Windshield plastic replace?

[chuckthebeatertruck]

I haven't made one in more than a decade, but like others, I used straight Lexan. At the time, I was mostly cutting fly screens with a compound curve. I had a nice buck and I can't remember the temperature (my brain wants to say 250 F) but the Lexan was easy to drape and shape when hot. I don't recall any issues other than going slow to cut.

In fact, I'm trying to remember ANY details on it. It really just didn't present any trouble making my own.

[chuckthebeatertruck]

As for adhesives -- we make a lot of lexan vitrines at the office -- the "glue" of choice is clear acrylic cement. It's not cheap and not exactly fume free. Generally around $1-2 per fluid ounce from online plastic suppliers. Just punch in: "lexan clear acrylic adhesive" and you'll get a dozen commercial choices.

Over the counter adhesives generally lose their chemical punch before they fully "solvent" weld the relatively thick lexan. The commercial adhesives don't have this issue and you MUST be very careful to only apply adhesive where you want it. Any excess can create a streaked or spotted mess instantly.

[BigLakeBob]

I bought a beaded windshield for my Panhead from National Cycle several months ago. In the lower corner it says 'polycarbonate'. The windshield in .085 thick. Attached is a picture of the molding. The smaller area that slips on the windshield in .083 and the wider top area is about .125 with a 13/32 (.406) diameter. I cut 3 inches off the top because it was too high for my liking. I cut the same amount off the bottom of the bead. The form of the bead snapped right back on the windshield even though I cut off the top of the shield and the bottom of the bead. If you find beading that will work for you I suggest heating and forming the bead before trying an adhesive. Good luck, let us know the results.

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[Jim]

Thanks for that Info Bob!!! I ordered my Polycarbonate today. I ordered a 24"X24X1/16"". My original plastic is 0.050 thick, whereas 1/16" = .062 This isn't the "hardened" stuff that National Cycle uses to help with scratches and stuff like that (There's is MUCH better than what I'm going to use. .085 is just a cat whisker thicker than .062 (1/16") I mean... what is .020? OK... it's 1/50th of an inch. SMALL! Thanks for that view of the National Cycle bead!! I'm going to do one thing at a time right now. First was to order the polycarbonate... then, after I get it, I'll cut it to shape, THEN I'll figure out what beading to use. I still haven't tried to remove the original stuff. But, I'm going to wait until the new plastic comes and I can start on it then.

[Tom Wilcock]

I cut my .085" thick Lexan with tin snips with no problems of cracking. I then sand the edge. Maybe I was lucky.
Tom

[BigLakeBob]

Thanks for that Info Bob!!! I ordered my Polycarbonate today. I ordered a 24"X24X1/16"". My original plastic is 0.050 thick, whereas 1/16" = .062 This isn't the "hardened" stuff that National Cycle uses to help with scratches and stuff like that (There's is MUCH better than what I'm going to use. .085 is just a cat whisker thicker than .062 (1/16") I mean... what is .020? OK... it's 1/50th of an inch. SMALL! Thanks for that view of the National Cycle bead!! I'm going to do one thing at a time right now. First was to order the polycarbonate... then, after I get it, I'll cut it to shape, THEN I'll figure out what beading to use. I still haven't tried to remove the original stuff. But, I'm going to wait until the new plastic comes and I can start on it then.

Hopefully the 1/16" will be fine as I do not know if National tested various thicknesses and settled on .085 for a particular reason. Even though .020 is only 1/50th of an inch your 1/16 windshield will be 25% thinner than a National. I guess you'll find out if it matters, hopefully not. I glanced in McMaster and didn't see any closely resembled trim right off.

[HDSmitty]

Having worked with both polycarbonate and plexiglass quite a bit, I'd say you got lucky cutting it with snips. If there's only a limited supply to be used, I would NOT use snips. A fine tooth blade on a band saw works well or a jigsaw if you put plenty of tape down to protect it from vibration scratches. Hope this helps.......Smitty

[Jim]

I was planning on using my dads band saw. I'll add extra tape as well.

