How to work with Balsa Wood for Bridge Building, Tower Building, Boomilever and Wright Stuff events:
25 Bridge Building Tips
November 29th, 2006
1. Humidity affects the weight of your bridge. Keep your bridge in a
closed container with a few grains of rice.
2. Go easy with the glue bottle. As a general rule of thumb, if you can
see it than you are using too much.
3. Keep your hands clean! Oils and grease from your skin can ruin your
4. Perfect practice makes perfect. The more bridges you build, the
your construction skills will be.
5. Keep your bridge from twisting by using lateral bracing.
6. An L-beam is more efficient than a square, but harder to build.
7. Balsa wood comes in a wide range of densities and stiffness. Weigh
piece that you buy.
8. It is cheaper to buy Balsa in sheets and cut your own wood strips.
9. It's still true, measure twice and cut once.
10. Keep a log of every bridge you build. Record notes and dimensions;
won't remember later on.
11. Try to videotape testing your bridge. You may get a clue on what
12. Always keep safety in mind when using sharp tools. Most mistakes are
made when you aren't paying attention.
13. By cutting a piece in half, you more than double its strength in
14. Good lighting when working will help you perfect those little
15. Always test your bridge before taking it to a competition, but leave
enough time to build another.
16. Draw out your bridge on graph paper to make sure that it is
symmetrical. I prefer the 11″ x 17″ graph paper.
17. Different trusses have different ways of spreading out the load.
18. Wood has about the same strength in tension, no matter how long it
19. CA glue is a fairly strong, light, fast-drying glue used by many
20. Balsa wood sands very easily. Be careful not to sand off too much.
21. You can mix wood glue with water to cut down on weight. Doing this
also helps the glue to seep into the wood, creating a stronger joint.
22. Remember to close your glue bottle when you are done using it.
23. Basswood will bend easier than Balsa wood. Try steaming or soaking
your wood to help it bend.
24. Use Lap joints whenever possible to get the best strength.
25. What you want to look for in glue: drying time, price, weight, and