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Discussion Starter · #1 · (Edited)
Hey guys,

Welcome to the way-more-than-you-ever-wanted-to-know-about-bicycle-finishing thread!

This is a thread dedicated to answering questions about powder coating (and other finishing techniques). I'm an avid rider and a powder coater in Virginia who shoots a lot of bikes. My intention for this thread is to answer questions and field concerns about frame material types and the effects of baking (such as on Easton scandium frames), repair options (for dents, rust pitting, etc.), about frame prep (how to ensure thin-walled frames aren't damaged during blasting, reassembly concerns), color/finish options (pearls, metal flake, textures, multi-colors, airbrushed graphics, pin striping, lug lining, clear coats, compatibility of finishes), and such.

Cheers!
Len

Here are a couple of pics of my Trance I coated the other day. Bass boat green flake with airbrushed ghost graphics. Should be finished building her up today and getting her dirty tomorrow!



 

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That color looks close to my Retrotec's powder coat. I used Moondust Lime over a black base to get that look. I love it, although yours looks even better.
 

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The single best thing you could do

is to find or create a nice even, smooth, standard background against which to shoot your product. All you have to show is surface and color and to do that you need to eliminate distractions. The one you used in this thread is close as it is a neutral hue but the edge and the multiple tones throw off the view. Good luck.
 

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Discussion Starter · #5 ·
Sasquatch said:
That color looks close to my Retrotec's powder coat. I used Moondust Lime over a black base to get that look. I love it, although yours looks even better.
Thanks! Good eye! This one is Starburst Lime. Same tone but a bigger flake size. Did Spectrum shoot your Retrotec?

Berkely Mike, thanks for the pointers on the photos! I'm a relative newb with photography, but I do try to use neutral backgrounds. Usually either black or silver slat wall. Those were quick pics. Haven't gotten to crop or adjust hues yet.



 

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LenMcC said:
Thanks! Good eye! This one is Starburst Lime. Same tone but a bigger flake size. Did Spectrum shoot your Retrotec?
Actually, my bike was coated by Maas Bros. in Livermore, CA but I know Spectrum does most NorCal frame builder's bikes, including alot of Retotecs. I like the big flakes on yours. They stand out more.

CharacterZero, the Lowrider Green color used by Ventana is the Moondust Lime over a Black base. I was inspired by one they did a few years back, posted by an MTBR member.
 

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LenMcC

You're right - there needs to be a sticky on this kind of stuff.

Far too many bikes, while good designs & engineered well, are poorly finished off with very little thought or creativity.

I've custom ano'ed or powdercoated all my frames & parts & I had to learn the process as I went along...& made mistakes sometimes. Trial & error can be costly.

People post all kinds of questions about powdercoating/painting/polishing/ano all over the place.Too much hit & miss on what should become an established thread...

Can you PM Francois & ask him?
Someone with your level of knowledge & experience is needed.

I think your frame needs to be seen in person to really be appreciated- great job!
 

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Discussion Starter · #11 ·
Shredr said:
People post all kinds of questions about powdercoating/painting/polishing/ano all over the place.Too much hit & miss on what should become an established thread...

Can you PM Francois & ask him?
Someone with your level of knowledge & experience is needed.
Yeah, I got the same impression. Questions here and there, sometimes gone unanswered.

Thanks for the suggestion, Shredr! PM sent!
 

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Discussion Starter · #12 · (Edited)
Easton Scandium Frames

EASTON SCANDIUM FRAMES

Frames made from Easton Scandium, like Niners, can be powder coated with special care. Scandium frames are heat treated, and the typical PC oven temperatures (400F) is above the heat affected temperature for that process. I.e. If you put the frame through a normal cure schedule, it will likely be weakened.

Easton product engineers recommend curing for no longer than 30 min at 325. This requires a low-temp powder, which limits color options quite a bit. Make sure your coater is aware of this ahead of time to see if they're willing to make it happen.
 

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Discussion Starter · #13 ·
Powder Coating Weight and Thickness

POWDER COATING WEIGHT

Myth 1: Powder is heavier than paint.

Fact 1: Typically, powder is lighter than paint. Most liquid paints require 3 coats: 1) primer, 2) color, 3) clear. Powders typically require a single coat.

Myth 2: Powder can add 1/2 a pound to a large frame!

Fact 2: If a coater tells you the job will take 1/2lb of powder (which it shouldn't), almost all of that is ending up on the floor as overspray. Typical weights I've measured myself are around 1oz per coat for a large hardtail. Most liquid painted frames from the factory lose around 2oz after stripping. I'll post up some hard numbers for factory painted, stripped, and coated weights for various frames.

