Powdercoating Questions

First, thanks to Gary Brady, and his site for his home built powder coat oven.
I'm getting geared up to do a PlasmaCam CNC setup. I would like to
powdercoat the finished products that people want powdercoated. Some of these will be small pieces, say a square foot, but there may be larger ones up to eight feet long and four feet wide.
Question: I have a powdercoat company about five miles from me. If they are reasonable, should I even mess with the extra work of building ovens and doing this myself?
Question: I will definitely be doing some cutouts of trees, mountains, deer, and the like. When painting the powder paint in, can it be layered so that, say I could paint the trees green, and the tips white? Or make the deer brown, and their antlers tan?
Question: Is there any detail that can be achieved in painting? Such as airbrushing the paints for fine color detail? Masking different colors? Blending colors in layers?
Question: On prep, how clean does the metal have to be? I would wirebrush it down, but past that, does it really have to be clean of all solvents, dirt, dust, rust, etc? And if I do have to clean it, what do I use? On the steel I buy, there's a coating of nasty oil that seems impossible to completely remove. I use gas rags and then dry rags to finish, and that gets it clean enough to paint with the paint I use. Would that be clean enough to powdercoat?
Question: Do the powdercoaters provide this cleaning service, or do they just paint and put in the oven? Like above, should I just check with them, and see if their cleaning charge is worth it for the extra work it saves me?
Question: What does a powdercoat gun cost? Do you use it on a regular compressor? How much is the paint, and where do I buy that? Would that be something readily available in a large city, or is it best to get over the Internet? What extras are required for the painting process?
That's enough to get started.
Thanks in advance.
Steve
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Steve B wrote:

I have been sending out work for powdercoating. All of my jobs tend to be small ones and the powdercoat shop has a $50 minimum. So far, I have not exceeded the minimum. I think I finally started bringing enough stuff to them that they dropped the $50 minimum to $35 for me (just about the time I got so busy with my day job that I couldn't work in the shop). That said, I really like the quality of their work and the fact that I don't have to mess with it too much. One of the reasons I work metal and not wood is that I hate the finishing involved in woodworking.

I do at least two passes with lacquer thinner saturated rags for cleaning. Most of what I do is welded tubing, so I have started dipping the parts in lacquer thinner and drying with clean rags. I have also found that cleaning the inside of the tubing improves the quality of my welds. The shop I deal with sand blasts everything before powdercoating, but I don't think they solvent clean. They would need a swimming pool full of solvent for some of the parts I see in their yard.
I have found that doing a decent prep job before taking the work over improves the result, but I have taken hot rolled scrollwork to them and the results weren't bad.
One of the things I am still messing with is filler. Since you bake powdercoating to 400 F, Bondo and lead are not usable. I don't have acetylene in the shop anymore, so braze filling gets done with TIG as the heat source. I need to get better at that technique.
I'm glad to hear your angiogram came out well!
Good Luck, Bob
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I called for a guess price on 17 16" long 1 1/4" square tube standoffs for my gutters. They have three "rail clips" on them, which is just machined punched flat bar. Two are 5" long, and the two hole base is 3" long. The gal said they would be about $6 each, which I thought was very reasonable.
Can you shed any light on the painting questions re: layering of paint, airbrushing, or painting with multiple colors.
Steve
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Steve B wrote:

Blasting and coating 17 pieces for $6 each does not sound bad.
Sorry, I have not tried anything beyond single color. One thing worth noting is that matte colors that I have had done tend to have a lot of surface texture that makes them absorb stains very badly. I did a steel and tile coffee table in a matte brown and it was a nightmare to get the tile grout out of the powdercoat. It also takes food stains too easily. A gloss black range top has none of these problems and cleans up well.
Bob
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Steve B wrote:

Parts are bead blasted prior to powdercoating at the places I've talked to. They do that, and the most recent rate I was quoted was $90/hour so you might consider adding a bead blaster setup if you want to go into business.
GWE
--
Posted via a free Usenet account from http://www.teranews.com


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Steve B wrote:

Depends on what "reasonable" is. I had a fellow come visit me to look at my oven who built some sort of bicycle frames. His coater was charging $25 per frame and sometimes held him up due to scheduling glitches. Personally, there's no way I would do a frame myself if someone would coat it for $25. The scheduling problems, however may be enough to make a person do the coating himself.

This is beyond my skill level. Go to www.caswellplating.com and read through their PC forum. Some of those guys do fades and other techniques. Also check out forums at www.eastwoodco.com

Some of these techniques are not possible with powder. Again, something I've not tried.

The metal has to be free of all oils and chemicals, sandblasted, and etched with a phosphoric acid solution before coating. Some items, such as cast items, must be pre-heated to drive out oil or other chemicals in the pores of the metal. Otherwise outgassing occurs during curing causing defects in the final finish.

