David,
In my experience, the chalk that I think you are describing is due to UV
exposure (the sun). Epoxy coatings should be covered with several coats of
UV resistant varnish. I think that Epiphanes has some of the highest
resistance. The chalkiness is not just on the surface but all the way
through the epoxy. If this is just on the deck and other exposed surfaces
that have no structural strength value, just sand with 220 grit and paint
it. If you want to finish the wood bright, you are going to have to sand
down to wood and recoat with epoxy and then apply 4 or more coats of
varnish.
Charles

Ervin, are you speaking to epoxy resin as opposed to epoxy paint? It is
understood that epoxy resin needs to be protected from uv.
However David said his epoxy paint is getting chalky. I have experienced
the same thing w/ Poly Poxy, which surprised me.
I thought the pigment protected the epoxy. I can't see covering white epoxy
paint w/ varnish.

"Ervin Charles" wrote in message
...
David,
In my experience, the chalk that I think you are describing is due to UV
exposure (the sun). Epoxy coatings should be covered with several coats of
UV resistant varnish. I think that Epiphanes has some of the highest
resistance. The chalkiness is not just on the surface but all the way
through the epoxy. If this is just on the deck and other exposed surfaces
that have no structural strength value, just sand with 220 grit and paint
it. If you want to finish the wood bright, you are going to have to sand
down to wood and recoat with epoxy and then apply 4 or more coats of
varnish.
Charles

epoxy chalk
 

Hi all
anyone know the best way to remove the chalkeness that forms on epoxy paint
over time, as i wish to to put the top finishing coat of paint on now.
David

Garland Gray II wrote:
Ervin, are you speaking to epoxy resin as opposed to epoxy paint? It is
understood that epoxy resin needs to be protected from uv.
However David said his epoxy paint is getting chalky. I have experienced
the same thing w/ Poly Poxy, which surprised me.
I thought the pigment protected the epoxy. I can't see covering white epoxy
paint w/ varnish.

The pigment protects the underlying finish, but it can't protect the
surface. The good news is that a light sanding to remove the UV damaged
surface is probably all that's necessary prior to painting. Paint it
with something other than epoxy and you won't have the same problem again.

sorry i should have been more specfic its the hull and deck on a 45' steel
boat i primed it with epoxy grey primer 12 months ago now i want to put the
top coat of white polyurathane paint on but first i have to remove the
chalkiness as you say caused by uv. i dont like to sand it as i may sand
through the primer and was hopeing there was something i could wash it with
thanks
david

david wrote:
sorry i should have been more specfic its the hull and deck on a 45' steel
boat i primed it with epoxy grey primer 12 months ago now i want to put the
top coat of white polyurathane paint on but first i have to remove the
chalkiness as you say caused by uv. i dont like to sand it as i may sand
through the primer and was hopeing there was something i could wash it with
thanks

I don't think you have much choice other than to sand. The chalky
material is UV degraded epoxy that must be removed completely before
paint. Otherwise, you're putting paint over a weak surface that will
likely result in a poor bond. Think about it this way, you can either
sand it now and possibly have to re-prime, or you can paint over it, end
up with a bad and/or flaking finish and have to sand/scrape all of it
off and do it all over again. Which would you prefer?

When it comes to painting, preparation is key.

Brian Nystrom wrote:

david wrote:
sorry i should have been more specfic its the hull and deck on a 45' steel
boat i primed it with epoxy grey primer 12 months ago now i want to put the
top coat of white polyurathane paint on but first i have to remove the
chalkiness as you say caused by uv. i dont like to sand it as i may sand
through the primer and was hopeing there was something i could wash it with
thanks


--------------------

most modern epoxies don't chalk much anymore (but they do still yellow and loss
their gloss). Used to be that chalking epoxies were called 'self cleaning' paint
water tanks etc would have the dirty 'chalk' washed off when it rained - that
said, I suppose you could waterjet the surface clean.

I wonder if you'll find the post chalked surface as smooth as the pre chalked
surface?? In not might affect the gloss of your 2 part poly.

paul oman
progressive epoxy polymers