Mag alloy wheels

[Pinky]

Hi my handsome friends,

Any advise on spraying mag alloy wheels please

I am looking to etch prime, 2 pack primer, gloss 2k
Or a resin based primer ? And forget about the etch prime

I understand the mag alloy wheels are porous, and after spraying the air can make the paint bubble
Any advise greatly received

Regards pink

 

[Chris Stevens]

If they are magnesium you need to get some specific primer. Place close to me uses a special epoxy which is £100 a litre.

 

[500e]

As CS says don't use self etch on Mag Dow Chemicals do special products for .Mag then primer & 2K

http://www.vintagebonanza.com/prep_magnesium_for_painting.htm

 

[Chris Stevens]

They used to chromate dip magnesium parts, but think thats fallen victim to health and safety.................

 

[Pinky]

Thanks for the information,

http://www.aircraftcoverings.co.uk/main.htm

Evidently the company above sales the treatment you suggest so I will give them a ring Monday

Pink

 

[Chris Stevens]

You might find they are very very expensive.................

 

[500e]

No Chris "they will be very very expensive" it's aircraft

 

[Pinky]

I will phone and ask Monday, and come back and let you no
However any other suggestions
The wheels are split rims, and are going on a triumph tr6 do you get diferent degrees of mag alloy wheels ?

 

[Chris Stevens]

I would forget putting magnesium wheels on a road car. Sell them and buy aluminum would be a much better idea.

 

[hotrodder]

do you get diferent degrees of mag alloy wheels ?

Kinda... there are real magnesium wheels which are insanely* light, rare, delicate and usually insanely spendy or there's mags, mag alloys etc which are/were generic terms for wheels that are aluminium in everything but name

If your wheels are 3 piece the rim halves aka [shudder] dishes [/shudder] will be aluminium and probably be forged/spun. The centre could be cast ally or cast mag and the later would very quickly become very dull/grey and 'furry' if when the paint gets damaged
2 piece wheels tend to be cast rim and centre and both pieces are almost certainly(?) cast ally

If you suspect yours are 'real' mag then the acid test will tell you in a few secs... clean the paint and any crud off a small area and add a drop of vinegar. The acetic acid in it will instantly react if they're magnesium fizzing/bubbling away as the reaction produces hydrogen. If this happens rinse it thoroughly and use a stainless wire brush to remove the dark stain before rinsing again and drying
If they're aluminium or any of it's alloys (including AlMg) vinegar won't do anything noticable

* even compared to a forged aluminium wheel... i've got some 15 x 6 Fuchs (Porsche) wheels which are forged ally (6082-T6 i believe) and while they are waaaaaaay lighter than the spare 15 x 7 MB alloys for my daily driver they're a chunk heavier than a mates Mahle 'gas burners' (also old Porsche wheels) which are cast mag and weigh 4.something kg versus 6ish kg for the Fuchs and 8 or 9kg for the cast MB wheels
FWIW he had the gas burners powder coated with the rim and spoke details left bare i.e. polished and waxed. The wheels were 'out gassed' before powder coating which is a posh way of saying they were preheated. Several years and the powder coat is still stuck fine but it only took a few months before he got very bored of having to repolish and wax them super regularly even when the car was sitting in a bone dry garage

 

[Pinky]

Kinda... there are real magnesium wheels which are insanely* light, rare, delicate and usually insanely spendy or there's mags, mag alloys etc which are/were generic terms for wheels that are aluminium in everything but name

If your wheels are 3 piece the rim halves aka [shudder] dishes [/shudder] will be aluminium and probably be forged/spun. The centre could be cast ally or cast mag and the later would very quickly become very dull/grey and 'furry' if when the paint gets damaged
2 piece wheels tend to be cast rim and centre and both pieces are almost certainly(?) cast ally

If you suspect yours are 'real' mag then the acid test will tell you in a few secs... clean the paint and any crud off a small area and add a drop of vinegar. The acetic acid in it will instantly react if they're magnesium fizzing/bubbling away as the reaction produces hydrogen. If this happens rinse it thoroughly and use a stainless wire brush to remove the dark stain before rinsing again and drying
If they're aluminium or any of it's alloys (including AlMg) vinegar won't do anything noticable

* even compared to a forged aluminium wheel... i've got some 15 x 6 Fuchs (Porsche) wheels which are forged ally (6082-T6 i believe) and while they are waaaaaaay lighter than the spare 15 x 7 MB alloys for my daily driver they're a chunk heavier than a mates Mahle 'gas burners' (also old Porsche wheels) which are cast mag and weigh 4.something kg versus 6ish kg for the Fuchs and 8 or 9kg for the cast MB wheels
FWIW he had the gas burners powder coated with the rim and spoke details left bare i.e. polished and waxed. The wheels were 'out gassed' before powder coating which is a posh way of saying they were preheated. Several years and the powder coat is still stuck fine but it only took a few months before he got very bored of having to repolish and wax them super regularly even when the car was sitting in a bone dry garage

Thank you, really interesting
They are split rim they are a lot lighter than the steel wheels and really nice to drive
I bought them second hand from a guy who raced tr6 there a wide wheel , and look the dogs on the car
The story was they were specially made
I will go and do the vinegar test and take some pics

Thanks again mr hotroder

Pink

 

[langy]

I would forget putting magnesium wheels on a road car. Sell them and buy aluminum would be a much better idea.

Could you give me one good reason why ?

 

[Chris Stevens]

Could you give me one good reason why ?

Mag wheels age harden and become far more susceptible to cracking, add to that problems related to corrosion and issues with properly refinishing, and cant see there is a lot of point for a road car......................

 

[Pinky]

Did the vinegar test no reaction so I can only presume they are light weight alloy and
Can treat them with etch prime

Thanks for your replies

Pink

 

[Chris Stevens]

If they were mag and not painted, they would probably be suffering from major corrosion by now. You might find its a real pain getting those bolts out though.............

 

[Pinky]

No, I have had them out and had then re chromed a couple of years ago and asembled them in cooper grease
I want to paint them gloss black, with the chrome bolts should look ok
I have used them and there a pleasure to manuvere

Pink