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jma, a jig is the best route to get perfect right angles. At this point in time, it cannot really be "fixed" because the tower has already been glued incorrectly. I have had times where I build most of my tower by some type of jig or right angle piece, but once it is removed and additional bracing is applied then the tower can warp slightly due to too high of pre-tension while bracing. For example, the "loop" discussed earlier in the forum describing thin pieces of higher density wood at the bottom of a base to withstand the outward force applied through the tower legs. These pieces can easily manipulate the tower if not glued correctly.

In my past experience the "best", and I mean at best, way to fix a problem once you have made a mistake is to cut the bracings with scissors and take a blade to wedge every so slightly between the bonded pieces of wood. SLOWLY rotate and tweak the bond while holding the leg in place, making sure you don't destroy the tower more than you want to. Once the bracing is off, take fine sandpaper, (in the 200 grit range) and sand away at the glue surface area until the glue has been sanded off. Reapply the bracing with a new piece of wood, keeping everything as constant as you can.

Thanks, LKN.
We did use the zig for the base but this time we only used the zig while gluing 1 diagonal of the X on the front of the leg, then we took the base off the zig and glued another diagonal on the back of the leg (we wanted to try this technique that we just learned from Thomsom' s post). We probably warped it when gluing as you mentioned. We never had this problem with other towers so we did not pay attention while gluing this time. We'll try to fix the base as you recomended.

Now I understand that this has absolutely nothing to do with towers, but what is a reasonable efficiency for boomilevers using the formula: grams held/grams of boomilever. I'm talking about for a reasonably competitive regional. My guess is over 1000, but what exactly is definded as poor, fair, good, great, or excellent/fenomenal...

thsom wrote:Now I understand that this has absolutely nothing to do with towers, but what is a reasonable efficiency for boomilevers using the formula: grams held/grams of boomilever. I'm talking about for a reasonably competitive regional. My guess is over 1000, but what exactly is definded as poor, fair, good, great, or excellent/fenomenal...

lets worry about this next year when we have dimensions or even rumors of dimensions haha its all dependent

mrsteven wrote:

thsom wrote:Now I understand that this has absolutely nothing to do with towers, but what is a reasonable efficiency for boomilevers using the formula: grams held/grams of boomilever. I'm talking about for a reasonably competitive regional. My guess is over 1000, but what exactly is definded as poor, fair, good, great, or excellent/fenomenal...

lets worry about this next year when we have dimensions or even rumors of dimensions haha its all dependent

lol, this is how i deal with my nostalgia

Last year we got burned at State. Our potentially winning bridge had a catastrophic failure. The design was tested and built before, so we knew it would hold. But one of our top columns cracked early on. Not a crisis, we still got top-10, but it made us think about whether we should pretest our towers, just in case there is some huge flaw.

Obviously you can't do that if you only have one tower, but this year we have two. Thanks to Balsa Man, we've got a testing tower too. So what do other teams do on this issue? Prestress to 70%, 85%, or what? What happens if the first one pops under stress, do you go with #2 tower or do you try to repair. BTW, we don't use CA glue, but I guess we could do a repair/replacement with CA.

Thanks

T-B wrote:Last year we got burned at State. Our potentially winning bridge had a catastrophic failure. The design was tested and built before, so we knew it would hold. But one of our top columns cracked early on. Not a crisis, we still got top-10, but it made us think about whether we should pretest our towers, just in case there is some huge flaw.

Obviously you can't do that if you only have one tower, but this year we have two. Thanks to Balsa Man, we've got a testing tower too. So what do other teams do on this issue? Prestress to 70%, 85%, or what? What happens if the first one pops under stress, do you go with #2 tower or do you try to repair. BTW, we don't use CA glue, but I guess we could do a repair/replacement with CA.

Thanks

We preloaded up to 10kg, 2/3 of what we expected the tower to hold.

On a separate note, how are people planning on transporting towers to Florida this year? Towers this year will probably be too tall to carry on the plane, which is what we did with bridges two years ago. Thanks.

TYG wrote:

T-B wrote:Last year we got burned at State. Our potentially winning bridge had a catastrophic failure. The design was tested and built before, so we knew it would hold. But one of our top columns cracked early on. Not a crisis, we still got top-10, but it made us think about whether we should pretest our towers, just in case there is some huge flaw.

Obviously you can't do that if you only have one tower, but this year we have two. Thanks to Balsa Man, we've got a testing tower too. So what do other teams do on this issue? Prestress to 70%, 85%, or what? What happens if the first one pops under stress, do you go with #2 tower or do you try to repair. BTW, we don't use CA glue, but I guess we could do a repair/replacement with CA.

Thanks

We preloaded up to 10kg, 2/3 of what we expected the tower to hold.

On a separate note, how are people planning on transporting towers to Florida this year? Towers this year will probably be too tall to carry on the plane, which is what we did with bridges two years ago. Thanks.

We have a trailer that our coach is driving up a day before the tournament in which we take all of our supplies. I think you should be able to take the tower on the flight; there was some discussion about that earlier but I think everything is under the specific dimensions.

The tower would be 70cm tall, in a box that is around 80cmx40cmx40cm. It seems a bit too big to fit on a plane as a carry on? Thank you for the imput, though. Last year we didn't have this problem since a teacher drove to Wisconsin with our tech devices. We aren't as fortunate this year

TYG wrote:The tower would be 70cm tall, in a box that is around 80cmx40cmx40cm. It seems a bit too big to fit on a plane as a carry on? Thank you for the imput, though. Last year we didn't have this problem since a teacher drove to Wisconsin with our tech devices. We aren't as fortunate this year

I think it will fit as oversized check-in baggage. Well, it does for at least the airline I am flying (AirTran)... The maximum dimensions was 80 inches (Length + Width + Height). However, I am kind of worried because the TSA holds the right to open the baggage and check what is inside...Are there any other suggestions on transportation?