Roger Zimmermann

Thanks Pat! This pre-installation let me discover an error: the differential's nose is too low; it should be aimed at the transmission. The error? The shoes on which the rear axle is soldered on are parallel to the differential's pinion. I could cheat by modifying the shoes thickness at one end or try to unsoldered them and rotate them slightly. We'll see.

After having a too stiff front suspension, it was logical that the rear one would follow. This time, I did only 3 leaves per side and, indeed, the suspension is rather soft. However, the rear springs are much longer than the front ones! According to the specifications, there were 9 leaves at the rear; I will add some later. As you can maybe see, the rear suspension is very unstable with shackles at the front and at the rear: the drive tube is the element which locate the rear axle longitudinally. As you can understand, some more work is needed to have a working suspension... I will soon do a test with the new resin: I just read that it's dry to the touch after two days and completely cured after five days!

Thanks! My door is open, just tell me a couple of days before your visit!

SUCCESS! This morning, I separated the positive molds from the negative ones. At first, it was difficult to get the edges being separated; once I got that, the rest was easy. No bubble, all the material is well cured. The next step: doing the definitive negative molds with a product like polyester. The product I used to do the negative molds was no more available at the store I'm going; a different product is no offered. Will it be so good as the previous one? There is a fundamental difference: the old product got cured with the addition of 3% hardener. This product is used by mixing tow parts from one element to one part of another one. Certainly easier to mix with the right proportion, but how are the characteristics of the cured product? I will have to make a test with a very small quantity.

Bad luck...I hope you will find the reason of that bad leak.

Thanks Pat! I tried to thinner the ends of the leaves; I quickly discarded this idea as unpractical unless I would have the proper equipment. The burrs on the edges are sanded away... As the negative molds were successfully done, I could cast the material into the recess to get the half positive molds. Right now, I don't know if this further step will be OK as many factors could lead to a disaster: the material can be uncured (it can happen), stick to the mold or air bubbles. I'm waiting another 24 hours to attempt the separation. People here already know the whole process; as I'm publishing this construction into the Cadillac LaSalle forum, members there are seeing it for the first time.

Hi Mike! I hope you are well! Thanks for the idea; funny, I got the same idea from somebody from Australia...I will however do differently: using flexible plastic leaves to have the proper look. I already removed 4 leaves; the rate is better but still rather stiff. Unfortunately, I have no driving experience with such kind of vehicle; I suppose the front suspension was not that soft. More like a truck, but I can be wrong.

There is nothing now to report about the tires because in between I began something else: the front suspension. The shop manual is stating that the V-16 models have 10 leaves in the front; I did 10 leaves for each spring. As I could not buy spring steel the exact width I wanted, I had to make the material a bit narrower; I did that work in the room where my cars and parts are stored. After drilling the holes for the central bolt (this bold is used to assemble all the leaves and to locate the axle on the springs), I installed the springs and axle on the frame. I discovered an error (this is not the first one nor the last one!) at the clips attaching the front axle: they are too short. I can hardly install some nuts, but this error is not that bad: with all the leaves, when I put a weight of 0.7 kg over the front axle, the springs are flexing about 1 mm! In the real life, a weight over more than 2000 pound would lower the front end by 1/2". Sure, those cars were not as comfortable as recent ones, but my springs are definitively too stiff, therefore I will remove some leaves until I'm satisfied.

As a help for my 1:12 Cadillac V-16 project, I have a parts list. Flat washers are used on the V-8 engines for the cylinder heads screws.

In parallel to the shock absorbers, I continued with the RTV product. All white walls are now done and, finally, I succeeded to have a decent pair of negative tire molds. Technically, I could directly cast the definitive tires with those molds, but it's too dangerous. If one of the negative mold is damaged, I can redo the whole scenario. At $55.00 for one kilo of the white RTV, I don't take the chance. Therefore, I will continue with my "regular" process.

Finally, the front shock absorbers are ready. It took a long time to add the latest details; maybe no one would have notice if skipped! Technically, those shock are ready for the viscous product I have. However, I will ad it when the actuating arm is soldered to the hub. The screw you can see will be the locking system, of course flush with the hub. I assume that the hub and arm assembly was originally pressed on the shaft. As my shafts are inserted from the back, I had to find another solution. The back is now closed by a plate and four 0.6mm screws. A short bearing is integrated to that plate; it should prevent a binding situation for the shaft. Maybe I will have to add a paper gasket to avoid that the viscous material is oozing. I cannot finish the rear shock absorbers because I don't know the position of the actuating shaft at nominal position from the frame. The locking screw must be more or less at 90° from the arm and the relation between the actuating arm and inner blade must be right. I will finish the rear shocks when the suspension is done. I deducted from my pictures the the actuating lever is horizontal for the front shock absorbers; therefore I could finish them.

When I have very heavy pictures, I can reduce them in the "paint" system from Microsoft. I'm sure there are other tools but as I'm not curious in that domain, you will probably get more ideas from other users.

With one white wall every second day, I have now seven pieces. As spares are always good, I intend to do another one. Then, I will have to begin again the tire itself... In parallel to the white walls, I continued with the shock absorbers. I added some cosmetic details; before closing both ends with the plugs, I did the shafts on which the actuating arm will be attached. When that was done, I silver soldered the blade which should render the shock absorbers functional. By looking at the size of the blade, I doubt that the shock absorbers will be really effective. Well, it's a fun design, even as a failure! The possible movement is about 120°, which is largely enough. There is a groove on the shaft: a very small O ring (I have some since many, many years) will be installed to prevent the loss of the Hivis. Of course, a closing plate will come at the back of the shock absorbers; some details are still to be added.

