Monday, September 08, 2014

Blast from the past: aging an authentic wood catapult kit, part 2

This is the second in a two part series reviewing the working wood catapult model made by Pathfinders. In the the first part, I reviewed the the kit and gave you some assembly tips. In this part, I'll tell you how I went about making the catapult look like it truly belongs on a medieval battlefield.


What is the Kit and Where Do You Get It?
The catapult kit is sold various places, but can easily be found from Amazon as the Pathfinders Medieval Catapult Wooden Kit.

Getting Ready to Get Old
Once the kit is assembled, you should have a bit of fun testing it out. I recommend throwing small grapes at a pyramid of empty aluminum cans. If you would like to make your catapult look old, read on. For this process, I used the following tools and materials:

* Carving knife
* Small wire brush
* Furniture finish touch-up markers
* Coarse twine
* Elmer's glue
* Sandpaper - 100 grit
* Minwax wood stain - Early American
* Round wooden disks
* Wooden wheel pegs
* Popsicle type "craft" sticks
* Soldering iron with wood-burning tip
* Gun bluing
* Portable hand drill
* Ball-peen hammer

None of these things are essential. You should feel free to use whatever tools and materials you have on hand or can obtain easily.

Making the Catapult's Wood Beams Look Old
The first thing I did was removed the string and washers from the model.

I used a carving knife to take the corners off of the straight edges of the wood. I didn't remove a lot of material because I didn't want to compromise the strength of the wood.

I just shaved off small, irregular shavings to make it look a little less perfect and perhaps as if the beams had been hand-hewn. I also rounded the spoon-shaped end of the throwing arm.

Next, I added the wood knots to the beams. I have a set of three wood finish touch up markers. I used the second darkest color. By gently resting the very tip of the marker on the unfinished wood, pigment from the marker is drawn into the wood fibers in a way that looks something like a real wood knot. Use the underside of the model to perfect your technique.

The knots may look a little too dark at this point, but don't worry. After placing knots of various sizes on the beams, I gave the entire model a coat of Minwax wood stain. I used "Early American" simply because I had some around. You can use whatever color you like, so long as it is considerably lighter than the knots you have made with the marker. This allows the knots to show through the stain. At this point, you should give your catapult some time to dry.

Later, I used a wire brush to give the catapult some scratches and wear marks to make it look like it had been used for years. I also used a wood-burning tool to add some grain lines and cracks to some of the beams. Make sure these lines follow the grain of the wood so that they appear natural.

I dipped the the string that comes with the kit in the Minwax and wiped the excess off with a rag. This makes the "rope" look old too.

Adding the Twine to the Crossbar and Throwing Arm
I am not sure if it is authentic or not, but I thought some cordage wrapped around the throwing arm and crossbar would look good. I also figured this would provide a bit of cushioning. I used a coarse three strand twine for this. I unraveled the strands so that I had a single strand. I tied one end of twine around the crossbar.

Next, I spread some Elmer's glue on the section where the twine was to be placed. I then wrapped the twine in a tight coil around the crossbar. I tied off the end and put a drop of glue on it to keep if from coming off.

This process was repeated on the throwing arm where it meets with the crossbar.

Making the Wooden Wheels for Your Siege Engine
I purchased a set of round hardwood discs that are 2 - 3/4 inches in diameter. I also purchased some wooden toy axle pegs and some craft sticks -- really they are just Popsicle sticks. All three items can be found at craft stores.

I used a soldering iron with a flat wood burning tip to create parallel lines on the wheels to make it seem as if they were constructed from individual planks. I also burned the edges of the wheels a bit to simulate wear and wood grain.

Next, I glued two short lengths of Popsicle sticks to the outside of each wheel to model the boards that would hold the wheels together.

I drilled a 1/4 inch hole in the center of each wheel and in the four corners of the catapult base. I sanded flat sides on the axle pegs and darkened them with marker.

Using the toy axle pegs, I mounted each wheel to the catapult. I glued only the holes into which the pegs go, so the wheels can move freely. Finally, I gave the wheels a coat of wood stain.

Finishing Touches to The Antiqued Catapult
The catapult was starting to look pretty old at this point, but the bright metal washers on the outside ruined the effect. I used the rounded end of a ball-peen hammer to dent one face of each washer. I then rubbed some gun bluing on the surface to give it a dark, oxidized look. DO NOT get this stuff on your tools.

In the end, I spent 30 to 40 minutes making the basic functioning catapult kit, and 4+ hours making it look old! I had a lot of fun doing it.

Where to Get the Kit and Other Supplies
Most of what you need can be found at your local hardware store, craft store, or hobby shop. If you have any difficulty finding these items locally, here are some online sources:

* Pathfinders Medieval Catapult Wooden Kit
* Wood carving knife
* STEEL SCRATCH BRUSH
* Sharpie Touch up Markers - 3 pack
* Sisal Twine
* Elmer's Glue-All
* 100 Grit Sanding Sheets
* Minwax Wood Finish - Early American
* Wood toy wheels
* Wood toy wheel axle pegs
* Cuisipro Frozen Pop Sticks
* Woodburning and soldering tool set
* Perma Blue, liquid gun blue kit
* Cordless drill
* Ball peen hammer



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Thursday, September 04, 2014

Blast from the past: building a wooden catapult kit, part 1

 
 
This is the first in a two part series reviewing the Pathfinders Medieval Catapult Wooden Kit. In this first part, I will tell you about the kit and give you some assembly tips. In part two, I'll tell you how I went about making the catapult look like it truly belongs on an ancient battlefield.

