Refinishing repaired vehicles is a daily task in today’s body shops. And since consumers are savvier than ever, they put your refinish skills to the test by checking for the perfect match and a flawless finish. To achieve the results your customers want, it’s important to maintain your refinish equipment so it performs as it was designed to.
Today, companies producing traditional and HVLP spray guns also offer various nozzles, pressure regulators and related accessories to complement their equipment – all of which require proper maintenance to achieve optimum efficiency. How do you keep these workhorses of the refinish process in top condition?
Several painters I spoke with shared the following tips:
- Keep nozzle caps clean by storing them in fresh lacquer thinner or paint-gun solvent in a separate tray in the paint-gun cleaning machine.
- Coat the seals with petroleum jelly or a special lubricant where the needles move through at the trigger. (Don’t go hog wild with the lubricant. Just keep the seals soft to help prevent dry-out and failure from exposure to paints and solvents.)
- Use only soft plastic or wooden tooth-picks to free up clogged caps, nozzles or other orifices. This prevents spitting and poor patterns during paint delivery.
- Use a screen at the paint inlet tube on pressure-feed guns to prevent clogs, and be sure to properly strain the paint when using gravity-feed guns.
- Replace the gun-to-cup fiber gasket often, and keep the air tube and orifice at the cup open with a non-metallic tool.
- Check the bail and lever mechanism at the cup for function. If you’re using a pressure-feed gun, be sure to tighten the transfer tube to the gun before spraying.
- When using gravity-feed HVLP units, the plastic paint reservoir lid is a vacuum seal during material delivery. Treat it gently during clean up. Also, don’t vent or alter its design.
- Avoid swapping nozzles from gun to gun because this may lead to thread damage and spray caps becoming cross-threaded. Damage of this sort must be treated first with a thread file and then with specialized dies.
- Get rid of old paint guns with worn parts that are beyond rebuilding.
- Use a bottle brush with soft bristles to remove paint accumulations in gun passages.
- If a gun won’t function after a good cleaning, a minor seal replacement and a new needle has been installed, send it to a factory-approved rebuilder.
When storing your spray gun, Colorado shop owner Bob Hamlin suggests placing it in an upright position after cleaning. Also, store the gun away from electrical equipment such as an air compressor, which may produce rubber-seal damaging ozone.
Hamlin also suggests you maintain reasonable security for the spray gun. If someone becomes careless and uses your colorcoat or clear gun for priming, it can lead to all kinds of fiascoes. Dilution and bleed out by the red oxide or grays from the primer pigments will kill a color match, as will a bad overcoat with contaminated clear. Then the next time you use the gun to spray clear, the clear will have a murky tint and the basecoat may not match in color or texture. Keeping tabs on your spray gun is part of keeping it well-maintained.
The ability of any booth to control the paint environment depends first upon regular maintenance. Here are a few spraybooth maintenance tips:
Today’s filters should always be used with the required fixtures and should be changed at the suggested intervals. Attempting to get by for a job or two with less-than-adequate filters will cost you a bundle in labor to remove the dirt afterward. Also keep in mind that even if your filter light isn’t on, you can still have poor airflow to the booth. According to a booth installer I spoke with, this is because the filter sensor only checks pressure drop across the filter element, not the average or minimum flow rates.
Cleaning up the work area inside the booth is also critical to performing a quality job. Applying strip coating to the inside walls of the booth will make for easy cleanup since the coating can be pulled off and replaced at regular intervals. Air hoses collect gunk, and if you keep the floor of the booth wet – as most shops do – the hoses can act as squeegees and pile up the dirt in corners or act as magnets, attracting the dirt to themselves.
The furnace assembly is a separate unit and, according to the spraybooth installer I spoke with, is best mounted close to the booth but not right over or attached to it. The reasons for this are to allow for the maintenance of the gas lines and for frequent intake air filter changes. The initial installation can make all the difference in the world in the maintenance a unit receives, says the installer. Furnace system maintenance aside, other important items – including intake and exhaust fans, their controls, etc. – need to be cleaned to keep them in balance.
To help prevent air leaks, use a quality caulk but avoid using the stuff that requires a wire wheel to get it off. Removing the paint along with the old caulk can cause rust pockets to exist under the new caulk you apply. This will damage the booth and create problems that are expensive to fix.
Other spraybooth maintenance tips to keep in mind:
- Keep explosion-proof light-fixture enclosures clean. Fixtures for lighting are designed to be serviceable by swinging down the explosion-proof paneling to reach the light tubes.
- Keep lighting fixture panel seals in good condition. Replace any light enclosure seals that allow overspray to penetrate the cabinet.
- Check for booth air leaks if the doors are difficult to open or spring back like a catapult when they’re released.
- Check booth gauge pressure readings at the control panel or use a manometer to verify a positive booth pressure. Look for leaks with a spray bottle with soapsuds around suspicious panels or at window moldings.
- Don’t forget to check control timers for infrared as well as thermostats for furnace temperature at regular intervals. Insert a thermometer into inlet ducts for make-up air to check for correct temperature settings.
- Water drains are critical in crossdraft and other dry-filter booths. Cleanup should include a scrub down of all floor surfaces after the enclosure walls have been attended to.
- Don’t haphazardly use solvents or thinners for cleanup of any booth parts. Check with manufacturers’ guidelines on approved cleaning procedures and materials.
- Check for rust along the lower walls of the booth. (This used to be a major concern, but the new powder coating paint systems that are becoming standard are eliminating problems encountered with corrosion.)
Writer Bob Leone, a retired shop owner and contributing editor to BodyShop Business, is ASE Three-Way Master Certified and is completing qualifications as a post-secondary automotive instructor in the vocational-school system in Missouri.