Build Techniques

[SLM]

Couple of comments back to SLM.

Very informative discussion. Since this is more related to design than construction technique, I am going to post some additional comments on this topic on Design thread.

[S4BB]

We just finished putting our tower jig together and posted an image up in the gallery section. Designed it in CAD and used a laser cutter to cut the parts from acrylic, took about 10 minutes of cutting. We are hoping it will help with alignment when we put the tower together.

[lllazar]

Wow, well ours is almost done but yours look so much more intricate...I used cardstock and balsa However, it still gets the job done quite well, the only difference is that our chimney section jig is seperate form the base jig - it just made things a lot easier and we had to sacrifice very little so all in all it turned out quite well. I think the use of accurate jigs in towers is going to really help with the structural stability, with such a tall structure, you really need to make sure nothing is off center and imbalanced...nice job though, autocad and laser cutting would be awesome but sadly our school only has a mediocre woodshop at that

[iYOA]

We are having an extremely tough time trying to connect the top and base so that the tower is straight. Does anyone have suggestions for this?

[hpfananu]

We're also having that same problem...

[Freyssenet]

Do you guys build a rigid jig? As discussed by other fellows, a jig is the best method for building the towers accurately...

Merry Christmas!

[Paradox21]

I cut my wood a little longer than I need it, then I sand it down to the correct length, however, I am having problems getting each end to be sanded to the perfect angle. Does anyone have tips on how to ensure that the correct angle is achieved?

[GeekyGem]

We have a tower built but its 25 grams. Is it too heavy ? How do i reduce the weight ?

[soccerkid812]

We have a tower built but its 25 grams. Is it too heavy ? How do i reduce the weight ?

thats a good weight to start of with
but can have some major improvements
try using different types of wood or less wood overall

[iYOA]

We have a tower built but its 25 grams. Is it too heavy ? How do i reduce the weight ?

well, i dont know what the tower looks like, but there are general ways to reduce weight.

1. first, make sure your base is not 20cm but 15cm rotated at a 45 degree angle. That will save a ton of weight and will also give you a stronger base(because the primary pieces will be shorter and less slanted)

2. use smaller cross sections for the trusses. The primary compression members of the tower are the ones which take most of the force. suppose they are given about 40N of force, the trusses will probably only get about 1N. Therefore, a 1/16in ^2 cross section will suffice for the trusses. Usually, they will never break. It is the primary compression members that break first

3. Use efficient gluing techniques and dont use a heavy glue. In general a tower should not break due to a joint failure. there a treatise on proper gluing techniques and good glues here: http://soinc.org/sites/default/files/up ... weight.pdf

if you do the above, it should be enough to reduce weight significantly. There is more:

4. weigh each piece of wood and do a stiffness test on it. The ideal piece of wood is light and stiff-which is a decent indicator of strength. It really helps to know what fraction of the weight is coming from where.


5. See if you can simplify your design. Of course, less wood=less weight so if a design is successful, then it is worth a try to simplify it(and if the simplification doesnt work, you can just revert back to the old design)

cant think of anything more right now