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September 26, 2017, 06:16:48 am


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Author Topic: Powder Coating - Just for Dragonfly  (Read 204 times)
Bob La Londe
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« on: September 12, 2017, 02:01:45 am »

HEY I SAID JUST FOR DRAGONFLY.  

NOW YOU JUST CLOSE THIS THREAD RIGHT NOW BUBBA, LLOYD, PIXELMAKER, AND ALL THE REST OF YOU GUYS.   Grin

While generally not a CamBam project powder coating is actually not all that hard.  Most of us have been conditioned to think of it in terms of large production operations, but small parts can be easily powder coated in a counter top toaster oven.  

What about spray booths and static guns?  Well, you can do that, and to be fair it probably delivers the best, thinnest, and most even coating, but its not the only way.  Essentially you are melting a film of plastic dust into a solid uniform coat of plastic, so thin and even are usually good. Thick and uneven results in drips, sags, and poor appearing results.  

My first attempts at powder coating did not involve a static gun.  In fact I have never used a static gun, although now I actually own two of them.  I simple heated a small metal object in front of a heat gun and swished it around in a pile of powder paint.  Then I clamped it up in a make shift rack (due to the type of part) and placed it in my toaster oven.  The results were quite satisfactory.  It was that simple.  Really.  

I've mentioned the toaster oven a couple times now.  Depending on the brand of powder paint I cook at 350F or 400F.  I always have to look at the container to remember the times, but ovens vary.  Usually about 30 minutes with a slow cool down works great for me.  I turn off the oven and crack open the door.  I've heard people talk about outrageous heats and special conditions, but for the average project with small sized metal objects its pretty easy.  

If you get excessive coating you can get nasty sags and drips and fine details can get filled in.  Its probably not an issue for a luggage rack, but it might be a huge deal if visible details are important.  

Now the way I have done it so far is not the best way by a long shot, but it works for quick and dirty small jobs.  Before I talk more about better ways to do it I want to mention a worse way.  You heat the object with a lighter or torch, swirl it in the powder paint, and then quick heat the object again with your lighter or torch until the powder paint turns glossy.  Takes literally a minute from start to finish and it looks good.  The problem is your powder paint is not strong, and it is not well adhered to the object.  Still in some circumstances it may be satisfactory.  Imagine fishing and finding out your target species all want green jigs today.  You can powder coat a jig green and be ready to fish with it in a minute using this method.  The powder coat will flake off when you bounce it off a rock or drag it through gravel, but the truth is you had a useable item in under a minute.  

Now lets talk about better methods.  

Baking is always best.  Some guys say they have gotten even tougher results by partially baking, allowing to cool and the finishing the bake.  I've seen a production line that did just that.  For the most part if you bake according to the direction on the container you will get strong durable well adhered results.  

A static gun will give you the smoothest thinnest, most even coat, but if you bump the part moving it to the oven the powder paint will fall off.  

Preheating and sticking it in the jar works ok, but if you over heat the part excessive paint will stick to the part.  It take a little practice to heat the part just enough so a single layer of particles (or atleast a thin layer) sticks to the part.  It can also require a little pushing and force to get it to work.  

A fluid bed is kind of a compromise.  Air is pumped in through a membrane (brown paper grocery bag seems to work really well as a membrane) into the bottom of a cup full of powder paint.  This causes the powder to fluff up and move around like a liquid making it easy to swish your object around in the powder paint.  The preheat of the object still takes a little practice, but it might require a little less heat because you can swirl it in the aerated powder paint particles much easier and faster.  

Last is selection of powder.  Quality powder coating paint will have very small particle size and not transfer heat easily from one particle to the next.  So far I have used bulk jars of Harbor Freight powder paint and small jars of PowderTech.  The PowderTech gave an order of magnitude better results with my quick and dirty methods, but a friend I trust said he was able to get decent results with Harbor Freight powder paint when using a static gun.  

That's it.  That's all I know about powder coating at this time.  I'm sure I'll learn more down the road.  


« Last Edit: September 12, 2017, 02:04:55 am by Bob La Londe » Logged

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Dragonfly
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« Reply #1 on: September 12, 2017, 08:59:07 am »

Thank you very much indeed, Bob!
I never thought about the possibility to do powder coating under home workshop conditions. That's why mentioning it attracted my attention.
Now, I have to convert some Fahrenheit numbers to Celsius and see what a static gun is Smiley

And ...
being a kind man by nature, I generously allow the rest to comment and share their views in this thread  Grin
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Bubba
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« Reply #2 on: September 12, 2017, 09:07:46 am »

 Grin Grin
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atwooddon
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« Reply #3 on: September 12, 2017, 16:03:02 pm »

Ok Bob   I won't read your info on powder coating.  Seriously, I won't read your info on different techniques and how you can actually do this at home in your shop.....   Really, I won't...   Grin

Don
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lloydsp
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« Reply #4 on: September 12, 2017, 18:12:33 pm »

Bob,
I do have a question:  I have a non-contact IR thermometer.  Can you tell us the 'best' temperature for the material prior to 'swishing' in the powder?

Lloyd
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Bob La Londe
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« Reply #5 on: September 12, 2017, 18:21:08 pm »

Bob,
I do have a question:  I have a non-contact IR thermometer.  Can you tell us the 'best' temperature for the material prior to 'swishing' in the powder?

Lloyd

Nope.  Sure can't.  With my heat gun on high I hold a 1/2oz lead jig in front of it close for about 1 second per side.  With Powder Tech paint that's about right.  With HF Paint I often get over coverage.  

Just barely warm enough for the paint to barely stick is the best description I can give.  

I suspect am IR gun (I have a good one and a cheap one) would be inadequate for this job.  Maye an IR camera and screen would work if you wanted a visual indication.  (Technically I should say thermal imaging camera.) 
« Last Edit: September 12, 2017, 18:36:54 pm by Bob La Londe » Logged

Getting started on CNC?  In or passing through my area?
If I have the time I'll be glad to show you a little in my shop. 

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Bob La Londe
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« Reply #6 on: September 12, 2017, 18:24:20 pm »

There are actually a BUNCH of videos on YouTube by tackle makers doing powder coating. 
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Getting started on CNC?  In or passing through my area?
If I have the time I'll be glad to show you a little in my shop. 

Some Stuff I Make with CamBam
http://www.CNCMOLDS.com
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