Chariots of Fire

Here is a photo of the simple drawing to show the frame and tire layout in plan view. With a drawing like this things can be kept in scale and proportional. The rear axle is now to the correct length. Still to go is the other axle for the tandem rear end. The front axle will have to wait until I get more photos of the actual truck. I also painted up two of the tires to see how they will look. Not bad but they can be better. 3D printing does have its limitations and they are evident here with a rougher sidewall surface than I would like. A little sanding after the first coat of paint is applied will make some difference.

Hello Arnd! Thank you for your kind words. The tires are 11:00 x 20 actual size and are 41mm diameter by 10mm wide. The inside diameter is 20 mm.That represents a real tire that is 41" high.

Been working on some basic drawings for the truck. In previous projects I depended too much on the way some kit pieces come out of the box. For instance the rear axles that are in the above photos are simply too wide (not the brass inserts, they are just temporary length). So by knowing from actual measurements the track width of the rear tires, I drew out a plan view of the frame and tires. Having had the tires cast to a predetermined width, they had to fit within a certain parameter. That meant that the distance that is between the two inner tires had to be enough for the frame width and the springs. So far so good. One rear axle has been adjusted and the tires and wheels checked for overall width. Now to do the same thing to the second axle. More photos soon.

I don't consider myself an expert in casting so what I explain probably goes against every proper way to do it. That having been said if you look at the last mold of the small 8 spoke rim the mold have next to the master is quite deep and includes most of the casting details. Resin is poured into this half of the mold and brought to overflowing. Then the top is put on squeezing out all but what makes up the mold cavity with the top on. Sometimes air bubbles do get trapped. (Maddening!) But most times they do not. After the resin sets the two pieces are broken apart. Same method was used for the tires for the brush truck project. If I had a pressure pot to introduce about a 10 lb. vacuum it probably would help a lot in expelling the air.

To: 426-Hemi: Here is the grill that you inquired about. It is resin and has a slight curve to it but it will straighten easily. There are also two clear resin lenses for the holes in the grill. The headlight bezels are separate but are the same as what are in the Linberg L700 kit.

After a bad start on making a mold for the tires, a new one was made up and 10 tires and wheels are now ready for the build. I was concerned that the deep tread might cause some problems for the mold tearing away when I separated it from the master but it held up fine. The secret was really swashing on the mold release so the small parts of the mold would not stick. Two part resin was made and poured in. Very little clean up was needed although on some of the castings there was a air pocket that needed filling afterward. Nothing in the tread area which was good. Next is to clean up the wheel pieces and begin on the frame so I can locate the springs. In this one the base of the mold has been completed. Next up is to pour the top of the mold. The mold box is complete and has the first resin pour in place. After the resin sets the mold will be separated. And here are all of the tires and wheels awaiting setup and final painting. JeffH is working on a 1919 Federal and needed some 8 spoke rims. The Mack AC kit has 5 spoke wheels in the front and 7 spoke wheels for the rear. What to do? He broke apart two 5 spoke wheels and drew up a circle with 8 segments. He trimmed the 5 spoke sections until they came together into a configuration of 8 spokes. He asked if I would make up a mold and voila! 8 spoke wheels for the Federal! In this photo, the resin has set and the mold has been separated to reveal the new casting. The original 8 spoke master is to the right. The resin casting is out of the mold. This was an easy mold to make but it took 4 steps to complete. 1. Build a box and fill the bottom 1/3 with RTV. Let set. 2. Make up more RTV and pour in just enough so that when the master is set in, the wheel is sitting on the first pour and the new RTV is even with the middle of the spokes of the wheel. Let set. The master is now secure in the mold. 3. Make up a third batch of RTV and pour it on the outside of the wheel only up to the top of the rim. Let set. 4. Coat the entire mold and wheel master with mold release and pour the last of the RTV over the wheel and up and over the wood plugs in the corners. The plugs will help allign the two mold halves so that the casting will be centered.

On the Scale Firehouse forum site there is a section called the Parts Bin. Look for Shapeways Store. Matt is a CAD guy who has been doing up detailing pieces for fire apparatus models. I sent him a photo of the tire tread I wanted and the dimensions of the tire for 1/25 scale. He took it from there, made the 3D drawing and shipped to Shapeways. He let me know that it was ready and gave me the link. I simply purchased the finished tire from Shapeways. He gets a small amount of the purchase price for doing the 3D workup. Kind of a neat thing.

