Powdercoat Questions

[ThruHull]

I purchased a New set of Keith Eickert headers about 6 months ago and had them powdercoated as part of the purchase. Not long after I got them I noticed a few hairline spider cracks in the powder coat but nothing to bad, but it seems to be getting alot worse over the last couple months. What could be causing this?

 

[Elite Marine]

Heating and cooling?? Powdercoat is simply a thin layer of plastic, perhaps the temperature change is causing it. Ive never seen powdercoat crack though.

 

[ThruHull]

Thats what I was wondering kirk, but they didn't act like it was out of the ordinary to powdercoat them when I placed the order. I guess I am trying to figure out if this is something that should fall back on the dealer I purchased them through or not.

 

[Geronimo36]

I was wondering how everyone feels about Epoxy vs. powdercoat?

 

[Ms PatriYacht]

I never thought of powdercoat as a layer of plastic, there are all sorts of powders for different applications and temperatures. Who did the powdercoat was it done in house or by a job shop, was it done in a professional powder booth or a homemade type kit.

If you get me some more information, I will try to get you the answers, I sell powder coating filters all over the US and one of my customers is the leading manufacturer of Powder Coating Equipment in the world, plus I sell to a lot of distributors that sell and service equipment.

If anyone works at a facility where they have powder coating equipment or dust collection equipment PLEASE send me a PM. I really need to validate some of the time I spend on SOS

 

[MarylandMark]

I really need to validate some of the time I spend on SOS

:biggrinjester:

Most likely a prep issue- your exhaust shouldn't be getting hot enough to do that if right temp coating was used (which I'd think it would be- not like they thought they were coating say a motorcycle frame).

 

[Geronimo36]

I really haven't had much luck with Powder holding up for long periods of time, regardless of who's done it. I had my swim platform done about 5 years ago and it's starting to bubble again in a few places. When I put the platform back on I made sure the stainless bolts did not come in contact with the metal etc... The platform was blasted and boiled by a well known powder coater...

the job was done really well I just lost faith in powder... It seems the first time it holds up well but the 2nd time it's almost impossible to get rid of all the pitting...

So whats everyones thoughts on Epoxy vs. powder?

 

[Chris]

Many simply don't understand powder. Like paint, it is simply a layer of plastic. Unlike paint, it doesn't contain compounds that cause bonding at a chemical level. It bonds due to molecular attraction. This doesn't typically happen with paint as it's either primed or is a self-priming material. If you don't pre-treat your base, you can and often will have problems. You may notice that spots that are nicked will start to peel in that area. If you don't pre-treat the surface the coprrosion will wick under the powder and travel outward, releasing the bond. Metals should be conversion coated prior to application of any powder- if you want it to stay on.

As far as the manifolds- most likely they used the wrong powder. It's really not the coater's responsibility to determine these things, although a really good one will give you some guidance. The one's I use as me to specify what powder. I do my own conversion coating prior to delivery. If you were a company doing your own in-house process, you'd have this nailed down. For someone doing this once and not familiar with the entire process, it's probably a mistake of mass assumptions- that the other person knows what they're doing.

Short version- You're a consumer. You have an expectation of having something done properly. If you wanted to do it yourself, you could have and saved the markup. You asked a professional to do it so you didn't have to learn all this on your own for a one-time deal. It's their responsibility to know how to do it right. They should correct this- and chalk it up to the learning process. Next time they'll know.

 

[Chris]

On "epoxy", it is typically too hard for many applications. Especially if there's alot of thermal cycling. The urethanes are typically better. Imron 5.0 is still the gold-standard for these sorts of applications.

On something like your swim platform, a conversion coating ceases all of those issues. It's a chemical process (typically using hexavalent chromium, but now there are options) that causes a controlled oxidization of the material that then stops and effectively seals the aluminum from further deterioration. It's commonly used in aircraft on EVERYTHING.

