Classic cars forum & vehicle restoration.

peppiB

Have been doing a repaint job on 1 of the cars, putting cellulose over cellulose. All the bodywork has been fine - except the bonnet. I sanded it down, used degreaser to ensure no trace of polish - and the paint crazed and bubbled in parts. I cleaned it off, used a power sander, degreased and it bubbled and crazed again. It is just like the cellulose has been put on 2K - only there has never been any 2K near this one. I tried 4 times and couldn't get any other result. In desperation I cleaned the whole lot down again and this time I used 2k paint - masking off the rest of the car which is fine in its cellulose - and that has crazed as well. Any suggestions? The paintwork is perfectly dry and all work was done in my garage

Uncle Alec · Joined: 14 Jan 2008 Posts: 734 Location: Manchester

The bonnet seems to be contaminated with something horrible.
Various things spring to my mind - the dreaded silicone, which can resist all attempts to shift it, certainly with degreaser. There are specialist anti-silicone additives, and panel wipes, but they aren't cheap.
Have any body repairs been done in the area of the paint problem?
Could you have it blast cleaned?
Have you tried barrier paint, usually alcohol-based? I used to use primasomethingorother (or maybe Protektacote?), which dried to a matt light violet colour, and that was supposed to go between anything as a foolproof barrier.
Other than that - excorcism?

peppiB · Posted: Thu Nov 19, 2009 8:39 pm Post subject:

My degreaser (panel wipe fluid) is supposed to shift silicone - and has done everywhere else. The bonnet hasn't had any repairs nor has the car ever been in a body shop. Will try a barrier paint and see what happens. If the worst comes to the worst a second hand bonnet (readily available) will be cheaper than sand blasting. Have never encountered anything as bad as this - even the basic grey primer blisters off.

I once had to have a house exorcised!! Shocked

Really strange goings on which had to be seen to be believed. Although successful in that there were no more incidents, I sold the place and moved - just to be safe!!
(Vicar was a close friend, and good at making spirits disappear - usually whisky though!)

Uncle Alec · Joined: 14 Jan 2008 Posts: 734 Location: Manchester

One other point - you don't mention taking it back to bare metal. Technically that should shift whatever it is causing your problem. If it doesn't then it will be time to call your vicar pal.

peppiB · Posted: Thu Nov 19, 2009 8:49 pm Post subject:

The problem areas have been sanded back to bare metal - but still give the same result. Will try the barrier paint and possibly red lead as that was the original primer. Failing that the Tyne runs very very close by (nearer than the scrap merchant!!)

47p2 · Joined: 24 Nov 2007 Posts: 2009 Location: Glasgow

Try Sikkens for a base coat
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Phil - Nottingham · Joined: 01 Jan 2008 Posts: 1252 Location: Nottingham

I had this once - it is always best to use a thin coat of waterbased isolator before priming. It is fast drying and never fails if the old paint film is well attached
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peppiB · Posted: Fri Nov 20, 2009 12:20 pm Post subject:

Thanks guys. Will sand it back to bare metal ... again .... and give it a coat of barrier primer. As it now has 2 pack on it, I will have to wait a few days for it to harden enough for me to sand. Interestingly I was talking to a paint supply chap the other day - he was saying I was mad for still using cellulose (a fact not disputed) and instead should use 2 pack with 1k converter instead of the isocyanide hardener. He also said it was a myth that modern water based paint could only be used with oven facilities and that it dries perfectly well without. The only drawback is base colours only available, so lacquer required.

clascar · Joined: 27 Oct 2008 Posts: 83 Location: mid cheshire

peppiB wrote:-

Quote:

should use 2 pack with 1k converter instead

Can you tell me more about this product please.
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Gaz · Joined: 27 Dec 2008 Posts: 92 Location: Geordie-Land

Hi Ray, most motor factors that sell car paint will be able to add a 1K converter into your 2 pack paint, which will then turn your two pack paint into a cellulose equvilent.

It works well as I've recently bought some to do the seat frames and head board in my van. Only problem, is that because the converter is like thick thinners, it then makes the colour slightly transparent.
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