KJ Shover[/I]]"The home depot has some nice lexan in stock here So that's a plus.
I'm trying to get as much behind it as possible. My brake lines will drop in and run behind it. When I get them made, I'm going to have the ends mated with different angled banjo's. and I'm considering a different throttle. For the windscreen, I'm going to use a smoked lexan, probably 50% tint.
How did you shape your plastic? I'm going to experiment with a heat gun and oven."
A few pics of bending jigs, and shields made. The smaller shield was a slightly larger, and darker, replacement for the OEM flyscreen , of about the same thickness. The larger one is 1/4" thick. Both made of dark plexiglass. This one has a slight "kick out"at the top edge, like the Kawa Concours windshields, to further deflect the wind over the rider's head. I think I did this part with a heat gun. You have to be very careful with a heat gun. Too easy to blister the plastic, and too easy to localize the heating, which leads to instant cracking. I found out the hard way!
I turfed the Lexan windshield extension, which was adjustable from level to the top - to 6" above the windshield. Did find a photo of it. You may recognize the location!
tips-
-use white bristolboard to determine the shape, size and curvature of your shield. Most shields, especially the smaller "flyscreen" variety, have a smaller radius at the top. They look more streamlined this way. You can bend the bristol by using two pieces of string , threaded through the lower and upper sections , and fastened with knots to obtain the radii desired. Then hold up against the bike to confirm that this is the shape you want. Before removing the string, cut out two other pieces of bristolboard, approximately the width of the windshield, with the cross sections being the two radii to be used
- to obtain symmetry from side to side( for a windshield, or anything else being fabbed up) is to first draw a vertical centreline down the length of the bristolboard mockup. Then trace out and cut one side only. mark and punch out any mounting holes that will be needed, on this one side only as well.
Then lay the mockup flat, and fold it along the centreline. Trace the outline of the cut side onto the rough side , and mark the holes as well. You now have a perfect mirror image to cut out, and a symmetrical mockup.
Now the fun begins. Transfer the outline onto your material of choice(plexiglass, Lexan, etc.) These plastics can be cut using fine-tooth hand tools (a scroll saw is my favorite) or with power tools, such as a variable-speed jig saw, as long as cutting speed is kept very low(too fast will melt the plastic) What ever the method used, the material must be supported underneath, as close to the cut line as possible, or cracking will occur. It's best to experiment with scraps first to get a feel for the process.
NOTE - leave two tabs on the windshield , as per the cardboard mockup pictured. Drill a small hole(3/16") through each one.
If drilling holes, support the material on wood, drill a pilot hole, then the finished hole. Windshield often start cracking at these mounting points. It helps to "cauterize" the holes, by heating up a tapered punch, and then using it to melt the hole diameter.
Now finish the edge of the windshield, excluding the tabs, by rounding it off. MUCH easier to do while the plastic is still flat! I find a hand-held 1/4" radius router bit ideal for this, but flat files work just as well. Coarse files to rough out the round, fine files to finish, then wet sandpapers, finally rubbing compounds, until the edges are as "clear as glass" Takes some time, but gives the shield a factory-made appearance.
Next, the bending jig. I use white cladding metal for the cover, over a framework of plywood. The jig has to be bigger than the windshield blank so that the fasteners used to secure the cladding to the framework are not within the dimensions of the windshield after bending - otherwise the impression will be imprinted into the plastic. But of course the jig must be small enough to fit into the oven you will be using (center rack) It's the radii that are important here. Transfer the bristolboard shapes obtained previously to the plywood end caps of the jig framework, cut them, and finish the jig.
Now the trickiest procedure. The bending.
Fasten the windshield onto the jig, using two small screws , tighten just enough so the shield doesn't move. Make sure there is no dust or debris between the jig and the plastic (especially important if using clear plastic.)
Heat the oven to 350f,(on "bake"- lower element only) then place the assembly on the middle rack. Close the door, but keep a very close eye on what's happening inside. Depending on the thickness and type of plastic, it will start to bend within minutes. Just the weight will be enough to cause it to form to the radius of the jig - no coaxing manually at this time.
Wait until the plastic is completely formed to the jig,or very nearly.You want to avoid leaving the plastic in the oven any longer than needed, other wise blistering will occur - this is also why the "broil" function is to be avoided. Next, put on work gloves and have some wet rags handy.
Sometimes the plastic will tend to curl away from the jig, at the outer edges, after being removed from the oven. To prevent this, use the moistened rags to press down on the edges of the shield, cooling it at the same time. It doesn't take long for the plastic to cool enough so that it retains it's shape without this extra persuasion - maybe 10 minutes or so.
After cooling for an hour or so, all that remains to do is to cut off the mounting tabs and finish the edges. For support while doing this, just place the now curved shield back on the bending jig, with a rag between the two to prevent scratching.
Don't expect your first attempt at windshield construction to turn out perfect. There is a definite learning curve involved here! But it's a steep curve - the quality of each successive shield increases at an exponential rate! Good luck!
DISCLAIMER - heated plastics give off fumes. These fumes will travel throughout a house at an alarming rate, even during the dead of night, when most wives and girlfriends are fast asleep - or so you may think.
Additionally, these same wives and girlfriends tend to get a tad annoyed -go figure- after having their beautysleep interrupted by choking fumes, and venturing out into their "Womancaves", only to find their new Kenmore Stainless Deluxe Model 65400f with a as yet unidentified huge mass on the centre rack, purpose and use unknown. Set at 350f. And not another soul around.
Most men would laugh such an event off. Not so, all women. Again, go figure.
Best to find a buddy with a home-made powercoating oven, stick your windshield in that. Bring enough beer, your bud will never notice the fumes.
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