Most coaters want to do their own prep, otherwise they won't guarantee the finish.

From $79 to $3000. I have the Eastwood hobby gun, about $130, but I'm not real satisfied with it. Caswell has a new gun, about $230, that I'm considering upgrading to.
Do you use it on a regular compressor?
Yes.
How much is the paint, and where do I buy that? Would that be

The powder varies, probably $8 to $20 per pound, depending on type. I buy mine on the internet since I usually use small quantities. You may get a better deal with local suppliers for a lot of the same color. Go to www.columbiacoatings.com, www.powderbuythepound.com, www.pendrypowdercoatings.com, to look at vendors.

There's also an online book that can be downloaded from the Caswell site that's pretty in depth on coating.

--
Gary Brady
Austin, TX
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Just adding some comments to what Grant and others said:
Cleaning: the parts must be grease and silicon free to get a good powdercoat. the painter will want to do his own wash and phosphate dip before powder. If not, ask why they think they can get a good job without good prep. I'm inclined to do an hot alkaline wash rather than solvent wipe down. Household hot water and laundry detergent (Tide, etc) is a good start, 180 degrees and lye is way better. Obviously a good bead blast will get it down to raw metal. A big issue is getting it to the painter before you get flash rust. In the humid summer, we get flash rust in 6 hours. (Who would have thought steel parts are more perishable than fresh tomatoes?)
Tubing is always a problem, you need to have good drain holes or seal it completely. One or the other, no halfway (ask me why I know!). The 400 or so degree oven bakes the mill greases out of the center of the tube, produces blemishes and spotting.
You can get any gloss level you want from flat to gloss. We had most of our parts done at 60% gloss, nice color, hides defects, still cleans up nicely. We also had most of our parts done in black, made it much easier to get things scheduled since the painter had one booth shooting black all the time, other colors traded off in a second booth. Switch colors meant they had to spotlessly clean the booth, 1/2 hour job.
I've never seen fading colors on commercial powder coat. I suspect that it would take some serious artistry to get the effects you are looking for. The electrostatic nature of the process will make it much more difficult than the same effect done with a spray gun and solvent based paints.
I found my local powder coat place to be very helpful about what they could do and better yet, what they couldn't do. Bring along some sample parts, ask they what they can do, what price, do they have suggestions for better quality or lower price. I know that my painter REALLY wanted hanging holes and drain holes.
Steve B wrote:

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Yes, you can do all these color variations and blends, but you gotta "cheat" a little: do it with acrylic paint, then seal it with clear powder coating. I am set up to powder coat in my shape, and I wanted the level of control you seem to want (I'm an artist too). I called my local shop and asked about doing acrylic and clear coating over it, and they said "no way, the acrylic will burn off at 400 degrees". But I tried it anyway, and they were wrong. I've done it dozens of times, and it seems to be durable. Here's an example:
http://www.judturner.com/hood_gal/hood_gal37.html
have fun!
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http://www.flickr.com/photos/deserttraveler /
Here's a photo of a nice powdercoated gate in Las Vegas
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On 6 May 2007 15:00:55 -0700, snipped-for-privacy@judturner.com wrote:

Yes, even cheap "rattle can" paint can survive over 500 degrees. For awhile... I work in rotational molding and the operators sometimes spray reference marks on the molds. Have seen them last weeks of ~20 minute trips through a 500+ degree oven before gradually fading.
--
William

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Powercoat also sun bleaches badly. We have a nice Horned Toad that was a much richer color on the whole body, now only the underside. It sees afternoon sun but is on the north side.
If you want to paint your oven with a can - get automotive exhaust paint - or engine paint - it is ceramic material based. Auto part store.
Martin
Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net TSRA, Life; NRA LOH & Endowment Member, Golden Eagle, Patriot"s Medal. NRA Second Amendment Task Force Charter Founder IHMSA and NRA Metallic Silhouette maker & member. http://lufkinced.com /
William Bagwell wrote:

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Hi Steve, Ive done a fair bit of painting, but never done any powdercoating. I have over the years though sent many (probably upwards of 500) things to powdercoated, mainly fences, gates, railings etc.

Probably not in the way that you are describing. Some powdercoaters will put a second coat on top of the first if, say, the color was slightly wrong. Get it wrong a second time and you'll have to blast back to bare metal. The bond with the metal is (may heve the term wrong here) electrical... the material is charged one way, the powder charged another. When you already have something on the material, you wont get things to 'stick'. Ive never seen a two-tone powedercoat job, let alone one that went into detail with painting individual parts.

