I have not tested this method out myself yet, but I will soon. It take very little prep or materials. All you have to do is soak the wood sticks for a couple days, bend them around a shape, and let it dry. He mentioned putting it on some low heat while drying.

My only question at this point is whether or not it reduces the strength of a popsicle stick. I’m not sure at this point.

Game description:
Construct a bridge and test your building skills. Help your people gather items located on the other side of valley.

How to play?
Build a bridge using your mouse and available budget. When it is done click “Test your bridge”.
Your workers will use it to get items located at the other side of valley, and bring them back to the shop. Your goal is to collect all items in level.

For each level you have limited budget. All money that you won’t use, become your score, so cheaper bridge = higher score.
Money collected in all levels of game will be your total score and will be sent to leader board. You will use those money in challenge mode too.

Building tips:
* There are two types of bridge elemets: “walk” – workers can step on them, “connectors” – used only to connect elemets of the bridge, workers do not collide with them.
* “Connector” elements are cheaper and lighter so use them as much as you can
* Each type of item have different weight and some of them will need stronger bridge then others.
* At the begining of game only wood elements of bridge are available. In further levels, aditional materials will be accessible also, so use them wisely.

Design the Bridge

To start building a popsicle bridge, first you need to come up with a design. Sometimes aspects of the design are set for you if you are building a bridge for a school project or a competition. Often the length of the bridge, as well as how many popsicle sticks you can use are defined by the rules you have been given. Other things, however, are up to you.

If you are just starting out building model bridges, I would recommend you use one of the three most common truss designs. These are the Howe Truss, the Pratt Truss, and Warren Truss. Each of these are very strong designs. Once you have picked out a design, then you can draw out your design to life size on paper, you even draw it out on the computer. The blueprints I have for sale have done all this work for you, and allow you to focus on building the bridge without worrying about how to design a bridge.

Build the Bridge

Now you are ready to build your popsicle stick bridge. Choose your popsicle sticks carefully, because when you buy them from a store some of the sticks in the package will be no good. Choosing a glue to use is also important. Often what I do is build each side of the bridge individually and then join them together. When you are joining the sides, be sure to make the bridge perfectly vertical. If the bridge is leaning at all, then it will be much weaker. I always include lateral bracing to make my bridges stronger.

After you finish your bridge completely, wait enough time to allow the glue to dry completely before you test the bridge. Sometimes you will want to test the bridge immediately, but your bridge will not hold as much weight if you test it before the glue has cured. Be sure to take pictures of your popsicle bridge and send them to me! I would absolutely love to see photos of the bridges you have made. In fact, I have a photo contest going on for the month of January, so be sure to check that out.

Test Your Popsicle Stick Bridge

Testing a popsicle bridge is perhaps the best part of making a bridge. I think so, that is. Perhaps it is something inherent in a boy’s nature to want to see things break and explode, I am not sure. I do know that I love testing my bridges to failure not only to see them fly into millions of pieces, but also to get an efficiency score and to learn how to build a better bridge. You can learn a lot more about testing model bridges on my Testing Tips page.

Testing the Warren

To start out building a model bridge, you have to decide what materials to use. Frequently I use Balsa or Basswood. These two woods are common, and you can find them in most any hobby store. You can also use popsicle sticks, toothpicks, paper, cardboard, and tons of other things. Often I choose to make a balsa wood bridge because they are versatile and fun to construct. What materials you choose will depend on the goal you have for your bridge.

Most competitions tell you what materials you can use, and limit your choice. If you want to build this model bridge to exhibit on your shelf, then you can use materials that have more aesthetic appeal. However, if you are building a bridge to test it to failure, in order to see how much weight it will hold, then you want to use efficient materials.

Once you decide what materials to use, you need to start designing your bridge. Decide how long you want the bridge to be. Are you trying to set the world record for the longest popsicle stick bridge, or are you going for an easy project? You also need to pick out a truss design for your bridge. There are three standard trusses used in engineering, the Warren, Pratt, and Howe. After you pick a design, I find it helpful to draw it to scale on graph paper.

