Finally picked up some Pre-cat lacquer to expand my
horizons. First attempt demonstrates it needs to be
thinned. From the sources I've found in books, I'm under
the impression that it's treated like regular nitro as far
as thinning goes. Is that correct? Today I sprayed it at
80 degrees, high humidity (unusual for northern Cal) with
HVLP. I couldn't get flow out without putting on so much
the result is that dreaded "plastic" look.
I've e-mailed the mfg. for viscosity cup timings but in the
meantime (and WITHOUT A cup) I'm looking for GENERAL
guidelines as to thinning ratios. 10-20%?
What's about the max you can thin this stuff? Ratio for
first 2 coats and ratio for topcoat? I'm thinking I should
go with thinning before I consider a retarder; correct?
Observation: the finish is quite soft after 8 hours. I
sprayed a sample board with Enduro WB poly and it's MUCH
harder than the lacquer.
Question: Granted, the lacquer was applied heavier than
ideal, but shouldn't a lacquer be hard enough not to peel
off with my fingernail after 8 hours??
There is no mfg. date on the can that I can find; something
I read tonight indicated (Flexner's book, IIRC) mentions
checking the date on pre-cat lacquer cans. Kinda like
canned shellac (drying problems, if it's too old)?
Pre-cat laquer definitely has a shelf life, and it's a lot less than
shellac. When I bought the Sherwin Williams flavor of precat, they put a 6
month use-by date on the can. I have no idea what the results would be of
using a batch of precat after the catalyst has "worn off" so to speak.
I've been shooting Magnamax from ML Campbell. The catalyst is added when
you buy it and it is good for 90 days. They have strict recommendations for
thinning and adding retarder, including using only their products for the
thinner and retarder. There is also Magnalac where the catalyst is added at
the factory. The shelf life is much longer.
In other words, each product from each manufacturer is different. It is
best to call their 800 number and talk to tech if you have any questions. I
find that all dealers may talk like they really know their product, but
sometimes they may not be as knowledgeable as they lead you to believe.
That is why I get what information I can from their literature and off their
website, then call tech if I have any remaining questions.
I DID get a callback from the mfg and was told to use 10-15%
acetone (I'm in CA) PLUS retarder to counteract the faster
drying of adding acetone. I got good results today from
just thinning the lacquer about 15% at 76 degrees.
Preston Andreas wrote:
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