I mistakenly mixed about 2 oz of pre-cat catalyst to a gallon of
lacquer, 1/2 oz more than what was called for. It never occurred to
me to simply add more lacquer. Anyway, my first coat of finish isn't
drying as fast as normal... more than 2 hours and it's still slightly
tacky. I sprayed late in the evening and the humidity has been at
least 80%, today, so I'm assuming these conditions play a small part.
Is too much catalyst the problem and will the finish dry over night.
I'll correct the mix tomorrow.

Sonny

Are you asking a question or simply commenting on the day's
activities?

Robert

On Apr 15, 12:17*am, "
wrote:
Are you asking a question or simply commenting on the day's
activities?

Robert

I was asking. Forgot the question mark. Is too much catalyst
possibly the problem, also?

Sonny

On Apr 15, 6:53*am, Sonny wrote:

I was asking. *Forgot the question mark. *Is too much catalyst
possibly the problem, also?

Sonny

Strangely, it probably is. You would think that the catalyst would
speed up
the actual reaction and cause something like cracking or glazing.
Maybe it is
extreme conditions like doubling the catalyst. But the catalyst isn't
a "hardener"
like one finds in epoxy, nor is it an activator to change the chemical
composition
of the actual finish. According to the wonks at SW, when you mix the
catalyst into
the base, you are actually creating an entirely new product.

Being interested in so many things that are mundane and sometime quite
pointless,
I actually went to a 4 hour class on using cat lacquers that was put
on by the Sherwin
Williams Industrial Coatings Division.

The only one I have used is SW. SW was completely specific about the
mixing
of their product, and advised using measuring cups for the catalyst,
and only mixing
in gallon batches as anything less than a gallon could produce an
unreliable or
strangely performing product. Since their product lasts well even
after mixing, it made
sense.

I would personally think that mixing in the exact percentages,
regardless of volume would
result in the same end product, but they say no.

The point is this; when you over catalyzed the product, you made you
own product, not one
that performs to the manufacturer's intention. For precats, adding
too much catalyst
will actually make the product dry slowly, and possibly corrupt your
finish. Until
understanding that the process that adding catalyst created a new
product (as opposed to
modifying an old one as one does when they add thinner to paint), I
thought adding more
catalyst would speed the process up like when you add too much
hardener to epoxy.

Not so, says the company rep. Since I like using really "hot"
finishes and spray
quickly, I am always open to speeding things up. I **specifically**
asked if more catalyst
would speed things up. The SW rep **specifically** told me that
fooling with the mix was
a recipe for disaster and also told me that adding too much catalyst
and under mixing
were the two most common culprits in precat problems.

I probably learned the most at the seminar/class in the trouble
shooting portion of using the
product. According to the SW guy, too much catalyst can actually get
your end product to
the point where it will not harden! It will dry to some extent, but
will have an oily feel to it,
and even then it might take a couple of days to get to that. This was
part of the "troubleshooting"
portion of the class. It will dry too soft, which defeats the reasons
(hardness and abrasion resistance) we use precats. It may also sag,
or even pool. Or is could go the other way and craze when drying.
Also, with too much catalyst it was pointed out that the final finish
may not be 100% stable
for a couple of weeks... maybe more. Remember, there is a big
difference in any finish between
"dry" and "stable".

Take that for what it is worth. This was one corporate man speaking
about the SW product
to a bunch of finishers that was wanting to make sure we followed ALL
directions perfectly
so we wouldn't blame anything on his product if it wasn't
satisfactory.

If I were you, I would call the technical help line usually found on
the can (or internet) and talk to
one of their industrial coating specialists. It won't be the same
guys that answer for consumer
goods, and some of those guys are really sharp and you have to know
you certainly won't
be the first one (or even 10,000 th) guy to do that. They will have
instructions specific to their
product on how to handle this. A quick call to one of my fellow
sprayers here was answered
with his opinion being that you will need to remove the existing
finish and start over again.

Do me a favor, Sonny. I don't use precats because I don't have anyone
calling for them, but I
am always interested in how things turn out in finishing. There is no
end to the learning
process in finishing..... none. We all get better, but no one knows
all of it.

If you call their tech line, please share with all of us exactly what
you find out, how they
tell you to correct the problem (in detail please) and who the
manufacturer of your product
is, and if they were helpful on the phone.

Good luck! Looking forward to hearing how this turns out.

Robert

wrote:


Strangely, it probably is. You would think that the catalyst would
speed up
the actual reaction and cause something like cracking or glazing.
Maybe it is
extreme conditions like doubling the catalyst. But the catalyst isn't
a "hardener"
like one finds in epoxy, nor is it an activator to change the chemical
composition
of the actual finish. According to the wonks at SW, when you mix the
catalyst into
the base, you are actually creating an entirely new product.


I can't echo Robert's statements loudly enough. When I mix, I go full anal
about following the manufacturer's directions for component parts - except
for reducers. I allow myself a fair amount of freedom with reducers, based
upon what I'm seeing with spray results on any particular day. But, as
Robert said, reducers do not change the product. Catalysts, activators,
etc. do. A lot of work by much greater minds than yours and mine, put a lot
of work into figuring out exactly how to mix this stuff and the biggest
mistake you can make is to mess up and not follow their instructions -
intentionally or unintentionally.

