BoatBanter.com - View Single Post - Painting with Two-Pack

In message
(mike worrall) wrote:

Steve:

I've just finished painting a 30' sailboat hull with two-part
polyurethane using foam rollers, and learned a lot along the way.

Hi Mike,
I am still learning how to use this two pack polyurethane and I thought
using it would be very similar to oil based synthetics,
The International 709 performs more like cheap fast drying house paint.

Today I added a little thinner No9 and tried to paint the off side
window frames, although the open time was only marginally longer the
addition of thinners made covering even worse. I have been painting over
a beige two pack primer and blathered on the black two pack but it still
left heavy brush marks and didn't even cover the primer properly.
Black is supposed to be a dense pigment meaning it should cover or
obliterate extremely well but this stuff was like coloured varnish
hardly possessing any colour depth or flowing out properties whatsoever.

Before anyone asks I am accustomed to brush work but I fear this
particular polyurethane paint falls short of my expectations.

I have deliberately left out my signature and website details when
posting here to avoid possible conflicts as people may think I am
looking for site hits but as I've said previously I am learning how
to unsuccessfully brush an unknown to me polyurethane material.

I was reluctant to even consider spraying the paint, since I have no
experience with spray equipment, and because of the potential health
ramifications.

I could not use a spray system where I am even if I wanted to as there
are other vehicles in the garage that must remain in situ so paint
overspray is not an option.

The suggested method of manually using these products - regardless of
manufacturer - is generally known as the 'roll and tip' method,
whereby one rolls on a small (say 6 sq ft) area then immediately
'tips' (lightly brushes) off the roller stipple.

I have painted large furniture removal vans in the past with synthetic
oil based paint without a problem but never experienced the problems
I'm having at the moment with this faster drying two pack polyurethane.
I couldn't even paint an area a foot square succesfully .

If you'd care to take a look at this picture of a Silver Ghost at:
"http://www.stephen.hull.btinternet.co.uk/examples/1921.jpeg" 132kb,
It is a similar model to the one I'm painting and you will see the size
of the tiny wooden windows frames and small metal panels, Compared to a
full sized boat I'd have thought painting a car would be quite easy.

I began by attempting to do this with the Epifanes two-part
polyurethane, with results similar to what you seem to be
experiencing, i.e. remaining brush marks (my environmental conditions
were 80 deg F @ 50 % r.h.). Unhappy with the results, I sanded off
the Epifanes, taped off the boat's transom into 3 similarly sized
areas, then applied Awl Grip (US Paint) to one area, Interlux two-part
the next, and the Epifanes two-part to the third, all using identical
equipment, and within a few minutes of each other. The hands-down
winner was Awl Grip, which had just detectable remaining brush marks.
The Interlux was second, and the Epifanes third (in my opinion).

I don't know if Awl Grip is available in the UK but if I ever need to
paint using two pack again I'll consider it my first choice, But having
forked out for the 709 I will persevere with it for the time being.

I subsequently was turned on to (via this forum) what I now call the
'fridge' method of applying this paint. CAUTION: This method worked
for me using Awl Grip Off White, and may not be applicable to any
other paint/color combination or in different temp/humidity
conditions.

This is an interesting forum and probably the only place I am likely to
gain this sort information (all gratefully received) on hand painting
using two pack paints.

It is usually customary to heat paint up to induce thinness to ease
application thus avoiding thinners but I must say the fridge method
sounds very intriguing although I'd imagine it would thicken up the
paint so much it would have to be applied by roller. The temperature
here in the UK at the moment is ideal to perform such painting tasks,
Perhaps a reducer would be beneficial if it could actually slow down
the curing/drying process.

By mixing up the base/reactor/reducer the night before application,
then covering and placing in the refrigerator (about 8 hours between
mixing and use), the Awl Grip was applied using only the foam roller,
with INCREDIBLE results. Flow out was excellent, zero roller stipple,
zero brush marks, in short a "sprayed" result without the sprayer.

I don't know if a foam roller is applicable for painting a Rolls, but
if you ever need to paint a boat hull...

I bought a small foam roller today to use on the side panels being a
straight black over black it may do the business but for the woodwork
I'm thinking of using a synthetic coach enamel instead of the two pack
polyurethane.

Mike Worrall
Los Angeles

Thanks for all the input it is very much appreciated

Steve,
The Wirral.