Friday, January 20, 2012

How to Hot Drop Powder Coat paint

The Quest continues

Operating out of limited space, you learn to cleanup (or live with clutter).  Seems like everything gets harder when you have to setup and cleanup between jobs.

I've gotten to points of frustration, where Ben and I both started to believe that if somethings not a pain in the ass, you must be doing it wrong. LOL.

In this case, let's talk about powder coat painting and lessons learned. I've been circling the bowl, learning stuff and refining skills. My learning strategy hasn't changed much over the years. Jump in, hit a few ditches, and finally keep it on the road. Even if you do a little weaving while you straighten it out.

Enough Intro. Back to the task at hand - sharing information about my experiences powder painting spinner components.

Buy them painted

I've bought them painted. Adds cost and my spinners have a bunch of components. More components = more Noise = more Cost. Quality wasn't that good on top of it. You might have to re-bake them.

Pay to have them painted

I've had them professionally done. Again, adds cost. These were sweet, done locally, no shipping cost. But you end up with choices. Green ones may not sell and now what do I do with all these little beauties?

Still, this might be the best end game if you have limited colors and turn over a lot of inventory. Cheaper and far better quality (IMO) then buying them painted. But...

They turned out nice, but were a pain to prepare and then separate. I strung lots of parts on 6ft lengths of stainless wire. Lots of them.

DIY, Paint your own

First, take a deep breath and get in the zone.

To test feasibility, I started dipping in the 2oz bottles. Had potential, and was fun. Built some tools. Bought some assets. Definitely good for small jobs. Bad news was different colors behaved differently with heat, IMO. Some orange peeled, some burnt, some over covered, and finally some looked great.  The good news is you can just torch them (wear a respirator) to recover the part and start over. It's labor intensive and stinks. Also, don't drop one in your lap.

What you going to do, when you got a passion?

People recommended fluid beds and heat guns, but I ignored them. Still cleaning the ditches.

Bought more assets. Saw a powder spray gun, bought it. Needed a compressor, bought it. Needed a spray booth, made one. See where this is going? Still not a professional job. Under coverage, parts too hot, orange peeling, etc. Setup and Cleanup was a pain, forcing you to play the make a bunch at a time card. Slippery slope, you end up back with color choices burning inventory.  I did end up with some new assets though. Never hurts to have tools.

After the Spray gun period, (the setup and cleanup lesson). I dug up the fluid bed comments again.

I could buy one from paint vender, but found forum posts showing a couple DIY versions. I was feeling a little asset rich in the paint department.

Still having fun in DIY land, I headed for Lowe's and Home Depot, eventually Hobby Lobby. Saw what they had and cobbled together my list.

Kind of Top to Bottom (with a picture)

3in Test Cap (used as top cover for storage)
3in PVC cut to 1 in length (for Cap to fit snug)
3in x 2in pvc reducer (top bowl of reservoir)
2in pvc riser (cut about 2in long - used to get some extra depth )
2in pvc coupler  (you need a filter to distribute air flow and contain powder - more later)
2in PVC riser (cut to 1.5in long - bottom air chamber)
2in Test cap (epoxy to bottom)

Do It Yourself Fluid Bed 

That's a picture from my window well photo studio, LOL. Great indirect light.

The fluid bed plan is to pump air up through the powder paint, fluff it up and even out part coverage when dipping - a bed of fluid powder. Air flow separates the powder in a suspension of air. Sounds cozy, right? Cozy, but meant to evenly coat parts and avoid dripping when baking.

You need to get an air feed into that bottom 2in PVC riser.

I had the R2D2 wonder compressor that I bought for the spray gun, so my first attempt was to try to use that. Which meant? Figure something out, then Spin the Wheel and try it out.

The line used by the spray gun was a 'fine' line (very narrow I.D.). Drilled a hole, got romantic with all the male and female fittings I had. Built FrankenFitting and epoxied it to the hole I drilled in the bottom riser.

Used a coffee filter as a filter (per a forum recommendation I had found). Dumped in some powder, stirred it up and hit the switch. Volcano erupted. Table top covered with Orange Fluorescent powder. Messy.

Maybe this thin 'fine' line was providing too much direct air pressure, even with the regulator low. The compressor came with another bigger line. Hobby compressor fittings are hard to find. Especially when you're in learn as you go mode. Different tools use proprietary fittings. Hobby shops don't stock fittings. Get the picture?

That's the nice thing about standards, there are so many to choose from.. I still have hope for that bigger air hose, but this project had a deadline and I was on underway. This ship had sailed. Take a note for V3 and keep rowing.

Went to Pet Smart and bought a small aquarium pump and one of those tiny bubble air stones. Cut another PVC riser, drilled a hole, fed the pumps air line into the hole and seated the air stone into it. Then pushed it back out to seal the hole. Seems to work fine, or good enough.

Aquarium air pump lined up for duty.


Replaced the riser being careful not to disconnect filter joint. Well maybe didn't do that once.

Crossed my fingers, and plugged it in. No volcano! Stirred the powder and got a small volcano, air was flowing. Powder must be fluffing cozily in a bed of fluid air. Sure can't tell to look at it.

The coffee filter seemed a little porous and skimpy to me. Especially after the joint separation lesson. I ended up replacing it with a furnace filter cloth. Then gluing it to the top risers bottom ridge. Much better, more stable.

Paint coverage consistency was much better. But the process still had labor issues and problems showed baking the little buggers.

I was using closed loop spinner wires to hold the parts as they were being dipped. I also built some custom dippers. I like to build stuff, what can I say.

When you heat a part hot enough to melt plastic powder paint, the dipper wire or tool gets real hot too. Guess what? Plastic paint bonds to 'real good' to hot wire. It was a wrestling match to separate the nicely coated parts. I found that even without baking the part, it was a pain to get them off the wire when I was heating it at it's resting place before dipping.

This is were the post title comes from - Hot Drop. I found you can suspend the part about mid way up the wire, resting it on a pliers. Fire it up, holding the wire with your fingers on top. Keeping the pliers kind of open will let you spin it and rotate while its getting the flame. Stainless wire seems to dissipate heat good (the ends stay cool). Hold on top with your favored hand, heat that baby up, rolling it with your fingers. Then drop it off the pliers to cool wire at the bottom. Quickly swish the part the air cushioned fluid bath. Problem solved.

Part coats nicely, and can be pretty easily removed from the wire. You'll figure it out. To each his own ditch.

Stainless Wire Part Dipper (SWPD) -
Stainless Wire All-Purpose Tool (SWAT)
If you want to get tough powder paint jobs you can't avoid the time in the oven and even dry powder paint on the dip wire can cause separation anxiety once baked.

Being a small friendly and adaptive business with more time then money, I choose to move them on to clean wires before baking. Nice paint jobs and less part wrestling. Much better outcome.

Heres's V2 of the Oven Hanger. V1 was hanging parts from the Oven rafters. This one slide in.


Office Clip Pinch hangers.

I love my job!

Here's a link to some finished products. Metal Spinner Assortments - plenty of color choices

Cheers and Noise on the Line!

1 comment:

Tammy said...

well, I must be doing lots of things wrong...hehe

My middle son loves to fish from his kayak. I'll have to tell him about your spinners.