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1Back to top Go down   Powder Coating: HOWTO Empty Powder Coating: HOWTO on Fri Nov 29, 2013 12:54 am

jjefferies

jjefferies
Silver member
Silver member
An aside/explanation for doing this: My wife once told me that I'm a prime candidate for the CABoA (Cheap Ass Ba****ds of America). Smile Not true. I just like a job done right for a reasonable price. Right now I'm restoring a '90 K75 for her use and modifying it as a cafe racer. I was willing to pay USD $120 to have the frame powder coated. But when they sand blasted the hell out of where the head bearings fit as well as the fork lock. Ok, it looked pretty but man was I worried that the bearing would be sloppy. And all would have taken to do it right was a little attention before the sand blasting. Then when I was quoted a price of $150 to do the fork lowers and the valve covers. Ach!! I started looking for alternative approaches.

As of this date, 11/28/2013 you can buy an el cheapo Chinese made powder coat spray gun with the electrostatic generator in the US from Harbor Freight, i.e. Chicago Electric Tools for USD $60.
http://www.harborfreight.com/catalogsearch/result?q=powder+coat
Powder coating material ranges in price from USD $5.00/lb(cheap Indian made stuff) to $30/lb(high grade in any color). In addition you need an air compressor (small) and most critically an oven capable of reaching 400 degrees F or 204 degrees Celsius. It is the oven that determines how large a piece you can powder coat.  There are a number of youtube videos on powder coating and I'll put links to some of those at the bottom of this. My intent is to basically talk this process up to fellow riders  and what some of the tradeoffs are. In the past I have used spray paint with hardeners, very poisonous, requiring breathing apparatus. Powder coating reportedly (according to the industry) is relatively environmentally friendly and does not require the same degree of protection. However it does stink during the curing, baking, phase and I personally do not like to breath the fumes given off. So doing that part outside makes a lot of sense to me.  When actually spraying the powder you are working with a very fine dust and should protect yourself from breathing it. All that I've read says the powder is not poisonous but I ain't that trusting so I do use a simple nose/mouth filter.

Powder Coating material: There is a wide range of materials available. Harbor Freight sells the cheap Indian made stuff in three colors (white, red, black(sort of greyish)). This is rather crude stuff and requires a full 400F for 15 minutes to cure. On the other hand you can get very high grade material in just about every color and shade you can imagine in 1 lb quantities. One advantage of the more expensive powders is that they don't have to be heated to such a high temperature but can be baked as low as 320F. Here take a look at the colors possible. And that includes clear coats and candy as well. Allpowder is just one of several suppliers available online:
http://allpowderpaints.com/products.html

The oven: As mentioned this is what determines how large a piece you can do. Obviously a whole m/c frame requires a good size oven. And you can see some of these large ovens depicted in the youtube videos. But some people have made do with toaster ovens for small parts. For my part after reading about other amatuer's experiments making an oven I decided to go with a regular electric kitchen  oven. They have temperature regulation, built-in lights, and timers. All the goodies that I saw people working hard to replicate.  ***CAUTION*** once you have used an oven in powder coating you CANNOT EVER use it again for food, human or animal. So don't even consider trying this with your household oven. Even once. Further what you want is an ELECTRIC oven. Gas heated ovens have open flames which can give rise to fire hazards when the parts are being baked. What I did was to go to Craigslist. There I found some folks who were throwing out an electric built-in oven because it was having problems. They obviously had decided it was more cost effective for them to replace it and they were offering it as scrap metal. So I called and they said they would leave it by the curb and I should come get it. ONE CAUTION: if you go this route, make sure you carry along a really thick pair of gloves to handle the thing. Old built-in ovens have a lot of sharp edges and it took a number of weeks to grow back some skin on my hand. But I muscled it into the back of my wife's pickup and with my bloody hand took it home. It required two bottles of easy-off oven cleaner to get through the encrusted food stuffs. But under the rough exterior was a working oven with two heater elements, a air circulation system, built-in lights and timers. It was the stove top elements that had failed. Once I had cleaned it I mounted it on a wooden roll-around. As I indicated while the fumes are not listed as poisonous I wouldn't like to breath them and the ability to roll the entire operation out of the garage into the open air was desirable I felt. So some rusted scrap shelving hit with rustoleoum paint and I had my powder coating station. Here are two photos from the front and back:
https://i.servimg.com/u/f57/18/43/58/50/img_1510.jpg
https://i.servimg.com/u/f57/18/43/58/50/img_1511.jpg
A couple of things about the station, you can see the box containing the powder coating gun on the back side shelf. Down below is air compressor. For best operation you need a steady supply of air and I included an air reservoir, not seen,  also available from Harbor Freight for $25. On top is the remains of the stove top (the oven and stove top heaters were two separate entities) which makes a nice catch all. On the photo of the front side you can see some of the stains left from powder getting knocked off the items as I put them in the oven. Also in this photo is the cardboard box which I use to shoot the parts in. It keeps the wind off while I am spraying/powdering the item. Note also the extended 220V line used to connect the stove to a power outlet of the kind used by dryers or ovens.

