quatumrulesoverall Posted March 25, 2007 Report Share Posted March 25, 2007 Hi guys, could anyone of you suggest how to build a wood tower (probably balsa) and glue in oder to be as much light and strong as possible? Which structure should I use to support as heavy weight as possible? Quote Link to comment Share on other sites More sharing options...
ronthepon Posted March 25, 2007 Report Share Posted March 25, 2007 Use arches to support the major reigions of your frame. Turtle 1 Quote Link to comment Share on other sites More sharing options...
quatumrulesoverall Posted March 25, 2007 Author Report Share Posted March 25, 2007 Use arches to support the major reigions of your frame. Great then, but how could I build arches from straight wood ? Quote Link to comment Share on other sites More sharing options...
HydrogenBond Posted March 25, 2007 Report Share Posted March 25, 2007 Besides arches, the triangle is a very strong shape. Once the apexes are pinnned or glued, the wood has to buckle before the shape distorts. Making support beams out of a lot of little wood triangles leads to a very strong shape, i.e., roof trusses, with the load distributed over more material. The compression strength can be further increased with lamination. This means plywood and maybe I-beams. These will increase compression strength for the same amount of wood. Try to combine plywood, I-beams and triangles. Quote Link to comment Share on other sites More sharing options...
eric l Posted March 25, 2007 Report Share Posted March 25, 2007 Great then, but how could I build arches from straight wood ? You can bend wood after steaming it. If it is something like a scale model that you want to build, you can steam the wood in a pressure cooker with a very little amount of water, and a kind of grid above it to support your sticks. If it is a full size tower you want to build, start with Wikipedia for info on trusses : Truss - Wikipedia, the free encyclopedia Quote Link to comment Share on other sites More sharing options...
ErlyRisa Posted March 26, 2007 Report Share Posted March 26, 2007 actually ''Not'' steaming the wood when bending, and bendind it so that it in-effect becomes the spring... will take a greater load for less weight than any other structure... you could distribute the load amongst many 'springs' allong the height of the structure... just watch it you don't go over the maxload rating! PS... this is the concept used in bridge building.... forces are 'pre-tensioned' throughout the structure and directed to an 'immovable' anchor. OH PPS ... the Galelian Arc.. is the most 'light vs force' arc that can be used. Quote Link to comment Share on other sites More sharing options...
Turtle Posted March 26, 2007 Report Share Posted March 26, 2007 Combine these two good classes of bridging ideas and support your bent arch with triangular trussing. No matter what form you use, make your cuts as precise as possible, as glue filled gaps are weak. :naughty: Quote Link to comment Share on other sites More sharing options...
ErlyRisa Posted March 26, 2007 Report Share Posted March 26, 2007 another good tip...and a bit of a challenge Dont cheat with glue joins at all. Medievil techinques, of split pins and tennoning will be infinitly stronger than glue... especially so becuase wood 'changes'. Quote Link to comment Share on other sites More sharing options...
CraigD Posted March 26, 2007 Report Share Posted March 26, 2007 Hi guys, could anyone of you suggest how to build a wood tower (probably balsa) and glue in oder to be as much light and strong as possible?…Combine these two good classes of bridging ideas and support your bent arch with triangular trussing. No matter what form you use, make your cuts as precise as possible, as glue filled gaps are weak. :naughty:This thread seemed to swerve quickly from building a tower to building a bridge – two very different design challenges. Assuming the tower must support a rigid object at least as wide and deep as it – such as a bricks on a sturdy wood board (pallet) – the challenge is to assure that one or more (wood) columns bear the compression force without flexing and buckling. Since it must prevent the pallet from tipping, a design with at least 3 columns is suggested, with light cross-braces to prevent flexing and shifting. The closer together the columns are, the easier it will be to have effective cross-bracing. The wider, the better it will resist tipping of the pallet. A lot of variable are involved, so making several prototypes might be a good approach. Keep in mind that its failure mode is likely to be flexing and buckling of the columns, not their failure due to exceeding the wood’s compression strength, so be as precise as possible in assuring the wood columns are straight. There are, of course, alternatives to the direct approach I describe above. Intentionally bowing the wood, then attempting to manage its obvious flexing, is one, though unless you are allowed to use a material with good tensional strength, such as wire or thread, I think the previous approach would be better. PS: Moved from math and physics to projects & homework forum, because it is. Quote Link to comment Share on other sites More sharing options...
Turtle Posted March 26, 2007 Report Share Posted March 26, 2007 …Combine these two good classes of bridging ideas and support your bent arch with triangular trussing. No matter what form you use, make your cuts as precise as possible, as glue filled gaps are weak. This thread seemed to swerve quickly from building a tower to building a bridge – two very different design challenges. I knew I should have left the 'e' in 'bridgeing'. :naughty: I was not referring to a bridge, but rather structural components referred to as 'bridgeing'. My bad for the jargon. :hyper: Quote Link to comment Share on other sites More sharing options...
