First of all, the measurements at http://www.desertdomes.com are 100% accurate and you can count on the measurements to be exactly what you need. There is certain dimensions to keep in mind though like the difference between the hole-to-hole length and the cut length. Make CERTAIN you know the difference BEFORE cutting your conduit!
Having the right tools will make fabrication SO much easier. Some use saws to cut their conduit to length but I found using a regular pipe cutter works better and results in cleaner cut edges. Hacksaws work but are tiring and dont provide a clean straight edge. An electric cut saw may work well but I did not try it because I couldn't find a way to reliably secure the conduit in place while cutting.
To smash the ends of the conduit you can use a hammer but it just doesn't look nice and takes too much effort. A vise works but is also super time consuming and doesn't provide a rounded inner edge that adds strength. A hydraulic press with rounded press plates is the only way I'd go. Oh and those 1 ton arbor presses at Harbor Freight are garbage even with some added leverage. Save your sanity and ask around to find the 12 ton hydraulic type.
After you smash the ends down I highly recommend putting the ends to a grinder and grinding down the sharp edges. If you use a pipe cutter like I did, the ends become razor blade sharp when pressed so this was required. While I was at it I also rounded off the edges to prevent the dome covering from snagging and tearing on the struts. This was the most time consuming part. I spent many evenings just grinding the ends down. I believe it was totally worth it as there were no injuries while assembling the dome afterwards. Your knuckles will thank you.
As for drilling the holes, I was super paranoid about making the measurements from each hole exact (almost to 1/16th of an inch) but later found that it was actually quite forgiving. At some point my jig for drilling moved and some struts were off by a 1/4 inch. I was bummed when I discovered it and thought I'd have to re-make them. I used them during the construction and found that it didn't make a huge difference. I would still be careful and measure constantly, but know if you're a lil bit off its ok.
Bending the angles for each strut took no time at all and I just eyeballed it against a protractor. During assembly there were a few times that I found my angles were a lil bit off but after some tightening, everything bent right into place.
I used 3/8 Hex head bolts with washers on the top and bottom of each bolt. 62 bolts in all. 15 of these bolts I got at 1.5 inches long and the rest were at 2inchs long to accomodate going through up to 6 struts. This worked perfectly.
To construct the dome, I figured out the method that best worked through trial and error and found this step by step process to be the most successful. I built from the ground up so those who build top-down will have different methods. This method worked using just two people:
1. Lay out the different size struts in separate piles in the center of where you will be building the dome.
2. Lay out the bottom pattern row according to your dome frequency. Mine was 3V so I only had 3 different sizes. My bottom pattern was C,C,B with 15 struts. Don't worry about making a perfect circle at this point. The dome will form itself.
3. Build your first triangle shape (I started on a "B" strut and added the "C"s to make a hexagon). The first row of triangles is the toughest because they can't hold themselves up yet. This requires two people. One to hold the form up and the other to bolt. Otherwise, frustration will set in and while juggling struts, bolts, washers, and nuts (haha... nuts...) you'll start wondering why you wanted to build this damn thing in the first place. Patience and teamwork is the answer.
4. Once the first row of struts is built, the others come pretty easy. I single handedly built most of the second row. You will be unbolting the lower struts a bit but you're just adding to them so it shouldn't come apart. Depending on the size of your dome, you'll need a ladder to get to the next layer. Put bolts with the washers and nuts on them in your pockets so you have easy access to them when you're on the ladder assembling. Have your partner hand you the size struts you need as you go across. I had major fumbling issues and kept dropping bolts, washers, and nuts while I was assembling. My building partner helped by handing me back what I dropped between swearing and saying I couldn't hold my breath if I tried. LOL
5. The last few rows went pretty easily except where my end angles were bent too far. I found that you're better off bending too little than too much. I had to wrench down on some of ther vertices to get some of the final struts to connect but it wasn't horrible. P.S. Don't fall off the ladder at this point. You'll swear a lot, look stupid, and waste 2 hours for a beer break.
6. Assemble the top pentagon on the ground and have your partner lift it up to you. Rather than wrestle the whole dome to fit your last strut, have the last few already connected at the center. I found it was easier that way.
YOUR DONE!
Some minor tweaks to get the bottom perfectly round were needed by simply pulling on the frame a bit. Nothing terrible.
Climb on it, (try to avoid on the center of the struts as they might bow a lil bit) wave to your neighbors, antagonize the kids, play king of the mountain. Its your own personal jungle gym! I was so extremely happy that I managed to take a stack of conduit and turn it into something so massive and strong. Once staked down I don't see how it could possibly move anywhere except by tornado force winds. Its solid.
I sat and had coffee with my dome the next morning and we bonded. She can't wait for the playa.
Next is the cover and once I have a solution for that, I'll post here again. Please comment and/or ask questions. I'm happy to help.
-A!
Believe me there was plenty of swearing and the best part was that my brother-in-laws brother in-law (who is a total jesus freak) was on the receiving end of my verbal assault on all things holy. Heheh. I loved it.
Another important point that I forgot to mention is to lower the RPM on your drill press when drilling into metal. You'll just wear out your bits if you are spinning at high speed. The bit needs time to bite into the metal. Low Low Low RPMs! And use Drill Oil!
