Roger Zimmermann

Construction of a Continental Mark II model, scale 1:12

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Thanks John! I don't remember if I mention it before: this method is the one described by the late Gerald Wingrove in one of his books about scale models. I adapted it to my needs and what I have (had) sas material at disposal.

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 Roger, as always, I am so blown away by the detail, and quality of the work, and the good photography to show it. Thank you so much for sharing this with all of us here.

Keith

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Thanks Keith! Sometimes, by searching details, I'm coming across an interesting topic with bad pictures or good pictures but no explanation. I know that you most probably don't want to do a scale model, but if the pictures or text are too miserable, nobody will have a look at that.

February 22, 2010
Good result !


This morning, I removed the half white tires (or positive molds) from the resin, picture 1. All is good, no bubbles, no major issue!

In between, the odor in the flat went away, no war will be declared!

You may wonder why there is a brass ring into each half mold. As the specific weight from the white silicone is near from 1, but I don’t know the one from the polyester resin; I suppose it’s higher than one. To avoid that the half white tires are floating into the resin, I added some weight to keep them down.

February 27, 2010
Things are getting serious

All what I explained before were the necessary steps to fabricate tires. Now, as the hard molds are ready, it’s time to make the first attempt to get a tire. The half forms are put together and attached with tape to avoid that the silicone is escaping. I did an aperture at the top to pour the silicone, picture 2.

Honestly, I had doubts about the issue (one failure from time to time is keeping the ego at the right level, isn' it?): the silicone is too thick and is taking a too long time to flow down; the mix begins to set after about 1 hour. During the process to remove the air, I saw a lot of bubbles at the top wich would not burst. I’m not feeling well…

This morning : I attempted to separate the mold from the tire which went without difficulties, picture 3.

However, my fear was justified : a lot of silicone is missing at the top, picture 4. This tire cannot be used, but just for the fun, I put a white wall insert and assembled the tire on a wheel, picture 5, and I installed the wheel on the model, picture 6.

I believe that the tire has a too large outside diameter, about 1mm. Maybe after some mileage, this will be down !

After this first attempt, I had to revise the method to get a good tire.

At first I’m pouring the material into both half molds, picture 7.

After about 2 hours, the silicone is almost set, but not quite. At this moment, I’m assembling both molds and squeezing the excess silicone with a lot of pressure. Some weight on the assembly prevents the upper part to lift and draw air, picture 8.

Tomorrow I will have the answer!

240 Moules.JPG

241 Première tentative.JPG

242 Démoulage pneu.JPG

243 Gros problème.JPG

244 Pneu et roue.JPG

245 Pneu sur auto.JPG

246 Seconde tentative.JPG

247 Après assemblage du moule.JPG

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February 28, 2010
Success!


The tire was taken out of the mold this morning; in fact, it was what I did first, long before breakfast! As the result is perfect, I can continue with that method. There are only 4 more to do !

 

Sometimes, I have trouble with chemical products. The white walls are a bit too thick; they are not flush to the black surface. No problem, I just mix again some white stuff and put the material into the mold. As I prepared too much, I put the remaining silicone into the freezer; at -18°C, it should not set.

Well, it did not go that way: after one week, the “new” white wall is still sticky and the one which was into the freezer is set!
As this new tentative is successful, I’m continuing the process. I did a picture when both halves were into the desiccator and began to evacuate the air. It’s impressive to see the surface of the silicone rubber when a significant vacuum is applied to the mix: one could think that it’s boiling!

After 20 minutes at – 0.5 bar, the surface is getting calm and further pumping as no more effect.

The cup into the desiccator has some more silicone to compensate the diminishing volume when the air is out. The trick is to catch the right moment to put both halves together.

 

In retrospect, I suppose that the proportion silicone/catalyst was not right. I did another one which is now installed into the good tire.

248 Aération.JPG

249 Avanti tire.JPG

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Thanks John!

 

March 04, 2010
The birth of a tire


After some failures, I believe now that I’m mastering the process, I did pictures during the birth of the tires number 4 and 5.

One tire begins its life with 35 grams of transparent silicone, plus less than 1 gram of black paste and 3.5 grams of catalyst. The whole is stirred very well, creating a lot of air bubbles. Without waiting time, the mix is poured into both molds, picture 1.

The embedded air bubbles are obvious on the picture 2.

When done, the air must be evacuated. Yesterday, what vas unavoidable did happen: the shaft pulling the piston from the plastic air pump broke. I could continue the vacuum process with a device using water; it was the method used many moons ago with the Toronado tires. I remember that this method has one or two inconveniences: it’s using a lot of water for a long period and, when the operation is stopped, the water can enter into the desiccator, which was the case yesterday, wetting the silicone! I took away so much water as possible with paper and continued the process.

After about 2 hours, the mix is no more liquid, more like a paste. At that moment, (time span : 5 to 10 minutes) both halves are put together and loaded with a maximum of weight to squeezed the excess silicone out of the molds, picture 3.
 

When the product is set, (8 hours minimum), it’s the dime to the discovery ! First, remove the excess around the molds, picture 4.

Then a small screw driver is inserted into a notch at the junction of both halves and use force to begin the separation of both halves, picture 5.

With more strength, picture 6.

Then, continue with the hands, picture 7.

 

When one half is released, you can see that, picture 8.

 

254 Remplir le moule.JPG

255 Remplir le moule1.JPG

256 Under pressure.JPG

257 ça a débordé.JPG

258 Séparation.JPG

259 Séparation1.JPG

260 Séparation2.JPG

261 Upper form gone.JPG

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My file was too large, this is the end of the tire's birth.

