Reconditioning Magnesium Alloy Wheels
Discussion
Want to get my magnesium alloys (1970's) reconditioned before I put new rubber on, been having problems finding someone who can do them (properly). Mag alloys just can't be painted (like most wheel reconditioners will, including the roving types) they need special treatment otherwise the magnesium powders and lifts the paint away.
Most places I've contacted either have no clue, would just paint them like aluminium alloys, or won't touch them.
Have found one place, but I could do with the PH masses opinion on the way they say they are going to refurbish them. They are quoting £120-150+vat per wheel, and this is what they will do :
Striped in acid bath
White etched
Given a thick powder coating primer
Final colour coat of paint
They say they can colour match exactly but "it might look a bit bright and fresh initially".
Anyone have any thoughts ? Is acid okay with magnesium alloys ? What's white etching ?
Thanks !
Most places I've contacted either have no clue, would just paint them like aluminium alloys, or won't touch them.
Have found one place, but I could do with the PH masses opinion on the way they say they are going to refurbish them. They are quoting £120-150+vat per wheel, and this is what they will do :
Striped in acid bath
White etched
Given a thick powder coating primer
Final colour coat of paint
They say they can colour match exactly but "it might look a bit bright and fresh initially".
Anyone have any thoughts ? Is acid okay with magnesium alloys ? What's white etching ?
Thanks !
nevpugh308 said:
Well there's thousands of Ferrari's out there driving around quite happily on 30+ year old mag wheels 
(and the only other choice being not to have any wheels at all which kinda defeats the object of having a car, lol
If its for a Ferrari i'm sure you would be albe to get some good quality replica's but it would be worth having them checked. A wheel failing would make you have a very bad day at any speed
ninjaboy said:
If its for a Ferrari i'm sure you would be albe to get some good quality replica's but it would be worth having them checked. A wheel failing would make you have a very bad day at any speed
You cannot get replicas of the 14" wheel, though you can get 16" look-e-likes BUT a) they are heavier, being made of aluminum b) my car never came with the 16" option so they are out of period c) I prefer the look of the 14"s
Unfortunately Ferrari UK have run out of the new 14" wheels (DAMN !) and are not likely to make any new ones.
There is the structural issue, which can be addressed through x-ray and magna-flux-type analysis. A lot of places in the UK should be able to do that.
Then there is the porosity issue - whether after any chemical treatment the wheels will still be airtight. If a wheel should develop a leak, there is a place near Slough that evacuates the magnesium and then infuses a plastic sealant into the thousands of individual pores. They've been in business for over 30 years and work for some F1 teams that have mag. gearboxes that contain highly-pressurised oil. I used the place (whose name escapes me but I can find it if necessary) for a leaking wheel that had to maintain 50 psi and have had no problems in the two years since they did the work.
Then there is the porosity issue - whether after any chemical treatment the wheels will still be airtight. If a wheel should develop a leak, there is a place near Slough that evacuates the magnesium and then infuses a plastic sealant into the thousands of individual pores. They've been in business for over 30 years and work for some F1 teams that have mag. gearboxes that contain highly-pressurised oil. I used the place (whose name escapes me but I can find it if necessary) for a leaking wheel that had to maintain 50 psi and have had no problems in the two years since they did the work.
GreenV8S said:That appears to be a tyre-sealant maker. The place that I have in mind infuses porous metals with a liquid plastic which hardens and seals the pores.
Tthere is a place near Slough that evacuates the magnesium and then infuses a plastic sealant into the thousands of individual pores.
Ultraseal?
flemke said:
Tthere is a place near Slough that evacuates the magnesium and then infuses a plastic sealant into the thousands of individual pores.
Ultraseal?
Yes, these are the guys that do the vacuum impregnation.
I'd be wary of slinging magnesium wheels in an acid bath... gives me flashbacks to school chemistry lessons - magnesium is a pretty reactive grp2 metal 
Of course I'm aware it's an alloy and not pure magnesium metal - but since I don't know, I'd like to know what sort of percentage mix the usual car-application mag alloys are? I presume they're alloyed with aluminium? Maybe a bit of silicon? Anyone here got the info or a link to specs for these sorts of automotive materials?
Just curious, you see
Of course I'm aware it's an alloy and not pure magnesium metal - but since I don't know, I'd like to know what sort of percentage mix the usual car-application mag alloys are? I presume they're alloyed with aluminium? Maybe a bit of silicon? Anyone here got the info or a link to specs for these sorts of automotive materials?
