1. Humidity affects the weight of your bridge. Keep your bridge in a closed container with a few grains of rice. or some silica gel packets.
2. Go easy with the glue bottle. As a general rule of thumb, if you can see it then you are using too much.
3. Keep your hands clean! Oils and grease from your skin can ruin your glue joints.
4. Perfect practice makes perfect. The more bridges you build, the better 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 each 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; you won’t remember later on.
11. Try to videotape testing your bridge. You may get a clue on what failed first.
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 compression.
14. Good lighting when working will help you perfect those little details.
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 is.
19. CA glue is a fairly strong, light, fast-drying glue used by many builders.
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 strength.
These bridge building tips will give you a head start when you start designing and building your model bridges. These tips come from my years of experience starting from my time in the Science Olympiad competition and continuing beyond building for fun. Disclaimer: these tips are my own opinion based out of my experience. Other builders might have different views and we might not agree. I encourage you to try things out on your own and decide for yourself what is the best way to build a bridge. Who knows, I could have been wrong about something.