Air Gun Protocol
This is about a high volume, low pressure, air-powered spray gun - like the Purple Classic by Harbor Freight.
- Let people know they are painting so they bring old clothes
- Rags should be available - so gun is cleaned from spills readily.
- Gun holder jig should be available for hanging gun for refills, with hose attached. Holder holds gun so strainer cup can be placed above cup.
- Strain directly into cups, using a ladle of some sort. For 5 gal buckets, ladle can be hung on side of bucket. For 1 gal paint, ladle can be left submerged. Put lid on partially to limit evaporation in both cases.
- Use 20 oz paint cups for longer spraying duration between refills
- Start at 80 PSI on regulator - it should be 40-60 PSI during operation, not when idle. Look at regulator.
- Use an air/dirt filter
- Air filter clean-out should be pointing down, by gravity
- Turn air on all way at bottom of handle- and use regulator to set pressure
- Use air pattern control to get spray wider or narrower - observe and practice with water.
- Practice spray pattern with water onto a visible surface, such as stone, cardboard, fabric
- Hang five for distance from work piece, hang five for spray width
- Always keep gun direction at a normal to the surface sprayed. This means 2 dimensions.
- If sheet is on floor, normal is impossible - the only way you can do it is if angle of substrate is near 45 degrees when working on panel material
- Long material can be hung on a wall with blocks - if using a temp structure
- Elevate panel on floor jacks as another option.
- If you take a break of any lenght longer than 2-5 minutes - take off cup, take off air hose, leave gun suberged up to handle in about 6" of water immediately - for water-based paints.
- This can be done in less than a minute
- Wipe gun with rags, so paint doesn't harden
- For oil paints - if you're taking a break - do a diesel or mineral spirits blow-out - this also takes less than a minute
After finishing the day, this is what will make your gun last for years without clogging -
- Take off cup, clean it in water or solvent with a brush.
- Take out needle, being careful about the jumpy spring when screw thread runs out - and submerge in cleaner (water or diesel)
- Take off nozzle
- Take off subnozzle with 17 mm thin wrench - the first time taking this off you may need to put the gun in a vise
- Now you have the back, front, and top of gun accessible for cleaning with the small brush and cleaner. All remaining paint in feed, outlet, and back should be cleaned.
- For the subnozzle - may need to poke center hole with 0.035 wire if center hole is clogged.
- Brush the nozzle and subnozzle and needle to get all junk off.
- Look through subnozzle - oberve light through center hole, and all radial holes. If light is not coming through - needle out the holes. The subnozzle appears to be steel - and smooth welding wire works great for center hole. Steel is not as susceptible to damage as is the outer nozzle.
- Look through nozzle - observe light through mid hole and tiny radial holes - make sure all holes are clear. Torch tip cleaner needles may be required if brushing is insufficient. But that can damage the brass nozzle - so torch tip needles are the last resort.
- Summary: 3 apertures cleaned, all light holes shine light in nozzle + subnozzle - and you are done.
- Final step - run diesel through the gun, which keeps the innards lubricated. Don't use water if you're using latex paint. Just do diesel.