ST Project: DIY home powder coating - tutorial on PC and doorframe restoration(pics)

[jpnovak]

As the ST project has moved along I was forced to refinish most of the car. The biggest setback was the window trim. As all know bright trim is the only look to have (just like having a long hood - they just go together). The PO sinned by painting the brightwork black.

First thoughts were to just strip the paint away to the annodized surface. This did not work as the painter badly scuffed the aluminum to get the paint to stick. So I was left with the only choice of sanding out the window and door frames and corresponding trim. AFter sanding out I was left with a partially annodized surface that looked smooth but crappy.

Reannodization was out of the question and I did not want to pay to have them powder coated since I had lots of other things to get coated.

The idea was then firmly planted in my head to get my own Powder coating system. I got the system from http://www.columbiacoatings.com I talked on the phone several times and really learnd a lot. They were very helpful. I got the basic system that had many hangers and plugs to protect threads. Its the same system available on ebay and HF tools. I chose this vendor due to its customer support. It came with great directions except for the oven. It only says do not use in the presence of food. REally!! I never would have thought of that. So... I set out to design my oven.

The oven was detailed in this post.
ST Project update: Hooking it all up.

The basic system arrived and you get a high voltage source and a powder gun. I powder cup is held on the gun and siphons the powder using a 10psi (@gun) air line. The siphoned powder is then charged via a tubular electrode to 80kV(static). It is key to use dry air or the powder may clump. I used an inline filter/dryer at the gun.





The parts must be thoroughly cleaned before powder application. Finish result is just like painting - more time in preparation leads to better results. Lab metal is a metal filler that works for powder coating. Use it to fill in defects.

A ground lead is then attached to the part to complete the powder "attraction." I clipped the lead to the hanger hook that was used to support the part. The parts were hung in the homemade oven and the powder sprayed. Make sure to hit all the nooks and crannies. Inspect carefully for complete coverage.



As you can see the "chrome" powder attaches to the surface with a static charge. Be careful not to touch the surface with anything now as it will knock off the powder. The surface appears to be rough as the powder is not cured.



The nice thing about the powder is that it can be reused. Just sweep it up (paintbrush worked great) onto a clean sheet of paper and pour it back into the gun.


Next we bake the parts. The door to the oven was installed and the heat turned up. I used a single burner Propane IR heater. Its mounted in the lower corner of the oven with tinfoil to direct the heat downward. I didn't want direct heat on the parts. Pretend they are fine pastrys - slow even heat. Cure time is 25 min at 375. Keep an eye on that thermometer (opposite upper corner from heater) it gets hot really fast.



After the heat cycle I shut off the heater and allowed the oven to cool down on its own to 100deg. My research has shown that rapid cooling will yeild a cloudy finish.

Here's the door frames. I compared them to the winshield trim and its almost indistiguishable. I was very happy. Not bad for a few hours work.



I also had time to bake up some more parts. Here are some examples. These are the trim rings to my Cibie hood lights and one of the carb linkage supports. For those following the project, The hood fill cap looks spectacular. Look for an upcoming thread.




I have the powders to duplicate the yellow cad finish but didn't get time to try it. Its a custom mix I will make myself. Testing is required. Maybe next week.

If anyone wants to try this don't be afraid. It was fairly easy. I suppose I will start offering services to the NoVA gang.

[Paul Thomas]

Just so we are clear, Jamie is my new hero.

I have had a hot coat system for about three years but have never used it. It is getting unpacked tomorrow.

Paul

[Tim Walsh]

Hmm... anyway you can bring the system down this weekend .. I might have a design change in the FT's engine trim.
joking aside,
I really like the way the chrome came out.

[Pat S]

Looks very nice! I'm going to have to add this to my list of tool to get.

Can you give us more info on the oven you made?

[masraum]

Looks pretty cool, at a PCA event one of the guys invited us to his house to give us a little tech session on home powder coating. He had a "kit" that included everything but the oven and had done quite a few parts on his various cars. He has a '67 Alfa, early 70's 246 dino (I think), and a long hood. While we were there he powder coated a valve cover for the Alfa in a black crinkle finish. He used an electric oven that he had bought at a yard sale for $25 or something like that. Just a regular old oven. He has done parts that are too long to fit and close the door. He said they worked just fine sticking one end in, and then when that was done flipping it around and sticking the other end in. He did the valve cover that way.

The main thing that I remembered was that the stuff smells really, REALLY bad while it's cooking.

[onewhippedpuppy]

That's awesome! Do you mind me asking how much you have in it, tool wise? It looks like a great investment for anyone doing their own restoration.

[thabaer]

I like it!

Does this mean that you feel there is no need to solve the 400 degree problems and get good results by using longer cure times at 375 ?

