Thinning ratio for precat lacquer?

[David]

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?

David

[David]

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)?

David

David wrote:

[Todd Fatheree]

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.

todd

[David]

Thanks, Todd. I'll call the store tomorrow to see what their story is on this stuff.

David

Todd Fatheree wrote:

[Preston Andreas]

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.

[David]

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.

David

Prest> I've been shooting Magnamax from ML Campbell. The catalyst is added when