Powdercoating Magnesium Dangerous???

[Jandrews]

Hello,

I am looking to get a few pieces of my disassembled engine powdercoated prior to re-assembly. At this point I am considering the fan, fan housing, chain housings and covers, valvecovers, blower ducts, and engine sheet metal. (By the way, the motor is a '73 2.7 RS spec).

I contacted (upon referral), a local powdercoater today to get some preliminary preparation questions answered. When I mentioned magnesium, he sounded very hesitant and mentioned that another local powdercoater had burned his shop to the ground doing some magnesium work. The shop owner was very courteous and professional, and said he would like to work with me. He described many of the issues with outgassing and temperature issues, and also mentioned the issues with water being an accelerant. He know about the gases created and seemed very knowledgeable in general. He did say that I was limited to one color per piece.

As I mentioned, he said he would work with me but we was not very excited about it. I have searched the archives here and read much of the background, but this is the first time that I have actually heard of scaring the powdercoater.

Is this valid, and has anyone else had this kind of experience?

1) How much can I expect to pay for powdercoating one of the above pieces? (I hope he isn't adding some additional insurance protection for his shop to my invoice!)

2) What kind of preparation should I do myself to minimize additional cost?

3) Is it true that you are limited to one color per piece?


Thanks as always....



JA

[T Bird]

Five years ago, when I decided to refinish my fan and housing, I contacted the outfit that has done powdercoating for me on other occasions. (Maryland Metal Refinishers, Eldersberg MD). This shop advised that magnesium could not be powder coated. They gave no explanation, and because they sounded so emphatic, I did not pursue with them the basis for their statement.

Generally, powder coaters have large blast cabinets and can strip metal parts down to their base in just a few minutes. I'd let the powder coater do the work here. Powder coating is not very expensive. For instance, I had all the engine tinware and the rear motor mount console and brackets (11 pieces) sand blasted and powder coated a satin black for $70. Due to the nature of the process, I would say that one color per piece is all you can get.

Good luck.

[TurboRuf]

I had some engine parts powder coated about two years ago. The shop I took them to had no problem powder coating magnesium. The coating has held up extremely well over the past two year, not a single crack or chip.

[jwill911]

I also had my fan and shroud powder coated ~ a year ago. Still looks good. The guy didn't say anything about dangerous, nor had I heard that before.

I paid ~$40 for the parts to be bead blasted, then decided to have them powder coated, which cost $60, they would have done the bead blast and powder coat for less than the $100 total.

Here's a so so pic of the finished job.

[makaio]

Here's the thing with magnesium that scares people: it is a combustible metal. Which once on fire, it can self sustain, untill it burns completly up, or is extinguished with special agents. When you add water to a magnesium fire, the oxygen in the water, contributes to the already burning fire, and adds to the intensity.

I'm fishing here, but what more than likely happened with the shop that went up in flames was, some magnesium shavings caught fire ( which is very easy, since the surface to volume ration is so high) and that started a chain reaction. Some employe tried to douse the fire with the wrong extinguisher, fueled the fire, and it was off to the races.

[Jim T]

I had my fan and housing (and other parts) powdercoated, no problem. As I recall, it cost $25 for both the fan and the housing. I had it done here in So. Cal. by the company that does most of the powdercoating for GT Bicycles, and other big companies.

It looks as perfect today as the day it was done, over 4 years ago.

[Chuck Moreland]

I had a powder coater refuse to do the work when he found out it was mag. Not the fire thing, he said magnesium doesn't hold up to the oven. Claims it becomes brittle.

He said his insurance wouldn't cover him for any magnesium work.

[dtw]

Is there such a thing as clear powder-coating? I would like to polish some engine components and have them sealed somehow- has anyone had any luck preserving a polished mag component?

[jwill911]

Yea. I think so. My shroud is done in what the guy called chrome, silver with a clear coat.

[Superman]

I'm not sure there's clear, but there are some beautiful silver and metallic powder coatings. Yes, magnesium burns very beutifully and brightly. Very much so! But what temp is required to get it started? More than a power coating oven, I think.

