"Lobster" wrote in message
...
I've got a stack of woodwork to gloss paint over the next week (mostly
bare
wood, but some already painted) and given the plethora of 'systems' out
there, I would be interested to hear what painting regimes people use and
why...

eg:
Primer + undercoat + gloss
Primer + self-undercoating gloss (two coats?)
Self-priming undercoat (two coats) + gloss
Primer + one-coat gloss
etc etc...

Then, acrylic or solvent based?

I'm aiming for the best and most durable finish within the quickest
possible
time (ie fewest number of coats!)

Thanks
David


Goodness knows what system works best - you'd have to undertake a lot of
comparative studies using different systems and woods then sit back and wait
and watch for ten years. I use Dulux Weathershield Trade exterior gloss for
outdoors, and for bare wood they recommend Primer + undercoat + gloss.
However, if it's untreated wood they recommend their Primer/Preservative +
undercoat + gloss
In fact, I used wood preservative + shellac knotting + primer + undercoat +
gloss + gloss and it took bloody ages ( fascia boards, untreated pine, I
didn't want to get up a ladder and remove the guttering again for a long
time ). If you're painting an oily hardwod, they recommend using their
aluminium primer.

For wood that I'd heat-stripped back to a kind of gungy brown original
1930's undercoat ( it wouldn't come off, just smeared out when I scraped at
it ), I just went
for an undercoat + gloss ( soffits, so not as exposed as the fascia
boards ).

My understanding is that for painting on wood, the function of the
preservative is obvious, the shellac knotting seals any sap in the knots so
that when the sun heats the wood it doesn't puncture the paint film by
oozing sap, the primer seals the wood surface ( against what I'm not sure,
I've never seen undercoat sink in when applied to bare wood ), the undercoat
matches the colour of the topcoat and also provides a suitable surface for
the topcoat to adhere to, and of course the gloss topcoat provides the
cosmetic finish and the weatherproof seal. Two more points, Dulux claims
their undercoat is elastic, and considering how wood moves, that must be a
good thing. Second, they claim their gloss is microporous so the paint can
breathe, and that this resists flaking. Who knows. If you use the full
system it'll take you more than a week to paint any surface, but I reckon
it's overkill except on exposed exterior woodwork.


My top tip is this; when you paint a surface with a sharp edge or
corner, the paint always is thinnest on that edge, in fact if you try it
with a white undercoat and black top coat, I reckon you can see through the
topcoat on the sharp edge, and this thinness may explain why flaking often
starts on an edge, so sand or plane all edges to a chamfered or rounded
profile before you start,

Andy.