Anybody know much about heating and bending polycarbonate?

I am making a screen for The Scream.

I did a 700 mile road trip on my Tiger 1050 last weekend, and realised just how much quieter everything is when you can get your head behind a screen.

So before I spend 2 full days on the motorway for the roadtrip to the R&S I am making a screen. It involves heating and bending a sheet of "clear but tinted" polycarbonate. I have been clamping it to my workbench, then heating it with a decorators heatgun in one hand and a hairdryer in the other, then applying my bodyweight to a flat section of plywood to bend it over the edge.

I keep getting these gas bubbles forming in the polycarbonate, which suggests to me I am heating it too much, but if I don't give it big amounts of heat it doesn't bend. Fortunately the area of the screen I look through remains clear , but it would be nice to know how to do it properly.

What do you guys know about it?

That tiger must have an awesonemely aerodynamic screen....

I always find wind noise with a considearbly louder than without.

Or maybe screens are designed for tall people such as your good self?

I've done some of this lately the key is to heat both sides evenly.
And go slowly.
I managed to bend some thick ass 10mm stuff without a problem.

june_whitfield wrote:That tiger must have an awesonemely aerodynamic screen....

I always find wind noise with a considearbly louder than without.

Or maybe screens are designed for tall people such as your good self?

The tiger has a powerbronze screen (which is taller than standard) and then also has some sort of extender thing on it. It's not tall enough for me when I sit normally, but when I lower my head, all the wind noise goes quiet and I hear engine instead, much much quieter. Suddenly now "I get" why people fit screens to bikes. So my plans are:

1, make a temporary "touring screen" for the Survival bike, which can be fitted/removed quickly and easily

2, make a longer version of the screen extender on the Tiger

I don't care if the survival bike screen is scruffy, but I want to get the Tiger's looking nice.

thefastestMelv wrote:I've done some of this lately the key is to heat both  sides evenly.
And go slowly.
I managed to bend some thick ass 10mm stuff without a problem.

And how does one heat it evenly and slowly? Does it require an oven, or will a decorator's heatgun out of screwfix get there eventually?

I do it with a blowtorch attachment on a camping gas doo daad.
But a screw fix gun would be just as good I'd imagine.

I do this for a living, but at work we use a BIG ASS oven. A heatgun will eventually work, but most important: heat it SLOWLY and evenly. with 2 heatguns from both sides would be best and 15-20 minutes heat for 5mm poly should do the trick (depending on the size of course)

usea bit of old street sign, much easier to bend, and then employ your xray vision to see through it, or alternately mount a rear view camera pointing forward and just watch a little tv screen inside the fairing
simples

that reminds me, back when i was a courier, half a plastic chair was a popular choice for a screen.

the kind of stackable moulded chair they used to have in dole office waiting rooms and the like

magnamaniac wrote:I do this for a living, but at work we use a BIG ASS oven. A heatgun will eventually work, but most important: heat it SLOWLY and evenly. with 2 heatguns from both sides would be best and 15-20 minutes heat for 5mm poly should do the trick (depending on the size of course)

The survival bike screen is 800mm x 500mm so that isn't getting into my kitchen cooker.

However, the offcut I have earmarked for use as the "bigger extender" to the Tiger screen is 500mm x 200mm,and I may be able to trim part of the 500mm dimension. I can also put baking trays on the floor of the oven, so in the event of disaster I can still cook, roast and bake.

I am giving up on the idea of a big screen before the R&S. After 2 days of attacking it with angle grinder and heatgun, then making steel frames to support it more, I have given up on version 1.0
I will just have to wear my best (non music-equipped) earplugs and accept 2 days of wind noise on my lid.

Bending the polycarb without getting the gas bubbles was nigh on impossible, i think is because I have small sources of heat but a very large piece of work.

The polycarb needs angles or curves in it to hold it firm. However, to give it steering lock given that I have handguards and mirrors meant cutting those angles away so much that it became flimsy.

The angle of my current tiny flyscreen thing is too shallow, simply bolting a bigger screen to it (which had been my plan) brought the screen too close to my head.

To quote Monkey: "Many lessons have you learned, Grasshopper"

So, plan B for a future attempt: Buy a "pre made" screen for a bike made in a reasonably large production run. That way what I have to make is a bracket which holds that screen to my bike. Time to take a good look at bike screens, the angle they sit at, and how they are mounted.

My guess is that a top of the range touring bike with a log history of R&D would be a good place to start. I'm thinking Pan European, anybody got any other suggestions.

Chris, how tall a screen do you intend to make?

I have an old "universal fit" screen here that I'm unlikely to ever use again, it's suitably ratty but not that tall.

Happy to bring it to R & S in exchange for some beer tokens!

june_whitfield wrote:Chris, how tall a screen do you intend to make?

I have an old "universal fit" screen here that I'm unlikely to ever use again, it's suitably ratty but not that tall.

Happy to bring it to R & S in exchange for some beer tokens!

Very tall, to be honest. That said, can you send me a photo of said screen? What does the "universal fit" actually attach to, cos there's a good chance I cut said parts off.

it's 40cm tall and attaches with two swiveling doodahs (the black bits) that go into clamp things (the brown bits), which in turn are attached to your handlebars or anywhere else you may see fit

then the bottom of the screen attaches any which way, to keep it from flapping about (I used cable ties & bits of string)

And it comes with free DHR stickers!

Those would need to be removed or blanked out if the new owner had not attended no?

Anyway, I've always gone for the screen on a screen on a screen approach until the correct level of height/ comfort is reached- braced to the handlebar with a length of threaded rod and assorted fittings.

June, if you can be arsed to carry it to R&S I can exchange it for beers.
All stickers which don't refer to the apocalypse will be removed

That's a an epic screen. I had the same one on my Cub.
They don't need to be head height they push enough air up and around.

thefastestMelv wrote:That's a an epic screen. I had the same one on my Cub.
They don't need to be head height they push enough air up and around.

Spoken by a shortarse . I'm 6'6"

>>
>> June, if you can be arsed to carry it
>> to R&S I can exchange it for beers.
>>

will do, probably attach it to the bike to remind me how much i don"t like it


>>
>> stickers which don't refer to
>> the apocalypse will be removed
>>

good luck with that....
those stickers are structural, to stop the screen from apocalyptic disintegration