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


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December 12, 2009
As slick tires are not recommended for passenger cars, I have to add some thread. As I could  recover enough bands from the Toronado master tire, I began to soft solder the bands one after the other on the piece of brass. The first one is soldered entirely ; the second one is at about .6mm from the first one. To have a constant distance between both and to help maintaining the band on the master tire, I’m adding pins at various places because I cannot held the assembly with hand during soldering.
About 5 minutes are needed to heat the brass with the soldering iron; after that heating time, the solder is flowing at both parts.

Once all is soldered, the excess tin must be removed.
Manufacturer’s name and dimension must be added to finish that master tire.

 

December 14, 2009
It seems that Gerald Wingrove gave me the inspiration decades ago to add the inscriptions on the master tire with first praying some surfacer, writing with a pen the name or dimension and scratching the unneeded paint. It’s not an easy task, but it can be done.

With tools from a carver, it would have been possible to cut each letter and attach it to the tire. With a CAD machine or a 3-D printer, the tires were already done!

207 Pose du profil.JPG

208 Profil terminé.JPG

209 Lettrage.JPG

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December 19, 2009
The primary reason to refresh the model was the wheelcovers and that will be almost the last task! One of the reasons why they are coming that late is because I was unsure how to do them. Some explanations are needed, but with a view from a real wheelcover.

The 5 parts which are dull are slightly in recess compared to the chromed part. I could have cut some silver tape and glue them on the disc but they would be higher than the disc! It was a solution which did not please me. To stamp the wheelcover with the recess was not possible with the tooling at my disposal. Therefore, I designed the part in two pieces: first a cover less the dull parts and a second cover soft welded behind. The recessed parts can be then painted silver.

I’m doing first the dies for the first part which implies a lot of work with a hand held tool as both parts must be well adjusted.

A first part is shown with the tools. The large tube is needed to guide both dies. The part is obtained by pressing a thin piece of brass between both dies.

The excess material must be removed and the 5 « holes » must be done.
 

Wheelcover.JPG

210 fabrication chapeaux.JPG

211 première empreinte.JPG

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January 07, 2010

The five basis wheel covers are ready to be reworked. The part in the middle is a prototype; its outside diameter is too small ; he will not be used but it was a good part as an exercise for the apertures.

 

January 12, 2010
 

All wheel covers are now ready. All five parts are not really identical: the holes have been done with various files, therefore variations are not avoidable. The small part on the second picture is a male shape of the holes and was a good help to have them more or less identical. The distance between the apertures is not absolutely the same on all pieces; there are differences between 0.1 and 0.3mm.

I spend about 1 hour for each aperture…
 

217 Wheelcovers.JPG

218 Five wheel covers.JPG

Edited by Roger Zimmermann (see edit history)
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January 13, 2010

The « under wheel covers » were easier to do, even if the thinner material (0.2mm) gave more trouble that the brass used for the wheel covers (0.3mm).

A completed wheel cover is on the first picture; it is attached on the wheel with a system which came to me during the night.
The system is shown on the remaining parts: these parts have the same shape as the main wheel cover because they were done with the same tools. I flattened the outside surface at the end of the apertures; this way, the wheel cover with stay on the wheel. Sure, this system will damage the paint, but real wheel covers do the same!
The apertures have a specific usage: I will soft solder the parts to the wheel covers through them.
Now, I just have to polish the parts, let sand blast the recesses (I came away with silver painting) and let chrome the wheel covers.

 

January 19, 2010


The wheel covers are now polished and almost ready to be chromed.  Almost ? Why ? Well, I have to cover with masking tape the surface which will be shiny. Once the task done, the plating company will media blast the surface which will be dull. Once the masking paper away, the tree with the wheel covers will go into the various bathes. The copper wires have been soldered before the masking paper was set on the parts to avoid that the glue is burning.
 

219 Back side.JPG

220 Back side welded.JPG

221 polished covers.JPG

Edited by Roger Zimmermann (see edit history)
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January 28, 2010
Manufacturing the tires

Now, I have all the material needed for the tires. The silicone which will be used for the molds had a successful test: strong and does not stick to the brass.

I got also the hand pump for the vacuum; this will be needed to eliminate the bubbles crated by stirring the silicone with the hardener. This will be excellent for the hand’s muscles !

Now I’m doing a job which is necessary. The brown mass is paraffin. For what this could be used ?
 

223 Moule en cire.JPG

224 Moule en cire.JPG

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January 28, 2010
The answer

 

Tires could be entirely black, but at that time, it was unusual, even if white walls cost extra. The material which will be used for the tires cannot be painted; I had to find a different solution (already in use for the Toronado) by inserting a white ring into a groove made in the tire. The picture below is the mold I will use for that. It's slightly conical to avoid that the ring is coming out. I just hope that my calculation will be right!

 

225 Moule flanc blanc.JPG

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19 hours ago, Roger Zimmermann said:

January 28, 2010
The answer

 

Tires could be entirely black, but at that time, it was unusual, even if white walls cost extra. The material which will be used for the tires cannot be painted; I had to find a different solution (already in use for the Toronado) by inserting a white ring into a groove made in the tire. The picture below is the mold I will use for that. It's slightly conical to avoid that the ring is coming out. I just hope that my calculation will be right.

 

I have every confidence in your calculations being correct.

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People who followed the Mark II construction have already seen something similar with the tires for that model. However, as the memory is fading, it’s a good opportunity to refresh what you learned!

January 29, 2010
Success or disaster?


