Suspension Arm Coating

[Kevin Box]

I would like some comments on the success or otherwise of peoples coating systems.
I and considering the following options
1 Powder coating
2 Two Pack paint
3 Ceramic coating
4 Chrome plating
5 Spraying enamel
6 Automotive Laquer

My preference at the moment is Two Pack as I can do it myself or easily get the paint shop down the road to do it. I was thinking of putting in some extra elastomer to reduce the hardness of the Two Pack. Most of the Two Packs seem fairly similar in properties and their success seems to be based on using the correct primers and undercoat.

I am looking at the same process for my chassis so would really like to know success or other wise of various coating systems on GT40s.

 

[Mark Charlton]

I have had best results with powder coating in terms of appearance and durability for suspension components. But if you are looking for a chrome finish then powder won't do it.

Each process has different aesthetics, costs and performance. You need to resolve your priorities to help narrow down the choices as depending on your criteria, each could be a good choice (or indeed the only choice).

Mark

 

[Howard Jones]

One thing to consider is the ability to crack check the pieces once in a while. It is nearly impossible to see a crack forming under chrome. I would think that power coating is the same problem. I have painted the suspension parts that I have made just for this reason. Light coat of rust inhibitor and a single top coat of semi gloss. Very easy to strip off paint and check for cracks at the welds.

This may seam excessive to some. Maybe............maybe not..........

 

[Woody]

Hi Kevin
All the suspension parts in my car Ive had ceramic coated, What our boys call " Hyper coat Polish" Iv'e used it before and had very good durability, and keeps its apperance for years.
I coated a set of headers for my XR8 and kept that car for 13 years and they still looked as good the day I sold it. Headers don't normaly last that long. Its expensive but worth it.

 

[Lim]

Have you thought about PRO 15. Good product.When using this product,make sure to wear gloves.
LIM

 

[Trevor Booth]

electrolous nickel plate about 5 micron thick.

end result in terms of sheen depend on surface finish prior to plating.

if you highly polish the metal first you will get a bright finish.

if you garnite blast blast you will get a satin finish.

will show up any cracks etc

I would not chrome plate unless you anneal afterwards, you can get hydrogen embritlement which may lead to failure

Powder coat can hide any cracking and corrosion underneath the powder coat

2 pack paint may also hide cracking.

You can also polish and clear coat

 

[Dave]

Trevor I don't know much about chroming, There is a bit of an arguement going on over here in WA about chroming.

One of the Guys has chromed all his steel suspension brackets and links, it looks awesome. I want to do the same and was told the process may weaken the steel. When talking to the chromer he says that's a load of crap and he only heats the steel to 65deg C to carry out the process. When you powder coat steel you heat it to 200deg C.

I think I may be missing the point. All the so called Engineers I speak to all say no, but they cannot explain exactly why, they just quote Hydrogen embritlement.

My view is that chroming may hide cracks, but so will powder coating and painting. Maybe we should all clear coat our chassis and links just incase a crack appears???? Who ever checks their suspension for hairline cracks anyway?

I ended up painting my rear suspension links black and will chrome after Engineering and rego.

 

[Dalton Veitch]

Dave, as a very crude analogy, think of a thin concrete slab with steel reinforcing. If you bend it all, the steel will bend but the concrete will initiate cracking at the surface. A component made of "normal" steel can flex and bend slightly when subject to high stress, without deteriorating. Add a hard, brittle surface coating (the chrome plating), and it can initiate minute surface cracks under stress conditions, which then grow and weaken the component. I remember our Metallurgy lecturer (decades ago now) saying that steel subjected to stresses, whether car wheels or golf clubs, should not be chrome plated. Of course, many items are totally overdone in terms of construction and strength such that they do not flex and do not suffer stress cracking. There may also be new technology and processes that completely avoid such problems currently, as I'm obviously not expert at this.

 

[David Morton]

I seem to recall we discussed something very similar to this quite a few years ago now. I can't remember how it all ended up and I also seem to recall a mention that chromed suspension might not be allowed by scrutineers but again I don't know if this has changed. Embrittlement was discussed in some depth as well. Personally, I wouldn't go there - there are other ways of making it look nice.

 

[Jim Cowden]

I was under the impression any type of plating will give you hydrogen embrittlement.
Hydrogen is trapped in the metal during the plating process , heating the component to X deg for x time opens the grain and allows the hydrogen to escape.
I could look up the exact procedure but not that interested.
Not shore about 65 deg as per Daves post, I thought it was much higher.

This is my experience with plating
A tubular arm capped at either end must have a small hole drilled in them because they go into a hot tank,if sealed the sealed section builds up pressure and causes an issue for the plater.

Maybe the plater I used was a dick head and his cleaning was not up to standards but I could never stop rust forming around the holes,seemed aggressive to me so I thew them out and made another set and painted with por 15

POR 15 is a great product ,I use a brush and I kid you not it looks like it has been sprayed.
You can touch up and you make, you paint, the next day or in the afternoon you fit.

Jim

 

[Howard Jones]

"Who ever checks their suspension for hairline cracks anyway? "

I do. It's idem # 4 on my check sheet to prep the car to go to the track. A-Arms, trailing links, chassis pickup points, ball joints, steering arms and linkage, shock mounts, and roll bars.

These cars are hand built race cars being run on the street. Nearly all of them use fabricated suspension parts. Every one of those welds are subject to cracking. Most don't. Some do. There have been a few suspension failures here on this forum. Nothing wrong with the design or abuse by the owner. Just a failure. It happens.

Do I need to tell you what will happen to you and your car if a lower rear A-Arm fails at 120mph in a corner with the fence 20 feet away? By the way it will be the loaded outside one too!

At least put the car up in the air once a year and look it over. It might save your life. I've had parts, I call them ITELKILLYA parts, break on race bikes at very high speeds and it hurt really bad.........One of them finished my Walter Mitty Motorcycle racing career.

Kevin asked a good question. There isn't a single right answer. I'm just trying to present a valid point to consider. He's a big boy and he can surely decide the question for himself if he has all the information. Right?

 

[Jim Cowden]

He was asking for everyones experience on coatings used so he could make a decision.
They look like experiences to me Howard.

Jim

 

[Jack]

For steel, a light gray paint. Clean often with WD-40. Any cracks will show as a much darker line. Aluminum, I polish and wipe down with Ballistiol. Good stuff.

Don't think I would trust dark color paint or powdercoating.

 

[Seymour Snerd]

"ballistol sportsman's oil " ?

Does it really smell like licorice? I'll get some on that basis alone....

 

[Jack]

Sort of like licorice. I understand it's pretty good for treating wounds too.

 

[Kevin Box]

Guys
Thanks for your opinions and experiences.
Having read them all and thought about it, I plan to spray them with a thin coat of lacquer.
A thin coat of etch primer first and then a thin coat of lacquer.
My reasoning is based on having a thin coat will make it easy to spot any degardation and it is really easy to do. My plan is to use a silver colour which shouldn't look too shabby and being lacquer I can rub it down and re-coat if it starts to look tired in the future.

My second choice wuld have been two pack which is maybe a bit tougher but is also a bit more risky to spray.

KB

 

[Andrew Robertson]

KB

I got all mine HPC'd in the std header coat when I did the headers, looks good and I think thin enough to enable decent visual inspection. Sounds like you're really ripping into it.

Cheers, Andrew