Spraying White Lacquer

Advice on mixing thinner and retarder into lacquer and primer for good coverage without runs. June 18, 2010

Question
This is my first time spraying white lacquer. Iím using HVLP and have used it to spray oil paints and primers before. Iím using SW Pro Mar white lacquer undercoat and Opex Production Gloss White as suggested by SW. I need some pointers, such as thinning of primer and finish coat. Any other advice to lead me in right direction will be appreciated. Which would you recommend - HVLP cup and compressor or turbine unit?

Forum Responses
(Finishing Forum)
From contributor M:
I would suggest you start with the spraying equipment with which you have the most experience and confidence. If you are learning to spray lacquer, and you are most skilled with the HVLP, I would stay with that until you better learn to spray lacquer. I did not see any mention of retarder being used in your finish coat. As I have said in other post, I spray shutters, and we have to use retarder to slow dry times, or we get a cross spray pattern. I would think that it is needed to spray the cabinets as well. We use SW r6k28 butyl carbotol. I also would recommend you use the SW brand lacquer thinner. I have had problems with using other brands, as some thinners are not as hot as others. I would stay consistent with my mixes, and write them down as you make adjustments until you find what works for your situation.



From the original questioner:
Yes, I do have SW lacquer thinner. I tried to spray lacquer a few weeks ago, just experimenting, and the finish was like a frosty windshield appearance. Maybe it was drying too fast? Also, I need to remove paste wax from a table top to repair top and then apply finish. Does anyone have any suggestions on product to remove wax before finishing?


From contributor M:
I was waiting for someone that sprays lacquer paint more often than I to say something more about thinning the paint, I am a little out of practice. Since the signs of overthinning paint are usually the most obvious (runs, etc.), I am going to address the other. If you have not added enough thinner, obviously the paint will not spray well. When I see any unusual texture, roughness or even a gritty appearance, the paint is drying too fast.

Lacquer can dry between the gun tip and your target, and it can also dry between the overlapping passes as well. Keep in mind, the amount of thinner you add can also influence the dry time. Your paint will be different, but when I mix clear top coat, I will add 1/2 cup of lacquer thinner and 4 to 5 oz of retarder to a one quart cup, fill the rest with the actual finish. This will vary on certain days due to temperature. My local Sherwin Williams carries a couple of different retarders for lacquer products. One is ten times more powerful than the other, so add which ever you use carefully, in 1 oz increments until you find what works for you. Seems like we use to add almost 40% thinner to some of the SW paints to get them to spray well, but this is from 10-12 years ago. Unless you get better advice, I would simply mix a cup of paint, 40thinner/60paint with 3 oz retarder and test it. The thinner to paint ratio is to best find the right viscosity, the retarder is to find the best dry time for your spray method and product. The good thing is, unless you load up your test mix with retarder, you can continue to add paint or thinner to work out your ratio. The downside to too much retarder, will be the project will take way too long to dry, and I guess would also have effect on the hardness of the finish. I say again test and write down your mixes and the results.

Another thing to consider is the priming. Lacquer paint will not hide mistakes made in the prep process. I would thin my primer, about 50/50 with thinner - depending on your product that will vary. A good primed and sanded surface has a lot to do with the final result. Any roughness in the primed surface, will telegraph thru the paint finish. Hope this helps and gives you something to work with.