Arc & spot welding
Automotive hand tools
Car enamel colors
Car paint colors
Car paint glossary
Car painting problems
Cleaning car upholstery
Infra-red paint drying
Interior automotive trim
Painting over paint
Paint surface preparation
Refinishing paint tips
Safe car spraying
Sanding, striping, rubbing
Shrinking sheet metal
Not finished yet:
Basements are not good locations for spraying. In the first place, they are generally damp, and that is harmful to the finished work. Furthermore, they are difficult to ventilate properly. And should a fire start, it is in a location from which it can work up and do the greatest damage to the rest of the building.
From the foregoing it is obvious that the upper floor of a building is to be preferred. If the building is of fire-proof construction, so much the better. Fireproof buildings are a good precaution, regardless of the kind of work being done. So are automatic sprinkler systems. And when locating the shop, remember that a northern exposure gives the most uniform light—a real advantage at all times and vital when doing the better quality of work, or matching colors.
If windows do not give sufficient light, a skylight will prove a big help. In fact a skylight gives the best distribution of light. Should artificial light be needed, use only electric lights that are protected with vapor proof globes and locate all switches as far as practicable from the actual spraying. Locating artificial light on the sides, rather than on the ceiling, does much to eliminate deep shadows.
Spray booths and rooms
While the use of approved spray booths is desirable in all localities it is required in some. For that reason it is suggested that local building requirements be checked up before engaging in paint and lacquer spraying commercially. If a booth is not provided, the room used for spraying should be as fireproof as it is possible to make it and should be shut off from the rest of the building by self-closing fireproof doors.
If at all possible, provide separate booths or rooms for the spraying of oil undercoaters and lacquer finishes. When the dust from these two different products mixes it is much more combustible than either one by itself. Of course, the logical procedure, when it is impossible to provide separate rooms or booths, is to see that the place used is kept immaculate.
In fact, cleanliness is probably the best fire insurance.
The dry dust from spraying is highly combustible and when once ignited
burns fast. And of course lacquer and thinner — like any other refinishing
materials — are combustible. The supply of refinishing material
should be kept in sealed containers and, preferably, in a metal cabinet.
It is best to keep the stock of materials outside of the refinishing room
away from direct sunlight, and in a fireproof place that is cool and dry.
Ventilators should be of the motor driven variety. Approved construction calls for the locating of the electric motor out of the stream of air handled by the fan. Furthermore, there should be a metal comb or similar protection that is well grounded and so located that it will discharge static from the belt as fast as produced—thus overcoming the chance of sparking.
One authority on the subject of spraying states that fans should be of such capacity that they provide a complete change of air every three minutes. This rate of air change is sufficient to carry away the fumes and dust and so provide safe, healthful working conditions. A lower rate of air change might prove inadequate—and a higher rate would cause drafts, the latter being injurious to the quality of the finish. If spraying is being done in a booth, the ventilating system can be checked in this way: if, with the spray gun in use no spray or vapor appears at the open end of the booth, the ventilating system is of sufficient capacity. However, if any vapor does appear, the fans should be larger or run faster.
When spraying in a room, it is suggested that the fans be installed about 3 feet above the floor and 12 feet apart. All exhaust fans should be turned on a few moments before beginning to spray and should be left running for several minutes after the spraying has stopped.
Under no circumstances should the exhaust from ventilating fans be permitted to discharge into air passages between buildings or into chimneys. To do so would increase the fire hazard—not reduce it. It is recommended that exhaust stacks be erected to aid the fans in their work. To prevent the accumulation of combustible solids in the stack, baffle plates covered with masking compound can be used. Then when the masking compound becomes covered with spray dust, it can be washed off with water and a new coat of compound applied.
Check everything that could possibly cause a spark. See that all electric motors are of the type that have no commutators to cause sparking or else are fully enclosed. Frames should be grounded. Keep switches of all kinds away from lacquer vapor. Prohibit smoking—and enforce the ruling. Never drive a car into or out of the spray room. Always disconnect the battery before bringing a car in. See that no nails project from the shoes worn by the workmen. Nails on concrete or steel floors can cause sparks.
Never use any local heater such as the electric variety. And never use any heater with open flame. All heat should be supplied by either steam, hot water, or hot air. Use enough heat so that the metal never feels chilly to the touch. It is useless to come into a cold shop and try to do good work in the morning. The services of a night attendant or someone who can "boom" the fire about 5 A. M. are well worth while.
And even though every possible precaution against fire has been taken, provide fire extinguishers where they can be quickly found and put into action. Inspect the extinguishers regularly in line with the recommendations of their manufacturers. Keep them fit for active duty. And keep them hanging up where they can be seen.