POWDER COATING THICKNESS

Myth 3: PC is thick.

Fact 3: PC, when applied properly, is very thin. Generally it is applied around 0.003" - or 3 mils. Many people are familiar with lawn furnature PC that has super-thick, often textured finishes. These finishes are applied using a completely different method, with the intention of hiding surface imperections of the relatively low-quality fabrication and preparation processes. If you have a lugged frame with nice detail work, you're not going to lose any of that detail with a proper coating. Conversely, if you have a beat up frame, don't expect a single coat of powder to fill the defects.

Myth 4: Thicker is stronger.

Fact 4: Thinner is stronger. With most powders, it just works out that way. Thinner coatings (applied at the proper thickness, rather than hogged on), are much more chip-resistant than heavy coats. They're much smoother, too.
 

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What are the benefits of powder coat primer, esp as it pertains to rust prevention on steel frames? Can you still do multi-coat powder colors over a primer coat? (I understand that the static attraction is diminished with each successive coat)

Tell us more about the graphic-in-powder process. I sent a frame to Spectrum for a 'full-powder' job, but received a bike with a powder base, and wet paint panel and clear... not what I was hoping for. I know that there are high-temp decals that can survive beneath powder clearcoat, but what is the process for airbrushed graphics with clear? Is there a high-temp-tolerant paint that can survive the baking process and live beneath a powder clear topcoat? I guess I would expect that any graphics placed atop the base coat and beneath the clear would become 'blurred' as the powder melts into place.

Thanks!
 

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Discussion Starter · #15 ·
Powder Primer and Clear Powder Over Graphics

Great questions...

POWDER PRIMERS
There are a few types of powder primers.

1) Zinc Primer:
The rust-prevention type is a zinc primer. It reduces steel oxidation because the zinc is more reactive than steel, so the zinc gets oxidized first. Same concept as galvanization. Zinc primers are primarily used on items that are kept in the elements and are subject to abuse, like fences and gates. For bicycles, it's not particularly helpful as long as the frame is prepped properly, which means the metal is "white blasted" immediately prior to coating (super-clean and free from all oxidation). Many coaters do not white blast their pieces.

2) Filler Primer:
Filler primers are more like liquid paint primers. The primary goal of these are to give the frame a nice smooth surface prior to the color coat. These are great for filling small scratches and rust pits. For heavy pitting, deep gouges, and dents, a special conductive, high-temp bondo-type body filler can be used.

3) Powder Primer Under Wet Paint:
Another use for either of those primers is as a base for wet paint. This can increase wet paint adhesion compared to conventional liquid primers.

Yes, you can still do multiple coats with primer. Powder guns are getting better and better, and combined with some application skill, it's perfectly feasible to do 5 or more coats. It's even possible to coat non-conductive items (like porcelin toilets) with the right techniques.

FULL-POWDER GRAPHICS
1) Airbrushed:
Full-powder graphics is something only a few coaters have figured out. Spectrum was a pioneer with it. The basic process is: 1) shoot the base coat and do a partial cure, 2) airbrush the graphics with a special pigment, 3) apply the clear powder top coat and final cure. During the final cure, the clear top coat will cross-link (basically melt) through the graphics pigment into the partially-cured base coat, making all three layers one.

That being said, there are some limitations to full-powder graphics. A notorious limitation is white graphics on a red base. During the final cure, the red pigment in the base coat will sublimate (vaporize) into the white, turning it pink. I haven't figured out a work-around, and I don't think Spectrum has, either. In a case like this, the top coat would need to be liquid. Here is a picture of white-on-red. You can see how it turned pink.



The resolution of airbrushed graphics is just like wet paint; there is no blur. Here are some pics of clear powders over airbrushed graphics. Clears come in high-gloss, matte, and in-between.









2) Decals:
Yes, there are hi-temp decals meant for use under powder. The only company I'm aware of that makes these are SSS, Inc. in North Carolina. I haven't dealt with them myself, but I know some frame builders get their decals from them and provide them to the coater (I believe Strong does this). SSS, Inc. has supposedly figured out how to avoid the sublimation problem with reds and blacks. Water slide decals still need to be liquid cleared.
 

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LenMcC

Great posts & excellent info! A few questions:

Is this always the normal operating procedure for powdercoat? 1) Base first, 2) Then Powdercoat in oven, 3) Then spray Clearcoat?

Should I tell the painter what series alloy my frame is made out of before putting in the oven?

