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Step 24: Make a Rebar Bender

Now it time to anchor your dome to the 12' X 12' area where you have cleared the grass. You will use twenty pieces of bent rebar to anchor your dome into the ground.

To see a visual of how to make a rebar bender (jig) and bend the rebar to hold down the dome, visit this website:

www.monkeyc.org/dome/d-gaskets.html
Brilliant. Great work!! I'm curious about wind though. Do you find that wind causes problems through that open portal? I mean in a ballooning fashion that tears the plastic off the beams? I had that issue from a small spot.
could i use PVC as substitute for wood
Another alternative for the connectors, is PVC pipe sections, and plumbing strap. You have to cut the end of the board at an angle, but it makes a fairly strong connection. The pipe is a little big in these pictures, optimally, it should be just big enough for all the pieces of wood to fit around.
nicely done my dear sir.
Try do it without connectors, for simplify, use cone-connection method. Regards.<br><br>http://acidome.ru/lab/calc/#7/12_Cone_3V_R2.5_beams100x50
I am going to build this with your center as my kids play-house this spring. I really like the improvement in the design.
Hmm... I've been wanting to make something like this for a long time, but I have two problems: (1) wood is expensive (and I'm 13) (2) I'm absolute carp at woodwork. So, is there any other material I could use? PLEASE?
hey dude, just find someone that knows how to do it and learn from them! take woodshop in highschool or something. i was lucky to have my dad who is experienced in carpentry, electrical work, plumbing, and car work. so i learned a lot from him. now im the leader of the fabrication/build and electronic sub teams on my robotics team. check out the bot we made :D http://www.youtube.com/watch?v=lrm1GxsA6hY (check 8-12. up until then i did all the work on building it ;D ) (i designed a lot of the frame and such, then cut it out and welded it with a TIG machine) if i can figure out how to tig weld aluminum in about a week to make that, im sure you can quickly master woodworking ;D just never give up! because you never truly fail until you give up :3 something else you might be able to use that'd be a bit easier than wood is PVC. its pretty cheap (not sure if its cheaper than wood or not) you can just come up with a design, get some tubes, some lil joint connectors and pop it all in place! :D then you can disassemble it and such (maybe use 2 end connectors and some zipties to hold it together?) also, if you happen to have one of those dome camping tents with 4-6 tent poles. just put those in the basic form of the dome, then put plastic over them instead of the tent ;D
Nick, don't be discouraged by woodworking. It's tough at first. When I was your age I said the same thing. I came back to it 30 years later and found that with a bit of patience, willingness to learn and a lot of cheap MDF that I'm a pretty decent woodworker. I wish I would have had the patience to keep trying I would be a master carpenter by now.<br><br>
I can imagine your difficulty, being only equipped with fins, and the tendency of wood to float out of your aquatic environment. "I'm absolute carp at woodwork "... Sorry about that. I don't usually poke fun at other's typos (I actually almost just typed "fin" instead of "fun" back there, for real and no joke). Myself being at best a four finger hunter and pecker (Man, that sounds rude!) and mine own typographical errors probably being legion. I reiterate, this is not a dig, but merely a giggle. Seriously, I suggest keep bashing at the wood. Skill will improve with time. Many "professional" homebuilders (I use that term loosely) have committed more sins and atrocities with wood, than you would care to imagine. As to the expense, if you go to the lumberyard and ask for "strapping" rather than "framing" lumber, it is somewhat less dear.
I think threecheers summed it up nicely! &quot;Absolute carp&quot; describes the syndrome perfectly :] And I agree with you packrat: I was tempted to verbalise my smile too. Still, it happens to the best of us: this is from Jomsom, Nepal and nicely balances threecheers' typo (pink highlight is mine).
I've been there.... Jomsom, Nepal... on my way to Muktinath to bathe in the glacial water 180 taps. Om namah Shivaya! ;D
Ha Ha. I suppose the farm and the forest could use the trout crap as fertilizer...
