Chevelle..... working in the industry for a while has helped me get a "touch" for what you are trying to do. Let's see if this might be of some help as even I have yet to use a "gauge" other than time and feel to whatever I have been coating, no matter the thickness spec.
I'll tell you what I tell all my clients when they ask me to tech them. Slow long broad strokes like using a spray-can will generally get you a good beginner's coat. I know...it sounds silly but the theory behind it is this....
A basic general pass with a poly (what you hobbyists use most) will net you between 1.2-1.6 mils. Most liquid coatings top thier build out at .6-.9 area (assuming the solids). A powder is 100% solids, so therefore not as much time is needed at each pass. Picure yourself holding a spray can in your hand. Start before the piece (a flat panel if you will) and paint the air. move from left to right in a straight deliberate manner. Stop sparaying after you have moved past the piece. There...one even strip of paint. No rough edges...nice and fluid. Well, the same goes for powder. Your thickness is determined by pressure,ground,diffuser,substrate and powder size (among other things) basically. One slow pass of the gun in that manner, will net you 1.2 mils pretty much. Keep the voltages low ( most of what you guys use works best at 30-40 Kv I'm assuming) and air pressure at a reasonable amount. Just because the powder is "charged" doesn't mean that it can't blow past what you're doing. Give it a chance to encapsulate and linger. Anything not fit will most assuredly pass by. If you really need a cheap alternative to the whole "thickness reader" thing after it's on (so you know what you just did looks like so, and builds like so).... Take a house magnet. Now take sheets of typical notebook paper. Measure the paper until you get 1 mil thickness. Now....place the magnet on the paper, and then on a nice hefty piece of steel ( your very own pre-coated piece if you wish). Now pull it off. You now know what 1 mil feels like. Go down in magnet strenghts until you find one that BARELY stays on the paper (one of those flat junk magnets they give you for free should do). When you find that one.....label it 1 mil. Find another magnet...go to 1.2. That will take a lot of time, I'm sure. Hoever...for the price of basically nothing, you have a tester as good as we use for the most part. They make pen-type testers out there that work on the same principal. Pull the spring loaded magnet away, and the reading gets stuck at whatever thickness it is. Nice and simple. Then again....you could fork over a few hundred for a dial electronic mete...or upwards of a grand or so for one of the many digital ones out on the market. Hope something in this long winded speech helped,lol.
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09-09-2003, 09:15 AM
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