Those of you who know me know that I am a straight forward guy who likes to give credit where it is due . You also know that my modeling budget is extremely thin . So in an effort to cover both of the above, I have a little story. My Santa Fe and Southwestern is set in New Mexico about 1954. At that time, most of New Mexico was very poor due to the post-war economy passing the state by. Automobiles were at a premium, and new cars could only be afforded by rich city folk and out-of-state tourists. In an attempt to capture this feeling, I purchased a set of the Classic Metal Works cars in N scale. These are very nice models, and I highly recommend them . They are also quite expensive in terms of overall layout cost (about 10.00 for 2 cars). Here was my delimmea: the cars were too new and shiney to fit the time and era, and in reality they were simply too expensive to have a lot of them. The solution was to buy some instant molding material at Wal Mart, make a mold of the vehicles and presto: I can make plaster (actually Durham's Water Putty) casts of the vehicles. These I can paint and weather without the guilt of doing it to the actual die-cast models. Dents, rust and dust are exactly what I needed, and for a fraction of the cost, I can have a street load of cars. Maybe this is a bad thing for the economy of modeling, but without doing it I could never afford to have as many cars as I need. I do intend on buying the other car sets, but these will also be copied. Also, these ARE NOT for resale, but use on my own layout. Just a thought for those of you operating on a shoe string as I am. Happy Modeling!! John
John, I see by the message traffic that your injury will allow you to use the keyboard. Good to have you back in the thick of things. What's wrong with what you are doing? Nothing. It makes good economical sense and gives you what you need for your own layout. Besides, automobiles are a small part of it--it's the Railroad that counts!
John, I do not think there is anything wrong with your idea. I think its great. I to have a small budget for my model railroad. Having been laid off for a month or 2. We work very hard to get that look and feel that is just write for our own model railroad. They say the need of necessity is the mother of all inventions. I think its great when molders like your self show the rest of us your handy tricks. You never know who might need them. I just wish the same could be done for a Rivarossi Big Boy. He he he….
Plaster cars! Sounds like a great way to fill the streets. I'm sure others have used this method in the past with other items. I sure wouldn't feel guilty if I were you, I'm on a severly strict budget also
Sean, there is no reason you can't make a mold from the Revelle scale model of the BigBoy boiler, and pour the boiler using Pattern Maker's polyurethane. It is filled with aluminum oxide for denseness so would be heavier than the injection molded boiler. It is the way we make prototypes. It sets up in an hour or so and you can pour again. Do the same for the other parts. All you would need then is the motors, wheels and couplers. Dad and I prefered to pour our boilers with 40/60 lead (Type metal used in printing). Our 6 pound bigboys would pull more cars than we had. One did pull 105 cars once when we were able to borrow enough from other guys to do it. It started and slipped drivers a little but finally got the whole train moving and got up to about a scale 25 or 30. I don't think they make any motors that big now days though. Where there is a will, there is always a way, you just have to figure it out. John Cater, I poured a mold of a truck once, then poured the inside full of polyurethane. Then I layed aluminum foil over it and smashed it in a vice to form several trucks that were to have been hit by a train. It worked fine. The wrinkles were covered by thin coats of paint, so didn't show all that much for the display. I see no reason plaster cars aren't as good as $10.00 ones. They wont run either. Go for it! John B. I used to play cars with some poor kids who made their cars out of mud, baking them in the sun. They scratched windows and doors and wheels in the sides. They got quite good at it. I'll always remember it because they had the only toy Bus I had ever seen in 1936. Their cars would "run" along the roads we scraped in the dirt a little better than our Tootsie Toy car's white rubber tires did. We had big emaginations back in those days. Today, if it doesn't look "real" in a close up photo, people aren't happy with it. What a shame to pi$$ and moan over a few rivits when they could be running trains! [ 14 August 2001: Message edited by: watash ]</p>
Like to ad my agreement to the pile. I'm at the tail end of a government contract that takes about three months to pay from completion, so i've got lots of time and little money myself. I went to Walmart and poked around in craft and paint area but couldn't find any mold making material and, of course, no one who worked there had any idea what i was talking about. So, if you please, what's it called and where did you find it? Sounds great and i already have the plaster. Thanks. Curt
Watash, I just got this great urge in me: I want to build a six pound big boy. Any chance you will publish the full story on creating one of these(or any other) bad boys? Especially, the part that has to do with running gear, winding the electric motors, etc. You know, the stuff that our society cannot comprehend why we would ever want to learn, yet they gawk at the shear size and strength of the finished copies. The motors seem to be the most dificult part, especially because I cannot believe that any of the comeecially available motors could handle the sixpounds, much less anything behind that. It would be cool...right after I finish Band Camp, and get steady with the class schedule.
