[TheForge] OT sort of Powder Coating

Sun Mar 18 17:29:58 EST 2007

Ries,

I haven't gotten the gun and the materials yet. What I
have is bead/grit blasting booth(HF), a good
compressor, a 18 inch bt 18 inch bt 16 inch oven and a
smaller one that in 12 x 12 x 12, both capable of
reaching 250 degree C. Spray booths are easy to build
and I have several shop vacs that can be used.

I want to look at what people have for the spray
process. 

Thanks,

Jerry
--- ries <ries@

> I have never done it myself, but I have been paying
> people to do it  
> since about 1988.
> I have sent several powder coaters kids to college.
> We used to do production pieces like candlesticks
> and soap dishes,  
> where we might do 200 at a time, or a dozen chairs,
> or sculptural  
> elements as big as 20 feet long.
> 
> Things I learned:
> 
> Sandblasting is good. Not essential, but it sure
> doesnt hurt,  
> especially on hot rolled. We did some production
> pieces for a few  
> years made from rebar (chairs, small tables, and so
> on) and it all  
> needed to be blasted.
> 
> Cold rolled can be run without blasting, but it
> needs to be really  
> clean.
> Wiping down with alchohol or a solvent will work.
> 
> All the pros use phosphate pre-dip systems- The vast
> majority of my  
> stuff had this done to it- my last guy had a 5 tank
> system- a mild  
> etch, then rinse, then phosphate, then rinse again-
> cant remember  
> what the last one was.
> Anyway, the point is, the stuff needs to be REALLY
> clean.
> 
> For clearcoated stuff, we would fine sand or wire
> brush it right  
> before blasting, then handle with white cotton
> gloves.
> 
> Aluminum, especially castings, but not only, needs
> to be preheated at  
> 300 to 400 degrees for a good 20 minutes first-
> otherwise, moisture  
> always shows up and makes bubbles and pinholes.
> 
> Good powder is expensive- I mostly used Tiger
> Drylac, Cardinal, and  
> the major brands just for stuff like Black Wrinkle
> or plain colors-  
> for the fancy stuff, the best, most distinctive
> colors and textures  
> come from Prismatic-
> http://www.nicindustries.com/prismatic_powders.php
> 
> they cost a lot more per pound than places like
> Eastwood, but they  
> are really worth it.
> 
> I recommend using textures or wrinkles in most
> cases- they wear much  
> better, hide scratches and handling marks.
> Gloss finishes are the worst, in terms of fragility-
> Powder is not as  
> tough as something like laquer, its pretty easy to
> ruin a gloss finish.
> 
> There is no touchup with powder- if you screw up,
> you need to remove  
> it, and start over- and it aint easy to get it off.
> The pro shops I  
> dealt with use a 2000 degree burnout oven- which,
> since they did  
> things like furniture, was big- it had a little
> railroad track going  
> in it for a dolly about 4 feet square. It does not
> want to sandblast  
> off without being burned first- and the fumes are
> nasty. You  can, in  
> a pinch, use a rosebud, but it will probably shorten
> your life by a  
> few months every time.
> My old industrial sandblaster in LA, who had
> something like 3  
> compressors, each 200hp, and air hoses as big as
> your arm, flat out  
> refused to sandblast powdercoating, as nobody would
> ever want to pay  
> what it really cost, as it took SO long.
> 
> Best type of oven is one you can roll a cart into-
> then you can hang  
> the parts, shoot em, and roll it right in.
> I like to deal with guys who have 20' x 10' x 10'
> ovens, as I tend to  
> do big stuff- and even with chairs, you cant
> economically do em if  
> you can only do one part every half hour, so they
> would rack up a  
> whole dozen or two at a time.
> 
> For itty bitty stuff, yeah, you could use an old
> home oven- if time  
> is not a concern. But if you get into doing it much,
> you are going to  
> want a bigger oven.
> 
> The $200 guns work. Just like a $500 Harbor Freight
> lathe will work.  
> But just like a real machinist will want a $20,000
> used Monarch, a  
> real powder coater will spend $5000 and up on a
> decent pro gun.  
> Partly its long life, ease of use, and volume, but
> the real guns do a  
> better job as well.
> So dont expect to get the greatest results from
> those little guns.
> Clean, dry air, of course, is a must.
> 
> If you are doing the occasional, jewelry sized
> object, and dont mind  
> fussing, then you may have success with the cheapo
> route.
> 
> If you are doing much for resale, and any kind of
> volume, I think you  
> will quickly find its worth it to use a pro shop.
> The average guy I dealt with ( 5 different big shops
> over the last 25  
> years- In LA, Ventura, and couple up here in
> Washington)
> had well over $100,000 invested in equipment.
> 
> Ries
> 
> 
> 
> 
> 
> 
> On Mar 18, 2007, at 11:28 AM, Jerry Smith wrote:
> 
> Folks,
> 
> Do we have any one out there who does powder
> coating?
> I wan to learn how to do it, and also how to avoid
> the
> mistakes.
> 
> I don't have the gun or the basic kit, but I do have
> a
> compressor and a good size oven.
> 
> Jerry
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> 
> Ries Niemi
> Industrial Artist
> http://www.riesniemi.com/
> 
> 
> 
> 
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