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-   -   Powder Coating Advisor (https://www.bikeforums.net/introductions/378838-powder-coating-advisor.html)

powdercoater4u 01-13-08 06:00 PM

Powder Coating Advisor
 
Hi everyone,
I have notice that many people have many questions and difficulty finding information about powder coating. I have a powder coating company and want to help people get the information they need about powder coating, the advantages, processes and limitations. I may also be able to assist with advice, resources and links to services you may need. Please feel free to contact me about your project. I'll do my best to take the guess work out of getting your parts powder coated.

East Hill 01-13-08 06:14 PM

Hi PC, what kind of bike do you ride? MTB or road?

Welcome to BF!

East Hill

powdercoater4u 01-13-08 06:53 PM

Thanks for the welcome EH
 
Not much of a rider myself but alot of my friends ride. In fact most of the customers I have that ride have become good friends.
I signed up on BF to offer my help because most of the cycle folks I coat parts for are frustrated from the lack of information available about powder coating. I can answer any question about the process and help them find the resources they need. I can also educate them so the get what they want without getting ripped off.

East Hill 01-14-08 09:42 AM

Sounds great! Perhaps we can convince you to turn into a rider one of these days :D .

East Hill

ebr898 01-14-08 10:15 AM

I have a question. How are the treads taped or sealed off? How do does the shop want the frame -bare metal, paint on etc.

powdercoater4u 01-14-08 08:45 PM

Covering threads
 
Hi eb,
I usually use silicone plugs to fit into the holes and silicone caps to fit over studs. They come in all shapes and sizes. They also make different types of high temp tape for masking. I also prefer if the part comes already stripped. It takes the guess work out of what could be under the current coating or if repairs are needed. If it still needs a detailed cleaning I prefer blasting with glass bead media for the cleanest finish.

Mark

Six jours 01-14-08 09:20 PM

I've heard that powdercoating is not as resistant to the elements as traditional paint, ie. if you strip off powdercoating from a steel frame after a year or two you will find evidence of corrosion underneath. Has this been your experience? And if so, does a clearcoat help?

powdercoater4u 01-15-08 06:00 PM

Corrosion
 
Hi Six,
Thankfully I haven't seen too much of that corrosion trouble yet but I'm sure I'll get my share.
I guess it all depends on what type of powder and paint you compare. There are several different type of powders: Epoxy, polyester, nylons, vinyls, acrylics and hybrids, just like paints. Different powders for different uses (Indoor or outdoor, Marine, architechture, machinery, furniture etc.) otherwise there'd be only one type. Epoxy is very chemical resistant and very hard but performs poorly outside in the weather a polyester also has good properties against chemicals and would work better out side in the sun. Chose the right powder for the application and it should have a long serviceable life but.... nothing lasts forever including other types of coatings.
Corrosion under the coating is usually caused by poor or inadequate pretreatment. I would assume it would get started where the coating has not properly bonded to the surface. Maybe from some oily fingers or deposits left over from the last cleaning or uneven curing. You do your best to clean and prep the part before you coat it.
Clear coats add thickness, depth, specific gloss, abrasion protection for the under coat like metallics but not a hole lot more then that.
I still think a powder coated finish will far out last spray urethanes and enamles and even some epoxies.

i_r_beej 01-15-08 06:26 PM

Hi PowderCoater,

Thanks for offering up information.

I've finally saved up enough money. I'm going to take my old MTB frame (with the remnants of an old rattle-can paint job on it!) to get it powder-coated. After some cursory research and crusing the forums here, I've settled on powder-coating as the best coating for my bike project-- it's gong to be a single-speed conversion and I'm going to put racks and fenders on it to use as my errand/around town bike. I'd like to get something nigh bullet-proof and powder-coating seems to fit the bill.

I've got a couple of local powder-coaters lined up...

I live in Portland Oregon and it's wet wet wet fall and winter. Are there any questions I should be asking of my powder-coater regarding the type of material used for our wet climate?

Thanks for any tips.

powdercoater4u 01-15-08 07:54 PM

wet wet durability
 
An exterior grade polyester hybrid or TGIC type powder should do the trick. "Super Durables" are good for extreme conditions. Ask your coater about an powder epoxy primer under the color coat. If it's a steel or aluminum frame ask him how he preps the metal. I use a iron phosphate rinse on steel to give the steel extra corrosion prohibitive properties. Aluminum should get a conversion coating too.

