Nitro finish curing problems

[Robert Freemond]

Just finished my first serious Lacquer job & it's not curing. After three weeks I sanded & buffed it out to a very nice finish, but after a couple of weeks you can see that it's still moving.
I now know that I put on too much too soon so - will it ever cure Or should I just strip & start over.

[Barry Daniels]

What brand?

[Robert Freemond]

Lawrence McFadden

[Aaron Helt]

What do you mean by "moving"?

[Barry Daniels]

When you say McFadden's it means that the lacquer is several years old. Usually that is not a problem, but it is something to consider.

So, how many coats did you apply, how thick is the finish, and how much drying time did you allow between coats? What did you use for thinner? How humid is it in your shop?

[Robert Freemond]

Hi every one & thanks for the response.
Berry,
The Lacquer was a couple of years old, I used Home Depot Thinner, I'm in So. California, It'b been Hot & the humidity varies daily.
My paint schedule was: First 2 coats thinned 50/50, following coats every 1-1/2 hrs. for a day.
second day - sand & repeat. for 3 days.
I have since learned that It was too much too fast so my question is, will it ever cure, or should I start over

Aaron, A couple of weeks After I sanded & buffed, the surface was becoming textured & was no longer perfectly flat.
Today if I press hard with my thumb nail It will leave a small mark.

[Barry Daniels]

The cheap big-box thinner is likely the problem. I had an issue with it once and it messed the lacquer up good. I had to refinish. It's a good idea to use quality thinner and I followed someones recommendation to go with Sherwin Williams thinner. SW has thinner with various degrees of retarder that is useful in my humid conditions in Houston. They provide thinner for professional finishers who are more demanding than the diy folks.

I would say that if your finish is still soft after 3 weeks, it will never cure properly. You will probably get a cured finish quicker if you strip and refinish.

[Aaron Helt]

Yep, agreed. Home store lacquer thinner can have anything in it. I bought a consumer brand name from a store one time that was oily and had a orange tint to it. I used it to clean stuff but no way I'd put it in lacquer. Crown and major paint manufacturers have the real stuff.
As far as if it will harden up in time, only time will tell.

[Robert Freemond]

Berry, what's the purpose of using a retarder in humid weather.

[Barry Daniels]

Retarder slows the curing so water has a chance to get out of the finish. This prevents blushing. Many lacquer thinners have retarders in them. The Sherwin Williams thinner I use is formulated for humid climates by including a certain amount of retarder.

You may not have had blushing in your lacquer, but eventually you will when the conditions are right.

[Robert Freemond]

If Lacquer can so problematic what do you folks think of Water based lacquer like KTM 9 ( I know it's discontinued).

[Aaron Helt]

IMO, nitro lacquer is the easiest, most trouble-free finish there is.

[Gordon Bellerose]

If Lacquer can so problematic what do you folks think of Water based lacquer like KTM 9 ( I know it's discontinued).

I use water base lacquer only.
I find it easy to use, easier than nitro to deal with, (fumes, extreme flammability, clean-up) and readily available.
I have not used KTM 9. I have used Target EM-6000, and am now using Britetone.

Here in Canada, our VOC laws are quite strict. There are many conditions that must be met before you can use solvent based products.

[Barry Daniels]

Making a blemish free, high gloss, quality finish is a challenging process no matter what kind of finish you use.