After you have designed your bridge, you need to start construction. Make sure you have all the tools and materials you will need, such as glue, saws or exacto knives, clamps, jigs, wax paper, and such. The glue you choose is important to the strength of your bridge. I recommend Cyanoacrylate Glue. Use your drawing on graph paper as blueprints to build your bridge on. Consider covering your blueprints with wax paper to help keep glue from ruining your drawing. You can do this step in two parts. Make one side of the bridge first, and then remove it from your blueprint. Repeat for the other side, and then join the two sides together to make a bridge.

Now that you have finished your bridge, you can enjoy it. If you are going to test it, remember to wear safety goggles. If you are going to display the bridge, or use it for a model train set, you are good to go.

How Does CA Glue Work?

CA glue is a acrylic resin. It uses water to cure. Yes, water. Other glues rely on the lack of water to cure, but CA glue is the opposite. Usually the natural moisture in air is enough for the CA glue to harden, but this is not always the case.

CA glue works best on porous materials, such as Balsawood or Basswood. In fact, any kind of wood is ideal for CA. Actually, one of the absolute best materials for CA is your skin. No joke, human skin is very porous and has a good amount of moisture built into it. This is why CA glue always seems to instantly bond your fingers together. I have accidentally glued my fingers together many times throughout my building career.

Cyanoacrylate Glue comes in different thicknesses, or viscosities. Thicker CA’s take longer to set, and are heavier. In addition, thicker types tend to leave gaps in the joints. On the other hand, a thin CA glue will soak right into the wood, creating a stronger joint.

Benefits of CA

• Quick Drying
• Can Be Lightweight
• Can Soak Deep Into Joints

Disadvantages of Cyanoacrylate

• CA Glue Is Expensive
• Easy To Glue Your Fingers Together
• CA Goes Bad Relatively Quickly
• It is Easy to Use Too Much
• Has Strong Fumes

CA glue has strong fumes, which some people react against. Please only use CA glue in a well ventilated area. Have a window open in the room where you are working.

Where Can I Get CA Glue?

• Local Hobby Store
• Online

Any hobby store ought to have some sort of CA glue. But you probably can find a better price online. In fact, here is a link that will take you to Amazon and show you their selection of CA glues from their various sellers:
CA Glue From Amazon

Tips On Using CA

Remember that CA glue bonds easily to human skin? Well, eventually the natural oils in your skin break down the glue molecules and the CA is worn away. Keep this in mind as you are handling the wood that you are using to build your models. As a general rule of thumb, always wash your hands to reduce the oil transfer to the wood you are using. Human oils weaken any glue joint, especially when using CA glue.

Don’t use too much glue. A little goes a long way.

To help CA glue last longer, keep it refrigerated.

To create a stronger joint, roughen up the edges of wood you are gluing with sandpaper.

I have found that if you do glue your fingers to your model, then don’t try to peel your finger off. Instead, rotate your model and twist until your finger comes free. This helps to prevent skin loss.

Additional Resources

Cyanoacrylate Glue and Other Adhesives
What is Cyanoacrylate Glue?
What Good is CA Glue?
Cyanoacrylate

Why Do I Like Basswood So Much?

Basswood has some advantages over Balsa wood. For instance:

• Basswood has significant natural strength. This makes it easier to work with.
• Basswood bends easily. For making arch bridges, this comes in handy.
• Basswood looks nice
• Basswood is relatively consistent from tree to tree in density.

However, Basswood does have some disadvantages. These include:

• Basswood is more expensive than other woods, such as Balsa.
• Basswood is not always readily available.

Basswood Information
Here is another resource about Basswood.

Glue for Basswood

Basswood does not require the use of special glue. I would still follow my recommendations at my Glue Tips page.