Just curious, you see
Ok its an old post.. but just to help.. I refurb wheels, have done for a long time now, magnesium wheels are a complete bind.. and there's no easy answer, a lot of companys won't touch them and with good cause. magnesium as we all know is very unstable and oxidises very repidly when in contact with air/ water/ salt/ acids.. the process to redo them is not quite as straight forward as acid strip etch prime and powdercoat!!
firstly yes you have to be VERY wary of acid stripping, it has to de done, however the timing is critical.. stripping acid will not only etch magnesium badly, but will also soak into the metals pores, they have to be bathed and bathed and bathed and soaked in alkaline solution before the next stage!
bead blasting, this has to be done at a low pressure as magnesium is a soft and easily damaged metal, also the risk of blasting any residues deep into the porus structure of the wheel is an issue..
after the blasting stage the true extent of corrosion is VERY evident, particularly where wheel weights have been attached.. I have seen 50% + of the actual stock completely gone where the weights have been!!, the other prime damge area is where the brake disc sits, you tend to get 2 big grooves where the brake dust has been thrown out from the pads on either side of the disc, I'v seen this so bad before that its almost rotted the wheel into two pieces!!.. at this stage you have to decide if the wheel is even safe anymore..
next comes a process called out gassing.. most wheel restorers wont even know about this and wonder why when they paint the wheels big air bubbles appear.. magnesium creates gas.. deep in the pores.. when sealed in it will build up and pop up big air blisters.. the answer is to heat them, allow them to cool and paint them immediately!!.. this will 99% stop the problem..
corrosion removed and structural integrity ascertained you then etch prime, high build prime, and paint either with powdercoat (cheap and in my opinion not recomended for mag) or a good 2k base and clear..
job done.. problem is that even the slightest contamination, or chip or scuff will set the mag off again.. basically mags are an ongoing problem and to my best knowledge cannot ever be gauranteed to last problem free for years..
so there you are.. the (I think) definitive answer about mag wheels.. personally I hate doing them, I mainly do ferrari ones and maserati, chromadora's and campagnolo's, and frankly the results can be dissapointing, as even though structurally sound the end result invariably shows some level of deep pitting..
steve
grindnshine.co.uk
firstly yes you have to be VERY wary of acid stripping, it has to de done, however the timing is critical.. stripping acid will not only etch magnesium badly, but will also soak into the metals pores, they have to be bathed and bathed and bathed and soaked in alkaline solution before the next stage!
bead blasting, this has to be done at a low pressure as magnesium is a soft and easily damaged metal, also the risk of blasting any residues deep into the porus structure of the wheel is an issue..
after the blasting stage the true extent of corrosion is VERY evident, particularly where wheel weights have been attached.. I have seen 50% + of the actual stock completely gone where the weights have been!!, the other prime damge area is where the brake disc sits, you tend to get 2 big grooves where the brake dust has been thrown out from the pads on either side of the disc, I'v seen this so bad before that its almost rotted the wheel into two pieces!!.. at this stage you have to decide if the wheel is even safe anymore..
next comes a process called out gassing.. most wheel restorers wont even know about this and wonder why when they paint the wheels big air bubbles appear.. magnesium creates gas.. deep in the pores.. when sealed in it will build up and pop up big air blisters.. the answer is to heat them, allow them to cool and paint them immediately!!.. this will 99% stop the problem..
corrosion removed and structural integrity ascertained you then etch prime, high build prime, and paint either with powdercoat (cheap and in my opinion not recomended for mag) or a good 2k base and clear..
job done.. problem is that even the slightest contamination, or chip or scuff will set the mag off again.. basically mags are an ongoing problem and to my best knowledge cannot ever be gauranteed to last problem free for years..
so there you are.. the (I think) definitive answer about mag wheels.. personally I hate doing them, I mainly do ferrari ones and maserati, chromadora's and campagnolo's, and frankly the results can be dissapointing, as even though structurally sound the end result invariably shows some level of deep pitting..
steve
grindnshine.co.uk
Old mag wheels are quite often dangerous and it is why a lot of them are date stamped. They are known to become brittle over time. I had some old 67 JA Pearce jobbies and whilst looking for a spare, saw a set of 3 advertised. The chap tore the middle out of the first one!
Get them tested and even if they come back ok, I would treat them with the utmost respect. They are still likely to be brittle.
Get them beadblasted and see if you can get them chromated.
The chromate treatment is the best for magnesium and is bombproof. It's the old magnesium "gold" coating. You may have a problem getting it done, but it would be possible (but difficult) to do it in your shed.
I know mag wheels are beautiful, light and high performance, but if one goes on you, you may not kill just yourself.
Get them tested and even if they come back ok, I would treat them with the utmost respect. They are still likely to be brittle.
Get them beadblasted and see if you can get them chromated.
The chromate treatment is the best for magnesium and is bombproof. It's the old magnesium "gold" coating. You may have a problem getting it done, but it would be possible (but difficult) to do it in your shed.
I know mag wheels are beautiful, light and high performance, but if one goes on you, you may not kill just yourself.
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