Hah! Didn't even notice that! Must have been when I put new batteries in the camera.

Hmmmm! Didn't realize I was that quick! Also helps to be retired from full time work!

Now that the 1929 Coleman is nearly completed (I'm in a slump about building the hydraulics and dump body) there is a new project on the board. This big 1957 Diamond T M-52 military tractor was turned into a brush rig for an adjoining town. I've been asked to build a model of it for someone who was instrumental in getting the chassis and seeing the construction completed. This has just been started after taking a number of photos and some basic measurements to come up with a side view of the cab and chassis. The axles were taken from an Ertl ALF kit and modified for the military style differential. The transfer case I made up some time ago for the Type O-5 Crash Truck. The tires were 3D printed by Shapeways based on a photo and dimensions I provided. They are quite well done and I was able to simply snap in the resin wheels with only very little sanding. Lots to do on this scratch building project including a Continental R6202 gas engine. I can see myself making several trips to see the real rig to get more info in the coming weeks!

NIcely done!

That's some nice work. Very impressive. If you don't mind telling, where did the tires and axles come from?

Everybody starts somewhere, John. Welcome back to a great hobby!

Thought of that but I think it is just a little to big and not quite flexible enough. The wiggly worm is just about the best except for that one flaw. I'll give it a few more days and if the paint doesn't cure I'll wipe it off and try the alternative.

Coleman shops are still at work making up details. Headlights were turned from aluminum rod as was the air cleaner. Fenders are sheet brass that was annealed to soften it for bending using a piece of brass tubing and a hard sponge. The hood hold down straps are just strip plastic and are only attached to the frame at the bottom. The hood end is made so that the hood can sit in a small notch. That holds the top of the straps in place but allows me to remove the hood. The clutch pedal is a bit floppy as it has no connecting rod yet. That will come later. Brake rods are installed on the connecting levers attached to the rear brake drums. The flex hose on the air cleaner is a piece of fishing lure called "wiggly worms". It is very soft and flexible but it did not take the enamel paint. After several days it is still wet! I may wipe it clean and try some acrylic to see if it takes better.

Lots of work, eh?? Have you considered using small brass imitation hex bolts for the lug nuts? Really saves a lot of work and they look great because they are so nice and clean.

That's a nice start Gino. Good looking color scheme also. Narrow tires for the period look good!

That's some nice work! I really like what you did for the sides. Tedious, yes but worth it! That is awesome.

Do ya hafta??? Ahhh. .........Go Ahead!!

I've been accused of that!

It may not look like there is much difference between these photos and the last ones but there is. The cab interior is now complete with gas pedal, brake and clutch, shift lever, hand brake and the levers that operate the 4 wheel drive. There is also a lever for raising the dump body that has yet to be built. The engine is nearly complete with a few small items to add to the steering column such as spark and hand throttle. The fuel tanks are now done but will need the fuel lines run to the engine. Driveshafts are done along with the hand brake disk and pads. The engine, radiator and cab are now secured to the frame.

Thanks, Chuck! Got a project in mind that this will work very well for!

Can anyone verify or debunk what I think I saw recently and that is a model of an IH Workstar? I'd love to get my hands on one if there is such a thing. The Jada flat bed truck is not what I am thinking of.

Oh, yes. I got my order from him only a couple of weeks ago. For those who are close enough he has a booth at the Grafton Flea Market on Route 140. There on weekends until the market shuts down before the first of the year. He will go back in the spring.

For anyone wanting to try hinges like Terry made I have a suggestion. Not far from here there is a supplier of all kinds of scratch building materials including very small brass tubing and stainless steel wire that make great hinges. The Tubing is 0.018" diameter and the stainless fits very nicely inside. If you clean up the brass with some steel wool and lay it on a flat surface just run some CA on the edge of the hood piece and move it against the tubing. When the CA sets fill in around it with more CA and sand the joint smooth. I used it on the 1929 Coleman. The supplier of the tubing and stainless is Precision Scale Model Engineering. psme@psmescale.com is Larry Milo's e-mail address. He also has a web site www.psmescale.com