Powder coating a C2 cooling fan

[Gary B.]

[Terry B.]

Re: Powder coating a C2 cooling fan

I am no expert but here is some info. Optional E-Coat (epoxy primer) is around .6 mil thick. Lower gloss powder coating can be around .7 mil and the high gloss super smooth finishes required the thickness to increase to maybe 1.5 mi to allow the powder to flow out. My exposure is almost 20 years ago. Things have really improved as evident by the super nice coatings on display at recent auto show booth. Auto trim parts are super nice but they were being coated using automatic guns with robots and computer assistance. I suspect small shops use manual gun and hand spray?
Call one of the coating shops and they will answer your questions.
Caution: If you don't like the powered results, chemical stripping is the only removal I would suggest.






0is typically .6 mil thick.

[Gary B.]

Re: Powder coating a C2 cooling fan

Terry,

Thanks for the info. For my education, do you have any idea what the thickness is of traditional paint that might have been applied to GM parts back in the day? Would paint thickness have been a spec on a GM engineering drawing?

Gary

[Edward J.]

Re: Powder coating a C2 cooling fan

Gary, I kind of like the idea of power coating the fan blade, I do think that the regular spray bombs hold up well on a moving fan blade, and paint does not flow out well, Just wondering what if anything have the readers found that works. another thing I find is that every maker has a different level of the gloss, black is just a tuff color, I think that the factory black on the fans was not a high level of gloss.

[Gary B.]

Re: Powder coating a C2 cooling fan

Edward,

Not only do different makers have different levels of gloss, but in the case of rattle cans, I know that spraying technique will have a substantial effort on the gloss level. From a Rustoleum semi-gloss black, I can get anywhere from satin to semi-gloss just by altering technique, say from dusting to laying it on very wet. I assume something similar holds to some degree when spraying with a real spray gun, but I have zero experience with such.

Regarding the level of gloss for the fan, several of the C2 TIM&JGs call for gloss black; maybe one of the C2-era TIM&JGs calls for semi-gloss. Some people talked previously on the DB about what is gloss black. One company local to me where I've taken chassis parts for painting always asks me if I want "wet" (conventional) paint, or if I want e-coat/powder coat. Next they ask me what gloss level I want, ranging from 0% (flat) to 100% (high gloss), and they show me a set of 1" x 2" samples in 10% gloss increments from 0 to 100. I suspect that original GM cooling fans were not 100%. But I don't really know what % they should be. I can tell you that most of the people I've judged with don't like flat (0%) and they don't like high-gloss (100%). If I have to take a stab at a number, I'd probably say 80%, which might be a bit more than what is typical of semi-gloss. I just know from observation, though, make it too glossy and the judges will complain.

Gary

Gary

[Joe C.]

Re: Powder coating a C2 cooling fan

Edward,

Not only do different makers have different levels of gloss, but in the case of rattle cans, I know that spraying technique will have a substantial effort on the gloss level. From a Rustoleum semi-gloss black, I can get anywhere from satin to semi-gloss just by altering technique, say from dusting to laying it on very wet. I assume something similar holds to some degree when spraying with a real spray gun, but I have zero experience with such.

Regarding the level of gloss for the fan, several of the C2 TIM&JGs call for gloss black; maybe one of the C2-era TIM&JGs calls for semi-gloss. Some people talked previously on the DB about what is gloss black. One company local to me where I've taken chassis parts for painting always asks me if I want "wet" (conventional) paint, or if I want e-coat/powder coat. Next they ask me what gloss level I want, ranging from 0% (flat) to 100% (high gloss), and they show me a set of 1" x 2" samples in 10% gloss increments from 0 to 100. I suspect that original GM cooling fans were not 100%. But I don't really know what % they should be. I can tell you that most of the people I've judged with don't like flat (0%) and they don't like high-gloss (100%). If I have to take a stab at a number, I'd probably say 80%, which might be a bit more than what is typical of semi-gloss. I just know from observation, though, make it too glossy and the judges will complain.

Gary

Gary

Gary,

I don't think the fan should be gloss or semi gloss black, The proper sheen should be semi flat black, which is the sheen that Krylon Semi Flat Black gives. This paint has not been available in retail stores for a few years now because it is acrylic lacquer. I buy it in Grainger's and it is known as Krylon Industrial Paint. It still shows the "5 ball" logo like it always did.

BTW: The new fan that arrived last week from GMPD is semi flat black.

[Terry B.]