If you're concerned about the price of wood, you can try pallets. We have a couple of personal-water-craft and motorcycle places around here that have piles of pallets they just give away, or else they have to pay to have them hauled off. The nice thing about free wood, is that mistakes are cheap. Another advantage to the geodesic domes, is that shorter pieces of wood can be used when building at higher frequencies. I once built a storage building entirely out of scrap wood. It was a 4 freq. 16' dia dome, no strut was longer than 30". (Lot more labor in a higher frequency though)
Free wood rules! A couple other good sources include: 1) Old box springs from beds. Not all beds have 'em, but those so equipped are a source of eight or so nice one by fourish planks. There's some effort and a mild degree of danger in the dismantling process, but it's fun and rewarding. I just built a rain barrel stand out of such lumber. 2) Roof truss manufacturers offcuts. Most of these places have a bin or pile marked "FREE WOOD" You can get loads of chunks of truss grade wood, many with nice angles already cut in them. Most are pretty short however. If you're lucky, you can score some of the banding support pieces (used to keep the steel strapping from digging into the bundles of lumber during shipping.) They usually look kinda rough and have a 1" or so wide channel routed into one side to hold the strap. They are crazy strong and usually a good three or four feet long.
pvc, rebar, steel pipe... There are designs for domes that use those materials which you've prolly already sussed out in this website, but in case you've been too bz 2 research. http://www.instructables.com/id/How-to-build-a-PVC-geodesic-dome/ Many hardware stores n construction supply stores can cut the pvc for you. Get free or extremely cheap scrap pvc at garden centers, construction sites, dump sites, and Habitat For Humanity type centers during spring or fall seasons. Those seasons are also best times to get the other hardware needed for the project. Craigslist often has them in FREE listings, however, you have to be diligent in your searches, be the first contact, and be available on the fly to pick the stuff up esp. if they're CURB ALERT listings. Most burners use pvc \&lt;&gt;/ esp. cuz it's lightweight and durable.
I've seen domes made with 3/4&quot; conduit tubing. This is cheap and it's galvanized metal. The pipes were cut to whatever length, and the last 2 inches or so was flattened and had a single hole drilled through it. Pipes were connected via a bolt through the holes. Super simple and elegant. And moveable too!
PVC which really doesn't do much for expense tho
How does it hold up to snow? Living in Northern Minnesota, and close to Lake Superior, snow and wind are a fairly big factor to consider.<br>
Well, the design keeps snow from building up. Most of it will slide down and collect around the base as soon as it reaches critical mass and can no longer fight the steepness of the dome design. Northern Minnesota gets about 81&quot; of snowfall annually with their deepest snow base month being January with fall rates in the upper 50s. Spread over a month, that's not much depth hitting the dome. If you're worried then periodically sweep off the top of the dome that month. It's phenomenally rare for Lake Superior to create large lake-effect snowfall so if you're worrying about six foot overnight blizzard dumps then expect that to occur every 100 years or so, if that. The most snowfall occurring in a 24 hour period in the northern region of your state was 36 inches on January 7, 1994 in Lake County, MN. That's nothing to sweat about for a dome greenhouse like this. I live in Denver, CO and we see near the amount of snowfall you do. We have these domes all over Colorado. Even in the high country where snowfall is greater. Just be sure to attach the plastic cover as tightly as you can and reinforce seamlines and replace the staples from time to time. Also, there are more rounded green house designs you can use; houses that have less sharp angles. :) \&lt;&gt;/
At this point I would add an additional 3 hole strip under each bolt for hanging interior lighting / etc.
very nifty <br> <br>build one big enough to cover a fig tree (up here in the great frozen snowy North Shore (long Island), and you got have a nice snow cover. Just use blue tarp material and pack straw and mulch all around the trimmed bundled tree. Then in spring remove the color tarp put clear tarp. remove the stakes pickup over the tree move to a spot and gentlem start your seedlings! <br> <br>You could also just use the clear as shown but do a color tarp and tarpaper on the tree. Put flanges on the outer perimeter so pulling the stakes is easier. leave the door opening BUT reinforce it with easily removable struts so to move the structucture you donot have to lift far to move it over the tree. <br> <br>great instructable
Buckminster Fuller Really had his game on when he invented this! <br>Fun and practical. Just remember water always wants to go down and out. <br>Cheers!
awesome instructable full marks :)<br />
WAY cool, guys!&nbsp;&nbsp; After following the step-by-step I think I could build one of these and I kinda-sorta su. . .uh, I mean stink at math/geometry. :-)<br /> <br /> Like I said, way cool.<br />
This is great - but there are no details about how to build the door and keep it closed!&nbsp; That's a pretty crucial step, if you want it to function!&nbsp; Also, it would be nice to have some info on how you make your flaps, etc.&nbsp; <br /> <br /> Those pieces of info would make this about perfect.&nbsp; Thanks for doing the work to present this!<br />
&nbsp;Why won't you just sew velcro onto it? Or zippers? But I'm not sure about the flaps.
