prparing epoxy for painting

[m.wijsman]

Can anybody tell me how to clean cured epoxy from amine blush. Can it
be sanded and coated with PU paint, or can it be cleaned with acid or
water?

[Karin Conover-Lewis]

Scrub it down well with acetone and fine scotch-brite pads. If you sand it
without removing the blush, it will drive the wax down into the epoxy and
you'll never get it all out.

--
Karin Conover-Lewis
klc dot lewis at gte dot net

"m.wijsman" <mmmlrw...@hetnet.nl> wrote in message
news:b641f1b2.03052...@posting.google.com...

[Ron Magen]

We're were just down this road.

Forget the 'exotic chemistry'; a bucket of warm water with a dash of
dishwashing detergent, and a sponge is all you need. Rinse WELL with lots of
paper towels.

The Amine is WATER-SOLUBLE; the idea is to dilute and remove it.

Use a course ScotchBrite pad if you want to 'scuff' the epoxy for 'tooth' to
add another coat.

Regards & Good Luck,
Ron Magen
Backyard Boatshop

"Karin Conover-Lewis" <spam...@nopam.com> wrote in message
news:_y8za.41224$Hy3....@nwrddc02.gnilink.net...

[Karin Conover-Lewis]

I wasn't aware that acetone is all that exotic ;-)

I've used soapy water in the past, never had the greatest results with it.
My best results have always been with acetone scrubbing. Could be that I'm
just more thorough when washing with acetone, though.

--
Karin Conover-Lewis
klc dot lewis at gte dot net

"Ron Magen" <qua...@att.net> wrote in message
news:mRbza.94163$cO3.6...@bgtnsc04-news.ops.worldnet.att.net...

[John R Weiss]

"Karin Conover-Lewis" <spam...@nopam.com> wrote...

>
> I've used soapy water in the past, never had the greatest results with it.
> My best results have always been with acetone scrubbing. Could be that I'm
> just more thorough when washing with acetone, though.

Soapy water worked fine for me with System 3 epoxy. Follow with a light
wet-sanding with 220 grit, and the varnish goes on great!

[mike worrall]

You're right to consider removing the 'amine blush' prior to doing
*anything* on top of cured epoxy, be it painting or adding another
layer of glass.

Fortunatly, it's an easy process! Simply scrub with water and a
'scotch brite' pad (usually green) then immediately wipe with a clean
cloth. Depending on the humidity while the epoxy was curing, I often
get an 'easy to see' white bubbly lather - the "blush" after a few
seconds of scrubbing. Change the water frequently.

To quote the experts at West System (see http://www.westsystem.com/):

"To remove the blush, wash the surface with clean water (not solvent)
and an abrasive pad, such as Scotch-brite(TM) 7447 General Purpose
Hand Pads. Dry the surface with paper towels to remove the dissolved
blush before it dries on the surface. Sand any remaining glossy areas
with 80-grit sandpaper. Wet-sanding will also remove the amine blush."

As to painting over epoxy, search this forum for the recent posting
""finishing coat on hull".

Mike Worrall
Los Angeles

[John R Weiss]

"mike worrall" <mike.e....@abc.com> wrote...

> You're right to consider removing the 'amine blush' prior to doing
> *anything* on top of cured epoxy, be it painting or adding another
> layer of glass.

Don't forget to follow the manufacturer's instructions for the particular epoxy
you use. For example, System 3 says no further preparation is required if you
recoat within 72 hours.

[Meindert Sprang]

"John R Weiss" <jrweiss@att*NOSPAM*global.net> wrote in message

> Don't forget to follow the manufacturer's instructions for the particular
epoxy
> you use. For example, System 3 says no further preparation is required if
you
> recoat within 72 hours.

That is only valid for a recoat with the same epoxy. It creates a chemical
bond because the underlaying epoxy is still partially uncured. For any other
form or coating you should leave the epoxy to cure fully for a week (or two
at lower temperatures).

Meindert

[Bob Walters]

I like to use a Scotch Bright pad with hot water and ammonia, but soapy
water works well too. Rinse well and sand before painting.

DO NOT use acetone. Amine blush is soluble in water. Plus it's the amines
that contain most of the nasty stuff in epoxy. Acetone will strip the
natural oil barrier from your skin, dissolve the bad stuff, and carry it
into your system.

Sooner or later you'll have a reaction to epoxy and then you'll be back to
making boats with nails and calked seams.

Be sure to use good breathing protection when sanding epoxy. The fresher
the cure, the more important this point is.

--
Bob Walters

"m.wijsman" <mmmlrw...@hetnet.nl> wrote in message
news:b641f1b2.03052...@posting.google.com...

[Karin Conover-Lewis]

When using acetone, it is important to always wear gloves and/or other skin
protection for the reasons you mentioned. But that, in itself, is not reason
enough to not use acetone it for cleaning and prepping. Use it properly, use
it safely, and it will not get into your system. But if soapy water does the
job either just as well or better, that is a great reason to use soapy water
instead. Less toxic is always preferable.

--
Karin Conover-Lewis
klc dot lewis at gte dot net

"Bob Walters" <joe...@aol.com> wrote in message
news:mDnza.67279$_e6....@news2.east.cox.net...

[Bob Walters]

What you say is true. I use acetone all the time where a strong solvent is
required, but I try hard to use proper safety precautions.

For example, I use it to clean up fresh epoxy spills and for cleaning tools
when hot soapy water would be inappropriate.

However, the main reason not to use acetone on amine blush is that the amine
blush is water soluble. You can do a MUCH better getting rid of this sort
of contaminate using a lot of hot soapy water and lots of clear rinsing
water than using a smaller amount of acetone where there is a tendency to
spread the amine blush around without properly removing it from the surface.

Plus, water won't burn at ordinary shop temperatures.<g>

--
Bob Walters

"Karin Conover-Lewis" <spam...@nopam.com> wrote in message

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