 

The first examination is positive. The thin film at the junction must be removed with a cutter, picture 9.

 

Then, the removal of the tire can continue, picture 10.

 

By pulling gently at the outside diameter, the tire is coming out, picture 11.

It’s now out and an examination is needed, picture 12.

It’s perfect! I still have to remove the center, insert the white wall and install it on the rim, picture 13.

262 Removing excess.JPG

263 Peeling out.JPG

264 Almost out.JPG

265 Out!.JPG

266 Perfect tire.JPG

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Wow Roger, amazing work.

 

15 hours ago, Paulie9fingers said:

Roger how easily do the tires fit onto the wheels, do you use an adhesive or are they just pressure fit ?

 

 

. . . . and I thought you used tiny tyre levers!?!:)

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Thanks Paulie!

 

The saga with the tires is the end of the Avanti story. I'm adding some pictures from the finished model.

This thread is not yet finished: since some months, I'm busy with a 1:12 1932 Cadillac V-16 engine and frame. I will publish here what I already did with that new project.

DSC01891.JPG

DSC01931.JPG

DSC02002.JPG

DSC02017.JPG

DSC02004.JPG

DSC02015.JPG

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In July 2019, I wrote this text in the Cadillac LaSalle forum. I did some changes here because some remarks are not relevant:

 

When I was finishing the Mark II, I was thinking that it would be the last model. Fortunately, I'm still able to do something, but I will not tackle a 10 years project. Slowly came the idea to do something with Cadillac. One, if not the most prestigious model, was the V16.
What I intend to do is a 1:12 scale rolling frame with the engine/transmission/suspension and steering. I would limit the MY from 1930 to 1933. 1934 have an independent front suspension; I have enough models with that type of front axle.
My issue is to find enough documents/technical drawings and/or pictures to be able to conduct this project. Of course, dimensions are a must and I hope that one or more viewers have informations or could tell me who has some. If costs are involved, there is not a problem. Once, there was a V16 in Switzerland; I will have to research if the car is still in this country but most probably I will not be able to take from it all what I will need.
Usually, shop manuals from that time have nice drawings from the mechanical features; this would be something to consider.
Who will cooperate? Anyway, thanks for the help!

 

I got some responses and suggestions. I got in touch with various people; a man from the Netherland promised me many pictures from a 1933 frame and engine he just restored. Slowly the idea came that I could go to that man and measure the frame. He told me that the engine and frame were already gone in North Germany at about 100 miles from his shop. If I wanted to et at the frame, I had to hurry because 2 or 3 weeks after, the body will be mated to the frame. As it was an unique opportunity to have that frame alone, I jumped to it. The car's owner and the body shop in Germany agreed that I would come and take as many pictures/dimensions.

In between, I bought the repro shop manual from 1930-31, the one for 1932-33 and a parts book as I still was not sure which year I would choose. Due to the situation with the available frame, I choose to do a 1932 unit.

Early August, Christine and me drove 530 miles one way to measure and take pictures from that 1933 V-16 frame and engine, just before the body was put on the frame. As usual when so many dimensions can be have, I forgot some essential ones, but I will survive. In retrospect, it was a fun adventure! We were one and half day at the body shop and we stayed a bit longer to see the countryside. We came back on Sunday because we had some commitment the next week.


I began indeed with the wheels. On the 3 other models I did, there were just steel wheels reproduced in brass and, for the Toronado, with aluminum. This is quite different for this model: wire wheels. They are much more complex than usual wheels; this will be an adventure in itself!
Due to other things I have now, I'm slow to begin the construction. I began the first part on September 8, a front hub, which is now in fabrication. The attached picture is showing it, but the part is not yet finished.

1 front hub.JPG

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I want to get into that Avanti and drive it away. Roger, you are amazingly talented and I am looking forward to following your Cadillac adventure.

 

Alex D.

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Roger, as always, looking forward to  seeing your work. The V16 should  be a wonderful project. Thanks, John

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Thanks for your comments; it's a motivation to continue to relate this new adventure!

Alex, you could go into the Avanti if I had a method to shrink you; unfortunately, you could not go very far as the motor is a dummy one!

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16 minutes ago, Roger Zimmermann said:

 

Alex, you could go into the Avanti if I had a method to shrink you; unfortunately, you could not go very far as the motor is a dummy one!

 

Maybe you can make a Mini Me with the same process you molded the tires. I would be happy just coasting downhill, assuming that the brakes work.

 

Alex D.

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Well, Alex, let me continue the Cadillac project! Oh, by the way, only the emergency brake is functioning! The steering too, but with a lot of free play...

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Roger.

1/8th wire wheel which I made for a hot rod model. If I can do this, you should be able to do it will ease. Spokes were 12 thousands of an inch. Had to make a rotary milling table to do the rim and hub holes. Used Gerald Wingraves book as a reference and information on how to do it, but did modify his method to my way of doing things.

 

Gerry

 

1115630738_PA210050640x480(2)(2015_11_1311_07_31UTC).JPG.7db11d9c2922251470e6a882415d4052.JPG

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Roger

There is a fellow on eBay (brassandgas) selling chassis, suspension and other parts for the 32 cadillac V12. Most should be the same for the 16. The pictures are not in the best quality but still could be used as a reference for your model. An example is item no. 123954208426 brake pivot cams. I hope this may help with your v16 project.

 

Alex

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Thanks Alex for searching parts! I save the pictures from most items. I have pictures from those items as assembled on the frame; it's always interesting to have them also as sole parts.

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