Very nice!&nbsp; How dies it hold up in the wind?<br />
&nbsp;lol!<br /> <br /> I feel like I'm watching tv - it's a repeat!<br /> <br /> It's a good project though - I'd love to do&nbsp;something&nbsp;like this.<br />
This is Great!&nbsp; Seems like a nice bunch of people too. I'm going to search your site.<br /> <br /> Excellent Job,<br /> <br /> <br /> <br /> Dario63<br />
The offsite link to the monkeyc.org rebar bender illustrations no longer works, but the rebar bender shown here is intuitively obvious: <br/><br/>Take one hunk of railway tie, four honkin' big bolts with large heads, and a four-foot piece of 3/4&quot; plumbing pipe or conduit. Sink the bolts halfway into the railroad tie as shown. My guess is that they're about an inch and a quarter apart. I don't know why the back two are staggered like that, but doubtless there's a reason for it. To use: thread rebar between the bolts. Slide the pipe onto the rebar. Stand on the railway tie. Have your friend stand on the railway tie too. Use the pipe as a long-handled lever to bend the rebar.<br/><br/>I found instructions for a somewhat more elaborate and full-featured DIY rebar bender here: <a rel="nofollow" href="http://diyrobj98168.blogspot.com/2009/03/how-to-make-rebar-bender.html">How to make rebar bender</a>.<br/>
The link for monkeyc.org's bender has changed to <br/><a rel="nofollow" href="http://www.fetchaphrase.com/dome/d-gaskets.html">http://www.fetchaphrase.com/dome/d-gaskets.html</a><br/>haven't checked out your alternate link..... great instructions so far!<br/>
Thank you for your Connecters I can now build a small green house with two growing beens in side.
Great Job you all I want to build a 51" foot Dome for Green House.
Great project. Stapling a second layer of plastic to the inside of the frame would improve its ability to trap heat, though you might have problems with moisture trapped between the layers. Rigging a two-layer door with overlapping flaps would also help keep the greenhouse warm in early spring and late fall.
what is the benefit of creating a dome rather than a simple rectangle? or any shape for that matter? i do understand that the bucky ball shape or dome is potentially really stable, but are there any other benefits to it for use as a green house i mean?
Air flow is supposed to be better in a dome, natural convection, so less temp. differences throughout.. There is also some efficiency in the use of materials. If you have a central standing area with the plants around the outside, you could use a smaller building for the same headroom. An "A" frame building would work in the same manner I suppose. Not necessarily a "better" greenhouse, but I like the idea of teaching the children alternatives to the plain "square" buildings that are so commonly used. Learn to think "outside the box" _pun intended. This also teaches some math and geometrical skills. For an easier to build greenhouse, 1/2"-3/4" PVC pipes can be bowed, and a plastic material draped over them, but this just has so much more style.
Great project! I am going to build one in my back yard.
Great design - I want to build one of these domes as a greenhouse but have struggled to find the perforated metal strap you used for connectors anywhere in the UK. Can anyone tell me where I can get hold of this stuff in the UK or suggest an alternative way to make the connectors?
There is a slightly less rigid kind of strapping called 'plumbers tape' in the US. The normal use of plumbers tape is: hang a pipe that is being run across a ceiling below joists in a basement, one might take a strip of plumbers tape (that has regularly spaced holes and is 1 to 1.5" or 2 to 5cm wide) to attach to the stringers or joists making a sling to hold the pipe. Attach a strip like this every couple of joists or few feet (meter or so) to keep the pipe close to the joists.
could possibly work if you put it on the inside as well as the outside of the wood.
I was thinking of the same thing, but plumbers tape is thin and if bent enough times in the same spot it will brake. So, I suggest double it (triple layers or double rows if you got, or can buy, enough plumbers tape).

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