OLD but NEW magnesium BRM

[banditina]

hi guyz..
In the past.. brm magnesium, when they were produced, came out from the factory painted in glossy black or matte black?......

[banditina]

P.s. if you can.. post detailed photoes... old magazine ecc....

[dyno don]

 Original Speedwell BRM's were manufactured non gloss and the closest paint that I have used to refinish with is satin/semi flat black.

[banditina]

bababababababaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa..... uhhhhhhhhhhhhhhhhhhhhhhhhh!!!
HI dear Dyno..
the finish of the merger was rough,  but paint used are you sure not glossy?

[.]

Original Speedwell BRM's were manufactured non gloss and the closest paint that I have used to refinish with is satin/semi flat black.

Dyno is correct !

[speedwell]

 
last one is NOS one

[Troy Palmer]

I would agree the accepted finish is Semi-Gloss.  I would guess they used a cheap Alkyd or worse yet a Water Reducable Alkyd when painted originally.  These type of finishes will lose gloss in 3 to 6 months leaving the finish satin to semi-gloss looking.  If a heavy exterior UV load (left outside for extended periods) they will appear almost flat.

Troy Palmer

[nlvtinman]

The original black finish on a BRM was a DOW chemical conversion coating process. DOW numbered their different processes depending on application, and I have unfortunately forgotten which it was.  I have a belief that it is DOW-9. 
BRM added this corrosion protective coating to the wheels prior to machining.

A modern way to acheive the desired paint sheen, outside of having the wheels re-Dow'ed, I reccomend a professional paint product made by SEM.   Trim Black produces a great semi gloss finish and it is made to be applied to metal surfaces.
I use it at work all the time.
In the USA, it's generally available through an automotive paint supplier, and it does come in aerosol cans.

[hotrodsurplus]

The original black finish on a BRM was a DOW chemical conversion coating process.

I've never held a real NOS BRM so I cannot make a definitive statement. However, I have held parts coated with the Dow process that produces a black finish and I cannot imagine that any manufacturer would use that as a finish coating. It is not very rich and it wears very quickly if left bare. It wears away rapidly at the surface of a sand-cast part.

I can almost guarantee that BRM treated its wheels with the Dow 7 passivation coating. Older magnesium alloys in particular have comparatively large amounts of iron and nickel and will cause a galvanic reaction with the magnesium itself. But the passivation coating isolates the alloy from oxygen. The coating itself is not very stable though and will wear off very quickly if not top coated. The Dow 7 slows that process down (it will never stop it). Dow 7 is a dichromate coating that is applied as a base for paint. Without it magnesium will oxidize rapidly and slough off the paint.

Dow 9 is very dark green to almost black and remains very matte in appearance. It is not very durable if left unprotected and will wear away simply by touching it frequently.

If you intend to paint magnesium it is a good idea to passivate the surface as the manufacturers do. That will make the paint surface that much more stable and durable.

I am aware of two commercially available conversion coatings. One is made by Henkel and is referred to as an alodine coating. Alodine coatings are very common in aluminum finishing. This one is specific to magnesium. 
 
http://tinyurl.com/7uytnqs

Another company makes a kit that it refers to as a genuine Dow 7. It is a two-step immersion process

http://tinyurl.com/8642t7o

Neither are inexpensive but they cost far less than paying a shop to do it--if you can even find one to work with you. Most shops that do Dow work usually work exclusively with aerospace manufacturers and consider our work too troublesome.

Apply the paint of your choice directly over either of these conversion coatings. I have also used SEM Trim Black. It offers a beautiful sheen--neither too glossy or matte.

[nlvtinman]

Hotrodsurplus

You make me aware that you know a lot more to the DOW process than I do. I can't say I am sure now. I do know that in a restoration on a Porsche 917 I was painter of, we obtained some NOS wheels and their appearance was strikingly similar to the finish found on my BRM's. Those I know were not painted.
Thanks for the linking info on DOW
Steve

The original black finish on a BRM was a DOW chemical conversion coating process.

I've never held a real NOS BRM so I cannot make a definitive statement. However, I have held parts coated with the Dow process that produces a black finish and I cannot imagine that any manufacturer would use that as a finish coating. It is not very rich and it wears very quickly if left bare. It wears away rapidly at the surface of a sand-cast part.

I can almost guarantee that BRM treated its wheels with the Dow 7 passivation coating. Older magnesium alloys in particular have comparatively large amounts of iron and nickel and will cause a galvanic reaction with the magnesium itself. But the passivation coating isolates the alloy from oxygen. The coating itself is not very stable though and will wear off very quickly if not top coated. The Dow 7 slows that process down (it will never stop it). Dow 7 is a dichromate coating that is applied as a base for paint. Without it magnesium will oxidize rapidly and slough off the paint.

Dow 9 is very dark green to almost black and remains very matte in appearance. It is not very durable if left unprotected and will wear away simply by touching it frequently.

If you intend to paint magnesium it is a good idea to passivate the surface as the manufacturers do. That will make the paint surface that much more stable and durable.

