Do any of you powder coaters have advice for avoiding thinning out on edges? The coater I'm using now gives the frame a phosphorus bath and then a single coat of powder from Prismatic.
IMG_8130.JPG
Thanks, Joel
Do any of you powder coaters have advice for avoiding thinning out on edges? The coater I'm using now gives the frame a phosphorus bath and then a single coat of powder from Prismatic.
IMG_8130.JPG
Thanks, Joel
Joel,
Edges are tough simply because of the lack of surface area...the powder will want to run and thin off the edge during the bake cycle, however, if you have a Coater who is willing to work with you, there are some things than can be done.
Media blasting before the phosphorus bath will provide a mechanical tooth for the powder to adhere to and increase the potential for retaining some thickness.
After the bath, if he runs the frame through a dryer oven, he can immediately pull it out at the end of the cycle and hit the target areas for a flash layer, in this case the dropouts and disc tab edges. Once the frame is cool, apply the powder as normal, turning up the gun when at the target areas to compensate for the increased layer thickness to promote surface adhesion of the new powder. This should allow you to build these areas so when it does thin during baking, the flash layer should help fight the transparency effect you are experiencing. This technique takes some trial and error, as flash application does not have any room for error and it is also easy to apply too much powder with increased gun voltage for the second pass, creating sags.
The issue is not insurmountable, best of luck.
rody
cheers,
rody
Nice shot Joel!
My powder guy says that he now has the ability to order powder tailored to his projects needs. Still basic catagories like; large flat surface, tubular, square corner picket stuff, small tubular ect.... We didn't speak at length about it but maybe your powder guy could call his supplier and ask.
How about oranges interacting with the silver brazing & turning purple?
- Garro.
Steve Garro, Coconino Cycles.
Frames & Bicycles built to measure and Custom wheels
Hecho en Flagstaff, Arizona desde 2003
www.coconinocycles.com
www.coconinocycles.blogspot.com
Very good advice (IMO) above from Rody. I powdercoat my own frames, (maybe painted 20-30 at this point?) and its still a huge learning process for me. One other little subtle thing is to make sure to knock down the sharp corner/edges a bit. The picture below was my first lugged frame and I worked really hard at filing super sharp lug edges. Little did I know (at the time) that the powder there would be super thin. I'll sometimes do a 2 coat similar to what Rody describes above. Another thing is that certain powders are just known for acting like this more than others. The 'mirror finish' tend to do this a bit more that most of the RAL colors I work with. :shrugs:
-Bernie
seatLugPainted.jpg
"How about oranges interacting with the silver brazing & turning purple?"
Steve...two words
Primer coat
Seriously, I've been preaching it for years.
rody
I know - but, what is the reaction?
Pretty much leaning hard to either Spectrum here (phosphate coat) or Ceramikote anymore - I'd try painting but sandblasting in a wheelchiar sucks more they you even think it would.......
Wet paint lasts about ten rides out here on MTB's..
- Garro.
Steve Garro, Coconino Cycles.
Frames & Bicycles built to measure and Custom wheels
Hecho en Flagstaff, Arizona desde 2003
www.coconinocycles.com
www.coconinocycles.blogspot.com
Steve Garro, Coconino Cycles.
Frames & Bicycles built to measure and Custom wheels
Hecho en Flagstaff, Arizona desde 2003
www.coconinocycles.com
www.coconinocycles.blogspot.com
Gold plated Garro.
Orange pigments are often quinones* and there are lots of reactions where silver ions participate in quinone oxidation, so I'm guessing it's something along those lines. I know there are purple photosynthetic bacteria which have quinone based electron transporters in the photosynthetic chain but not much else about possible purple quinone derivatives.
You did ask.
* quinones are also responsible for some of the the orange / brown colour of oxidised wines, hence the interest in the chemistry.
Steve Garro, Coconino Cycles.
Frames & Bicycles built to measure and Custom wheels
Hecho en Flagstaff, Arizona desde 2003
www.coconinocycles.com
www.coconinocycles.blogspot.com
Steve Garro, Coconino Cycles.
Frames & Bicycles built to measure and Custom wheels
Hecho en Flagstaff, Arizona desde 2003
www.coconinocycles.com
www.coconinocycles.blogspot.com
Etymologically yes, but I don't know why. Perhaps one of quinine's breakdown products is a quinone.
Structurally no, quinine is pretty complex, with two fused nitrogen containing cyclic structures. Bonus factoid: complex structure = interesting photochemistry; although quinine is white it's fluorescent so your tonic water will glow under UV light.
Quinones are a whole class of molecules each with two "-one" groups on an aromatic ring.
Dustin Gaddis
www.MiddleGaEpic.com
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Pete Ruckelshaus * Teacher, Fat Guy on a Bike * Collegeville, PA
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