That's the day’s question. I will get the answer in one or two days…

Some explanation:
This day is the beginning of the tire’s fabrication. I’m doing first the preparation for the first negative half mold. The brass tire is put into some plastiline; to have a nice surface, a disc of brass is put on that plastiline. The inner diameter is a tight fit over the brass. (firt picture)

Then, the white silicone is prepared with the right hardener proportion. The silicone is put into the desiccator; then some vacuum is applied to that silicone (second picture). Not a lot, about ½ bar ; after that, my hand can’t any more.


The picture is not too clear, but the surface is full of bubbles which are bursting one after the other. At the same time, the volume is increasing as the trapped air into the silicone is inflating. Then, the more or less free of air silicone is poured into the can and go back to the vacuum chamber. (third picture)

Some bubbles are still coming at the surface, but less than before. I probably did a mistake by mixing the silicone with its hardener because I was surprised by the difficulty to mix both products. The result is that the mass is not hardening at the same rate everywhere.

As I had no more space into the desiccator, the first white wall is not under vacuum. (fourth picture)

After a long time under vacuum (my poor hands can no more!), I’m taking the « assembly » out of the desiccator. If there are still bubbles in the mixed silicone, they will be squashed by the normal air pressure as long as the silicone is not yet set (fifth picture).


The next operation is to remove the plastiline and pure again a next mix of silicone. When this second operation is over, I will then know if the whole process was a success or a failure.

At that day, there was like sunshine before the forecasted snow: the wheel covers are ready and I went to the plater to reach them.

I’m satisfied at 95%. To avoid that the dull part is getting too shiny, the copper coat was reduced. The result is that on the shiny surfaces, polishing “scratches” can be seen. I still have some black paint to do on them.

 



 

226 Première préparation.JPG

227 Mise sous vide.JPG

228 Demi-forme sous vide.JPG

230 flanc blanc.JPG

229 Saisie du matériel.JPG

222 Chapeaux chromés.JPG

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February 01, 2010
As I did know that the tire story will not go without difficulties, I did something else to let the things calm down, the rear license plate, for example. There are decals for that kind of job, but I don’t want to begin with a new experiment.  Therefore, I did an « Avanti » name with brass and glued it on a black plate.

Another small job I did: put some black paint are the right places. Here is one, installed on a wheel. The comparison between the new and the old one don’t need any comment.

231 License plate.JPG

232 Old and new wheelcovers.JPG

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February 08, 2010
Victory?


It’s still too early to say it, but things are gook looking. The second half of the negative mold was done yesterday. Why did I wait so long to do that ? Well, I needed a releasing agent; I got it yesterday. All my attempts with silicone grease, soap or other products failed. What I got is a wax spray can ; this is needed to avoid that both parts are definitively glued together.

This morning, I took away the tube. The surface which was contacting the steel tube is looking good. What will I find inside at the separation line, full of air bubbles?

Indeed, the surface at a first glance is perfect. The product is also a good cleaner: even if I washed the brass tire before the job, the surface has some black traces. The spraying of the wax was not very good; I missed a small surface and the silicone stick together, but this small problem will have no effect for the rest of the job.

The next operation: pouring the same product into both halves. For that, no error is allowed. otherwise, I will have to go back to the starting line.
 

233 Démoulage.JPG

234 Formes négatives.JPG

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February 14, 2010
Yesterday, I poured some white silicone into one of the negative molds. The question was : will the product stick or not ? The problem with such a work is that the result can only be seen when the product is entirely cured, usually the day after.

This morning : attempt to remove the positive mold from the negative one: The half tire on the right is perfect!

At the top of the picture, there is something few would like to see at home: a syringe. This is needed to mix the catalyst with precision. No, I don’t have the needles !

At the picture’s bottom, you can see the product which will used to do the definitives tires. I did a test to see if the colo ris suitable because the ground product is clear like water ; a tinted product must be added; 1 to 4% are enough according to the manufacturer of the product. I poured a small quantity into one of the Toronado molds; with only a very small quantity the products is getting black, a nicer color that I had with the Dow Corning product (which is now extremely expensive, more than $ 300.00 for one kg).

I’m doing now the other tire’s half.
 

February 14, 2010
The breakdown!


By creating vacuum with this hand pump, my hands are still OK, but not the pump ! Those tools in plastic are not worth…I will attempt a repair but I’m sure something else will go bad!

By luck, I was at the end of creating enough vacuum…

 

235 demi-pneu.JPG

237 Pompe à vide cassée.JPG

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February 21, 2010

 

Ah ! Those plastic tools…The axle at the handle broke. Repaired. The axle at the plunger partially broke. Repaired. Sometimes later, the other axle broke; was repaired with brass. At the next break-down, I will have to replace it and buy another one in metal.

Obviously those plastic pumps are just good for demonstration.


It goes forward !
Yesterday, I was ready to pour some polyester resin into the negative molds, first picture.

A piece of cardboard was shaped as a tube as a barrier for the liquid resin, sealed on a piece of flat brass with tape. Then I sprayed some wax to facilitate the removal from the brass.

The second picture, just after the resin was poured.

The green color is accidental, the resin is clear: to measure the resin quantity, I did a small spoon with brass; the chemicals into the polyester reacted with the brass and gave this green tone.

THE question : how many air bubbles will be trapped into the tire’s grooves? The answer will be available when the resin will be set.

I did that exercise into the flat because it was too cold outside to do it there. I could not wait for summertime !

238 Prêt pour la résine.JPG

239 Demi-pneus recouverts.JPG

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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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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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