I had my valve covers (4), Chain housings (2), Chain housing covers (2) fan (1) and fan housing (1) blasted and powder coated for $100. He baked the magnesium parts in the oven for a few days first, to outgas it.

Once color per piece, I imagine is the limit, based on the process (cover the part with powdered polyester and melt it on in an oven). My fan housing is black, the rest are RED. People stare.

[Targa Dude]

Hello, I too have had all my engine parts powder coated..
All Sheet metal, Engine cross mounting bar, Pulley housing: Black
11 Blade Fan and upper Valve covers, Strut tower Bar: Red
Fan housing, Air pump bracket, Lower valve covers: Clear
Cost for all my parts Listed plus a few more Misc. pieces and 3 colors $150.00

Oven temp for Powder 350 Deg.F - 400 Deg F for 10 minutes

Magnesium Autoignite Temp, 1200 Deg. F
Optimum Magnesium working temp, 350 Deg F - 500 Deg F.
Cases are 80% Magnesium, 9% Aluminum, .13% Magnese, < 1%
Siver.


Jorge (Targa Dude)

[ischmitz]

Does anyone know a powder coating place close to the Santa Barbara or Ventura area?

I need the engine sheet metal and the engine cross member sand-blasted and powdercoated.

Ingo

[SK]

I just had my fan and housing powder coated. I asked the shop (which only does custom cars and bikes) if they were concerned about the magnesium. They said no, because many parts on these custom bikes are magnesium alloy, and they do it all of the time. Total cost was $90.

[Doug Zielke]

Originally posted by SK
I asked the shop (which only does custom cars and bikes) if they were concerned about the magnesium. They said no......

A good thing to remember.

When the powdercoat questions come up here, I always recommended using m/c and hot rod guys. If the shop of your choice is doing patio furniture......keep looking!

[Targa Dude]

Sk.. That really looks nice....Very Clean and it presents itself well..
Good choice of color combinations..


Jorrge (Targa Dude)

[scottb]

I've heard you have to trim the fan just slightly when you powdercoat. True? If so, how did those of you who powdercoated your fans and housings trim the fans? Thanks!

[SK]

Thanks Darga Dude.

Scottb, I was also concerned about the fan tips contacting the housing. The powder coat shop told me that it only added 2 mils. After looking at my feeler gauge to make my brain comprehend, I quit worrying....In the end, everything cleared just fine.

[Jim T]

Originally posted by scottb
I've heard you have to trim the fan just slightly when you powdercoat. True? If so, how did those of you who powdercoated your fans and housings trim the fans? Thanks!

No! If it doesn't clear, 2 minutes with some sandpaper will clean the powdercoating from the ends of the fan. They are such narrow edges, it comes right off.

[Joe Bob]

Typical powder ovens operate at 350-400F.....

Magnesium oxide Mg(II)O the only form of Mg that exists at high
temperature has a melting point of 2800 deg Centigrade (Celsius) or 5070
(+/-) deg Fahrenheit. But this seldom happens in a well formulated glaze
since other ingredients influence the melting point, and bring it down to
the usual highfire range (22-2400 F, 12-1300 C).
In a glaze, the element Manganese undergoes chemical change in a
more complex manner. Potters generally use either Manganese Dioxide
Mn(IV)O2 or Manganese Carbonate, Mn(II)CO3. The MnO2 switches to
Mn(III)2O3 at 535 C 1000 F... this compound sometimes is called Manganese
Sesquioxide. Later, at 1080 C 1980 F, the Mn2O3 changes to the monoxide
(see below).
The Carbonate undergoes a change at 1000 C 1800 F and becomes
Mn(II)O or manganese monoxide, a compound that by itself would melt at
1650 C 3000 F but since it is with other glaze materials it will
participate in the general fusion of the glaze at a lower temperature.

(Data from Condensed Chemical Dictionary and Handbook of Chemistry
& Physics).

[scottb]

For those of you that have had the strap holding the housing powdercoated, how big of a job is it to get the strap off?