CLEANING & PREPARATION
The paint will only stick to whatever is already on the stove. If there is grease, oil, graphite, rust or foreign material of any sort on the surface, it must be cleaned off. Tri-Sodium Phosphate (available in most paint stores) and water with a wire brush. After the surface dries, wipe down with steel wool pads (without soap) and white vinegar to kill any rust spores. Many household cleaners leave an oily residue that cause more problems than they solve. Furniture polish and stove wax both leave residues that make it nearly impossible to paint over, so please don't use them on your stove. In extreme cases it may be necessary to sandblast or sand the old paint off the stove. Remember, the object is to get a surface which is extremely clean.
THICKNESS OF PAINT
Stoves are generally painted once at the factory. Dealers will often customize the stove to another color. Problems arise when, in repainting the stove, or in changing again to a third color, the total paint film thickness gets too thick. In each normal painting of the stove, about .9 mils of dry paint are applied. Peeling will occur when the total film thickness reaches 2.0 mils or higher. If the factory color is to be changed, only change it once. If a third coat is to be applied, use a sander or solvent (see the last section on cleaning) to remove most of the first two coats.
You can usually tell why paint doesn't stick to a stove by the way the paint comes off after the stove has been used. If it peels or it looks like shattered glass and comes off in thin strips, this is caused by too much or too many coats of paint. On the other hand, if it comes off in large patches, it is usually caused by a dirty surface before painting. Rusting comes from painting over old rust, not thoroughly cleaning the surface to be painted or not applying paint thick enough in factory production to prevent rust in transit or storage.
Many problems can be avoided by using some common sense in using the paint. The paint is pushed out of the can by the pressure of gas in the can (caution, this gas is highly flammable, a close relative of natural gas, and should be kept away from any spark or open flame. Use only in a well ventilated area). The can is designed to work at room temperature. If the can is cold from being left in a storeroom or a truck at night, heat it up to 70-80ºF before using. A couple of minutes under a hot water faucet will usually do it. Do not get the can hotter than you can hold comfortably. A cold can will sometimes "spit."
There is a marble in the can which is there to stir up the paint before using. Unless the paint is stirred by shaking the can thoroughly, the paint will be non-uniform. Shake the can for at least two minutes after you hear the marble rattling around, which will insure a better paint job. This is critical when using some of the lighter paint colors. Spray a couple of squirts onto a piece of cardboard until you see the paint color being applied correctly (see next section). Paint should be sprayed from about 12 inches; too close and the paint will pool and run - too far and the paint will "dry spray" and appear textured. We find the best technique is: depress the spray tip, paint in one continuous stroke from left to right, release spray tip. Repeat as needed. Don't paint in a circular motion and don't continually depress the spray tip.
PLUGGED SPRAY NOZZLES
Inside the spray can there is a plastic tube which goes to the bottom of the can. The paint is then drawn into the bottom of the tube from the bottom of the can. If, in storage, any material separated in the tube, it could be slightly different from the main paint. When first using a spray can, it is essential to spray the first shot onto a non-critical surface like a newspaper. This clears out the tube. Make sure your finger is not extending over the front of the nozzle. If it does, paint will collect on the tip of your finger and spit onto the stove, causing spots. "Can Guns" are available at most paint and hardware stores to depress the nozzle using a trigger. This will prevent the finger problem.
After using a spray can partially and if you intend to keep the remainder, turn it upside down and spray until the colored material no longer comes out of the can. By turning the can upside down, the tube is removed from the paint.
CURING THE PAINT
Most high temperature paints operate in the same way. They use a resin, which dries at room temperature giving the paint the initial properties seen on an un-used stove. Then, when the stove is burned, this air dry resin burns away. At the same time, the silicon resin (silicone gives the paint it's high heat resistance) in the paint will not cure until it is heated to high temperatures. This occurs at about the same time that the air dry resin is burning. We have found that this "transition" takes place at about 475ºF.
At the time of the first burn there will be a ring on the top of the stove. Within this ring the air-dry resin will have burned away and the silicon resin has cured. Outside this ring the silicon resin is still uncured and the air-dry resin is still there. On the ring, however, you will notice that the paint is soft, or may even be wet; this is where the transition happens. After the stove has been burned about three times, the entire surface will have cured, and there will be no further changes. It is important to ventilate the house during these initial burns while the paint is curing. Although the smoke is primarily Carbon Dioxide, there are other components of the smoke which make it smell bad and may irritate some people. These problems will go away after the first few burns, depending on the duration and the surface temperature of each burn.
While stove paint is a little glossy when first applied, it loses some of this gloss when it is cured. This means that a stove which has begun its cure cycle will sometimes show a ring that is visible when curing. Often, the cured paint will look lighter in color, because it is "flatter". Again, after the paint is fully cured this condition will not be as visible. If this is a major problem, one solution is to use a "flat" paint initially, which will not exhibit this phenomenon.
Stove paint is sticky during this curing process, so be careful not to set kettles, trivets or other items on the stove as they will mar the cured paint finish. Also, if you have painted surfaces that come in contact with door gaskets, be aware that the door gasket may stick to the stove the next time you open the door so it's preferable, when possible, to leave the door slightly open and burn small fires to help cure the paint, or to not paint the area around the door that will come in contact with gasketing material.
This article copyrighted by THE FIREPLACE CHANNEL