You've got my sympathies if you have to strip that whole job. I shot a car
for one of my daughters several years ago. I used a different base and
clear than what I had always been using. The distributor was careful to
explain to me to shoot the base no heavier than medium wet, and that the
base was actually catalyzed by the clear. I did not believe that last part
one bit and was prepared for the worst. I did however, follow the
intructions to the T. Well, I shot the base and I was very uneasy about how
it looked and what would happen when I shot the clear over it. For good
reason... the clear went on worse than anything I've ever shot - including
my first attempt at painting. It fish-eyed on areas of the base where the
base had shown no signs of contaminants under it, it was impossible to
bridge, it was having difficulty flashing, and all sorts of worrysome
things. The finished job was horrible and I just knew I was going to be in
for a complete repaint.

Well - it got worse, and this is where I symphathize with you... The car
sat outside all winter long. In the spring, when the sun started warming
things, the car started to blister. When I say blister, I mean blister,
mister! The clear and the base in some spots, where lifting in bubbles over
a foot in diameter and two inched high. It looked like someone had stuck a
garden hose under the paint and turned it on. Are you getting a picture of
****ed? In the end, my daughter and I hand stripped the entire car with
razor scrappers. Some of it came right off, and some of it was a flat out
bitch to get off. It tooks us days to strip that car. DA'd the whole thing
down again, touched up the body work, and started from the ground up,
repainting the entire car. This time I went back to the paint system I had
been using (and have not departed from since this experience...), and turned
out a show room quality paint job. Rework is so bad...

--

-Mike-

My catalyst and lacquer are Sherwin Williams. The first spraying,
yesterday, seems to have dried very well over night. I did add 1.3
quarts lacquer to the erroneous mix and sprayed a second coat. I'll
take pics, after while, and post them. I usually call the local SW,
when I need advice, but I had hoped for some sort of experienced
answer, last night, before calling today. I haven't called SW, yet,
but I will.

I've been using this product for years with no problems. I just
screwed up with this mix.

I'm refinishing woodwork on 2 chairs (upholstering, also). These
chairs are my cousin's, to be ready by September (new home being
built), so I have time to repair any refinishing mistakes.

Sonny

On Apr 15, 10:24 am, "Mike Marlow"
wrote:

Catalysts, activators,
etc. do. A lot of work by much greater minds than yours and mine, put a lot
of work into figuring out exactly how to mix this stuff and the biggest
mistake you can make is to mess up and not follow their instructions -
intentionally or unintentionally.

That was really hard for me to understand. I am not sure why, I just
didn't believe it. I had it in my mind that they guys at SW were
simply trying to get us to follow the instructions. They know most
don't read or pay attention to their instructions, so I thought it was
some kind of juvenile scare tactic. But at least as far as the pre-
cats go, I agree completely with your post. There is actually years
of science behind those coatings, and to fool with them is flirting
with certain disaster.

Here's my donkey-eared moment. I was shooting a cool new coating as a
test for one of my suppliers that was trying to get me on their
product. I think it was one of the offerings from Coronado's Corotile
line, I don't remember for sure. It was to be used to paint the metal
doors that are so popular now, and I was finishing a lot of them for
myself, and some for other contractors. I had used their product a
lot and liked it quite a bit. Goes on well, lays out well, no sags,
and super fast drying. Recommended reducer was naptha, and smart guy
over here was using high grade lacquer thinner. Worked like a
champ. Got to thinking I was a little bit more in tune with their
product than they were.

They promise NO performance difference with the hardener in it, and
the sheen went from satin to a little under semi gloss. Since almost
no one can tell the difference in that, I wasn't concerned with the
sheen. I CAREFULLY mixed in the hardener. I put in my normal 10%
reduction of lacquer thinner. That stuff shot out perfectly. I was
impressed. 10 minutes and dry to the touch. I like it.

Donkey ears time for me. I was ready to go to the job and coat 3 - 4
doors. So I went to clean out the gun before leaving, and that's
when I got it. I cleaned out the cup and the brushed the internals
and cleaned all the air holes with round maple tooth picks. To clean
the last of the coating out of the gun and give one more clean rinse
of the the whole thing, I put in some mineral spirits to shoot out
any remaining finish or debris.

But.. the coating turned to plastic. I mean, it looked like the teflon
tape we use on plumbing. **Instantly**. It not only clogged the gun
completely, but with the pressure turned up to clean, it pushed the
plastic film into every part of the gun. Then it got hard. I called
my commercial rep, and he told me to try something hotter like toluene
or xylene. Nothing. I called SW technical assistance, and they told
me in no uncertain terms, it was my fault, and that was why the
specified NAPTHA. They expressed sympathy, but they told me they
thought I was "screwed". I was indeed.

No, I didn't have to sand or refinish any doors. I did better than
that. I ruined my expensive gun. I mean actually ruined it to the
point of not being able to use it. Some guns seem to shoot better
than others, even if they are the same model from the same
manufacturer. This was one of those; it was my favorite gun, a real
pleasure to use. Man was I ****ed off. It was ruined by me in
literally seconds.

I kept that gun for a long time as a reminder to myself to read the
MSDS sheets and follow instructions on anything that is beyond adding
a bit of thinner for better spraying. Anything that you have to mix
to use gets my 100% full attention when mixing it.

I still find plenty of other things to screw up, but not mixed
finishes !

Robert