Dangers of powder coating

[jako999]

I was with a friend today and one of his jobs is safety officer for a large top end car company who own multiple brands. He told me he has just finished an investigation into 3 major crashes, the 3 cars were all different and one was a different brand and different ages, the finding were all the accidents were cause by the same initial problem an alloy wheel cracked and disintegrated the wheels were of course all tested and it was found that all had been powder coated and that something in the process had changed the molecular structure of the alloy. Maybe there are some companies doing something different in the way they are doing it I don't know but its a bit scary as there are lots of companies out there doing refurbs.

Thanks

[tolsen]

Re: Dangers of powder coating

Weakening of aluminium allow material caused by rim repair and straightening is more likely. The powder coat itself cause no harm or danger.

[Thrumbleux]

Re: Dangers of powder coating

What about cleaning agents used in the preparation?
I was given dire warnings from an aeronautical engineer not to use paint stripper on a magnesium wheel - or cracking would ensue.

[tolsen]

Re: Dangers of powder coating

Too high baking temperature will weaken alloy rims. Same reason powder coating is not advisable for painting Smart plastic body panels.

[Yorkshire Devil]

Re: Dangers of powder coating

Powder coating is baked around 200C same temperature your lasagne cooks, ! I would be looking at the shIte cast aluminium that its been cast with, that's more likely to be the problem or gas in the casting that hasn't been gassed out.

[madDan]

Re: Dangers of powder coating

So how many molecules deep does the cleaning and coating actually effect?

Any experts care to answer factually?

More likely this is being used as a get out to save addressing the state of the roads!

[jako999]

Re: Dangers of powder coating

As I said this is high end stuff he deals with one of the cars was a lambo and all 3 cases will go to court so the finding have to be spot on the company he works for allow him a budget of millions to do his job so he doesnt mess around, all I know is that all the wheels were tested and although the remaining wheels looked ok after being tested the actual alloy quality had changed and I can guarantee my friend would have got hold of identical wheels of other cars of the same age to build his case.

Thanks

[madDan]

Re: Dangers of powder coating

So given that there are no ulterior motives, are we going to see refurbing and powder coating on car wheels made illegal in the UK?

Surely if this research is correct this has to be the final outcome, is there going to be a service or facility offered to analyse all refurbed wheels?

Given that in 2006 and many since

joec

04-08-2006, 04:37 PM

just found this on the web whilst looking for a alloy refurb company

Complaint:

RM Coatings Ltd objected to a national press ad for a wheel refurbishment company. Text stated " ... POWDER COATING ALLOYS We do not powder coat alloy wheels as this can cause serious stress damage to the alloys, which can result in cracks and buckles to the alloy as they become very brittle, therefore we do not recommend this type of refurbishment for your wheels. We apply manufacturers finish through all our refurbishment process ... N.B. For safety reasons do not have your wheels powder coated". The complainants challenged whether the ad was misleading, because they believed it exaggerated the likelihood of alloy wheels being damaged by powder coating processes.

Codes Section: 3.1, 7.1, 20.1 (Ed 11)

Adjudication:


Complaint upheld
Wheel Services said the powder coating process took approximately 60 minutes and, during that time, wheels were subjected to temperatures of 200 to 210 degrees Celsius; they said the process caused alloy wheels to expand and contract and therefore subjected the wheel to structural damage. Wheel Services submitted photographs that they believed showed damage to an alloy wheel at temperatures of 149 degrees Celsius. They asserted that powder coating damaged alloy wheels and disagreed that the ad would mislead in the way the complainants suggested.

The ASA noted the complainant's assertion that the powder coating of alloy wheels could be carried out at temperatures lower than 200 degrees Celsius and, because this was below the ductile region for aluminium alloys, no structural damage would result to the wheel.

The ASA took independent expert advice. We understood from the expert that the powder coating process typically involved temperatures ranging from 175 to 210 degrees Celsius, although some powder coating could also be done at 145 degrees Celsius. We noted the aluminium alloy wheels in question were likely to be made of alloy 6061, which contained elements such as magnesium and silicon to help improve strength and resistance to hot cracking, and that a typical 6061-T6 aluminium alloy wheel would not be expected to suffer a significant decrease in its strength following powder coating that involved temperatures of up to 210 degrees Celsius and for up to 30 minutes. We understood, however, some different alloys could suffer and the thermal history of a previously-used wheel could also mean it had already experienced damage before powder coating. We also noted repeated powder coating of the same wheel could eventually lead to a decrease in strength.

We noted structural damage could occur to a wheel following the powder coating process, depending on the type of aluminium alloy used. Although we considered it reasonable to alert potential customers to this and for Wheel Services to express their opinion on the matter, we considered that the claim "N.B. For safety reasons do not have your wheels powder coated" exaggerated the possible damage that could result to alloy wheels following powder coating and was likely to mislead. We told Wheel Services to remove the claim and advised them to avoid implying that powder coating would definitely result in structural damage to all alloy wheels. We advised Wheel Services to consult the CAP Copy Advice team for help with amending the ad.


The ad breached CAP Code clauses 3.1 (Substantiation), 7.1 (Truthfulness) and 20.1 (Marketer denigration).

Seems odd how it depends on which experts are consulted as to the outcome.

Plenty of discussion over the years and counter claims


Is bead blasting safer than chemically stripping for instance (surely blasting must actually remove some alloy in the process)

Should we all be panicking know ;-)

Is a car with a large mass on rubber band tyres more likely to suffer than a lighter car on reasonable sidewalls. Are finer spokes more likely to suffer than fewer thick spokes?

Will we all wake up at the weekend to find our cars collapsed on the drive?

We need to know

What about OEM wheel manufacturers who powder coat their wheels?


I await a raft of my alloys exploded posts now....................

[Thrumbleux]

Re: Dangers of powder coating

As I said this is high end stuff he deals with one of the cars was a lambo

Aren't the wheels on a Bugatti Veyron supposed to be X-rayed after X amount of tyres?
Could this be a higher magnesium content in hyper car wheels?

Powder coating is baked around 200C same temperature your lasagne cooks, ! I would be looking at the shIte cast aluminium that its been cast with, that's more likely to be the problem or gas in the casting that hasn't been gassed out.

Aluminium in a 2-stroke tuning book I've been reading is described as losing strength above 'ambient' temperature! It is very sensitive to temp. Anneals at the temp that soap blackens (on a stove) and will harden if the cooling is opposite from what it takes to anneal.
Happy to be running on steelies!

[tolsen]

Re: Dangers of powder coating

Good I already have a full set of steel wheels just in case.

[Thrumbleux]

Re: Dangers of powder coating

Good I already have a full set of steel wheels.

Me too! Really, must give them a wash.....