Even though .020 is only 1/50th of an inch your 1/16 windshield will be 25% thinner than a National. I guess you'll find out if it matters, hopefully not.

I hadn't thought of it like that!

Would I prefer the .085 with the UV protection and hardened against scratches Polycarbonate? YES, absolutely... but...I look at it this way... my original windshield is .050 (thinner than 1/16) and the "new" Polycarbonate is .062 then, I'm already ahead of the game .012". Now... if this does NOT work, I'm only out $22. I had thought about calling National and ask them for a windshield for a 1946 Indian and see what they say, but... I'm going to try this first and see what happens. I was only planning on using it for the "transition" weather anyway and not to use during the summer warmer days.

[camsaure]

Aircraft supply outfits sell Plexiglass and Lexan in various thickness, They probably have glue also. I once had a repop windshield that was a bit thinner then stock, I hated it because it would suddenly cave/fold back around 70 mph. somewhat startling. For my 50 Pan I needed a pointed style. This was before you could get repops. I used Lexan and removed my old original beading, It was not too much of a problem.

[Jim]

Aircraft supply outfits sell Plexiglass and Lexan in various thickness, They probably have glue also. I once had a repop windshield that was a bit thinner then stock, I hated it because it would suddenly cave/fold back around 70 mph. somewhat startling. For my 50 Pan I needed a pointed style. This was before you could get repops. I used Lexan and removed my old original beading, It was not too much of a problem.

I had read on some other forum that a guy had one pop backwards so he also hated LEXAN after that and went to a Plexiglass windshield. But... I know I won't be doing 70. 45-50mph is about my limit. I like to look around too much to be going faster. GOOD Tip on the aircraft supply outfits. My Polycarbonate is "In the Mail". So... who knows how long that'll take.

[Jim]

OK, so I had a bit of progress on my homemade windshield. I cut the Polycarbonate the same size as the original stuff. I drilled the holes and I mounted them on the brackets to see how it "fits" together and this is what it looked like. I'll update soon with more progress. I'm trying to keep it as cheap as possible... Cutting on my dad's bandsaw and drilling with regular drill bits was easy. I used a small (I think) 1/64" bit as a pilot hole and then a 1/4" bit.

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[Jim]

I tried heating the Poly with a heat gun.... that didn't work because the area was too big, plus it's kind of cold out which allowed it too cool off to fast. So... I used a BULLET heater, or "Salamander" heater and held the Poly about 10" away constantly moving the Poly. After about 10-15 min. I let it cool and then took it apart and the Poly held it's shape. I put it back together and then took it for a ride. Temp was nice and warm at 45F. I have NOT put any edging or "bead" on it yet, but I wanted to see just how much it would flutter. Between 45-50 it started to flutter on the top left. NOT so that it scared me, but made me look at it constantly. Now I'm going to try some of this stuff called Edge Trim Rubber Seal. This is the type that has "metal" in it. I won't be riding the Chief until after I try it on there. IF it still flutters, I have other ideas... See the photos. One pic shows the two Poly pieces, but hard to tell them apart, BUT, you can see that it held the curve after taking it apart. The other is my "heat" source and a bungee cord that helped hold it with just a tad more bow to it to help if it decided to "spring back" when it cooled. The next is a photo of the windshield on the Chief. PLUS, a photo of the original "Bead" on the original (not sure what year) windshield, but the "Bead" is SOLID with a thin groove cut in it. Now that Bead is VERY STIFF which I assume would help the original plastic from fluttering. I'm thinking that the "original" windshield is a RE-Pop from the 1980s when "other" stuff was bought for this machine.

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[Jim]

This is what I ordered from Ebay to use for the Edges.

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[PaulCDF]

Looking Good Thanks for keeping us posted.

[LUVMYSHOVELS]

BMI Karts sells supposedly nos harley windshields 7 hole bottom with beading. maybe you can make one work. Ibought 2 and used 1 on my shovelhead and worked good. They also have national stamped in bottom right corner. They also sell bottom pieces. The only problem i see with them is they have a terrible odor that wont go away. Hope this helps.