HydrogenBond Posted March 30, 2007 Report Share Posted March 30, 2007 This is sort of cheating but uses only the materials available. I would pressure treat my balsa with a glue-water solution. After that dries, the balsa will be super-balsa. Bending the wood into arches can be done with steam. The trick is to do it slowly and in stages using braces. Bend only a small angle at a time, let it relax, then steam and bend a little more, let it relax, etc. It is sort of liking putting braces on one's teeth; tightened in stages. A simple triangle based beam could look like a crane boon. You use 4 crane boons to form the outline of a skinny pyramid with your platform below the apex. Most of the compression will be on the inside of the 4 boons. Maybe add some I-beams to double up the inside wood to help out with the compression. Quote Link to comment Share on other sites More sharing options...
Turtle Posted March 30, 2007 Report Share Posted March 30, 2007 This is sort of cheating but uses only the materials available. I would pressure treat my balsa with a glue-water solution. After that dries, the balsa will be super-balsa. Bending the wood into arches can be done with steam. The trick is to do it slowly and in stages using braces. Bend only a small angle at a time, let it relax, then steam and bend a little more, let it relax, etc. It is sort of liking putting braces on one's teeth; tightened in stages. A simple triangle based beam could look like a crane boon. You use 4 crane boons to form the outline of a skinny pyramid with your platform below the apex. Most of the compression will be on the inside of the 4 boons. Maybe add some I-beams to double up the inside wood to help out with the compression. Well Hydro, as always you have written an entertaining post with some on-topic words included. If I may be so bold as to offer my comments? :cup: First, pressure treating with anything requires a pressure vessel & compressor which few have at hand. Even given one had one, I have my doubts about using it to infuse glue into wood. Second, steaming requires a vessel as well. A simpler method is to use thin bendable strips to begin with and glue laminate them together over a form. (called 'glue-lam') . The last bit I think a drawing would be helpful. I think an excellent example of a tower to follow that uses arches and trussing is the Eifel Tower. Quote Link to comment Share on other sites More sharing options...
ErlyRisa Posted April 2, 2007 Report Share Posted April 2, 2007 I was waiting for some-one to say 'Eiffel' ... but why do what's already been done.:naughty: how about an asymetric tower...? 'suspend' everything from one side... like maybe a 'lean tower of eiffel' how to make a pressurised steam box.... plactic tub... cut large hole into it.Kettle ... place a pipe over the spout and put it into the box.Turn on kettle - note: pressure can build up ALOT!!! - make sure you have some other hole to release pressure. Quote Link to comment Share on other sites More sharing options...
Boerseun Posted April 2, 2007 Report Share Posted April 2, 2007 Be it a tower or a bridge, whatever you do, avoid boxes in your construction. Wherever you end up with cubes in your construction, you'll have problems. If you end up with a rectangular or square-sided structural cube, rather build it out of two triangles. I once build a completely functional glider that was 100% edible. It was made out of spaghetti sticks and rice paper, and edible glue. It flew a record distance of about 70 meters, then we cooked it. It had a considerable wingspan of close on 2 meters, and was only structurally sound because there were no boxes included in the design. Boxes are BAD! Quote Link to comment Share on other sites More sharing options...
Turtle Posted April 2, 2007 Report Share Posted April 2, 2007 Be it a tower or a bridge, whatever you do, avoid boxes in your construction. Wherever you end up with cubes in your construction, you'll have problems. If you end up with a rectangular or square-sided structural cube, rather build it out of two triangles. Boxes are BAD! Unless they are torsion boxes...>>> The Torsion Box :) :( Quote Link to comment Share on other sites More sharing options...
Scrubbrush Posted February 4, 2009 Report Share Posted February 4, 2009 Im in some sort of "science club" and have been building model towers for three years. There are many designs you can try, however we have found the strongest and lightest balsa design of them all. Get some balsa wood, as thick as you want, depending on the sort of weight you want to support. Lighter is better though. Next, cut the peiced in half (from the thin side), flip one over (wood grains in oppposite directions makes it stronger), and glue. Be very sparing with the glue. Get a pin and just dab drops on. now clamp or pin it together so it dries straight. Do this to all of the peices. Make your tower sketch on a piece of wax paper, and attach it to a wood board. Make sure measurements are right. Next, put the peices on the sketch and glue. Again, be very sparing. Then you have your tower. With our winnign design, we made 2 towers, one small thin one made of triangles and a big one of x's. Put them together, with small on top. Make sure that you leave space in the center to hand the weight. You can probably find pictures online if you cant get a picture in your head. Try soinc.com if you have any problems. There might be suggestions there. Quote Link to comment Share on other sites More sharing options...
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