METAL PREPARATION: Obviously your item to be coated must be clean of all rust, grease etc. If you have access to a bead blaster that's the best choice. I didn't, so I used a bench grinder with a wire brush mounted to take off paint, rust and everything else. This works but you really need to respect your eyes and use a really good shield in addition to glasses. Wire brushes have a tendency to throw out broken metal wires which will go through heavy cardboard, wood, your clothes and your eyes.

Shooting/spraying your metal object: If you can use a spray/rattle can then you can shoot powder coating. Other than a couple of tricks it really is forgiving. And if you mess it up you just shake off the powder and reuse it.

First this system uses air 10-30 lbs/sq in for the spray gun. In addition there is an electrostatic generator, a small box with an 110 AC plug, a foot pedal, and two wires. One wire goes to the spray gun and the other to the item being coated. From others I learned it is useful to have a small booth to shoot in. Keeps the wind and bugs out and the excess powder in where you can sweep it up for reuse. The cardboard box seen in the front photo above is what I came up with. It has two copper wires running across the top. The item being coated is hung from one of these by another piece of copper wire. The ground wire from the electrostatic generating box is connected to the two copper wires running across the top of the box. When you want to begin spraying you have to press the hand switch on the gun (turns on the air) and press the foot pedal (turns on the electrostatic generator).

DANGER WARNING:: **** when you are spraying and the electrostatic generator is operating it is not unusual to touch or get the gun so close to the item being sprayed that you get a spark. This is common and doesn't seem to affect the spray gun's operation. But IF THE BOX IS FULL OF AIRBORNE POWDER the spark can set off a flash explosion ******.  I've had this happen. It is possible for this to start a fire or cause a burn. STRONGLY RECOMMEND PROTECTIVE GLASSES. In my short experience this is the primary safety concern I've encountered.

TRICKS: I mentioned tricks, there are several. If you are shooting into a space such as a corner or where two surfaces join you will find you have difficulty getting the proper amount of powder in. This is due to the combined electrostatic charge from the two surfaces joining to push the powder away. Sometimes with small parts it serves to tilt the part so it is below and shoot downward using gravity as well as the electrostatic phenomena.

Also it is possible to reshoot an item if you find a place where the powder was too thin and you didn't catch it before baking.

Another tricky bit is to move the part from the spraying area into the oven. I found a couple of super long nosed pliers very useful. And a bunch of copper wire hooks that you can hang items being coated from are essential.

Lumps in the powder. The better grades of powder will be finer and have fewer lumps. The lumps come from the powder having being heated during storage or transit. Sun on a delivery truck can be the cause. If you get some material like this a flour sifter will fix the problem and sieve out any lumps which cannot be rendered back into powder.

BAKING: is just what it sounds like. You turn on the oven and get it to the right temperature. In the meantime you can be spraying your item. Once the oven is at the correct temperature, usually the baking temperature and how long to bake are on the powder's container, you put the powder sprayed item in hanging from a hook or on one of the oven's shelves and let it bake for the recommended time. Checking of course just like you would with brownies. At the end of the time pull the item out and hang it up to cool. I found that doing one item at a time worked well enough with this home made system. Timing was 10-20 minutes and if I worked it well that was long enough to shoot the next piece, get back and pull the current item out of the oven and put the next one in. Of course YMMV. The oven I rescued is 17"x17"x21" and I easily fit a fork lower or a valve cover in. With 400F as a max temperature I feel you can do most steel and aluminum. Not sure about parts that have been brazed but that's on my list to experiment with. Sadly fiberglass and plastic are definitely out. Crying or Very sad 

That's it for the moment. I'm supposed to be doing other things right now. Hope to come back and annotate with additional photos and links.

PPS: Recently found that the "Tech Shop" http://techshop.ws/ has a very nice program for former military, a free membership and funds for a number of classes. Took two classes in sheet metal and one each in MIG and TIG welding. Sweet. Then found that they have a walk-in powder coating oven with all the best ventilation, Super Sweet. So if you are in the S.F. Bay area or anywhere else they have their studios/school suggest you look them over.