Ah! the quarter...I will do it next time! Thanks for the pictures; Bugatti is out of my league!

Yes: on the shaft, there will be a blade immerged into the product I will use. I have this Hivis (the product's name) in two viscosities; probably the thicker one will be OK.

It's better to put things aside until better days when it was a flop! As there are enough to do, this is just a temporary set-back. Last month, I began the shock absorbers; it was the right moment to continue with them. The design was more or less performed during the assembly of many parts all silver soldered; this bad method let me do some errors later corrected. As pictured today, they are far from finished, but I'm confident I will have working shock absorbers.

There are good days as well as bad ones, it's life. Today is the second category: yesterday, I did another white wall; thinking there was still enough wax on the mold to avoid issues. There was not, white wall destroyed, fortunately, the mold is not damaged by taking away the sticking white material. I opened this morning the negative tire's molds. One half is so-so, the other one some tread was ripped away. The material was more or less bonded on the brass at the recess to hold the white wall. Usually RTV is not sticking to metal but this time it did. I have a possible explanation: when I cleaned the uncured RTV, some stayed on the brass and, generally, there was still a trace of that RTV on the whole brass surface. With the proper catalyst added, this uncured RTV acted as a bonding agent between brass and the fresh RTV. The result: back to the starting line...

A Randy! Nice French sentences! The white wall fabrication is going well, about one each day. A fourth is to be separated from the mold soon. On the post dated March 18, I was pouring white silicone into the mold. As you remember, it created a mess as I used not enough catalyst. I did this job again and, today, I removed the plasticine from the back. To avoid that the plasticine in going into the tire's grove, I used some masking tape to avoid it. I noticed that the tape was not sticking to the brass but did not thought more about that. The result: the silicone went between the tape and brass and filled up the groves! After painfully removed the undesired material and using wax, I poured the silicone into the other side. To tell the truth, I'm not at all confident that I will succeed. I will see that this week-end when the new material is completely cured.

Pat, thanks for the kind words. When I'm sometimes searching something I wrote here, I have to scroll through many pages I know the time needed to just look at one page...

Yes, it was be about 12 years ago! Times is flying...Indeed the comments and pictures I will publish the next few weeks are indeed déjà vu for some people. However, there are always differences and set-back...

The first white wall is born. It's good looking but the tire's dimension is somewhat weak, depending to the lightning. Still 5 to do!

The third tentative for the white wall's mold seems to be the good one. The first picture is showing the little quantity of material was mixed with the catalyst and black paste (the used product is transparent). When some vacuum was applied to the mix, the volume expanded and expanded. I had to stop the pump to avoid an overflow. After some pump's cycling, I could let it run for a longer time. After almost one hour, I opened the vacuum chamber and purred the RTV into the mold; I used simple cardboard to create the wall. Then, back into the vacuum chamber. There was still air trapped, you can see on the third picture the elevation of the mix. After 1 1/2 hour, I saw almost no bubbles and I let the mold out of the desiccator. After 2 hours, the mix began to set. This morning, I took the cardboard away; some plasticine was used to close the interstices between cardboard and brass mold. The crowning of the day: the black rubber is removed from the brass part. Now I have a perfect mold for the white walls, one at the time.

Finally, I could clean the mess I inadvertently created. The use of soap and nitro thinner removed the uncured material. This time I did the mix right and used the electric pump to removed the trapped air. It's impressive to see how the volume is increasing when enough vacuum is applied! I did also an interesting observation: when I had 25" vacuum, I stopped the pump. Of course, the vacuum diminished slowly; I restarted the pump to get at about 25", and so on. I was surprised to see the small bubbles on the upper surface, but almost none burst. Finally, I let the motor run and there was much more action! It seems that the removal of air is more efficient when the pump is running for a long time. in the situation, the vacuum is about 27.5" Hg. Anyway, the black rubber part is perfect, but not usable. I need to modify the brass part to have a dam at the outside diameter. With the actual mold, I could only do a partial white wall as the exterior wall is lower than the inner hub. I had a long time to figure what was wrong and how I have to modify the brass part. This is the next task!

When I ordered the machine, I had no idea where it was manufactured. Suppliers usually don't tell it! As the price was right (about $ 120.00), I did not search further. My explanation was probably no very clear: I took nothing with me to France but, to avoid taxes from the Swiss customs , I ordered the vacuum tool when I was there and took it with me. The sole very small inconvenient: the electrical plug is one made for France; I have now to use an adapter as, of course, the Swiss plugs are different. We have the same issue using a Swiss electrical device in France: most of the time an adapter is needed.

No, I cannot clamp it, because it's too rigid. The cover on the recipient is a flat surface; I'm "sealing" this surface with liquid soap. When the vacuum is applied, I see tiny bubbles going into the recipient. The leak is there. With a rubber seal, it would be more tight. As I have anyway to monitor the process, it's not a huge problem to start the pump from time to time. I'm assuming that with a greater vacuum the bubbles trapped into the silicone rubber will be quicker eliminated. I will report it when I'm that far. For the moment, I'm cleaning the mold for the white wall. Both scripts survived, but the final cleaning is tedious. I cannot take a too aggressive product because it would wipe the scripts.