I've had successful results using Lazertran waterslide decal paper but there are some steps which are very very important to achieve professional looking results.
For Bare Metal and Powdercoated Panels Using a Lazer Printer
1. Print your design in reverse onto your sheet of regular Lazertran. It's entirely up to you weather you want to print the panel as a whole or if you want to print it as individual labels like "level", "threshold" or whatever, but make sure you print it in reverse. For rack type stuff I usually do it in two pieces on one sheet of 'tran.
2. Put the sheet of printed lazertran in the over on fairly hot (150 deg. cel.) (on a stack of paper to protect the Lazertran) for 3-5 minutes until the toner goes nice and black. If you longer the surface of the 'tran will discolor.
3. Cut your design out once the 'tran has cooled and put your first piece into a bowl or container of clean, lukewarm water.
4. After a minute or two, take the piece out of the water, shake it free of excess and place it face down on the panel and slide the backing off the decal.
5. Repeat for remaining pieces.
6. Take a brand new, clean sponge and rub all the air bubbles out of the 'tran. Take your time, do a good job. It gets easier as the lazertran dries a little.
7. Once you've got the air out, put the panel aside to dry for 3 days to a week. This part is really important and you really should go for a week if you can. If there is any moisture at all under the decal it will evaporate in the oven and make bubbles.
8. 7 days later, put your panel in the oven at its lowest setting for 45 minutes with the door partially open to do any last drying.
9. Close the oven door and over the course of about 2 and a half hours, longer if you've got it, increase the temperature a few degrees at a time until you reach around 150.
10. Around 150 the decal goes visibly shiny, this is when you know its done. I usually leave it 10 minutes after I see the shine just for good measure and make sure its finished.
11. Leave the panel in the oven until it cools. I've found out the hard way that some cheap powdercoats will actually melt at this temperature.
12. When the panel is cool, place it face down in a shallow dish of isopropyl, as pure as you can get your hands on. Leave it for 20 minutes.
13. The isopropyl melts the clear component of the 'tran and with some paper towel or very very very fine steel wool you can rub it away. The toner should have fused to the metal/powdercoat and wont come off with the clear decal.
14. Clean up and if you feel the need give a couple of light coats of clear (matt looks better) to finish.