BotchedSurgery 02-12-08 07:26 PM

Powdercoating for durability
 
Hi PowderCoater....I think lots of us could use a general info session on powdercoating. My main concerns (in this order) are that the paint job on my bike be:

1. Resistant to environmental damage: sunlight and moisture. Especially moisture!
2. Hard; resistant to scratching and any kind of flaking/scraping.
3. Long-lasting.
4. Inexpensive.
4. Reasonably attractive.

I know that a lot of people will have different priorities but I think everyone wants most of these things.

That said, what media for blasting will give the best results (even finish while stripping off as little of the frame as possible) on a steel frame?

What kind of preparation steps should I look for regarding stripping, cleaning, frame preparation, etc.?

Should I ask what kind of facility (climate and or humidity-controlled) the powdercoater has access to? What kind of blasting and/or painting equipment should be used?

What questions should I ask regarding my powdercoaters experience with bicycles? Is powdercoating a bicycle frame very different from powdercoating a steel motorcycle frame or car part?

What kind of paint should I choose? Should I have a base-layer or clear-coat top-layer applied? If so what kind? How many coats of paint would be ideal?

.......you're right that a lot of bicyclists don't have much access to this info, and we can certainly use an expert like yourself. Welcome to the forums :).

THANK YOU!

3speedcliff 02-12-08 07:59 PM

sand blasting
 
Hi, I'm an amateur framebuilder and have had 3 frames powdercoated locally with good results. I have heard though that an overzealous blaster can weaken the frame. My frames are generally 4130, not the super thinwall high strength alloys. It concerned me a bit when I picked up a frame and the owner of the business said that the guy doing the blasting couldn't get rid of the bronze filler. The owner realized the frame was brazed and told the guy to not worry about it. I just made me wonder how hard the guy tried and if there was damage to the tubes in critical areas.
Thanks, Cliff

powdercoater4u 02-14-08 10:18 PM

General info session
 
Hi Botched,
Let me put it this way. There is no such thing as a perfect finish. If thats what you expect you'll never be satisfied. All surfaces and finishes can be scratched, damaged and will wear out over time. Obviously if you put it away in the closet it'll last longer than if you leave it out in the rain. The performance of the finish is a direct result of the abuse its exposed to. Generally speaking I think Chrome is probably the hardest finish (and the most expensive) you'll find. You'll get what you pay for!
I'll try to address your concerns 1 at a time.
1) Blasting - The least aggressive way to remove a prior finish is chemically. Abrasive blasting is just that abrasive. There are numerous types of blast media. The hardness of the media, the grit size and the blast pressure all effect the surface. The more aggressive the blast the faster the removal (including metal material). Talk to several blasters and ask them what they think.
2) Preperation - You need to remove all items that won't be coated or parts that can't take the heat before you strip or blast it. Once its stripped to bare metal you'll have to get it coated ASAP.
3) Facility - Don't worry about things like climate controlled environments that too intense. Go look around at the coaters operation. If they're a serious coater they'll have some serious equipment. Ask the person to show you around and explain the process. I'd have more confidence with someone who was excited to show me and proud of their operation. If they have no time or can't be bothered I'd move on.
4) Experience - Buttons, brackets, bottles or bicycles it shouldn't matter. Ask if they've done bicycle frames before and do they have any suggestions or concerns. Ask how they treat different metals like steel, aluminum, magnesium.
5) Paint Type - Usually a single layer or application of powder is all you need. If you get into translucent colors, some metallics, multiple colors or other custom colors or designs It'll get expensive. Ask the coater to explain the difference between interior and exterior grade powders. You don't need to know chemical composition just that the coater would chose an exterior grade or "super durable" grade powder. Keep it simple!!

While liquid paint is easier to customize a powder coat finish is far more durable.
I hope I answered your concerns.

BotchedSurgery 02-15-08 12:14 PM

And then some....thanks a ton :). I know it's been said before, but this is a great help you're providing.

o_perkins 02-25-08 02:16 AM

Hey, this is along the lines with 3speedcliff but I was looking to get my frame powder coated and my friend told my that the process in general, i.e. blasting and heat, weakens the frame. So I was just wondering if this is true and if it is, is it significant enough to matter?


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