About Lipowiz alloy and little details

[watson2]

Hi guys. I hope this topic can help.
When I discovered the reason for which my clock was not working I began to look for an alloy with a low melting point.
The built in fuse that MB has used is welded with an alloy melting at 90°C . In some watches of other models MB put inside the clock a little cylinder of that material.
It is not so in the W113.

So I found in Genoa a foundry that produces this alloy , named Lipowiz Alloy, with a melting point at 75°C. I used it for the clock and....

I had the left handle with a little problem : when I extracted the key the cylinder followed the key coming out of its seat for some mm. (photo nr.1)
A comparison between the two handles of the car put in evidence that a little detail was missing ( Photo nr.2 )
Where could I find this little piece sold separately from the handle    ? Well, I decided to do it by myself.

So I took an imprint of the little piece with a silicone material.
Then  just boiling a cup of water and putting a little quantity of the Lipowiz alloy into the cup I obtained a liquid metal ready for use.
So I quicly pured the metal into the imprint and I waited just a few seconds until the water has cooled and the metal has returned  solid.

I repeated the procedure to obtain a little number of pieces. In this way I could choose the best piece produced and in order to have also  some pieces of reserve (Photo nr.3)
So the 2 handles were both working correctly.

Even if in Italy we have a nice sun in the summer , I hope that the temperature of my door doesn't exceed 70°C   

Hope this helps for little details difficult to be found.
 

[tel76]

Flavio,
It does beg the question, why go to all that trouble when you could have made that piece out of a large metal washer?

[stickandrudderman]

Why go to all that trouble?
Because some people get enjoyment out of manufacturing something from scratch and I applaud Flavio for the result.
I would like to see more details pictures and description of the process Flavio.

[tel76]

He could have made it from steel, at least that will not melt in the summer heat.

[watson2]

Flavio,
It does beg the question, why go to all that trouble when you could have made that piece out of a large metal washer?

Well Eric, I had already told somewhere that this type of work for me represents real amusement. I don't see this as a trouble.
Coming back to this piece ,as you well know, a washer could make nothing else than avoid that the cylinder came out. But the main job of that piece makes is to lock and unlock the car through the rotation of the key. This function is  performed by that 'tooth' that you can see in the pic, absent in a simple washer. It was necessary , if you wanted to use a washer, to weld a little tooth to the washer.

More : all the details contained in that piece, as circular steps and internal joints, are not contained in a washer.

I had previous experience with casting and I found that it's not so easy to find a foundry that takes in charge a job of this type. They see it as a waste of time.

And, at last, it's not so easy that the internal part of a door can reach 75 °C (167° F), even in the desert of Australian NT in december.  

    

[watson2]

Why go to all that trouble?
Because some people get enjoyment out of manufacturing something from scratch and I applaud Flavio for the result.
I would like to see more details pictures and description of the process Flavio.

Thank you, Stick.
The thing is so simple that you have already seen everything. If you look around on Google for a 'silicone for reproduction' or aluminium casting you will find a lot of products.
Into this, in the flowable state, you will put the piece to be reproducted and that's all. When you obtain the first imprint you have two choices:
1- directly reproduce the piece with an alloy like Lipowiz , just pouring the material into the imprint. After this you have finished.

2- obtain a model in resin , a sublimable one, through which you can make castings with a method that literaly is called 'lost wax' . In italian it's called 'cera persa' and the resin has the same property of the wax. It's sublimable and in the oven the empty space resulting from the sublimation will be filled with metal.

Here you can see 1 kg of Lipowiz alloy . The bigger bullion is about 10 cm long ( about 4 ") .
and here is a video where you can appreciate the result of simple  boiling water on this alloy.

http://youtu.be/qhdk-3wR1sE

The other pictures show the other way to make repros . In this case the difficulty is to find someone that acceptes to make the cast.

On the beginning  on my hard top I had only the poor hardware that you see on the end of the third image.

[Raymond]

Flavio,
I hope you had some fun doing it.  That is one of the great joys of owning and tinkering with one special car.  I'd love to know more about the results.  How about coming back to us this fall and letting us know how the cast pieces faired over the summer?  

[watson2]

Flavio,
I hope you had some fun doing it.  That is one of the great joys of owning and tinkering with one special car.  I'd love to know more about the results.  How about coming back to us this fall and letting us know how the cast pieces faired over the summer?  

    OK, Ray . It's already autumn ; I'm already back because that piece has already spent last summer on the car. Before using that material I exposed it to the full sun for hours in june 2014. Nothing happened.
Everything was ok. 75°C or 167°F are not so easy to be reached.

About the joy , yes , it's a great joy and a real and satisfactory amusement for me. I adore working with hands, discover new things. Although I'm a doctor,  mechanics is my passion.


P.S. The only piece made with Lipowiz alloy was the one of the door handle.
The hard top handles were made two with the fusion of full aluminium and the other two with full Constellium (a very strong aluminium alloy)

[watson2]

Last note : the extraordinary thing of the Lipowitz alloy is that it's composed by elements that melt between 200 °C and 330 °C. But when these elements are put together in proper proportions you obtain a material that is melting at about 75°C . The elements are Bismuth 50% , Lead 26,7% , Cadmium 10%, Tin 13,3%.

So I discovered that the Lipowiz one is not properly an alloy....  it's a solid solution !!! Wow !    Here is explained the secret.
If you want to see something more you can read this page on Wiki.

http://en.wikipedia.org/wiki/Solid_solution

 

[stickandrudderman]

Fantastic!
I bought some silicone about two years ago with a view to casting some parts but have never found the time to pursue it.
I do make thing from scratch in my spare time for my aeroplane but these are usually from wood, carbon fibre or fibre glass. I must try to find the time to try some casting.

[watson2]

Wow , Stick  !!! Are you a pilot?  I have a PPL since 1995 and I use the planes of the club: a five seater TB10 (an iron), TB9 and PA28 in various models. Which is your one, tell us.

(excuse this O.T.)

[stickandrudderman]

Stelio Frati's finest!

[watson2]

His planes were all fantastic , really elegant , with a perfect handling and fast.  Frati was a genius....
But .....  may be you have a SF260 .... ?  The mythical 260 ?

[mnahon]

Flavio, you'll probably appreciate this thread and the article there.

http://www.sl113.org/forums/index.php?topic=19251.0

[watson2]

Thank you, Mnahon and great history, Colin. I had some suspicion seeing the nicname.... But this ....
And how many flying people here ! 

[stickandrudderman]

https://www.dropbox.com/s/knefa1y7h16t1e6/oh%20yes.JPG?dl=0

[Mike K]

Thank you, Mnahon and great history, Colin. I had some suspicion seeing the nicname.... But this ....
And how many flying people here !  

Helicopter pilot- 26 years, mainly on Bell205 (Huey), Bell 206 & Bell 407 I used to fly about 150-200 hours per year all over Southern and Central Africa. Since moving to Europe for half the year, I no longer do as much flying.  I'm letting my licence lapse at the end of this year. I'm now spending more time in my Pagoda!

Any other pilots out there?

Best,
Mike