Re: Powder coating a C2 cooling fan

Repair / replacement parts purchased such as a fan , bracket, black metal air cleaner, power brake booster are most likely E-coated. Typical e-coat is about 50% gloss level. I think that is in the correct range for semi-gloss (50-60%).
Examples: John Deere tractor specs class A gloss of 80+% to get that mirror reflection when looking directly into the coated surface. Their black e-coat parts are about 50-60% and their black powdered parts are about the same. The 4000 series tractor's driveline, engine, trans, differential is wet sprayed and too would be considered semi-gloss. These numbers are from about 20 years ago when I was involved with John Deere as a supplier of powder and e-coat services both in their plants and at our plants

[Gary B.]

Re: Powder coating a C2 cooling fan

Gary,

I don't think the fan should be gloss or semi gloss black, The proper sheen should be semi flat black, which is the sheen that Krylon Semi Flat Black gives. This paint has not been available in retail stores for a few years now because it is acrylic lacquer. I buy it in Grainger's and it is known as Krylon Industrial Paint. It still shows the "5 ball" logo like it always did.

BTW: The new fan that arrived last week from GMPD is semi flat black.

Joe,

Based on the language in all of the C2 TIM&GJs, I think if you go with semi-flat for the cooling fan you are going to have many judges comment negatively on that sheen level, and you are at risk of taking a deduct either for originality for finish (improper gloss level) or under condition (dull, oxidized, or aged paint). Just a prediction of mine.

Gary

[Gary B.]

Re: Powder coating a C2 cooling fan

Terry,

I didn't know that e-coated was different from powder coated. What's the difference in technology?

Gary

[Edward J.]

Re: Powder coating a C2 cooling fan

IMG_0590(1).jpgJust thought I would post a picture of a fan and clucth from a 75 GM car that has 40k miles and never been doctored. this is what the gloss level should be.

[Edward J.]

Re: Powder coating a C2 cooling fan

IMG_0589.jpgHere's another maybe a better pic.

[Terry B.]

Re: Powder coating a C2 cooling fan

Google e-coat for full description. Our was a 14 stage process for cleaning, pretreatment, painting, triple rinsing in a deionized water bath , and then passing through an overhead oven at 360 degrees for 30 minutes. The end product is an epoxy primer that is used under wet spray or powder coating to enhance endurance. E-coat is accomplish in a water / paint bath. Anywhere the water can reach, no air bubble areas, you will get the surface primed.
Powder coating is spraying charged powder particles from a fluidized bed onto the part that has the opposite charge. Due to Faraday cage effect, the powder does not want to reach inside corners and pockets. The powder will travel to the adjacent sides of the corner and tend to be light or no coat at the actual corner where metals meet. Hence, priming with e-coat and them powder coating is far superior. This is evident if you observe an aged John Deere tractor with e-coat under their powder vs lower priced tractors with pretreatment and powder coating or wet spray only.

GM like and other manufacturer has volumes of specs for their painted parts and all suppliers have to qualify their process and the cost could easily run into thousands of dollars.

Previous question you asked: wet spay paining thickness probably ranges between 3-6 mils.

[Gary B.]

Re: Powder coating a C2 cooling fan

Just thought I would post a picture of a fan and clucth from a 75 GM car that has 40k miles and never been doctored. this is what the gloss level should be.

Ed,

Clearly that's a nice example. And I'd agree with you about the gloss provided the part in question was something other than a fan that spins, essentially being blasted by dirty air for thousands of hours, i.e., 40K miles. But I think one should be careful about concluding that the gloss on a 40K moving part like a fan is the same as what it was when taken out of the box. I've just heard the same story from too many people not to believe it that a cooling fan will soon lose most of its original gloss with use.

Gary

[Edward J.]

Re: Powder coating a C2 cooling fan

Yes Gary 40k and the years behind it will be a factor, I will unbolt the fan from the clutch and see if this may give some details, But being a GM tech for many years I remember the fans being closer to a semi gloss. and really have a smooth finish, the fans have that dipped appearance, I found a run in the paint which makes me think it may have been dipped??

[Gary B.]

Re: Powder coating a C2 cooling fan

Ed,

Great idea on looking at an area not exposed to the abrasive effect of rushing air.

I think you're correct about dip painting. I did that to all of the bumper brackets on my '66. I made a linear moat from two plastic sheetrock mud trays glued end to end and filled it with thinned Rustoleum semi-gloss black. I dipped and then hung to dry. I love the way the brackets came out, including a few runs that match NOS GM brackets I have. The process took quite a bit of fine-tuning to find the right amount of thinner to add in order for the end result to look right.

Gary