Benny, you would have to buy the drivers, and the only solid brass ones available now are $18.00 a pair. Dad sold his gear cutter and I am not aware of where to get 60 to 1 and 80 to1 worm gears sets of the small size needed. The motors are still available, but I don't know what todays prices would be. The bar and sheet brass is no problem, but getting a permit to buy the lead might be a problem, and then getting a foundry that will even touch it now. It is deadly poison they tell us now. Wish I had known that 50 years ago, I been dead a long time. So I'll lay down. Yeah I'll help you Benny, but it will cost you!
As for pouring the lead, at least here in the U.S. you won't need a permit. Go down to the local gun supply store. You can buy a 5 lb. or a 10 lb. pot with a heater, and the lead. Guys like to cast their own pistol bullets, and some fishermen like to cast their own lead weights. When there's a will, there's a way out there! Mark.
Yah, lead will poison you pretty good (about as damaging as the stuff in aerosal cans) only it is through touch instead of breathing it, and it builds over time. But just don't play with it much and you will be fine. And don't let any moisture get in the molten lead (like a drop of water or sweat) or the whole pot of molten lead will blow up all over you (not fun). Anyway, that is the joy of playing w/lead. You can find miscellanious lead almost anywhere (weights they use on tires at BIG O) but don't breath the fumes when you are melting it down, especially if you don't know where it has been.
Well folks we have quite the deli-lam-a here! We have the basic blueprints for the Dream BIG Boy, we have the Tech and we have the will. But once we have the Steamer, we dare not touch her, so she must not be run for fear that she might pick a switch and then how'd we get her back on the rails? The dream steam engine, like having the dream wife whom we can never have sex with……
It really isn't that bad, I just happen to have had a run-in with an EPA HAZMAT freak once while I was melting a pour one afternoon, inside the city limits! I was able to get the pot and lead out of town to my dad's place before they came by for the inspection. Its like in the gun world, its ok if you don't get caught. After that, I had a foundry that would cast whatever you brought, no questions asked, if you brought your own molds, and or waxes. They went out of business for something or other. I haven't poured any lead since (yet). OK, you all know how to make scale model airplanes, shelf model engines, etc. You know you can get one pour off a rubber mold, and you can use plaster to coat a wax for a lost wax pour. You must either have the oven large enough to heat your mold for pouring, or take it to a foundry and pay them to pre-heat and pour for you. The old Varney, Mantua, and HobbyTown castings were usually sand castings, so needed a LOT of finishing, so rivits were basically out. Varney and Mantua did make some lost wax castings along at the end, but few survive today. They all went to die casting for greater quantity which after paying for the die cavities, were much much cheaper, although the cost to us had to go up. For a time there was Kemtron Company who would make you a free pair of lost wax dental quality brass castings if you would send them a master part, or master wax, and relenquish all rights to sales. Shortly after they went out of business, everything went sky high for scratch building stuff, and the injection molded plastic stuff took over the market. So don't plan on going into business, just plan on hopefully making one fairly presentable hand made old time engine. Depending upon how great your skill is, what machinery you have to work with, and how much time you are willing to spend on it, and mainly, how much it is going to hurt your feelings when the nit-pickers start in on you, you just might end up with something you can be proud of. One tool room I worked in had a motto about the projects we were assigned to make, "If you know you can't swim, don't jump in the ocean!" Back in my dad's day, if the company classified you as a Class A Tool and Die Maker, you could be expected to make a watch from blueprints, because you were capable of making parts to those tolerances, and had the craftsmanship and skill to do it. It will take about a year from the time you start, the first time, working alone. The tools, jigs, and fixtures you will have to buy and make, will be useful to make another engine, so the time gets quicker as you go. It isn't easy. The first phase is the running gear. You can machine the frame out of half-hard brass barstock, or steel. That means you must have a milling machine, and necessary cutters, drills, and reamers, and the micrometers and calipers to use it. The mill will have to be accurate and tightened up to where you can certify cuts holding .0010" tolerance which means you can be .0005" over, or under a given tolerance. You understand what that means? If your frame is over a halh a thousandth of an inch on distance between the driver axle holes, then the siderod holes must be over the same amount or they will bind. On solid frame driver sets, there can be as little as only three wheels on the track at any one time. All the horsepower in your motors will be wasted, and the engine wont pull much because you have no traction. You must equalize all drivers. You do not have to spring any, but you may. Your model isn't