I am aware of two commercially available conversion coatings. One is made by Henkel and is referred to as an alodine coating. Alodine coatings are very common in aluminum finishing. This one is specific to magnesium. 
 
http://tinyurl.com/7uytnqs

Another company makes a kit that it refers to as a genuine Dow 7. It is a two-step immersion process

http://tinyurl.com/8642t7o

Neither are inexpensive but they cost far less than paying a shop to do it--if you can even find one to work with you. Most shops that do Dow work usually work exclusively with aerospace manufacturers and consider our work too troublesome.

Apply the paint of your choice directly over either of these conversion coatings. I have also used SEM Trim Black. It offers a beautiful sheen--neither too glossy or matte.

[hotrodsurplus]

I can't say I am sure now. I do know that in a restoration on a Porsche 917 I was painter of, we obtained some NOS wheels and their appearance was strikingly similar to the finish found on my BRM's. Those I know were not painted.
Thanks for the linking info on DOW
Steve

You are welcome, Steve. I admit that I don't know exactly what BRM did but as an owner of magnesium wheels I am somewhat familiar with what mag does over time. I am forwarding the information that I have gotten from people who restore Halibrand parts. Ted Halibrand used magnesium exclusively and many of his parts were treated with Dow 7. I pay attention to them as I have very early Halibrand wheels for my roadster and I am going to have them Dow 7 treated. 

The 917 wheels may have had a Dow 9 coating. If they are forged then they may take the coating more consistently than a casting will. BRM may have used Dow 9 but I am not inclined to think that it did.

Also odd things happen to raw magnesium over the years. If you keep it coated with wax it will turn a beautiful charcoal gray or even black much like Dow 9. If someone waxed the wheels on this Scarab or sprayed them with oil they would turn almost perfectly black. 

[Straight Time]

Thats great information.


Will these products also work on the Porsche Mahle Gas Burner mag wheels too ?

[hotrodsurplus]

Thats great information.

Will these products also work on the Porsche Mahle Gas Burner mag wheels too ?

As far as I know they will work on the magnesium alloys common to automotive use. Note that one vendor uses a Porsche case as an example of the surface finish that the process will yield. That process is the reason that VW engine cases are gold when new. Just understand that the finish if left alone will wear away rather quickly. VW and Porsche cases are a good example of that: they turn dull gray rather quickly.

But if painted fully as it was on the original Mahle wheel the magnesium would remain stable for many years or until the paint chipped. Also note that any breach of the coating (the ribs and lip that people expose on the Mahle and BRM wheels) will introduce oxygen to the base metal and cause the metal to oxidize from the edge inward. It is for that reason that Mahle, Campagnolo, and Cromodora coat their wheels entirely with paint.

[banditina]

thanks guys...really all the best!
 but...
my question is less technical...
i would like to know only if the NEW magnesium BRM appeared to the eye black gloss or matt...

..... SEMI-GLOSS???

[speedwell]

banditina , the new brm aren't magnesium they're aluminium

[speedwell]

he're the picture of the flat 4 new brm similar to the real one but in aluminium

[hotrodsurplus]

thanks guys...really all the best!
 but...
my question is less technical...
i would like to know only if the NEW magnesium BRM appeared to the eye black gloss or matt...

..... SEMI-GLOSS???

Oops!   Information overload! Sorry.

I would go with Don's recommendations to use a semi-gloss finish. He has done detailing stories for decades and I know he has worked on many of those wheels when they were almost new.

I have a new favorite semi-gloss finish. It is Rust-Oleum Painter's Touch Ultra Cover Semi-Gloss black. I know Rust-Oleum has a European presence so you may want to look for that product. It has the perfect sheen--neither too shiny or too matte. It looks like baked enamel from the '60s and '70s. It dries very slowly though.

[hotrodsurplus]

banditina , the new brm aren't magnesium they're aluminium

I may be wrong but I believe that he means to ask what the finish was like when the original BRM wheels were new in the 1960s. Is this correct Banditina?

[Flow]

banditina , the new brm aren't magnesium they're aluminium

I may be wrong but I believe that he means to ask what the finish was like when the original BRM wheels were new in the 1960s. Is this correct Banditina?

That's what I believe too 

[banditina]

hi Fabian...yes sure... i know..   
when I say new, i say just out of factory, not MWS or flat4 .. , for me means not NOS (that storage may changed paint color, over time) but when i say "new" i I mean in 1964 

[banditina]

banditina , the new brm aren't magnesium they're aluminium

I may be wrong but I believe that he means to ask what the finish was like when the original BRM wheels were new in the 1960s. Is this correct Banditina?

yes....




P.S. newBRMflat4 uses black gloss paint finish with varnish and  this is not correct...

[Fritter]

Wow, some great info here!

For a cheap, good option, I used Duplicolor semigloss black trim paint on the black part of the Fuchs on my '68 911 and it has held up very well over the past 4 years.  Has a great sheen to it.

I also used Duplicolor silver metallic wheel paint on the steelies on my '64 Bug and was very happy with that.

The key is in the prep, though.  The painting part is easy.