Magnesium wheel renovating?

[pfenlon]

Why can you not have a magnesium wheel power coated in the same way an aluminium one is done, or can you?

 

Oven temp is around 180c /400F, this doesn't worry the Alloy.

 

Would it damage the magnesium.

 

Having done the cleaning by hand on my Black TR4 and then wet painting, I would sooner have it done in an oven next time!

[RogerH]

Hi Pete,

mag is very reactive. Although it doesn;t corrode away to nothing like steel etc it does produce a corroded skin that then protects similar to Ali, Copper etc.

You need an etch primer as your first coat if you want the others to stay there.

 

Can you powder coat over an etch primer.

 

Regarding your temp. I think you would need higher than that to set light to the Mag.

 

Roger

[AlanT]

Try these:

 

http://www.kustomkoating.co.uk/

[YankeeTR5]

I think the problem with powdercoating magnesium is that it starts to 'outgas' at a certain temperature - right around what you need it to be in order to powdercoat. So you can powdercoat, have outgassing which produces pockets between the metal and the powdercoat, which will eventually corrode and eat the wheel from the inside out.

 

It can be done though. I have a set that I bought powdercoated and last time I checked they still looked fine. Probably should go pull them out and inspect again in any case.

[BlueTR3A-5EKT]

My memory says we used selenium dioxide diluted in water to treat corrosion and finish coated with phenolic varnish on magnesium engine castings.

Corrosion was removed with a stiff bristle brush, rotary file or vapour blasting, wire wheel brush use was outlawed as it could leave embedded steel fragments.

Cheers

Peter W

[Rob Briggs]

A couple of years ago I used Steve Turner in Melksham, Wiltshire (tpcs-magnesium-refurbs.co.uk) who did a first class job on a set of wheels. His process has several stages and takes a week or so but handles problems such as outgassing and treating some existing corrosion. Steve was very enthusiastic and was happy to describe the whole sequence to me.

Rob Briggs

[stephen cooper]

If memory serves me right I now have the wheels Rob talks about and they are still spot on.

 

Cheers

[oldtuckunder]

Of course with Magnesium wheels one does has to ask the question "do you want them refurbished?" I was offered a lovely set of Minilite Magnesium Wheels for my Vitesse last year that I was sorely tempted over. They wern't the standard pattern but upon investigation were a genuine minilite pattern from the 1980's. They looked a little tired so I inquired direct to minilite what it would cost to refurbish them? The first question with its own answer was "how old are they" and the answer was if they are over about 20 years old if you want them for a static display then fine, but just don't use them as by that age they are just getting too brittle!

 

I don't know what experience others have with old magnesium wheels, but as I was looking at competition use I decided that discretion was the better part of a £300 experiment.

 

Alan

[RogerH]

Hi Alan,

I'm suprised at the answer. The Mag wheels would use an alloy with a high % of Magnesium.

If the material spec is known then a heat treatment process would/could bring them back to original.

 

The surface of the metal corrodes and lays down a protective coat unless something nasty, containing chlorine, attacks it.

Mag was (is) used for a long time on aircraft because of the weight factor. Admittedly these would have been painted.

 

For a car Mag wheels are there to get the last nibblings of performance - not really TR related.

 

Roger

[stephen cooper]

Mag wheels are approx half the weight of standard steel items, over 4 corners that's 15+kg of unsprung weight removed. While I admit for my road use it is not essential, I think plenty of TR racers would consider it a relevant option.

[Motorsport Mickey]

Sorry to disappoint Steven, I've done a fair bit of racing in TRs and sometimes using mag wheels and I guarantee ANY TR driver whether racing or otherwise will not tell the difference.

 

If you were using a 500kg lightweight series racer of some description the reduction of unsprung weight (two bags of sugar per wheel ! ) could be beneficial allowing more compliant springing to be used and consequential grip betterment at the very edge of the handling envelope. We are talking a couple of tenths max reduction in lap times here, as regards a 800 or 900 kg stripped down TR Racer...forget it.

 

People don't need to make excuses, if you want to put these bits along with 4 pot disc callipers, alloy rocker covers, alloy sump, carbon fibre wings (huh) and all the other ephemera that are sold onto your TR, please do. Just make sure that you've fitted a rear cockpit alloy firescreen behind the rear cockpit fibreboard trim, I think that 10 gallons of fuel deserves to be kept out of the cockpit in the event of an accident or even low speed roll.

 

Mick Richards.

[stephen cooper]

Hi Mick,

 

I think the effect is cumulative.. If for arguments sake you wanted to make a TR as light as possible would you ignore a 15kg saving? That's as much as the bumpers weigh and you don't see those left on race cars.

 

(Of course SOME alloys which are lighter than a steel wheel do exist, but most of the cheap ones are no lighter!)

 

Cheers