going to tear up the rails like a real engine would without springs. All the springs do is absorb sudden shock like a gap in the rail at joints. It is cheaper to mount a small coiled spring on each driver bearing, than make all the monkey motion to an equalizing system. If you decide to make a BRASS quality model, then you can fake the equalizing links as they do. If you are going to make a CUSTOM Precision Made engine, then you will enjoy the thrill of seeing the equalizers actually work over switch frogs, and when going on or off a turntable, uneven track etc. And it wont derail unless you hit a curve too fast. You have to make up your mind; are you going to make a Test engine, a Show Piece, a Museum quality piece, or one that runs like a Swiss watch? It makes a whole lot of difference in how many hours you spend lapping a bearing to fit the axle, the frame, the side rod. You want to build the BigBoy to start out with? OK take notes! (Tune in net week to Chapter 13)
<blockquote>quote:</font><hr>Originally posted by rmathos: Like to ad my agreement to the pile. I'm at the tail end of a government contract that takes about three months to pay from completion, so i've got lots of time and little money myself. I went to Walmart and poked around in craft and paint area but couldn't find any mold making material and, of course, no one who worked there had any idea what i was talking about. So, if you please, what's it called and where did you find it? Sounds great and i already have the plaster. Thanks. Curt<hr></blockquote> Curt, The stuff is called "Botanical & Science 3-D Gel Instant Molding Compound" and it comes in a little yellow packet. I found it hanging on the rack in the craft section of Wal Mart. Hope you can find it...it is fun and easy to use!! Happy Modeling!! John
Benny, What ever material you use to make the mold for your wax master, must be flexible, and able to withstand 185 to 212 heat for an hour at a time. You may find that you will have to remove some features that are on a plastic injection molded boiler, in order to remove the wax master from its mold, such as using one boiler to fashion into another engine. I would not recommend using a good running one-of-a-kind model for this work. Since you want to make a BigBoy, my suggestion, is to buy the Revell scale non-operating shelf model to obtain the necessary shapes. That boiler is identical to the Rivarossi model, but is already dissassembled. Use a detergent to wash the boiler all over, then dry it. Do not touch the out side surface with your fingers. Any holes, such as the holes for handrail stanchions, smoke stack, whistle etc. will have to be filled part way. Carefully use modeling clay from the inside of the boiler to plug these holes just enough to prevent molding rubber from running through. You will want to leave enough of the hole to locate it for drilling in the final lead part. Try to work the clay up into the holes until the hole is no more than 1/32 deep from the outside, do not fill the hole. Do not get any clay on the outside of the boiler. A good mold release is a product named "PAM" that is also used to "grease" a pan for cooking. Spray the sealed boiler all over with PAM. Let it dry 24 hours, then dust it with a lady's face powder, while holding the boiler only from the inside. Do not touch the outside surface with your fingers. Blow off any excess powder. Lightly spray a thin coat of hair spray over the face powder, but not enough to run, just enough to seal the powder, and DO NOT TOUCH IT! Work carefully from here on. You are going to apply the mold rubber in certain places, and may find that they will have a tendancy to lift off if your mix begins to setup while you are working, or when you come back to put on the second coat, so watch for this. Do not try to paint by "stroking" as paint is usually applied by brush, you must daub it on while it is very "wet" so it does not lift the powder off. Mix a small amount of the flexible rubber mold material, (about a half cup) and using a soft camel hair artist's paint brush, about 1/8 wide, carefully daub a light bead around the smoke stack base, over the bases of all domes, all over the backhead, over the smoke box front, then start daubing along the detail on either side of the firebox. If your mix is beginning to get stiff, stop, if not continue daubing at the holes where the handrail stanchions will go, then go along the foot boards in the corner next to the boiler. This is to prevent entrapping air bubbles in tight corners and around detail. If you are still going, paint a line over any rows of rivets, and apply a bead along all sharp corners like around the smoke box front, and around the boiler at the backhead. You should have used up the first mix, or run out of time by now. Make a new mix, and use a larger brush about 1/4 inch wide to daub a coat all over the top half of the boiler, domes, stack, and all, being careful to work from the original rubber and working out away from it. Cover the whole boiler upper half. If you have some mix left, start again daubing more on top of the last coat starting where you started before and continuing until you use up the mix, or it sets up. You will need to apply the mix until it becomes at least 1/8 thick all over the top half down to the running boards. I have run out of time, so this will have to continue later. This coaton the top half needs to gell before we continue anyway.