If the alloy frame is machine polished first, can you skip the base step or not? I always go for bright, shiny, flashy showroom-quality colors that really stand out & "glow".

Also, what if I want to do a type of 2 tone paint color fade job? (like red to black to red)?
Is it possible with powdercoat?

Finally, If I bring a Chris King hub (sour apple color ano) & ask for an exact match with powdercoat is it possible or asking for too much?

Thanks LenMcC!
 

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Discussion Starter · #17 ·
Always glad to help!

Shredr said:
Great posts & excellent info! A few questions:

Is this always the normal operating procedure for powdercoat? 1) Base first, 2) Then Powdercoat in oven, 3) Then spray Clearcoat? Most powders are done in one shot. The powder is applied, the frame goes into the oven, and the powder flows out into a smooth finish. Multi-coats may be required to get a certain look (e.g. that heavy green flake Trance... The green flake is suspended in a clear powder, so you see what's underneath, in that case black), to change the gloss, to protect graphics, or to protect metallics that use aluminum flake (to keep the aluminum from dulling).

Should I tell the painter what series alloy my frame is made out of before putting in the oven? The only bicycle frame alloy I'm aware of that's a concern is scandium. Steel, aluminum alloys other than scandium, and titanium all coat great. Care needs to be taken with magnesium, too. It won't burst into flames, but it becomes unstable at 300-350F or so, which means it can warp.

If the alloy frame is machine polished first, can you skip the base step or not? I always go for bright, shiny, flashy showroom-quality colors that really stand out & "glow". Polished isn't the best prep for powder (from an adhesion perspective... it looks trick as hell with a candy over it, though!). Powder sticks to it - still far better than wet paint - but not quite as well as a blasted piece. Blasting leaves the piece a little bit rough (called an anchor profile), which allows for maximum mechanical adhesion. The end surface finish of the powder has to do mainly with 1) the way it's applied (coating is too thin -> small orange peel; coating too thick -> heavy orange peel, 2) the way it's baked (some like to be heated fast, some like it slow), and 3) the powder itself (some just flow out nicer.) Good coaters also communicate with their powder suppliers and can get "special" hi-quality-grade grinds for a smoother finish.

Also, what if I want to do a type of 2 tone paint color fade job? (like red to black to red)?
Is it possible with powdercoat? Yes, fades are possible. Powder-on-powder fades aren't typically as fine as wet paint fades. Up close you can usually see the powder particles. I haven't really played with fades, but I'm sure they can be better than what I've seen.

Finally, If I bring a Chris King hub (sour apple color ano) & ask for an exact match with powdercoat is it possible or asking for too much? This is going to depend heavily on the coater. We do a lot of color matching. One of our suppliers has 6500+ colors (not including combinations), and if they don't have it they can also custom match (but it's expensive). We have over 1000 powder sample chips, and if I don't have a match, we'll usually send a customer's piece to the supplier to see what they have. We can usually get very very close.

Thanks LenMcC!
 

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Thanks for starting the thread LenMcC. Is it a good idea to powder coat a bike in wrinkle finish? Is dirt going to stick in the crevices, making it always dirty?

 

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Discussion Starter · #19 ·
rallyraid said:
Is it a good idea to powder coat a bike in wrinkle finish? Is dirt going to stick in the crevices, making it always dirty?
Textures (wrinkles, veins, hammertones, leatherettes, rivers, casts) are great for economically hiding imperfections. So for frames that are heavily rust pitted, or naturally rough cast pieces like many valve covers, the textures are popular.

How much they collect dirt depends a lot on the type of texture. Textures will always take a little more elbow grease to clean than gloss or glaze tones (scrubbing with a brush instead of a sponge), but some textures would be cleaning suicide. "Cast" textures, for example, have an almost sandpaper-like texture, and would trap dirt like crazy. The rough textures are typically meant for indoor use (and some aren't UV stable, so they'd fail in the sun). A good coater should be able to tell you some low-maintenance options AND show you a chip so you can see it, touch it, and make a good decision.
 

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LenMcC

An observation:
It seems like these days (with all our great technology) we're only limited by our imagination when it comes to custom paint jobs & tinkering with the finish on parts as well.

A suggestion:
Can you find a link to a good site with high-quality pics of custom painted frames?
Or perhaps put something together like a gallery?

You can point out good paint jobs & poor ones...& help point out the differences between spray jobs, powdercoat & ano.

I think artists are inspired by other artists. It helps to see others custom work.
I'm learning a lot from this thread.
 
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