What are the advantages of using the roving over using unidirectional cloth? I assume that you get nice straight fibers that way, but is there anything else?
Brian Kraut Engineering Alternatives, Inc. www.engalt.com -----Original Message----- From: krnet-bounces+brian.kraut=engalt....@mylist.net [mailto:krnet-bounces+brian.kraut=engalt....@mylist.net]On Behalf Of harold woods Sent: Monday, September 19, 2005 11:43 AM To: kr...@mylist.net Subject: KR> building fibreglass geer legs. Hi Netters. Steve Phillabaum wanted information on making a fiberglass gear leg. I built my own. I used roving, which is fiberglass string, about the thickness of "butcher string". It came in a spool about a foot in diameter. I decided to build both legs at the same time I built a box form over twice the required gear length. It was about 3 inches wide and 1 inch deep.At each end of the box were rows and rows of nails. At this point I painted the entire inside of the box, nails enclosed with hot melted parafin wax., as a mould release agent.The roving was attached to the first nail strung along the bottom of the box, hooked over a nail at the other end, then strung back to the next nail in line. after the entire bottom of the box was covered with this "string" it was fibreglasses. I used a very slow hardener, Versamid 140. This gave a pot life of about 4 to 6 hours. After the box was full I set a piece of polyethylene over it and planed a closely fitted lid on the box.I squeezed the lid down with clamps starting at the center.This squeezed the excess epoxy out the ends. I removed the lid and plastic and added more layer of roving This was repeated until the box was filled to a depth of 1 inch with compressed roving. The lid was left on until the next day.The gear leg was removed and the wax was washed off with gasoline. I sacrificed an old band saw blade to cut the leg in half. I made this cut at an angle of about 25 degrees.Then back about a foot from where the cut slope begins I cut it off at 90 degrees. The short piece was then epoxied onto the main leg with the two 90 degree cut end together.This gave me a 2 inch thick leer leg which tapered down to 1 inch. The leg was mounted on a suitable aluminum bracket which was bolted to the front of the front spar.The gear leg has only one hole in it where it attaches to the bracket. Aluminum bars bolted to the bracket on the front and back hold the gear leg in firm position. A cover of 3/8" aluminum on top hold everything tight together. the other end of the gear leg has a spring steel plate bolted to it with 4 bolts. It was bent to suitably accept the wheel axel which was then bolted to it. I tested the gear leg by bolting it to a heavy support on one end and affixing a 2 x 2 x 1/8" x 10' angle iron to it. Weights were added and removed, checking to see that the gear returned back to it's original position. The weight was a 150 pound man that walked out on the angle iron. It bend of about 12 inches , the angle iron collapsed where it was bolted to the gear leg. The man was at about 9 feet from the gear leg end when the iron failed. I consider the gear leg good and strong. I subsequently have heard that the rear spring in a Corvette car has a suitable fiberglass spring . This should be investigated. before making your own. If any one wants diagrams of the box I would send it to them as an attachment. Regards Harold Woods Orillia,ON. Canada. haroldwo...@rogers.com _______________________________________ Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net please see other KRnet info at http://www.krnet.org/info.html
