Powder coating is occasionally mentioned as a way of finishing flashlights. Granted, its thermal properties aren't as good as anodizing or bare metal but it still seemed worth a try. A variety of textures and colors are available and the process promised to be practical for small parts in a home shop. Harbor Freight had its powder coat kit on sale and, with an additional 20% coupon, it was only $40, which falls within the reasonable range for experimentation. A fairly large toaster oven turned up on sale at Sears, so that completed the outfit.
A new light was needed to serve as a guinea pig. A Solarforce 2xCR123 body and tail cap was in my junk box and seemed like a good place to start. A Malkoff host is always nice to have around so a new head was sketched out for that purpose. The lathe was fired up and the Solarforce parts were given a thorough makeover before machining the head from a chunk of 6061. Care was taken to round all sharp edges so they wouldn't show through the coating. Light bead blasting was used to clean the surfaces to be coated and to provide a mechanical key for good adhesion. The parts were then cleaned with a degreasing solvent and baked at 400 degrees for about twenty minutes.
To apply the powder, the parts must be grounded to the power unit. There is nothing on the inside of most lights to clip the ground wire to, so a compressed spring was used to maintain contact. An alligator clip was soldered to a piece of bare, tinned, 18 gauge wire and clipped to the spring. The wire was run out the end of the light, providing a convenient ground connection.
A discount store provided a silicone oven mitt at the bargain price of $2.99. Disks were cut from this to plug the ends of the light. These keep powder from being drawn to the interior surfaces and provide support for a ¼" rod that suspends the light in the oven.
Finally, the threads were cracked about twenty thousandths so that the joints wouldn't be painted shut.
When spraying a small piece like a light, it's no problem to work indoors without a spray booth. A six foot square of newspaper was laid out on the shop floor and this proved more than enough to contain the powder. Don't try it in the living room, though - it's not that tidy! The goal in application seems to be to get complete coverage without overdoing it. Too thick a coat is said to promote orange peel. My finished product does have a very slight hint of orange peel in spots but that may be due to the cheap HF matt powder. I've got some classier stuff on order to see if it gives a better finish.
There are different types of powder and it is important to bake at the time and temperature recommended by the supplier. The curing process put off some obnoxious fumes so the oven was put outside to complete the cure.
The final result was even better than I had hoped. My initial impression is that powder coating is a useful technique to have in your bag of tricks if you want to create unusual lights or do interesting mods.
A new light was needed to serve as a guinea pig. A Solarforce 2xCR123 body and tail cap was in my junk box and seemed like a good place to start. A Malkoff host is always nice to have around so a new head was sketched out for that purpose. The lathe was fired up and the Solarforce parts were given a thorough makeover before machining the head from a chunk of 6061. Care was taken to round all sharp edges so they wouldn't show through the coating. Light bead blasting was used to clean the surfaces to be coated and to provide a mechanical key for good adhesion. The parts were then cleaned with a degreasing solvent and baked at 400 degrees for about twenty minutes.
To apply the powder, the parts must be grounded to the power unit. There is nothing on the inside of most lights to clip the ground wire to, so a compressed spring was used to maintain contact. An alligator clip was soldered to a piece of bare, tinned, 18 gauge wire and clipped to the spring. The wire was run out the end of the light, providing a convenient ground connection.
A discount store provided a silicone oven mitt at the bargain price of $2.99. Disks were cut from this to plug the ends of the light. These keep powder from being drawn to the interior surfaces and provide support for a ¼" rod that suspends the light in the oven.
Finally, the threads were cracked about twenty thousandths so that the joints wouldn't be painted shut.
When spraying a small piece like a light, it's no problem to work indoors without a spray booth. A six foot square of newspaper was laid out on the shop floor and this proved more than enough to contain the powder. Don't try it in the living room, though - it's not that tidy! The goal in application seems to be to get complete coverage without overdoing it. Too thick a coat is said to promote orange peel. My finished product does have a very slight hint of orange peel in spots but that may be due to the cheap HF matt powder. I've got some classier stuff on order to see if it gives a better finish.
There are different types of powder and it is important to bake at the time and temperature recommended by the supplier. The curing process put off some obnoxious fumes so the oven was put outside to complete the cure.
The final result was even better than I had hoped. My initial impression is that powder coating is a useful technique to have in your bag of tricks if you want to create unusual lights or do interesting mods.