Again, Ive never seen this. I may be wrong, but it doesnt sound very likely. If you could get it done it would probably be a specialised service. My understanding of the process is that since poweder coating uses *powder*, mixing is precluded. If you were to mix, say, sugar and coffee in a bowl.... you'd still end up with sugar and coffee. They arent going to mix. Paint is still the leader in this area.

extremely clean. Forget about gas rags, most powdercoaters use a multiple bath system with, i think 2 or 3 baths of different makeups. The chemicals involved are nasty, and smelly. I think they start with some sort of acid bath and end up with a neutralising bath or something. Even a fingerprint on the workpiece will prevent the finished product from being perfect. something else to bare in mind is that you need to have holes drilled in most hollow sections, just as you would for hot galvanised dipping. Powdercoaters are none to impressed at things that turn up without holes and here in australia most places would charge $1 per hole they have to drill themselves. Doesnt sound like much, but lets say that i send down a railing with 10 uprights where each one needs a hole drilled in it... now imagine its a big job with 200+ panels..... oops.

I dont have figures on this type of stuff, but like anything i know the cost varies depending on the quanity and quality of your work. Automated gun setups are vastly more expensive than manual guns. If you get into this type of work then you will probably also need a sealed room, you wount be doing it out in your backyard. You also need the machine that proveds the charge to the workpiece. Then you'll need lights. You might want to think about extraction systems (not sure what the law says in your state). you may need a forced air respirator with filtration to be safe. You may want to consider a powder recovery system in your extraction unit... these catch all the unused powder so you can use it again. You'll need cleaning baths, lots of space to store them, maybe another extaction unit with filtration for those, then chemicals for that... maybe a permit in your state? then you'll need to contract someone to take the used chemicals away for you....

The short answer : no. From the sound of what you are describing, I'd say you're in the *very* low volume category. If you get a trade rate at the commercial powdercoater then the results will be vastly cheaper than doing it yourself, vastly better in terms of quality, and you'll have recourse to point the finger if the final product isnt up to scratch. saving yourself the potential costs in time/labour of blasting and respraying. you can pass on the costs of powdercoating to your customers and charge 10% on top of that for yourself. That frees you up to do what your main business is. Even mid size engineering shops with 25+ staff that employ 2 full time painters dont go to the trouble of setting up their own powdercoating workshop - the volume required to make it cheaper than getting someone else to do it just isnt worthwhile. Here in Australia, many of the smaller powdercoating companies (that have 5-10 staff) are actually just a spinoff of a bigger company. bigger companies decide to do their own powdercoating but still come to the conclusion they cant justify it on their own volume, so they offer their powdercoating services to other trade shops.
powdercoating is highly overrated in my opinion. Having used a lot of powdercoating services through work, Id say the advantages are that its a consistent finish, with even coverage and no runs etc, the cost is comparable to painting or not much more at volume, and the appearance is quite nice. On the downside, the colors available are extemely limited (mixing not possible, so you have to buy *every* color you need), its really no more durable than paint and scratches quite easily. Touch up us difficult/impossible.
if you research paints more then you may find some industrial grade hardeners will give you a finish that is much more durable than powder, gives a good final appearance and can be gotten into for much less money
Shaun
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There are multi-color powercoat stuff - some of it was really nice. There were statements on a card that indicated the coloring process was patented. Hum.
I suppose in the light of the Supreme Court - stating that Microsoft can use without payment or thought patented stuff of AT&T and build it into products to ship if done outside of the U.S. I think that was the death of the patent office.
China will make everything patent free. And that decision is wrong.
therefore, yo could do it way and begone and not pay.
Martin
Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net TSRA, Life; NRA LOH & Endowment Member, Golden Eagle, Patriot"s Medal. NRA Second Amendment Task Force Charter Founder IHMSA and NRA Metallic Silhouette maker & member. http://lufkinced.com /
Shaun Van Poecke wrote:

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what about cheating? in glasswork, i can coat a piece of glass with mica, heat it up, mask and sandblast back to the base glass, recoat, reheat, and the 2nd coat of mica will only stick to the glass and not the mica layer that was left under the mask.

regards, charlie http://glassartists.org/chaniarts
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charlie wrote:

Did a lot of two and three color work in the old shop. Mostly on "government" jobs and one custom bike outfit. The way I did multi color work was to mask off the two largest color areas. Cure the first color at a lower temperature (just the gel point). Then peel the second color and back mask the first. Now coat the second color. Shoot it and low temp cure that one. Then peel and repeat for the final color. Now cure them up to proper time/temp. It is also possible to do some tricks using just air pressure to remove sections of the powder while it is raw.
As for recoats two coats is about the max you can go. Then it's either blast or burnoff the bad coats.

It all depends on the type of powder. Some will blend as they cure while others will not. Mix two types and you get a mess. We used to do a "chrome" finish for CP tool that used a blend. It had a black base and a silver top coat made by blending two types of powders. Looked about like every other "chome" paint out there.