Where to Buy Basswood

I would always recommend that you go to a local hobby store to pick up your Basswood. However, if that is not an option, here are some places to buy Basswood online:
Basswood Sheets

Basswood Sticks

To help clear up any confusion when I talk about the “efficiency” or “efficiency score” of the bridges I build. This is a mathematical equation to determine how well a bridge performed.

Simply take the mass that the bridge held, and divide that by the mass of the bridge.

Mass held
________ = Efficiency

Mass of bridge

Some confusion comes up when I weigh the bridge in grams while add weight to the bridge in pounds. These units do not have the same base, and cannot be divided against each other. I usually convert pounds to kilograms (1kg = 2.2 pounds) and then multiply the number of kilograms by 1000 to get grams.

So if my bridge held 54 pounds, I would convert that to kilograms. 54 pounds equals 24.54 kilograms. That equals 24540 grams.

To get the efficiency, I take 24540 and divide that by the mass of the bridge, which was, say, 33 grams. The efficiency score is then 744.

This bridge building kit from Amazon actually has three different bridges. It comes with all the supplies you need to build a suspension bridge, a truss bridge, and an arch bridge. All of these combined make this kit an excellent gift idea, or something you can build just for fun. The package also contains an informational booklet which talks a lot about how bridges work, and is really quite good. I remember referring to this booklet time and again when trying to figure out the different forces that act on bridges.

If you are looking for a good bridge building project, this could be perfect. The kit is not expensive, and contains a lot for the price. I definitely recommend this kit. The Kit is called “Our Amazing Bridges Architecture Kit” and can be purchased at Amazon.com here.

Here is an outline I made for the presentation:

• History of Bridges
• Nature
• Greek
• Roman

• Types of Bridges
• Arch
• Da Vinci Bridge
• Truss Bridge
• Suspension Bridge
• Cable Stay Bridge
• Moveable Bridges

• Tacoma Narrows Bridge

• For A Contest
• Read the Rules!
• Design Within an Envelope
• Why use Triangles
• Compression and Tension
• Building: Wood and Glue
• Joints
• Bending Wood
• Construction Techniques
• Check Bridge Against Rules
• Weigh Bridge

• Testing a Bridge
• Different Techniques
• Safety
• Efficiency

What do you think about this presentation? Is there anything you disagree with?

Important Link in Video:

1997-2006 Academic Years – Mechanics: Bridges

I want to put x-shaped supports on my bridge, but I don’t know how best to join them. I’ve heard of something, I think it’s called a half-lap joint, that I think might work best. You cut half of the wood off the part of the strip that will be the actual joint, and then connect the two pieces at those joint parts. There isn’t any part of the wood sticking out, and they are very connected, I think, as far as how the weight/force is distributed, which I figured would be good. But is there a better way to make an x?

Perhaps a more simply way to describe this is cutting a notch out of both pieces of the X at the point of intersection. The reason to do this is to avoid one pieces laying on top of the other, which makes it slightly harder to glue and adds additional pre-load force on that piece.

However, I think cutting notches is more trouble than it is worth. All the bridges I have built (see my Science Olympiad Bridge ), using X’s for lateral bracing, have had one piece laying on top of the other. This does mean you have to use clamps or tape to hold the pieces down while gluing. But I consider this less of an inconvenience than trying to cut two notches out of the lateral bracing. In fact, most of the time my lateral bracing is so thin that I couldn’t cut a notch out of it even if I wanted to.

The notches must be cut exactly to the right size. If they are even a little too large, then you weaken your lateral bracing pieces. This may not be a problem, however, because most people use pieces of wood that much bigger than they need to for lateral bracing. Still, I do not see cutting notches as the way to go.

Another way around this issue is to not use X shaped lateral bracing. Instead, you could use a zig-zag pattern. This will look like a Warren truss on top of your bridge. A stronger pattern is the Warren with vertical supports for lateral bracing.