METALIZING PRACTICE TILES
After mixing and preparing your metal spray solutions in their respective pump sprayers; place the pump sprayer tanks on the bottom shelf of the service cart, and position the spray wands into their holders.
Prepare your warm space by turning on the heater – allow the temperature inside the warm space to reach 80 to 120 °F, with humidity below 50%.
Always begin by purging the fluid lines of each pump sprayer. Place your runoff collection bucket on the floor, and spray each wand into the bucket for approximately 10 seconds. The spray wands may sputter as residual air and leftover rinse water is expelled from the lines.
This step “primes” the spray wands; and ensures that only freshly mixed A, B, and C chemistry is delivered from the pump sprayers onto your work pieces. Once you are confident that the solutions have been purged through the lines, place the runoff collection bucket back under the service cart.
The air pressure delivered to the air blower can be adjusted by turning the regulator valve on the air filter housing. Adjust the air pressure to a reasonable setting that will allow you to blow the tiles dry in a controlled fashion – the pressure gauge should read around ~40 PSI with the blow gun trigger fully depressed.
The stainless metal stand included with your LI System is ideal for holding the practice tiles during metalizing. The stand positions the tiles at a 60-degree angle, which helps the chemistry solutions to run off the part quickly. Placing the stand on the turntable makes it easy to rotate the part while spraying, to allow for thorough rinsing between each step of the process.
Be very careful to not touch the basecoated surface of the tiles when positioning them. Touching the basecoated surface will cause artifacts to appear in the silver finish.
Pick up the green-accented spray wand, and spray the entire surface area of the tile with sensitizer solution as quickly as possible. Start from the bottom up, and keep the “wet edge” of the sensitizer solution moving. Do not stop the flow of sensitizer solution until the entire surface area is covered.
“Stopping” the flow of chemistry on the part can cause a sensitizer stain that can be seen in the silver finish after it is done. This staining looks like white scale or spots in the silver – similar to soap scum on a shower door.
Immediately after sensitizing, pick up the blue-accented spray wand and rinse the tile with zero TDS water. Be sure to rinse very thoroughly. Any leftover sensitizer solution can cause yellowish-brown staining if it comes into contact with the silver solutions applied in the next step.
It’s a good idea to rinse the front of the part, the area around the part, the back of the part, and then finish with rinsing the front of the part again. You can never rinse too much. When you feel that rinsing is complete, rinse a little bit more just to be sure. This is most important on work pieces with complex geometries that may trap sensitizer solutions.
After rinsing, your tile should have an even sheet or “film” of water on it, with no water breaks or beading. If water breaks appear, it indicates that the basecoat is not dry enough. Simply rinse and blow the tile dry; then return it to the warm space for additional dry time as described in the Drying the Basecoat section. Be sure to examine your tile closely – silver will not deposit well in areas with water breaks.
Immediately after rinsing; pick up the red and white-accented spray wands, and spray the entire surface area of the tile with silver solution as quickly as possible. Start from the bottom up, and keep the “wet edge” of the silver solution moving.
Do not worry about the reflective shine appearing right away — instead, focus on “wetting” the entire surface area of the part with an initial coverage of silver solution. Once the initial “wet” layer is applied, continue spraying the silver solution evenly over the part. The silver will slowly “fill in” and build up reflectivity to a perfect mirror shine. Do not stop the flow of silver solution until the entire surface area is covered, and the silver has a uniform, mirror reflection.
Aim the spray nozzles away from the tile when first pressing the trigger down, then move the spray onto the tile surface. Never start or stop the flow silvering chemistry while aiming at your work piece – “transients” from starting or stopping the solution flow can cause artifacting in the silver.
Immediately after silvering, pick up the blue-accented spray wand and rinse the tile again with zero TDS water. As always, be sure to rinse very thoroughly. Remember to rinse the front of the part, the area around the part, the back of the part, and then finish with rinsing the front of the part again.
Residual metal spray solutions left to dry on the part can cause “water marks” in the finish. If water marks appear, they can be removed by performing another rinse with zero TDS water.
Immediately after rinsing, pick up the compressed air gun and blow off the rinse water until the part is completely dry. Start from the top down and let gravity assist. Be sure to blow the part dry on the back side as well. If any blemishes or imperfections are seen, it is OK to perform another rinse, and then blow dry again.
After blowing dry, carefully move the completed tile into the warm space for protection. Take extreme care to not touch the “raw” silver deposit when handling. Once completely dry, the tiles are immediately ready for Topcoat 311.
The Spectra Chrome metal spray layer is pure silver metal – once applied, it is vulnerable to temperature and humidity, and will start to oxidize and degrade if left unprotected. Even inside the warm space, the “raw” unprotected silver should not be left overnight.
The next step is to apply a light protective coating of Topcoat 311, to seal in the silver layer and preserve the perfect mirror reflection.
Sometimes the lighting conditions in your shop can fool you; so we always encourage examining your parts with a high powered LED light after spraying the silver. We call it a “truth light”, because it allows you to see the true quality of your silver deposit.
Under the truth light, you can diagnose and correct issues with your metalizing technique to ensure a perfect finish. Here are some examples to look out for – click the links to learn more in the Troubleshooting Guide.