We have made the top half mold, and need to "clean" it up to prepare for the lower half. Use a new ExactO knife to carefully trim any rubber that may have run onto the underside of the running boards. Next, lay a small straight edge on the bottom of the running boards and extend it out along the boiler toward the smokebox front. Carefully cut just through the rubber along the straight edge from the running board to the end of the boiler on both sides and stop. Now repeat this process working back to the end of the boiler to the corners at the backhead, and stop. In order to provide some "draft angle" on the lower half mold so the two mold halves can be separated, you must carefully by hand cut away the rubber starting at the lower center of the smokebox front on center at the bottom of the boiler. Be sure you have located this point before cutting. You will want to end up about 1/8 to 3/16 back from the smokebox front when your cut arrives at the running board cut. Both sides do not have to be exactly the same, but as close as you can. At the firebox end, cut across the bottom rearmost edge of the firebox but tilt your blade so this cut angles about 60 degrees toward the front of the boiler when you have cut down to the boiler surface. Now, as before, cut down the sides and again try to angle the side cuts to end up about 1/8 to 3/16 toward the front of the boiler when you reach the running board cut. At this point, you are ready tomake the support for the top half mold. I found a plastic pan or tray, that was 2" longer x 2" wider and was 3" taller that the boiler. All four side and end walls of this tray were tapered, so you would have "draft" built in already. It is worth looking for. The one I found had rather thin walls, so I constructed a small wooden box with a bottom to support the tray, preventing the sides from bulging out from the weight. If you can not find a suitable tray, you could make the box perform the same function, by applying several coats of a hard paint, like a cement floor coating polyurethene mix paint like used on garage, and school floors all over the inside, sealing all corners as you go. You may want to run a small beak of caulk along each seam to prevent leaks. When dry, coat all the inside of the tray/box with pam twice. Use spring clamps or other means to support the boiler/rubber from the inside. Lay two sticks across the mouth of the tray and fasten them to the box. Clamp the boiler supports to them to locate the boiler 1" above the tray bottom, and equal distance from all sides. This is necessary, because sometimes the boiler will tend to "float" when you pour the plaster. Mix plaster to a viscosity of milk or cream, and carefully pour all around the outside of the rubber filling the box allowing the plaster to seek its water-level to just at the bottom edge of the floor boards. You may find you have to re-level your mold tray to achieve this, so watch it as you get close to the running boards and correct level as needed. When you quit pouring, gently tap on all four sides of the tray/box to vibrate the plaster to allow any air bubbles to rise to the surface. Allow a couple of days for the plaster to set up and dry out. I usually wait a week to be sure. The next step is a little complicated, so I'll stop here and answer any questions on anything that may not be clear.
Another quick note about these plaster car casts. Sometimes they do not come out of the mold just right or have some flaws. These things, when weathered, make GREAT junk cars. I filled a whole arroyo bank with them. They look real good, and there is no guilt at wrecking a good metal car! Happy Modeling!! John
Benny asked me about making boiler castings awhile back, and I just now found a couple of photos in my Portfolio when I did this. Back then I was Project Engineer developing some prototypes for a large automated assembly line and the forms you see were for some of the mounting fixtures to be used on that machine. I got permission from the foundry and paid for my own form tree to cast 14 boilers using the same lost wax process, but poured in brass. (The other items were poured in aluminum and stainless steel). They later cast some in 60-30-10 lead that came out better than I expected. The first photo id during the pouring while the form trees were white hot. The next photo is showing the boilers closest to the camera during the cooling down shock. That also "sets" the metal and fractures the mold ceramic so is easier to clean the sprue and castings inside. My total cost was $45.00 for the wax, and the metal, and the "dipping-up" and it was professionally done.
