Tuesday, September 23, 2008
My low tech spraying system
This is going to be a long post, so either grab a cup of coffee, or a beer or a glass of wine. And put your feet up.
I've been thinking about glazing lately. So I posted something on the ClayArt board recently, asking how other potters do it. People recommended books and videos. I bought the books, and probably spent more time than I should have on YouTube, watching some glazing videos. It's amazing what's out there on the web, some really great, most moderately helpful.
I've been fighting that eternal nagging question - do I dip or do I spray? I've been spraying for a while, but sometimes I get frustrated at my results. After watching the videos on YouTube, I'm not sure there IS a definitive answer to that question.
The answer is.... do what works for you.
Then, someone from the Clay Art board asked about low cost spray booths. If you're not a potter, you're probably wondering how spraying a finish fits into pottery. Simply put, a spray booth allow potters to spray things onto their wares - usually glaze. Traditionally, there is some sort of a lazy-susan type wheel in the booth, so that you can spin your work while spraying it, thus assuring even coverage.
And an exhaust fan to suck away the harmful airborne glaze. Here's my problem - every spray booth I've ever seen has looked like a cross between a toxic dump and a cool piece of spin art. They're usually covered by layer upon lay of glaze, drippy and dried, and unfortunately, ready to flake off when a blast of air comes.
So my aversion to spray booths stems from two things - they require too much cleaning, and (at least for a decent one) they're too expensive. Even this little Hobby Shop Spray Booth, while on the lower end of the price range, is limiting.
It's on the small side, and really, it's only a metal box with some filters.
So of course, being the frugal artist that I am, I was determined to come up with a cheaper, better system. Before I started spraying my pieces, I did the research about buying a sprayer. You know what's funny, I have a couple of good friends who spray their woodworking finishes, and in the past couple of years, they've both quit using their sprayers. See, I think the biggest drawback of spraying finishes is cleaning the sprayer when you're done. Of course, a sprayer that clogs is a bitch, too. Add to the mix that some of the high end sprayers are just too damn expensive... and - well, there has to be a better way to do things.
After doing a ton of research, I finally settled on this sprayer, a cheap, low tech unit that uses Mason Jars for it's reservoir.
There are only two adjustments to this sprayer - the air supply pressure and the height of the liquid nozzle.
Basically, you fill up a mason jar, screw the top on, and you're good to go. In fact, I bought a case of mason jars at the local grocery store, and keep them filled with the different glazes that I use most often. Here is an assortment of the Waterfall glazes I use.
A few vigorous shakes of the jar and I'm ready to slap on the Critter and start spraying.
Simple. Exactly what I need.
Back to my "spray booth" dilemma - and believe me, it WAS a dilemma. I considered buying one, then after checking the booths out at a couple of local potteries, I was convinced it was going to turn into one more white elephant, cluttering up my shop. My studio here in Las Vegas is one-third the size of what I had in Ohio. It sucks, and it makes me constantly think of space-saving ideas, whether it involves tool and supply storage or actual floor space where I work.
So I started thinking about the concept of a disposable spray booth. I rigged a system made of a large cardboard box, with the front cut out. After placing a lazy susan inside, I could place a piece of bisqued ware on it, and give it a whirl. Sure, because there wasn't an exhaust fan, nothing pulled the airborne glaze from the atmosphere. But it more or less did a fine job until the glaze buildup on the walls started to flake off. As long as I was spraying the same color of glaze, an occasional fleck of glaze landing on the piece didn't really matter.
Still, it left me stuck with a glaze coated box... and what the hell am I supposed to do with that? And after I experimented with this a couple of times, I ran out of boxes to use.
I pondered this over a beer or two, and realized that the answer to my spray booth dilemma was simple - a trash can disposable system. This dawned on me one evening, when I was making dinner on the grill. Grilling is always messy, and it seems like I'm always scrubbing a pan or two afterwards. Once I switched to using nonstick aluminum foil and cooking in foil packets, life got much simpler.
It was a "light bulb over the head" moment.
My "spray booth" set up is simple, probably too crude or labor intensive for some, but it works perfectly for me. I start with a trash container from my woodshop. Honestly, a full one works better than an empty one. That's mostly because I throw the liner out when I'm done spraying, so I don't want to toss an empty can liner if I don't have to. Crank up the compressor, fill up a mason jar, and slap on the spray head. Of course, I've laid out all the pieces I want to glaze ahead of time, cleaned them off and sorted them into piles that will all get the same glaze.
Did I mention that I keep a giant roll of paper in my studio?
I read about that years ago, someone mentioned how handy a roll of paper is, for everything from making full size sketches, to wrapping finished pieces, to lining dirty shelves. So whenever I'm glazing, I'll put my bisqued pieced into piles on a fresh sheet of clean paper, and then either write on the paper which glaze I intend on using, or put the jar of glaze right by the pile. I need simple stuff like this in my life. Sort of like Rain Man.
I have my kiln loading down to a science. I know I can load roughly six shelves into my kiln, and I know how my pieces fit on them. Generally, I'll glaze only the pieces that are going into the kiln; otherwise, they'll just sit around and probably get damaged.
As crude as this system is - that makes it all the more important to wear a respirator. And of course, if I'm working with anything highly toxic, I'll either brush it, or put a set of elbow length gloves on. No sense in temping fate. So - let's start glazing.
In between pieces, the sprayer can hang right here.
Starting with the largest pieces first, I hold the piece in one hand, and spray with the other, using my trash can as my "booth". Of course, I do this outside, usually off in the gravel, as few feet away from everything.
It's simple to spray and rotate the piece at the same time. My hand holds the piece from the bottom, and rotating it is simple. The reason I spray the largest pieces first is that my hand is covered by the piece, so it stays cleaner longer. If anything, I get a little overspray on my wrist or forearm. A bucket of clean water and a sponge takes care of keeping myself clean.
I'll spray all the large pieces, and then move to the smaller ones. When holding a small piece, like a small soy sauce bowl, I'll generally support it with just two fingers. When I spray the next small piece, I'll use the other two fingers, which are clean. A quick hand rinse in the bucket, and I'm good.
Oh - and cleaning the sprayer is this simple...
Layering glazes is really easy - in this next short video, I'm holding a platter that already has a few coats of Waterfall Brown. But I want to shoot a little Waterfall Green in the center, it's a very nice combination.
Here are my pieces drying, you can see the various layering that I've done on some of the dinnerware sets.
After spraying everything, the last bit of glazing I do is with a brush, touching up the edges where the glaze didn't cover. It goes quickly. There is virtually no overspray to clean off on the bottom.
I leave the pieces to dry and start the cleanup. Screw the sprayer off the mason jar, and submerge the unit in my bucket of water. Pull the trigger and it forces the water up through the nozzle, cleaning everything. Like I said earlier, I keep the glaze in the mason jars, so there isn't a need to clean them. I just wipe them clean and put on a lid. And sure you label them, so you know what you're spraying.
To complete my cleanup, I tie the bag shut and throw it away.
A simple solution to a messy problem. The worst part of the clean-up might be scrubbing the red iron oxide out of my clothes. I used my shirt as a towel, as might notice in the image below. Note to self: wear dark shorts next time.
Anyway, that's how I do it. If it looks like it might work for you, sweet. A small compressor and the spray gun are pretty much all you need. Good luck, and don't forget to take off your jewelry before spraying.