikely to react. Once fully cured it then becomes fully inert.

 

[jo1010]

Just lightly abrade whatever surface your going over to provide key for adhesion....

 

[marlinspike]

If it's any consolation I once bought a cheap car from a dealer when it was getting dark. Realised the next day the wing was an entirely different shade.

 

[steveo3002]

id bite the bullet and have that back to bare metal , only a small car shouldn't add much work and you're guaranteed zero issues from crap old paint jobs

 

[charlysays]

Good advice above.
I can recommend Nisocoat 2 for an isocyanate free top coat. Very durable paint with excellent weathering resistance.
As a beginner I would probably go for direct gloss/ single stage but two stage might ultimately be more correctable. With single stage paints you can experience changes in colour if sanding a significant amount of runs/ orange peel out due to the way the pigment settles as the paint is curing. As such probably worth considering using a standard automotive solvent basecoat with nisocoat 2 clear for the lacquer. I would definitely avoid using cellulose or 1k paints if the car is parked outdoors, spends a lot of time outside and/or gets daily use. 1k paints just don't hold up anywhere near as well.

 

[Morris]

Another vote for bare metalling, what's already there looks absolute rubbish.

 

[qwakers]

A Poly strip disc in a angle grinder will make short work of ripping all that c*** off.

 

[norsa]

What ever you flat your paint with, keep the machine as flat as possible. Given its been done by an amateur, its rare to find its not had an amount of filler. Dig that out and its a new can of worms. You shouldn't get blisters in your primer unless the substrate is wet but it's likely you will get ghosting and pickle if you go over a feathered edge where you didn't get maybe all the original stable primer out. If so, cure, flat back and re prime. Good luck my friend, lots of lessons about to be learned. Don't try and go it alone, we're here to help with even the most obvious questions, so long as you're prepared to listen and heed advice.
Nick

 

[keithski122]

Be careful if power sanding the bonnet as if you get too much heat in it it will warp.

 

[Misterg]

Thank you.

It will have filler in it, as it has previously had the back end of both sills cut out and replaced. I've no desire to dig that out only to have to replace it.

My assumption is that the blistered paint is the result of painting the previous repairs, and that underneath some of it, at least, I'll find factory paint that I was hoping would be sound enough to leave in place. I'm trying to avoid touching the door shuts, boot and bonnet lips, etc. so there will be old paint around there, at least. I don't *think* it's ever had a full respray.

The bonnet might be different - the paint 'feels' very thin and I suspect that someone has sprayed clear coat over the top of failing factory clear coat. It's a bloomin big panel to keep flat, as well. I guess I'll see how difficult it is to sand it back to the colour coat, but contemplate paint stripper as an option.

I emphasise that I'm not trying for concourse, just something that'll look tidy for ~5 years.

 

[Misterg]

A point of clarification if you wouldn't mind from those recommending that I "take it back to bare metal":

Do you mean the whole car or just the problem areas?

 

[steveo3002]

any problem panels i would bare metal , thats anything with bubbles , blisters , checking , peeling etc

if its sound original paint then you can just key that , but really whats another days work and box of discs in the scheme of things , can leave the shuts if theyre sound paint

 

[julianf]

The others on this thread have way more experience of painting cars than i do, but they may also be more "perfectionist".

Id comment that application gives reference.

These are a couple of sides that i bought for the vehicle in the picture. They're different colours as (as discussed elsewhere here) i had indecision / confusion with paint codes -

They had been brush painted with who knows what before, and plenty of dents. I got the bubbling i mentioned prior on the feathering etc (they required a skim of filler in places where i knocked the dents back) but its not a show car.

This doesnt degrade what others have said at all - but, with all these things, whats good for one person may not be needed by another. It depends on how far you (or in the case above "I") want[ed] to go.

ps. these are alloy panels, so less corrosion issues - and, obviously, you can see all the ripple in the reflections - but thats standard landrover - it was the dents and the brush strokes that i wanted rid of, and this got me what i wanted.

 

[Misterg]

any problem panels i would bare metal , thats anything with bubbles , blisters , checking , peeling etc

if its sound original paint then you can just key that

Thank you - makes sense.