I don't have any plans, but here is a write-up I did, and you can see some scanned photos at http://ken.serack.com Ken ******************************************************* This was all really my wife Lynn's idea! We started with 2" schedule 40 pipe and fittings. I too, was leery of the strength, but was willing to try it as it did not cost too much. I did not know too much about buggy geometry at the time, so I just put something together and tried it. The first test was really whether it would hold together with my (240lb.) weight. I let it cure for 24 hours before putting weight on it. Then I carefully sat on it, and it held! I got braver, and actually stood on it and jumped up and down! It held fine! There was some flexing, but it gave a nice suspension feel. So, we took it to the beach and tried it out! There certainly were some strange looks from people upon seeing it for the first time. Well, I learned a lot about it that weekend, and went home and built a second revision. What I changed, was the steering geometry, and the width of the rear axle. I had the steering angle on V1.0 set at about 15 degrees, and that was much too steep. It really became unstable above 15 mph. The axle was too narrow, and would allow easy rollovers, but the biggest annoyance was that I kept rubbing elbows and shoulders on the spinning tires! Ouch!!! Well, I built V2.0 with a 35 degree steering angle, and about a 1 meter rear track width. I have looked at a lot of buggys, and there is a lot of variance in the steering geometry, even in buggys from the same manufacturer! My guess is that there is a fairly wide range that works just fine. I like my buggy where it is. It is stable! I have been up to about 22mph, and it tracks straight. The rear track width is probably too wide for 2-wheeling, but I'm not into that yet. OK, so I took V2.0 to the beach for my week of summer vacation, and ran it 5-6 hours every day for a week! Boy was I sore, but I sure did like the way it worked. Then, the day before we were to leave for the Long Beach Kite Fest, the buggy broke! I was trying to buggy in very low wind, and was not steering enough down wind. The pull of the 10m2 Peel was all the way to the side of the buggy, and rather than sliding, it twisted the frame of the buggy, and broke the center tee fitting. I partly attribute this to the fact that I jumped pretty hard on the buggy when it was freshly glued, and to the fact that I did not have smooth tires (they are knobby scooter tires) that would have slid, and to the fact that I weight 240lb. Well, the really nice thing about pvc is that you can cut and re-glue it. I went to the hardware store the next morning, and got the replacement fittings, and cut out the broken pieces, and re-glued it. I buggied 2 more days with it including at the Long Beach Fest. I went home and built V3.0. This is what I am running now, and will post photos of it soon. It is a combination of 2.5" schedule 80 and 2" schedule 80 pvc. I have used the 2.5" in all of the high stress areas, and the 2" for the seat frame. Not only is the schedule 80 pipe thicker, but the 2.5" fitting are much stronger. This buggy is very stiff, and I have no fears of it breaking at all. It is not light! I have not weighed it, but it weighs a little more than a standard Peter Lynn buggy. Well, I can live with that! PVC pipe and fittings come in a variety of strengths and thick nesses. The schedule number (20, 40, 80) refers to a standard of some sort that specifies how strong, what sort of pressure it can take, what sort of chemicals it can withstand, etc. The common plumbing material is called schedule 40 and is white. The schedule 80 is mostly used for electrical conduit, and is gray AND sunlight resistant. It also has a wall thickness that is almost twice that of schedule 40. I have not found fitting that are rated schedule 80, but found that the schedule 40 fittings in the 2.5" size are more than strong enough. I really do believe that 2.5" schedule 40 pipe is more than enough for the buggy. IO don't believe that you need the schedule 80. It is too heavy, and more expensive. Also, the structural failures that I have had were never in the pipe, but in the fittings. And, I have never had a 2.5" fitting break! Only the 2". PVC cement is basically a pvc solvent. It melts the two pieces together. It comes in a various forms: fast, medium, and slow setting, as well as different colors. The purple primer is mostly acetone and is used to clean the joint of oily residue from the casting process. I am still running 14" scooter wheels, but found smooth tires! My next modification is to put standard fat buggy tires on it. The plastic scooter wheels work great, but flex a lot in corners. I don't think that they will fail, but I prefer something stiffer. I used them because I had them. If you have to buy wheels anyway, go for the fat tires. I still have not found a reasonably priced source of plastic wheels. The wheels from Peter Lynn are too expensive for me. I will (if I can't find a source of plastic wheels) just use the steel wheel-barrow wheels. They are $17.98 from Northern Hydraulics. To attach wheels, I just used pvc reducers on the end of each axle that were threaded with .75" pipe thread. I them drilled out a .75" pipe thread brass bushing, and bolted the axle through this. I will probably end up using a length of threaded rod all the way through the axle when I go to the fat tires. I have already straightened the axle bolts on my rear wheels, so I really need something stiffer and stronger than the 5/16" axle. Going to a 1/2" (or whatever size