Instructables

Trying my hand at: Sand Blasting and Powder Coating [Pittsburgh Tech Shop]

Picture of Trying my hand at: Sand Blasting and Powder Coating [Pittsburgh Tech Shop]
Today at the Pittsburgh Tech Shop, I took a class in sand blasting and powder coating. Powder coating is a fantastic technique for painting just about any metal you can think of. Not only that, it's fairly straightforward, safer than other methods, and gives you a nice glossy finish. This Instructable is the documentation of the class in which I powder coated a sheet of metal and a key that I had lying around. 

I will discuss the process from start to finish beginning with material preparation, the sandblasting cabinet, cleaning the material, the painting process, and baking.

More information about the Pittsburgh Tech Shop can be found at http://techshop.ws/

I made it at TechShop!
 
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Step 1: Before you start: The Setup

Picture of Before you start: The Setup
Powder coating is a straightforward process but requires access to certain resources (which the TechShop happily provides). Make sure that you have access to all of the following tools and materials before beginning: 

Time: about 2 hours for a small project
Tools:
-compressed air (dry and filtered)
-air supply (regulated from 30-90 psi)
-blasting cabinet
-appropriate media for the blasting cabinet
-powder coating gun
-spray booth with filtration system
-curing oven large enough for your piece
-industrial sink
-latex gloves
-heat resistant gloves
Materials:
-powder coating media
-polyester tape (for masking)
-wire (for hanging)
-paper (for filling holes you don't want sandblasted, e.g. threaded areas)
-trisodium phosphate (for cleaning steel) OR Simple Green (for other materials)

It is also advisable to wear a long sleeved shirt made of a natural material such as cotton as well as closed toed shoes.

[Source: TechShop course handout #FIN105, available at the front desk upon class signup]

Step 2: First question: What do you want to paint?

Picture of First question: What do you want to paint?
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Choose something to paint. You can paint anything from scrap metal to bike frames to car parts to tools with powder coating. It should be conductive and be able to withstand temperatures of about 400 degrees Fahrenheit. Choosing a metal is your best bet. I was given a piece of metal to paint; I also decided to paint an old Master Lock key I had on me.
Did the powder coat thickness affect the function of the key? I have been wanting coat my keys for identification, but I'm concerned that the extra mm or so of coating will hamper the lock function.
I chose this key specifically because I'd lost the lock for it. What I would suggest is either (a) to test the function with a lock and key you don't care about (b) copy your key first to test it (c) use a tape that can stand high temperatures to mask off the teeth; that way, you can coat the top of the key without the risk of losing functionality.
I understand that powdercoating only adds 1 mil of thickness (1/3 the amount of the thinest visqueen or dry cleaner bags).
dwilliamson110 months ago
Try denatured alcohol or acetone to do a final cleaning of the metal, glass or any material that can stand 375° to 400° for 20 minutes.
Mask the teeth with vinyl tape so as not to thicken it with powder coat.