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MG Midget and Sprite Technical - Paint prep advice

I've pretty much got the bodywork of the Frogeye as good as I'll get it, just a few slight low points, pinholes and edges to finish off, probably with stopper.

Anyway, I have a combination of metal, filler and etch primer to cover so I'm intending to spray a coat of epoxy primer (thin not high build) to seal it and provide a consistent surface to apply high build (celly) to. The colour coat will be celly BRG (I already have the celly and would not want to spray 2 pack in a domestic environment). Does that make sense?

Despite extensive reading, I'm still not sure how smooth the existing surface should be sanded to i.e. what grit. As the epoxy is not sanded AIUI, then what I do now will be the foundation for the high build, correct? So, what grit should I use?
Bill Bretherton

Bill
just my opinion, others will probably do otherwise
,i believe the rubbing down ready for the primer is quite important to get an adheasive surface.
I'd use 320 paper and as soon as possible before spraying -If you rub it down and leave it for days it sort of seals the surface again defeating the reason for rubbing it up in the first place
If possible its best to block it off with the 320 and hit it with the primer on the same day or at least the next day
I'd be giving the 2pak primer a light rub off as well before the highbuild to get good adhesion, just a rub over with a fine scouring pad to knock the surface off will do it

Also i notice you mentioned thin in your description of the 2pk-
I've fell into the trap before suggesting thin coats, it's wording I'm now carefull of-We need light coats not thin coats
Don't thin it out too much
you need to put it on in light coats not thinned out coats, just dust the first coat on and let it dry off then a bit heavier coat----plenty of drying time between

willy
William Revit

I used 400 grit between the primer coats when hand blocking. Plus several repeats with a light dusting of a guide coat.
Are you doing it in your single garage, Bill?
GuyW

Willy, thanks, that makes a lot of sense. When I said "thin" I was referring to thinner version of epoxy rather than a high build version, which I believe you can now get for "direct to metal". I should have been clearer! 320 it is then.

Guy, Yes I'd use 400 to block sand high build but I was referring more to the prep for the initial epoxy sealing coat. I presumed you don't want to leave rougher scratches in the metal or the filler but wasn't sure how smooth to get it when you still want some "bite" for the epoxy to get hold of. In terms of the garage, I was intending to put primer on at home but I'm not sure about colour coats. I do know someone with an outbuilding but it's the faff of getting the car there plus my compressor and associated painting stuff. I don't know anyone with a car trailer so I'd have to hire one twice, or make the car driveable but that would mean fitting then removing too many parts. Decisions, decisions!
Bill Bretherton

I thought they had introduced legislation limiting the sale of cellulose paint to people who had applied for a licence to use it. I can’t find anything about this on the net.
L Langley

AIUI, cellulose can be used on classic cars. Far safer in a domestc environment than 2 pack as well.
Bill Bretherton

I'd heard about the licensing scheme idea but later saw it mentioned that the government had scrapped the idea as the use of cellulose for vehicle refinishing was so limited it wasn't worth the effort.
David Billington

Right David - I was wondering if the aerosols,off the shelf, would be 2pak so the public could super glue their lungs. Then again there must be other sorts of paint, I have seen French cars where bird droppings have burned the paint to bare metal.
L Langley

I think aerosols are generally acrylic based. Comparatively safe to use at home. It's what you'd use to repair a modern car finished in 2 pack.
Bill Bretherton

This thread was discussed between 03/09/2020 and 05/09/2020

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