The kit comes with nearly everything you need to assemble the catapult. The only material you need to provide is white Elmer's-type glue. The kit comes with a small swatch of sandpaper and suggests that you have a ruler and scissors available. The kit arrived in a slender cardboard box with instructions and parts separated into two plastic bags. No excessive packaging, no impossible-to-open-plastic-clamshell. I like that.

The kit contains just over a dozen wooden parts, two washers, some string, a small bit of wire, and some soft Play-Doh type clay -- otherwise known as "ammunition".

The wood is a clear-grained pine. Just one of the pieces of my kit had a medium sized knot in it. It had been filled with a little plastic-wood type filler to keep things solid and smooth.

How were the instructions?
The instructions are printed in black and white on 8 pages. There are instructions in English, French, and German which is nice, though they are intermingled in a way that requires a bit of scanning and rescanning. I found the directions to be very good, though there were a few vague spots. I'll address these very minor pitfalls in the next section. The line drawings in the instructions are simple and clear and serve as the primary means of instruction.

What helpful hints do you have?
Overall, the kit itself took me a little over half an hour to make, though they suggest that you set aside 1 to 2 hours. The kit is suggested for ages 9 and up. That sounds about right to me.

Here are a few helpful hints for the assembling the catapult kit:
  1. Read the entire instruction manual all the way through, paying attention to the drawings. This won't take long and this will prevent any possible confusion.
  2. At first, I wasn't sure how to tell the crosspiece that the holds the trigger from the upright braces. It's quite simple really: just read the directions (I hadn't yet). Note that they have thoughtfully placed red marks on the crosspiece and the base with which it mates.
  3. The kit is held together with pegs that are glued in place. There are 18 total. Be sure to sift through the lot to find the two that a just a bit longer than the others. These are used to add tension to the string.
  4. I found that the pegs fit rather tightly. The glue helps to lubricate them a bit. I gently used a nonmarring hammer to tap the pieces together. Alternatively, you could use the included sandpaper to slightly taper the ends of the dowels and ease their entry.
  5. Add a safety/trigger - The trigger arm didn't always want to hold the throwing arm in place when under tension (OK, yeah...so maybe I have it wound too tightly). I rigged up a small diagonal piece of wood that fits in a notch to keep the trigger arm from swinging. By pulling this diagonal piece out, the trigger arm is free to swing and the catapult will fire. (See image below for my safety/trigger addition.)
  6. A small hobby or razor Saw is handy if you want to trim some of the dowels that are left a bit over the surface of a few parts.
  7. Consider staining and/or sealing your model to increase its beauty and lifetime. More on this in part 2 of this series.

So...does it work?
The packaging claims that the catapult can throw a soft clay ball over 15 feet. This is absolutely true. I easily achieved distances over 20 feet and don't think I have put undue strain on the model. Should you choose to add extra horsepower to your model (and this is just my speculation), I believe some added string and a reinforced crossbar would allow you to throw a grape twice as far as advertised.

The Verdict?
This is a well proportioned and historically accurate catapult. More specifically this is a mangonel variety of catapult that uses twisted fibers for its power source. I gather that many had a sling on the end rather than the spoon shape we typically see. (You can learn more about catapults from The Art of the Catapult: Build Greek Ballistae, Roman Onagers, English Trebuchets, and More Ancient Artillery)

Everything that was promised was delivered and the model outperformed the advertising copy. When was the last time you purchased a product that did that?

I give the Pathfinders Medieval Catapult Wooden Kit high marks.

What's next?
In the next installment of this article, I'll show you how to the catapult model look ancient and ready for a siege.


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Saturday, May 25, 2013

Five machines that changed the world: bow, waterwheel, trebuchet, escapement, and governor

Ingenium: Five Machines That Changed the World

In his book Ingenium, physicist Mark Denny examines five devices -- the bow and arrow, the waterwheel, the counterpoise siege engine, the pendulum clock anchor escapement, and the centrifugal governor. The author combines narrative, illustrations, and even equations to cover the history of each device. As a physicist, he is able to explain the physics behind each machine, how it was used, how it changed over time, and the impact they had on the world.

From the book description:

Consider the bow and arrow, which transformed warfare by allowing soldiers to attack their enemies at a safe distance. Or the waterwheel, which enabled Old World civilizations to grind grain, pump water, and power machines during a period of extreme labor shortages. Medieval warriors engaged in an early form of biological warfare by using the trebuchet to launch dead animals or plague-ridden corpses over enormous fortress walls. The pendulum clock forever enslaved modern humans to the clock by linking the accurate measure of time to the burdens of schedules, deadlines, promptness, and tardiness. And the centrifugal governor gave rise to an entire branch of modern engineering science: feedback control.

Here's where you can learn more about the book Ingenium: Five Machines That Changed the World



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