In message
(mike worrall) wrote:

Steve:

What 'synthetic' material are you proposing to put a two-pack paint
over?

Linseed oil synthetic based.

Since this is a boat-building forum, I take it that you've primed a
polyester resin, gel coat surface and are now wanting to paint it with
a two-part polyurethane paint. I also assume this is a 'topside'
(above the waterline) application?

Sorry Mike, My question was misleading particularly with this being a
boat forum but I have been told that applying two pack paint with a
"brush" on boats is quite a popular method as opposed to spraying.

This question may not be answered in a car forum because people
generally don't paint cars with a brush using two pack paint.

I am actually painting a vehicle that was re-painted in oil paint twenty
years ago but it's top coat was done in two pack, After twenty years the
paintwork now needs completely re-doing but I want to paint the vehicle
in the same way by applying synthetic oil primers and undercoats to the
wood and metal areas first with the intention of finally painting the
whole vehicle in a suitable two pack finish.

The vehicle is over eighty years old and I intend painting it in the old
fashioned way using oil paints. This would not normally pose a problem
only for the final coat being a modern two pack as opposed to the older
original oil based synthetics.

All two-part paints (that I'm aware of) require a specific 'epoxy'
(i.e. two-part) primer or under-coater. You cannot apply two-part
topside paint over a primer not designed for two-part polyurethanes.
See : www.blakespaints.com for additional information from this UK
paint manufacturer.

I agree but I am unclear as to what types of two pack paints are
available suitable for my purpose, Years ago we simply had two pack
Synthetics, now we have Acrylics and Polyurethanes.

Yes, you can re-apply as many coats of two-part polyurethane 'on top
of' each other as you want, (generaly) sanding between coats.

However I must emphasise that absolutely no spraying will be involved.
I know you can "spray on" multiple layers of two pack but can you
"brush on" multiple layers?.

Cheers,

Steve.