nitro lacquer question

I live in England where the whether is very temperamental, meaning it is rare to get 3 or 4 days in a row where the humidity is low enough to spray nitro. Is it ok to spray 4 coats on a suitable day (today) and then not spray the next coats for another week or so?

Cheers Guys

Just wait at least one hour between coats to reduce the risk of sloooooooow curing trapped solvents.
Good luck on your project,
Rob

I live in England where the whether is very temperamental, meaning it is rare to get 3 or 4 days in a row where the humidity is low enough to spray nitro. Is it ok to spray 4 coats on a suitable day (today) and then not spray the next coats for another week or so?

Cheers Guys

I too suffer the inconsistency of the English weather, and also have to visit my parents to spray nitro (I live in a flat). What this means is I often go weeks between spray days. Never had a problem yet (although I've only been properly spraying nitro for the last 6 or 8mths, so I am a total newbie really); have had the odd day where I've had a bit of blushing, although only ever on clear coats.

On an average spray day, I might do 4 or 5 coats, then usually end up waiting a minimum of a week, but more often a couple of weeks until I am able to spray again.

I believe this to be absolutely fine, but someone else more knowledgeable may well correct me shortly!

Is it ok to spray 4 coats on a suitable day (today) and then not spray the next coats for another week or so?


Beneficial, IMO. The more time that finish has to cure and outgas the better, period.

Best finish I ever did involved a Brazilian rosewood OO (Brazilian is notorious for pore sinking), shooting 8 coats over two days, six weeks cure, sanding, shooting last 2 coats with about 30% thinner (you've got to be careful doing this and know your lacquer well, as this can lead to checking with some lacquers), about three months of cure and then final sand and buffing.

A decade later it was still as flat as a sheet of glass.

You need an understanding customer to wait that long, few are, but this guy knew enough about finish to know why I was doing it. It paid off big time.

It's no problem at all to wait for extended periods between coats of lacquer. "Coats" become one solid (well, sem-solid, as lacquer continues to cure for years) film - each coat melts into the preceding one and there is no visible delineation between coats.

I have a paint inspection tool called a "Tooke Gage" that makes a precise angled cut in a coatings film; it's then turned on its side where the cut is viewed through a microscope with calibrated lines that indicate the thickness of individual coats based on the width of the angled section of the cut.

With normal paints you can clearly see each coat, even if they are the same color (and even with clear varnish-type products. But with lacquers (whether 100% nitro - not a very common product - or acrylic/nitro blends, which make up the bulk of the products made) they melt into each other to the point that even different toning lacquers or different colors melt together to the point of obliterating any clear "coat" lines.

It's no problem at all to wait for extended periods between coats of lacquer. "Coats" become one solid (well, sem-solid, as lacquer continues to cure for years) film - each coat melts into the preceding one and there is no visible delineation between coats.

I have a paint inspection tool called a "Tooke Gage" that makes a precise angled cut in a coatings film; it's then turned on its side where the cut is viewed through a microscope with calibrated lines that indicate the thickness of individual coats based on the width of the angled section of the cut.

With normal paints you can clearly see each coat, even if they are the same color (and even with clear varnish-type products. But with lacquers (whether 100% nitro - not a very common product - or acrylic/nitro blends, which make up the bulk of the products made) they melt into each other to the point that even different toning lacquers or different colors melt together to the point of obliterating any clear "coat" lines.


That's good to know, thanks for sharing. :smile:

Thanks guys thats exactly what I was after. the weather was great yesterday and today so I managed to get 8 coats of clear on the guitar. I was only after a thin finish so I think that will be enough but if I change my mind, given all of your advice, i can change my easily change my mind at a later date.

Yep, no worries. Just make sure it's cleaned flawlessly if coats are added later.

Yep, no worries. Just make sure it's cleaned flawlessly if coats are added later.

What would you recommend as a cleaning process for a guitar body that has nitro paint on it but has been sitting in a box for nearly a year without ever being assembled? I want to clear coat it.