I need to build a bigger oven to do some 48" roof racks and have been looking for a good material. Your insulation looks like just the trick. yeahhhh, that's the ticket...

[stealthn]

Jamie,

Excellent report WITH PICTURES!

One point did you add any additive to prevent UV fading?

Cheers

[jpnovak]

Here is a little more info on the system.

Pat, Here is the text from the other post on the oven...

"The homemade oven is simple. I bought two 4x8 sheets of roofing insulation foam at the local home improvement store. This is they type with the aluminum backer bonded to it. Highly insulating and cheap. I cut into 2 4x4 and 4 2x4 sections and assembled a box. The corners are held with dowels pressed into the foam and then all corners taped with Al foil tape. on the roof was attached 3 rails of perferated angle iron to hang parts from. There is hole cut in one end the size of the reflector for my propane catalytic heater. This heats fast without a true open flame. Simple grill thermometer goes in the top. I have test fired it a few times and learned something. It heats very quick. The box needs to be assembled a bit loose. It expaned on heating and pulled the tape from corners allowing the heat to hit and melt foam on the edges. These problems started about 375 F, right before my 400 deg cure temp. Phase 2 of the build is in progress to correct these problems."

I fixed the smoking problems by using aluminum tape and foil to place a double layer of insulation/reflector around all corners and edges. Just a slight wisp at curing temps but I am not sure this is not due to the powder baking. The box will fit those 48" bars with no problem. I had to build it large enough to fit the door frames. ITs also large enough to do bike frames and wheels. Yeah wheels. Stay tuned for that...

It is possible to cure one section at a time. I prefer to cure at once since it takes less total time. besides I don't need a 220V outlet for an oven and my box easily comes apart for storage. I just slide it under the deck and cover to keep the dirt out.

Yes it smells like burning plastic. Use outside or with proper ventiilation.

I have about $250 in the entire system. This is not including the propane tank which I swiped from my grill or the aircompressor and associated lines. Cost breakdown:

PC system with plugs tape etc $130
Misc powders $60 - about $10-15/each color.
Two sheets of insulation foam - $38
Propane heater $35

It would have cost me this much just to do the parts on my engine. I have not even gotten there. I used the POR paints instead. Time to go back and strip them.

The powders do not require a UV treatment. At least its not listed in the literature that came with them. The cure temp is dependent on the powder as well. The actual melt temp is near $350. You need to go just above this temp for a longer period of time to ensure that the surface underneath the powder is warm for adhesion. You can improperly cure the powder by melting it and not having it stick to the surface. I looked in the box and saw the powder melted near 250.

[makaio]

Awesome Jamie!

[Rick Lee]

Totaly awesome. You have mail.

[BGCarrera32]

Fantastic...thanks for taking the time to post all this on the BBS...I know it takes a few extra minutes to upload all the photos...the powder coating is one of my winter projects coming up in a month or so...I'm fabbing the oven out of a 55 gallon drum layed on its side...I'll post pics when finished...

Thanks again!
BG

[Harlan Chinn]

This is a very cost effective means of powdercoating. I have a friend that owns a plating and powdercoating business where I do many of my parts. There is a curing chamber large enough to run entire car frames through. Your homemade oven is great!

[Craig Roche]

Hi Jamie!

Nice job! I love it! Thanks much for taking the time to post all the info and photos. Very timely, I've been trying to decide which gun to go with and just how I was going to cure.

The approach of coating inside the oven so you don't have to move the pcs is a very good idea! Thank you!

I want to build an oven myself and I'm going to follow your method! Thanks again!!

Craig

[jpnovak]

glad to know that everyones winter projects may include some powder coating.

Let this be the ultimate powder coating thread.

[stealthn]

Jamie,

Cool, I guess it really depends on the types of powders you use, some will fade, others are UV and gas resistant.
Other products can be found from Eastwood in case anyone is interested.
http://www.eastwood.com/HCpowders.asp?Dep_Key1=pwct&

[BGCarrera32]

Hey Jamie,

How much powder do you think you went through doing the parts shown above in your oven? I need to do some valve covers, and was wondering if you had any suggestions as to how much I should order...

Thanks!
-BG

[no substitute]

Infrared heaters can be used for curing without a surround. Spray in a box to recover powder.

[jpnovak]

A little goes a long way. I think that a quarter pounde should be more than enough to do the fan/shroud valve covers and many other parts. I was surprised how far it went.

The vendor I bought my powder from says a pound covers 50 ft^2. thats a lot of valve covers.

[MMARSH]

Very cool. Is that the same type of system that Eastwood sells? Always wondered how those would work. Looks like something else I need to put in the garage