Last edited by jjefferies on Tue Apr 15, 2014 2:57 pm; edited 5 times in total (Reason for editing : I forgot the baking process and wanted to clean it up a bit)

    

2Back to top Go down   Powder Coating: HOWTO Empty Re: Powder Coating: HOWTO on Fri Nov 29, 2013 8:22 am

92KK 84WW Olaf

avatar
Life time member
Life time member
That is a really excellent post and very informative too.

I have been looking at a few smallish items and the annoying thing with some is that it means taking them off and then doing without them for a few days, so much easier to be able to plan this at home.

Speaking for our European K bikers we have 220/230/240v as standard so the power supply is easy. You can actually buy a cheap new oven for €200!!! [Would it be better to get one without the fan or at least with option of turning it off. Our cookers generally will go to 220C [for those who love Baked Alaska its essential] so a cleaned up used one will work perfectly.


__________________________________________________
1992 K100LT 0193214 Bertha Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 106,950 miles Deceased.
1983 K100RS 0011171 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 36,188  miles
    

3Back to top Go down   Powder Coating: HOWTO Empty Re: Powder Coating: HOWTO on Fri Nov 29, 2013 9:02 am

robmack

robmack
Life time member
Life time member
Excellent post!

@jjefferies wrote:There I found some folks who were throwing out an electric built-in oven because it was having problems. They obviously had decided it was more cost effective for them to replace it and they were offering it as scrap metal. So I called and they said they would leave it by the curb and I should come get it.
One can also check for ovens through the FreeCycle Network . There are chapters for most every major city. This is a network that puts people who need items together with people who want to recycle items (i.e. One man's garbage is another man's treasure).


__________________________________________________
Robert
1987 K75 @k75retro.blogspot.ca
http://k75retro.blogspot.ca/
    

4Back to top Go down   Powder Coating: HOWTO Empty Re: Powder Coating: HOWTO on Fri Nov 29, 2013 9:49 am

xpc316e

xpc316e
Gold member
Gold member
I never cease to be amazed at the ingenuity of some of you K owners.  I need a couple of wheels powder coating, but I shall pay to have it done.  However, that does not mean that I did not find your post really interesting and informative.  Not only was it fascinating to read, may I say how well written your piece was?


__________________________________________________
VIN 0191428, 1991 K100LT, formerly owned by Lancashire Constabulary. This old warhorse is now 'out to grass' and living in retirement in Suffolk, where it will be showered with appropriate love and care.

VIN 6459609, 1992 K1100LT, another ex-Police machine, even though she now looks like she is a former fire engine.
    

5Back to top Go down   Powder Coating: HOWTO Empty Continued on Fri Nov 29, 2013 4:12 pm

jjefferies

jjefferies
Silver member
Silver member
Hi guys, thanks for the kind words and interest. Seriously think that for some applications powder coating is the right way to go. But as always YMMV. There are any number of video tutorials on youtube about powder coating. No sense reinventing the wheel, But here are three that looked interesting to me:
Someone's Neat Powder Job
Some Basics
Some Interesting Details
And there are quite a few more. Some general comments. Eastwood is one supplier that's definitely into the amateur market and they do provide a lot of supporting information. But they are expensive and you can find cheaper alternatives. One link describes spraying the powder on and then brushing it off to achieve an effect. This works neatly for doing things like high lighting the "BMW" logo on valve and bottom end covers. Also note that you can clear coat bare metal. And this is one way to keep that brushed aluminum look from oxidizing.  The third link is about a fellow's spray booth. Neat and the use of a vacuum to pull the powder in certainly reduces the risk of the flash explosion I mentioned. But another point to consider is that you want to reclaim any unused powder, i.e. powder that goes any where but the target. So after shooting each color you need to reclaim then. Mixed colors are for the trash. And the question of how to seal off places where you don't want to powder coat. There are aluminum foil and specialty adhesive foils. But plain old blue masking tape works just fine for the projects I've done. One time use and it's mainly needed during the spraying process. So if it burns or goes brittle during the baking process, who cares. There are way more tricks and tips than I've been able to put here. Hopefully others will add on what they learn.
best regards
J.
PS: Here are two forums that probably will overwhelm an amateur such as myself. But some interesting tidbits to be gleaned:
powdercoating Forum
PowderCoating

    

6Back to top Go down   Powder Coating: HOWTO Empty Re: Powder Coating: HOWTO on Sun Apr 13, 2014 6:57 am

billtr96sn

billtr96sn
Silver member
Silver member
Hi I am a newcomer to these forums, but a few years ago I bought a powdercoating kit from these people  http://www.electrostaticmagic.co.uk/ and have done many odds and sods from tiny to large. They carry a large range of colours some of which are RAL colours and will do their best to match them for you.

By the way, the only connection I have with this company is as a happy customer.


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Something witty is supposed to go here... help!! Powder Coating: HOWTO Uk-log10
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