After the times discovered and reported the problems with the resin floors provided with the IHP Illinois Terminal PCC [87169] and Shaker Heights PCC [87153] kits, Custom Traxx decided to work with Bowser Manufacturing to see if some floors could be made to salvage these kits. They felt that the workmanship in both shells was too good to be wasted by being mounted on those almost worthless floors. So in early October, they visited Bowser to finalize floors for their own Boston, ex-Dallas PCC. While there, patterns and molds were made for both IHP kits.

In the case of the Illinois Terminal (IT) and Shaker Heights (SHRT) cars, since the resin floors had the correct shape to fit inside the shells the IHP floors were used as a pattern for the shape of aluminum patterns to be machined by Bowser Manufacturing. At no time was the floor used to prepare any type of pattern. There were also internal dimensional errors on both IHP floors, particularly in the truck center-to-center wheelbase as neither car uses that standard 22' 9" PCC center-to-center truck wheelbase. The floor for the Boston ex-Dallas PCC was designed by Bowser Manufacturing and has the same center-to-center truck wheelbase as the Bowser PCC. The floors for the IT PCC were assigned part number 125164, the SHRT PCC 125165, and the Boston ex-Dallas PCC 125166. Shown below are the shells, the resin floors and these aluminum patterns for the 125164 and 125165 floors.

As stated earlier, we found out that the both IHP floors for the IT PCC and the Shaker Heights SHRT car used the incorrect truck center-to-center spacing. The correct spacing for the IT car is 22' 11" and the SHRT is 25' 1 1/2" so had we just copied the floors as is, we would have been wrong for more than one reason. Always check the prototype dimensions before proceeding with any model or portion thereof.

Meanwhile, we proceeded to move forward on casting the 125165 and 125166 floors, which is the subject of this article. The rubber mold comes in two halves, between which we will be placing our patterns. Our aluminum patterns were placed on the bottom half with several tinerman nuts as shown below left. These nuts ensure that the two halves of the mold top and bottom will always mate correctly for repeat castings. The top half of the mold rubber is then placed on top of the patterns. The entire mold is then inserted into a mold frame, shown below right.

The mold frame is then inserted into the vulcanizer, which will subject the mold frame to 320 degrees Fahrenheit and 10 to 15 tons of pressure for about thirty minutes. Vulcanizing is the same procedure used to make automobile tires. The soft rubber becomes hard and makes a great mold. This is the main reason why a metal pattern must be used. Resin and plastic floors just won't make it through this process.

After vulcanizing the rubber mold, The entire assembly is allowed to cool and then the mold frame is opened, revealing the entire mold, which looks somewhat like a layer cake. The patterns are between the two layers so when the mold is opened, and the patterns removed, the mold is finished and ready for casting.

The blue arrow in the photo at right shows the top of the mold. You can see the top half of the mold. The brown arrow points to the bottom of the mold with the patterns still in position. The patterns are then removed and we can prepare for the casting of the floors. The 125166 floor pattern is in the foreground. You will notice a discoloration on one end of the pattern. This is because in the evaluation of the pattern, we had affixed a small piece of brass to the pattern with ACC to attach a coupler. There were two jig locator holes in the pattern and one of them was where we needed to locate the coupler. The discoloration resulted from the ACC boiling during the mold making process. At this point we will cut grooves, better known as casting sprues from various points along the pattern to the center so that the molten metal will be able to reach the mold during the spinning process.

The next step is to heat up our pewter, which is 92% tin, combined with antimony and copper, to 700 to 900 degrees Fahrenheit. The blue arrow is pointing to the molten pewter just before the ladle is used to pour the pewter into the center of the mold. We were fortunate to have Betty Ryder, with over 31 years experience, casting our parts on this day. In the right photo below, Betty is shown removing small parts from molds cast earlier in the day with the stove with molten pewter and the casting machine in the background.

It takes almost no time to make a casting. The casting machine is closed and secured. The spinning at 750 RPM starts and the molten pewter, now heated to the correct temperature is poured into the center of the tub. The art is to get the right mount of pewter into the mold, not too little and not too much. The mold frame is removed from the tub and the cast parts removed and set aside to cool. You can measure this process in seconds.

Custom Traxx is using this process to make pewter floors for the Boeing LRV (125147), the San Francisco "Milano" Peter Witt Cars (125162), the Canadian LRV (125163) along with the IHP IT PCC (125164), the IHP SHRT 71-95 PCC (125165) and the Boston ex-Dallas PCC cars (125166) . See their website, Section V, for more information!