 

[Geronimo36]

On "epoxy", it is typically too hard for many applications. Especially if there's alot of thermal cycling. The urethanes are typically better. Imron 5.0 is still the gold-standard for these sorts of applications.

On something like your swim platform, a conversion coating ceases all of those issues. It's a chemical process (typically using hexavalent chromium, but now there are options) that causes a controlled oxidization of the material that then stops and effectively seals the aluminum from further deterioration. It's commonly used in aircraft on EVERYTHING.

About the epoxy being too hard seems to make sense... I had my valve covers done in epoxy and although the surface was really strong it chips easily.

Interesting on the conversion coating, I wonder if Slingshot used this process when he did my platform. It's not to the point where it looks bad but in a few years it will...

I have the bolsters bases out of the boat and going to have them done this winter. I might go with Imron this time around.....

 

[Chris]

Be aware that all catalyzed paints use isocyanates in the activators. Imron has massive amounts of them. No filter respirator removes them. They are very detrimental to your health- and in some cases, one exposure can do significant lung damage. Use in a well-ventilated area or use a fresh-air hood.

 

[ThruHull]

I never thought of powdercoat as a layer of plastic, there are all sorts of powders for different applications and temperatures. Who did the powdercoat was it done in house or by a job shop, was it done in a professional powder booth or a homemade type kit.

If you get me some more information, I will try to get you the answers, I sell powder coating filters all over the US and one of my customers is the leading manufacturer of Powder Coating Equipment in the world, plus I sell to a lot of distributors that sell and service equipment.

If anyone works at a facility where they have powder coating equipment or dust collection equipment PLEASE send me a PM. I really need to validate some of the time I spend on SOS

I am not sure who did the powder coating, but it was whoever does it for CPperformance, so I would assume it was a proffesional, I sure paid for a professional!

 

[ThruHull]

Thanks for everyones feedback

 

[Madcow]

I powdercoated almost everything in my engine compartment. All of it has held up well withthe exeption of my manifolds. I was told the problem is powder takes heat to activate, cosiquently heat makes it want to reactivate. I was warned this may happen when I had it done.

 

[Chris]

Powder doesn't "activate". There's no chemical process (I shouldn't say that- there's none I've ever seen that uses any sort of heat or chemically activated polymerization- theoretically it could exist). Powder is finely ground polymer. The heat causes it to go into a liquid stare and for all the powder particles to fuse into a sheet. Given enough heat, you can re-melt it. So you don't use a low-temp powder in a high-temp application. I use some metallic/ceramic powders that once fused (500 deg) will withstand 2K/deg.

Paint on the other hand is a chemical compound that, when mixed with other chemicals (activators) a chemical reaction takes place and causes polymerization after application. A common mis-conception is that paint dries. Paint polymerizes. Latex house paint does it with a reaction to atmospheric oxygen. The carriers in the paint (water, ammonia-based compounds or petroleum thinners) do evaporate, but without a chemical reaction they would just get thicker.

 

[Chris]

P.S. I have seen plenty of 20+ year-old Gil manifolds that were powder coated that look just fine. They use the proper powder.

 

[Madcow]

That makes sense. So to have a higher temp powder, you would need a higher temp oven to bake it in then. Right?
Also to help with your explination. Powder coat is just that, a powder. It sticks to whatever your coating by using static electricity untill it is baked on to the metal. It only sticks to metals.

 

[stinger]

OK then can out drives be powder coated with good long term results? Can they be done without disassembly? What about fadding?

 

[Madcow]

Can't be done without disassembly. Also have to mask anything that needs to attatch because powder is a LOT thicker than paint.

 

[Audiofn]

There was a guy that I used to use that would allumacoate things prior to powder coating. He did some gill brackets for a friend of mines boat years ago and they still look as good as new. He is out of business now so I took my tabs to another guy. The stuff did not stick well at all. As Chris said you need to find some one that is willing to take the time and do it the correct way.