I'm sorry, I meant to mention that when you make the "master" for a mold, it may be a store bought auto, plastic boiler, or whatever, and you coat it with plaster, you have a mold to reproduce another. A Lost Wax "master" will be melted and run out leaving an exact shaped cavity to pour polyurethane, lead, plaster, or gold into the mold it makes, to make another whatever. That is a single service mold for one part. The white stuff you see in the photos is a type of plaster that is fired just like a coffee cup. No mold release agent is required. You may have found that when pouring hot lead into a plaster mold, the mold exploded! Even if it did not explode, your part's surface was covered in small cavities. That was from steam generated from moisture still in the plaster mold. This can splatter hot metal on you, so make sure your mold is dry and hot before you start to pour!! Hard plasters that contain lime, get hot during their cure, so make sure your mold is absolutely dry, and may be warm, but not hot, when pouring into it. To make successful metal poured castings of any of the cerro alloys, always slowly raise the temperature of your mold to dry it out, then raise the temperature to the melting point of the metal being poured, then you get fine detail. A cold dry mold will freeze the metal in thin sections preventing the cavity from being fully filled, spoiling your part. The best "free poured" or "gravity" (non powered) castings are "Lost Wax" Castings invented by the Chinese. (they say). Here you make a wax "master" for each auto you want to cast. So you have to sculpt, or cast a wax auto yourself. You can make trucks, engine details, jewelery, or people, and cast all of them at once, but you can only make one part from each wax/mold set, so it is often advisable to make a mold to cast the "waxes" if you need several. In the industry, we make up what is loosely called a "Christmass tree", or form tree in a foundry. The tree is all wax. The trunk is the pouring sprue, and there can be one to many branches, each leading to a wax "casting pattern" (the auto). There is sometimes plaster "cores" inserted if the casting is to be hollow. The whole wax tree is then dipped into a powder cloud of molding plaster, and slowly drawn back out and allowed to "dry". The powder is so fine it allows detail like rivets. The other dips are made with a more granulated plaster that will allow trapped air to excape without bursting the hot mold when molten metal is poured in. It is dipped as many times as is needed to build up the calculated thickness needed to support the weight of the material that will be poured in when molten hot. Then the wax tree with the plaster coating is very gently placed into a drying oven and allowed to pre-cure. That "sets" the plaster and is inspected for any cracks or broken pieces. Then the temperature is slowly raised until the wax melts and runs down out of the pouring sprue and into a recovery pot below, usually around 400 degrees. The temperature then is raised to vitrify whichever grade of plaster is being used. Some times it gets incadescent like for stainless steel and gold, other times it is only about 500 degrees for plumber's lead. The mold sits at temperature until all wax residue burns away not even leaving any ash, just hot air inside. Then the guy in the fire suit gets ready, another guy gets the molten metal ready, and another guy opens the furnace door; the fire suit guy gently but quickly grabs the upside down mold out of the furnace, turns it over as he sits it down in a sand box, and cools his gloves but stays ready to support the mold in case it starts to fall over. The pour man starts pouring molten metal into the mold, ready to stop and step away if the mold spills, or keeps on pouring until the mold is full to the top of the sprue. As soon as the mold was removed from the furnace, the third man closed the oven door to maintain the temperature on any other molds still in the furnace. The fire suit guy pushes sand up all around the poured mold to make sure it will stand while solidifying, then goes after another mold, and the process is repeated as long as the men can stand the heat. They may pour several different kinds of metal from other ladles into separate molds all at one pouring session. This all happens quickly and these guys are expert at it. Cast iron toy cars and trains were cast the same way, as is jewelery. It produces very fine detail much different than is possible from a "sand" casting. When casting plaster to make a plaster auto, the mold has to be a two or more part type of mold in order to remove the auto and cast another, IF you are casting bottom detail, or want the auto to be hollow. This type of mold can have what is called "flash", which is usually a tiny line of metal, plastic or plaster that tries to run between two parts of the mold. This is call "hard Molding", usually used to make a lot of parts. Some sort of mold release agent is required for this type of molding, because the mold is to be used over again. Of course, high production parts are always made on hard plastic or metal molds in the thousands. Today we have rubber molds that will make a number of parts before becoming damaged, looseing fine details. It is usually advisable to use a mold release agent on rubber molds to prevent damaging the mold surface. There are two part rubber molds which do very well in prototype work where only a few parts are needed. There are some cerro metal alloys that are of low enough melting temperature that they can be poured into rubber molds for a couple or so parts, like pewter. The finest detail will be achieved by using one of the art type plasters that is used to make the "picture frame" ginger bread work found in expensive homes on their ceilings, of which Hydrocal is one. It also will make a more durable mold, to cast the softer plasters in, as well as polyurethanes, epoxies, and even lead and the cerro alloys. Use all mold release agents sparingly, and if you lightly spray paint the mold cavity after applying a little mold release, sometimes your part can come out painted. I started casting lead soldiers back in 1937 and you must be told that the EPA forbids you from having that much fun today, because they say lead will kill you, which means I should have died back in about 1940 according to the EPA. I'm 71, and I haven't even had a cold since 1974. I did destroy my lungs from pouring polyurethane castings though in the 1980's, so do be careful of that one. Otherwise, have fun, experiment, you will find all kinds of things to make from plaster, and Play-Doh. [ 31 October 2001: Message edited by: watash ]</p>
