Club 80-90 Forums

I was up in Dublin yesterday collecting some parts (a subframe and suspension parts off a Mercedes Im restoring at the moment) that I was getting shotblasted. I have known the shot blasting guy for many years and we were chatting about stuff as you do. I mentioned I was going to get all the parts powder coated and he asked me why I would do such a thing. I explained it was for longevity purposes as well as aesthetics and peace of mind. He suggested that I should galvanise the parts first, age them and then get them coated.

Hmmmmm

I know you should age galvanising before you paint but wasnt sure about powder coating. Anyway off i went to the powder coaters, and, armed with this new insight in coatings, I decided to ask the coaters their opinion on what I had planned. This is what they told me and it may be of interest to those of you who are thinking of powder coating in the future.

Powder Coating is for aesthetics and light protection only and should not be used on components that will be weathered or run the risk of having the coating damaged. The reason being, if the coating tears, moisture will ingress and rust quicker than normal as usually the coat is applied directly to bare metal. His first statement to me was .....

"I wouldn't use powder coat as it has no real grip onto the substrate. A tiny chip or edge will allow water to percolate under the coating. Powder coating was originally designed as a cheaper option to painting for use on displays, etc, where longevity wasn't expected."

.... and this from a guy who earns his living form powder coating!

So according to this guy, (who earns his living form powder coating) powder coating subframes, suspension arms and the like is a waste of money and may actually accelerate the very rusting process you are trying to stop.
At this point may I say 'dont shoot the messenger' ...... but I saved €110 and bought some Lowe products instead!

Good point
one company I worked at made switch gear housings and if the powder coating was not applied thick enough or evenly ie edges covered, the steel would rust and the coating come off in sheets. I think as long as the surface is blasted first to create a good key and well de greased it can be a good coating.
VW did and do use powder coating on external parts.
I agree if you want real rust protection then galve dip is the way to go, only thing to watch out for with galve any hole or bore for bushes that needs to be accurate will require reaming after coating.

there was a time andrew when you were telling me that gavanising was a waste of time and money, and that all i should do was to slap on some hammerite on to my suspenshion parts. powder coating has its place, for example the old cast iron radiators in my house look wonderfull after they have been blasted and powder coated black

neil

axeman wrote:there was a time andrew when you were telling me that gavanising was a waste of time and money, and that all i should do was to slap on some hammerite on to my suspenshion parts. powder coating has its place, for example the old cast iron radiators in my house look wonderfull after they have been blasted and powder coated black

neil

Hi Neil .... Im still saying that! I painted those parts instead of galvanising and coating using products from the Lowe range! Im sure you old CI rads look great

I took some Merc 15" steel wheels I had to a powder coaters some time back; They were black and i wanted them grey/silver for the Tristar. I was told not to waste my money because they would not last and the powder coating would not penetrate into the folds of the welds; so I used Hammerite instead.

Mudlark wrote:I took some Merc 15" steel wheels I had to a powder coaters some time back; They were black and i wanted them grey/silver for the Tristar. I was told not to waste my money because they would not last and the powder coating would not penetrate into the folds of the welds; so I used Hammerite instead.

Exactly as my man said. No matter how you prep the components you wont get 100% coverage and that is where the danger lies. The section where there is no coverage will be where the moisture will start to lift the coating and rust will form.

being a blacksmith in the land of salt sea air, i always get stuff galvanized one way or another.
all of my van underneath parts when they come off are shot blasted, hot zinc sprayed and then powder-coated. its what i call the belt and braces approach.
the hot zinc spray method is just gagging for a topcoat and the company i use bake it once after zinc spraying to "gas" the zinc and then powder coat which give as rust proof a finish as you can get.
that is what i recommend. best of both worlds.

I just wonder with all this protection of components built heavily in the first place, how many spend as much effort looking as deeply into the structural soul of their vans...

AS for the powder coating on raw steel, what Andrew & others say, reminds me of those awful plastic coated steel products that abound, with sheets of it peeling off to reveal , nada.

The last one from memory I threw out extra fast, was a roof ladder attachment, you know, the hook thing with wheels for rolling up and over the apex...

it had been outside on a ladder rack for years and the sheets of thin plastic WERE the strength in it, no steel tube at all remained in some parts

Wheelbarrows like that are another one, and of course the centre rear of the main T25 rear cross member, between the outer 2.5mm 'L' and insert, yielding 6 to 8mm of 'iron oxide shale' (on mine anyway), yet another

Anywhere two layers come together in fact and theres plenty of them...

Of course, I understand the aesthetics of pretty bits hanging off every bracket and hole, but Pad makes a good point... a good wire brush and the correct paint system is much harder work, but not far behind some expensive treatments in robustness, though hot galv for steel is the biz.

My current one is chip, brush, clean, de-grease, RC900, inspect and more RC900, Chassis Black, 2 coats

Of course even paints cost and everything adds up, but keeps it in-house & under control

PS. Isn't powder coating used in production for alloy wheel finish? Is it a better chip resistant finish on ally/mag ally?

I had my wheels powder coated when I got my bus and they look terrible now. Waste of money unless on something unexposed without the risk of scraping etc.

Tony