Spraying - the light goes on...

When I started spraying I didn't have a filter/moisture trap in line and I set the amount of air through the gun using a screw in the gun itself. I taped over the screw which was at the base of the gun so I would avoid 'turning' it with the side of my palm as I sprayed. Now spraying has been my Achilles heal - the only process I have no training in.

In the new workshop I built a proper spraybooth with in line filter but still struggled with getting that glorious fan showed in Allens excellent videos. So I took apart my gun and looked closely again at what I was doing with some coloured lacquer through it and hey presto, that pesky screw had been restricting the amount of lacquer producing the ideal fan pattern. Now I can spray like Allen with a huge fan delivering a fast, even, fully loaded coat. Eurika!

It also shows what a complete idiot I have been for the last 3 years that I have been spraying my own pieces... Hope that's shattered your illusions about me now

I'll post a few images of recent work next week so you can see my new black/stained finishes on uklectic and a gorgeous koa s.oprano

Pete,
What type of spray gun do you use?

I use an HVLP system, eliminating the need for in line filters. No more contamination from water from the atmosphere or oil from the compressor. There is very little overspray, saving me money and helping the environment. That "huge fan" you're talking about means you're losing a lot of lacquer. For my money, the Fuji Q4 is the only way to go.

You are right of course Chuck. I've tried HVLP and I can't get on with it. My compressor is oil-less and the filter works great. I'm not using a lot more lacquer than before and I am using Allen's process of a high reduction to get multiple thin coats - french polishing with a spray gun

You're still losing a lot of lacquer to the atmosphere. I too reduce my lacquer 1:1 but I put it where I want it. Bounce-back is also pretty much eliminated allowing the lacquer to get into corners and tight spaces. I used a compressor spray system for years and always had trouble with pinholing, and sometimes fish eyes. No more with the HVLP. But unlike a compressor system where you can do an adequate job with minimal and inexpensive equipment, with an HVLP system you need to spend some money to get one that works well. I previously has a $300 3 stage that didn't perform well. The Fuji 4 stage at $1000 is up to the task though. (I saved that much in lacquer during the first year.)
The biggest advantage to me is to my health though. I spend a lot of time in the spray room and I would often stink of lacquer at the end of the day, even with an adequately ventilated booth. The HVLP leaves very little over spray in the atmosphere simply because the droplet size is much bigger and heavier. (I also use a fresh air respirator now.) My wife, who works in the shop next door to mine, used to complain any time I sprayed. Now she would be totally unaware of it if it weren't for the noise the turbine makes.
The big trick in getting an HVLP system to work well with lacquer, (outside of having a powerful machine and proper needle and tip for the gun) is knowing your lacquer and thinning and retarding it correctly. As with anything, it has a learning curve to it.
Needless to say, I'm a huge fan of HVLP. Having used it for 3 or 4 years now, if I had to stop I'd probably give up spraying nitro. (I'd still like to anyway!) Nitro cellulose lacquer and all of it's related solvents is very, very, very nasty stuff.
Mind you however, if I ever need to do any shading or sun burst, I will use my compressed air system. Nothing beats it for fine atomization.

I can't get on with the droplet size - like an orange skin with the system I tried... I have 6 instruments in the sprayshop at present. Each session takes about 10 minutes; three sessions per day. Suits me. This business is all about what suits

Pete, I agree with Chuck on HVLP, although I use a conversion gun. I have a cheapo $100 PC HVLP I'd send to you if it didn't cost so much, just so you could take a stab at it again.

Let's put it this way, my jamb gun (conventional) has WAY more overspray than my full size PC HVLP. I think one of the better things about HVLP is because you're spraying at low pressure, once you get it, its almost impossible to orange peel or run, especially since you're so close when spraying such a small area, as compared to a car. The key is once you get it. The Sata is really nice, with the standard air and volume settings, as well as the fan settings. The really nice one is the atomization setting, where you can get it so fine, its smaller than dust coming out, but feels like sandpaper once its on, so you HAVE to adjust accordingly.

One of the things I overlooked in the past is the compressor. I've gone through 3 oilless ones in 10 years, 30 gallon ones. I finally splurged and got an upright 26 gallon, 5hp, oiled (which is more than double the cost of an oil free in some cases). Go figure, it takes up less space and runs quieter. Overkill for my little Sata? Maybe, but I use if for other stuff too (like the micronizer on the resaw). However, that much air takes care of the High Volume part of HVLP, which I, like many, have overlooked in the past. Although I had good results with the smaller compressor, the larger one makes a big difference. Yup, installed a filter AND a dryer, and voila!

I believe your current lacquer usage will be the same as before, probably because you now have a quality spray. My experience, and here's lessons learned for anyone else if you underestimate the quality of gun, or paying attention to the learning curve in setting up the gun. Between my PC Full size HVLP, and my Sata Minijet, I'll go through almost a full cup on the PC compared to a full cup on the Sata, for the almost the same amount of coverage. Yup, even with an HVLP, a LOT of it ended up on the floor with the PC. Granted, most because I probably didn't adjust the PC correctly, and the fact that I spent time learning to adjust the Sata correctly (hmmm, lets see, $100 gun, or $300 gun - I think I'll learn to use the $300 gun).

Now, if we could only get great oiled finishes from a gun. . .

-Aaron