--
Steve W.
Near Cooperstown, New York
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Steve B wrote:

Maybe use them for the larger items and do the smaller stuff yourself. BUT get VERY familiar with the process and different powder types and process methods before doing items for money.

Yes IF you DIY and do the masking and prep work yourself. Most companies don't do that type of coating unless paid big money.

Yes to ALL, But again it depends on what and which types of colors you want to use. You can get powder primers and use it as a base coat. Blending is not easy to do with powder. It is possible but unless you know exactly what the powders are and how they behave during cure.

Metal must be VERY clean, sandblasting, chemical etching, and bead blasting are all commonly used. Yes to solvents,dirt,rust. No on the clean enough. Use something like Naphtha or MEK and coat as soon as it dries. OR blast them clean.

Depends on the shop. Some will add cleaning into the price and some won't. You also to specify EXACTLY what you want them to do to prevent any slips. That means cleaning, masking, type of powder to use and what an acceptable finish level is.

Depends on the gun. The small home units are 100-200 bucks. A commercial shop gun will wipe 30-40,000.00 out real quick. If you can get them used then you can get a better deal.
http://www.sames.com / http://www.itwgema.com / http://www.powdergun.com / http://www.nordson.com/Businesses/Powder/Products /
Powder sourcing depends on what types you want and quantity you need. Eastwood and the like sell 10-15 pound containers. Standard box for industrial purchase is 50 pounds. Industrial powder can be purchased through
Sherwin Williams Industrial http://www2.sherwin-williams.com/chemicalcoatings /
Akzo Nobel http://www.interpon.com/en/default.htm
Inver http://www.inver.it/powder/index.html
Dupont http://www2.dupont.com/Powder/en_US /
Prism http://www.prismpowder.com /
PPG http://www.ppg.com/car_indcoat/powder.htm
And a few dozen more, but these are the top outfits.

Spent 12 years in a powder/liquid coating shop. WW Custom Clad http://www.wwcustomclad.com/ for the OLD outdated site.
--
Steve W.
Near Cooperstown, New York
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I worked in a plant where we did motorhome trim and such, the rig used was definitely NOT something for a small shop. The parts ran through a continuous washer on an overhead conveyor, then through a drying oven, powder was applied in a spray booth with two people to handle both sides, the booth had a lot of airflow to a bag house to get the dust out of the air. Powder ran between $10 and $50 /lb, depending on whether it was polyester or epoxy and the color. Gloss was the order of the day.
Powder coating really is a pretty good production finish for aluminum, which is what were were doing, the other half of the plant produced the extrusions we finished. If you're doing steel or iron, I'd look for a different process. The reason being is that when it rusts(and it will), you won't be able to retouch without stripping it all off. I'd look to automotive finishes and airbrushing if you're looking to get very fancy with your workpieces. Automotive finishes are probably some of the toughest stuff available, custom motorcycle tank and helmet painters use the stuff almost exclusively, at least as a top coat. The best part is no heat is involved and you can have almost as many layers as desired in a very wide variety of colors and appearances. No metal flake pearlescence in powder coat!
Stan
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snipped-for-privacy@prolynx.com wrote:

Stan, your bringing back memories I'd rather forget.... We had 4 continuous lines and 4 batch areas. Then two liquid areas and three fluidized bed. On 3 of the lines we had two sided booths but normally only one sprayer. Also had two automatic booths for items that could be coated without light areas. Just before I left they were adding another continuous cleaning cycle area to feed the batch areas.
You guys never got to play with the metallic colors from PPG? They were a real PAIN. Damn flakes would bond in the corona off the tips and cause problems. Then the gloss would be all screwed up due to the extra metal... We also developed a neat "smoked clear". That got used on some parts for a Chrysler show car. Then they wanted production runs of it for the Vipers, nothing like running a clear that comes out of the gun looking white, next to a line running White... The only good thing about the place was that you didn't get cold in the winter, We used to be the only place in town that ran with the doors open in the winter. Nothing like having about 14 ovens running 350-500 degrees to keep a place warm.
--
Steve W.
Near Cooperstown, New York
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snipped-for-privacy@prolynx.com wrote:

Powdercoating is a relatively simple process and the equipment can be purchased from about $60 (Sears, HF) to thousands, depending on your needs. If there is a powdercoater not far from you and they can handle the jobs reasonably then why bother with the costs of building and operating your own ovens? Powdercoating works on a static electric principle in which the piece being worked is negatively (I think) charged and the powder is positively charged coming out of the gun. I saw a demonstration at SEMA a couple of years ago and the powder just sits on the object until fused in the oven. I don't know about two or more color coating but I would assume that it could be done. You might consider paying a visit to the coater near you and observing the process and discussing what he would charge you.
Kim
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