fits the bearings in the wheel-barrow wheels) stainless threaded rod supported in the middle of the PVC axle should be sufficient. The steering fork is a kids scooter fork I got at a garage sale. Standard bicycle headset bearing fit very nicely into 1.25" pvc pipe, so mating the fork to the pvc buggy was very easy. I just used reducers and 1.25" pipe and screwed in the fork and bearings! They are not very sand proof, but are easily serviced. For a seat, I used seat-belt webbing and adjustable buckles to make a supporting criss-cross woven webbing with a foam pad velcro'd to it. It is very comfortable, and can be adjusted as close to the ground as you feel safe! :-) For the seat back, I cut a slot out of 2 tees so that the would spread and fit on the axle. I slipped them on to the axle before gluing on the wheel fitting. Hose clamps allow the angle of the seat back to be adjusted. I found that the seat back would slip easily, so I slide a piece of sandpaper in between the tee and the axle before putting on the hose clamps, and it stays put. Foam padding on the pvc backrest makes for a very comfortable ride. Painting: I painted my rev 2.0 buggy and the tandem, but will probably never paint any more. Paint, (without a lot of preparation) does not stick very well, and these things are used in a harsh environment. Sand, dirt, and salt. Not to mention transporting them. The paint does not stay looking good for long. I spent some time cleaning the printed lettering and marks off of the pvc, and just left it natural color. On the V3.0 buggy, I used the gray schedule 80 pipe, and white fittings, and it really has a nice look. I suspect that you could find paint that is specifically formulated for plastics, and clear coat it with a very hard finish, but I am not sure it is worth it. The tandem unit is much easier to make than a buggy, as it is just a flat shape. I just put an eye bolt on the front, and clamped a drilled piece of angle iron to the rear axle of the buggy. Use a clevis pin to attach it. I have the passenger put their feet on the rear axle of the buggy, but it would be very easy to put foot-pegs on the tandem unit as Dave Lord did on his. In any case, put non-skid tape wherever the feet go to keep them from sliding. Be sure that you make the seat frame wide enough for your passenger's seat! Gluing technique is important! You need to clean the pvc joint area well, (I use acetone) and use the purple primer. I then use a medium setting cement (lots of it) and then let it cure for a couple of days. It is VERY important to practice your assembly before gluing! ***************************************** Well, here is an update on wheel attachment. If you haven't built your buggy yet, wait until we figure this out. This should not affect tandems, as that typically do not take the side stresses that a buggy does, but keep it in mind. It appears that my method of wheel attachment on the rear axle is not strong enough. I buggied hard for two days, and one of the wheel attachments broke. I was able to glue a new bushing in, and buggy the rest of the weekend, but I am convinced that this is a weakness in the design that needs to be fixed. What broke: I used 2.5" pipe for the rear axle ending with a coupler and a 2.5"X3/4" pvc pipe reducer. I then glued a 3/4"X1/2" pipe thread reducer into that. The brass bushing with the axle then screws into that. The 3/4"X1/2" reducer failed. There were too many glued joints and too much stress. I suspect that if I had used a 2.5"x1/2" pipe thread reducer (I could not find one at the time), this may not have failed, but I am re-designing the whole axle. What I am planning: I plan to use a thin wall stainless tube inside the rear axle. I will put about 8-10" of either delrin or aluminum into each end of this tube (I'll use epoxy, and/or set-screws to hold both the insert and the axle tube in position). The ends of this will then be drilled and threaded to match the wheel bolt. What this will do is support the twisting force of the wheel across that entire width of the axle, rather than with just the PVC reducers on each end. I know, it's not PVC, but it still does not require welding, and can be done with hand tools When I started this whole thing, I knew that there were some weaknesses, and was willing to suffer some breakdowns in order to find them. I feel that I have now found most, if not all of the major flaws. The 2.5" pipe and fittings really have taken care of the frame strength, and I believe that this new axle design will solve the wheel attachment problems. ******************************************************************************** I ended up just putting a 5/8" threaded rod through the PVC axle, and putting the steel wheelbarrow wheels on that. It works great. I just found brass bushings that fit in the ends of the PVC axle, and drilled that out to fit the threaded rod. I also had to make this buggy fold up for my trip to Ivanpah, so I cut the main up-tub, and put in threaded pvc couplings so that the whole thing could be unscrewed and split in two. I had to cross drill these couplings to keep them from turning in corners, but once that was done, I had no problems, and buggied all week at Ivanpah. I put over 200 miles on the buggy that week. ****************************** Last summer, after 5 years of buggying on the PVC buggy, I was going about 15mph and hit a hole in the sand, and the buggy broke into 4 or 5 pieces. Not repairable! I bought a new Libre V-Max a couple months ago, and took it to Ivanpah. The PVC was a very fun thing to do, and I learned a lot by doing it. Ken