Roger Zimmermann

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

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December 06, 2009


All five wheels are ready. Two are seen at the back and the other ones at the front.

The next step: either the wheelcovers or the tires, I don’t know yet!

Regarding the tires: in contrary of my plan, I will do the tires for the Avanti first (at that time, the Continental Mark II was still in planning). The exterior diameter of the Toronado master tire is almost the same as a tire 6.70 (which is the tire’s dimension for the Avanti) but too small for a 8.20 tire for the Mark II.

December 07, 2009


I began today to modify the Toronado master tire. Compared to what I must have, it’s too wide and only 1 mm too tall. The white wall was very thin for the Toronado; it will be wider for the Avanti. I regret that the name « Good Year » will be destroyed with the modification. As usual, I don’t remember how I did it, but by looking carefully at the letters, it seems that I painted the surface, scratched the unneeded paint and added some with a brush to have more thickness.

 

202 finished wheels.JPG

Master tire.JPG

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December 09, 2009
Master tire

The first operation is to remove the brass bands which are soldered to the main « tire ». I hope to salvage most of them.

The master tire is coming on the lathe to modify it: a bit lass tall and narrower. Most of the work is done with the conventional tools belonging to the machine; the sides are modified with a hand held tool, like you would do with a piece of wood. The difference is that the metal is harder to cut!

The job is quicker than anticipated; the master is more or less ready: I have to add the bands for the profile and do the name.

The groove on the side is for the white wall. It will be made with silicone and pushed into the tire.

To do that groove, I used an improvised tool, very thin (the black arrow is showing it) ; due to its shape, that tool created a lot of vibrations. To maintain the white wall into the tire, the inside diameter of the groove is larger than at the outside.
 

203 Profil pneu.JPG

206 Travail du flanc.JPG

204 Master tire.JPG

205 Outil.JPG

Edited by Roger Zimmermann
spelling (see edit history)
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1 minute ago, Roger Zimmermann said:

Keiser31, it seems that you like it!

I like ALL of the posts that you share with us. I love to see how you cope with the tiniest of problems in the build, but somehow seem to come out ahead of the game. Your work is FABULOUS and I see nothing to "dislike" about it.

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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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On ‎10‎/‎27‎/‎2019 at 8:56 AM, Roger Zimmermann said:

The brown mass is paraffin. For what this could be used ?

 

I am glad I did not guess - I would have been wrong!

 

Keep up the interesting and informative reports.

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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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The calculation was correct, but another other factor gave me trouble. I will tell what in due time!

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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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1 hour ago, Roger Zimmermann said:

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

 

That was very lucky. Are the vacuum pumps sold for creating vacuums when checking vehicle components in the workshop made any better, or are they the same? 

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In fact, I ended buying one in metal as this fracture was not the sole incident. This new pump survived the remaining tires and the ones from the Mark II. The metal ones are definitively worth the extra costs!

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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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Fantastic work Roger. I am watching a Master's Class. John

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