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Showing results for tags 'scratch building'.
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Scratch Building - OMG, I lost my dizzy
Alyn posted a topic in Tips, Tricks, and TutorialsThe first step in scratch building is usually to break down a complex shape into simple geometric shapes. Take for example a distributor. This is a fairly simple shape consisting of three progressively larger cylinders. The top and largest cylinder is surrounded with equally spaced 1/2 round cylinders. Step two is to reduce the dimensions to something reasonably close in scale. In most of my modeling, this is 1:25 or 1:24 scale. The difference between these two scales is merely 1/2" in a foot, so I don't worry too much and generally will use the same scale conversion for either. After doing this exercise numerous times, you get to know some of the common measurements. For example, 1/8" rod is about 3" in scale, 1/16" is about half that, or 1 1/2". Another common measurement is 1" which is about .040" in scale. Therefore, .030" should equate to 3/4" These measurements should be about all we need to build the distributor. Start with some 1/8" styrene rod for the cap and .030" half round styrene to surround it. The most difficult task in building a distributor is to keep the 1/2 round equally spaced around the cap. I start by drawing vertical and horizontal lines on the end of the rod as accurately as possible. Find a stable platform to hold the rod and glue some 1/2 round along the length of the rod in-line with one of the marks.Once this dries, roll the rod 180º and glue another strip on the opposite side. After the second strip dries, the rod can be rotated 90º. At this point, my first two strips help the rod sit nicely in my impromptu fixture with the guide line perfectly vertical. Glue another 1/2 round strip in this position and once dry, rotate another 180º and add the fourth strip. At this point, you should have four 1/2 round strips glued on the rod at 90º increments. Hopefully, they look equally spaced and run straight down the length of the 1/8" rod. Four additional 1/2 round strips are now glued between the first four. We no longer need the marks on the end as it is easier at this point to position each 1/2 round strip evenly spaced between two of the existing strips. Glue on all four and you should end up with something like this. I make a point of being generous with the liquid qlue. Correctly applied, the plastic will fuse together and eliminate any sign of a gap. A coat of primer should reveal the quality of you work so far. The folded edge of some 400 grit sand paper can be run up and down through the grooves to clean things up if necessary. At this stage, I liken the part to an extrusion. It's far longer than needed for one distributor. When you need to build one, just cut off a slice and continue with the final steps.
1/16th 69 Camaro ProMod 7/22/14 motor painted
Romell R posted a topic in WIP: Drag Racing ModelsHey fellas vacation time is over and its time to get started on another build. Actually I got started on this one a couple weeks ago I never stoped building once the daytona was done. I'll be fabricating a Reher-Morrison 5.3 nitrous motor from brass and aluminum. As a side note I will be using parts from my buddy Jim Littken of http://www.micronitro.net/ And from Charlie Of http://www.protechmodelparts.com/ and any other source that will make the job easyer. Anyway Sassy and I invite you to come along on another journey as we endevour to build a better model. sassy says Hello...... Ok I started with some brass stock and drew my pattern out for the motor block ends, which were then cut out.... its a good thing I cut out four because my first set cam out loped-sided, sorry I didnt get alot of pics but heres where the engine block is as of now..... Oh and before I forget heres what I built a couple weeks ago. The guys at the DSC have already seen it. Notice my special jig (which is still under construction) it will help me to pump out the chassis for RR Speed. Hope you enjoyed see ya real soon.
Scratch Building - OMG, even Harry gets one!
Alyn posted a topic in Tips, Tricks, and TutorialsThis topic is just for Harry. He's right about all the floating alternators and generators. We've all been guilty of this for years.So, just to appease him, I scratch built a generator bracket for my 62 Catalina 421. Many kits mount the alternators and generators by nothing more than the fan belt. This kit and a few others at least add the upper adjustment bracket. To go a step further, I added the lower pivot bracket. It's not based on any particular design. I couldn't find a good image of the real bracket on a 421, so I just made up my version of a typical design cast in aluminum. This is a very simple project consisting of a scrap piece of .030" styrene card stock and two small strips of .010" square styrene rod. The long tail will eventually be cut off, but makes a great handle while I fit, drill, file and prime the part. After creating the basic shape and drilling the bolt holes, the styrene rod was laid into position and fixed with liquid styrene cement (Ambroid ProWeld). Several steps were needed to get it to fit, so the handle really came in handy. The cut-out between the bolt holes is a relief cut for the freeze plug at the end of the cylinder head. The curved indentation at the opposite end of the ribs fits nicely under the generator. Here's the finished part with the handle cut off and a coat of Model Masters Aluminum Plate. I added a couple of Grandt Line bolts to dress it up. Here's the bracket mounted in place. A big thanks to Harry for pointing this out. Not much of a tutorial needed for such a simple part, but I think it's a nice addition to a detailed engine.
Scratch Building - OMG, I am pumped Up!
Alyn posted a topic in Tips, Tricks, and TutorialsIn another thread, John Pol asked for some tips on building an electric fuel pump similar to the style used in 60's and 70's drag cars. The first thing that came to mind was Stewart Warner. I've built a few electric pumps, but they were generic cylinders with fuel line fittings on each end. Here's an example on the chassis of a Revell 32 Sedan (in front of rear axle). I'm sure this in not what he had in mind, so I decided to try building one a little more like the old SW pumps. The pump consists of a main body, with some slightly larger diameter bands, and a sediment bowl on the bottom. Essentially, this breaks down to various diameter cylinders. Rather than glue a bunch of cylindrical slices together, I went a different route. 1/8" tube was used for the main body. To duplicate the protruding bands, I wrapped some styrene strap around the 1/8' body. The strap in this case is .015" X .040". For starters, the strap was laid perpendicular across the body. A small amount of liquid cement holds it in place. After a short waiting period, the glue was set enough to finish wrapping the straps around the 1/8" rod. More drying time, and then the excess strap was cut off with enough left to completely circle the body. Now it's time for yet another application of glue. This represents the main body casting for the pump. Now for the sediment bowl. I found a scrap of 3/32" rod which is slightly smaller in diameter than the body. Another scrap, in this case 1/16" hex styrene rod, was glued onto the 3/32" rod to serve as a mounting pin. It will slip into the end of the pump body. Why make it separate? This piece and the body will be different colors. To get the best color separation line, the pieces can be painted separately and then assembled. Here's the sediment bowl.
Scratch Building - OMG, extrusion madness
Alyn posted a topic in Tips, Tricks, and TutorialsIn my tutorial on scratch building distributors, I mentioned the concept of extrusions. Real extrusions are forced through a die to create the necessary shape. The parts I am making only mimic this effect, but their usefulness is the same. To me, this concept was the most important part of the tutorial. Here's another example to show how handy this technique can be. Once again, I'm starting with some round and 1/2 round styrene. In this instance, the core shape, at .080" is slightly smaller than the rod used for the distributor. This rod was too small to fit in my aluminum heat sink, so I used a triangular file to cut a shallow groove in a small wooden block. The round rod was laid in this groove with a piece of masking tape holding it in place. The half round is then positioned along the top of the larger rod and also taped into place. Liquid cement is then applied to bond the two parts together. It's important that the pieces of 1/2 round are directly opposite each other. To ensure this, the dot on the end of the 1/2 round will make it easier to check the orientation of the parts during construction. Once the glue sets up, this part is turned 90°. The mark on the end aids in making sure the rod is positioned correctly. Place another strip of 1/2 round opposite the first and glue it in place. That's about it. How easy was that? Give this assembly 24 hours to allow the glue to thoroughly dry and then it's ready to slice. The next post will show a few of the uses I've found for this particular shape.