Powder-Coating an Old Bike Rack

This old hitch-mounted bike rack has been through a lot. Since I got it for $50 on craigslist about 3 years ago, it's been rear-ended (twice), taken apart and re-welded, and slowly rusted in the rain and weather. 

But today, it has new life. It has been powder-coated.

Powder coating is a way to apply a very durable finish to metal parts. You basically spray tiny particles of plastic, which are charged with electricity, onto your part, which is also charged with electricity. The charge helps the powder to stick until you can put the whole thing in the oven, where you then melt the powder into a solid coating. It's actually pretty easy, if you have access to the right equipment.

What you will need:

• An angle grinder
• A sand-blaster (or a lot of time with sand-paper)
• Water and a pre-powder cleaner like TSP (Trisodium Phosphate)
• Powder (from Harbor Freight, or an online vendor like Columbia Coatings Inc.)
• A powder-coating gun system (these can be $100-$200 for the basic models. They plug into the wall and into an air supply (like an air compressor), and they spray the powder through a nozzle that charges it with electricity).
• An oven that will fit your part and can hold the temperature you need for your particular powder.

I made it at Techshop (www.techshop.ws), which has all of the above equipment.

An angle grinder fitted with a sanding pad or a flap disc works really well for taking off old rust and paint. Do as much as work as you can here; it's faster than sand-blasting.

Sand-blast the surface to finish cleaning up rust / paint from hard-to-reach places. If you have the patience, sand-blast the whole part to remove sanding marks and get a nice, even, slightly-rough surface.

Preheat your oven.

Clean your part thoroughly with TSP or another recommended pre-powder cleaner. Rinse thoroughly with water.

Hang your part in the oven to dry thoroughly (30 minutes in my case).

While your part is drying, connect your powder coating gun to the house air, to your can of powder, and to its electric box. Attach the ground wire to some metal that will be touching your part. This is important because it will cause the powder to stick to the part.

Keep your gun a little under a foot away from your part (don't touch the part with the gun; you'll make a spark and the powder will fall off of the part). Spray a nice even coat over the entire part.

Holding your part by its hook, place it in the pre-heated oven. Opening the oven will probably cool everything down, so wait until the oven comes back up to the recommended temperature again before starting your timer for the bake cycle. In my case the bake cycle was 15-20 minutes at 375-385 degrees (as indicated on the powder can).

That's all there is to it. Now you have a durable, sharp-looking protective coating on your part.