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Old 10-08-2019, 08:25 PM   #1 (permalink)
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/// Kamm back on Jetta Wagon ///

Hi All,

Thinking about making a Kamm Back for my Jetta Wagon.

I was planning on using this as material :

https://www.speedwaymotors.com/Color...-Ft,31414.html

Anybody have experience with is ? Stiff enough ?

I am assuming 2 feet long (past the glass on the back of the wagon glass)should be plenty long ?

Which brings me to my proposed mounting method ....

I was planning on fabbing up some "L" shaped mounting brackets and attaching the brackets using high strength double sided tape .... to the glass!

The reason I was going to fasten to the glass was so it doesn't damage paint or be a possible spot for rust to form plus if I make a series of aluminum "L"
brackets it would possible reduce the stress on the glass should the aluminum expand and contract at different rates than the glass this preventing possible glass breakage...

Plus if I follow the glass on the rear hatch of the wagon, it would place the kamm back in almost the ideal place .

I would like to use 1 continuous piece of plastic to avoid seams but I'm not sure this is possible because of the need for taper etc...

I wish the material was available in clear so as not to lose potential rearward visibility ( I had though of using plexi glass from Lowes and make something similar to a Tractor Trailer foldable "Trailer Tail" BUT if its only 2 feet out or so maybe permanent fixed is OK.

What are your thoughts on this ?

Thanks in advance for any and all help.

Andrew

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Old 10-09-2019, 12:29 AM   #2 (permalink)
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I have some of that material and was disappointed with how difficult it’s been to work with. I tried to flatten it out with little success. Laid a section flat for a few days, took the weight off and it sprung half way back to being coiled up. Extensive use with a heat gun and bending, and it’s a flattish but wavy. It’s difficult to cut neatly, best success is scoring deep with a razor knife and bending to snap.
It’s actually been great for random non automotive projects
Made some nice wheel spats for my old Saturn, but used a heat gun to almost melting it to make a sharp bend like I wanted.
Actually thinking to get it out soon to make a grill block out of.
For bigger areas, if you could secure the edges and wanted a pretty heavy plastic it would be good. For a 2’ kammback, I think you would need a frame to help support or at least give it its shape
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Old 10-09-2019, 08:40 AM   #3 (permalink)
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From the Q & A section........................

Quote:
Can this plastic be painted ?
Asked by Roger 11 months ago

Verified Reply - Eric This is high density polyethylene (HDPE) plastic. I suggest you check with your paint supplier for the best choice of primer and paint. With the flexibility of this plastic there will certainly need to be a flex agent added.
Quote:
How much does the roll weigh?
Asked by Jesse 4 years ago

Verified Reply - Eric This 25 foot roll of plastic weighs 23 pounds.
Also clarified that it's 22 inches tall, roll is 25 feet long.

Related, and perhaps with clues as to best installation practices.

Speedway Motors Racer's Crash Repair Kit
https://www.speedwaymotors.com/Speed...lQuery=9162009


2000mc's experience reinforces my worst fears.

Polyethylene HDPE
https://www.polymerplastics.com/corrosion_polyeth.shtml
Quote:
HDPE has a working temperature of 212 degrees F - 220 degrees F under low load conditions and it may be autoclaved at sterilizable temperatures.
Maybe you can source this as a flat product in sheets and avoid the recoiling issues?

Perhaps bonded to a rigid cellular foam backing?
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Last edited by kach22i; 10-09-2019 at 08:46 AM..
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Old 10-09-2019, 11:07 AM   #4 (permalink)
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Hi

Thanks for the info .... if I have to build a frame for it I might do clear plexiglass instead....

Probably what I'll do is I'll make a mock-up in cardboard and see how much visibility to the rear I lose...

If it's a lot I may use the clear if it's not a significant amount and might just use the rolled material because its cheaper overall.

Thanks for the help
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Old 10-10-2019, 10:03 AM   #5 (permalink)
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I used smoked/tinted plexiglass, but just because it was free.

All gone now.
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http://forums.pelicanparts.com/off-t...effective.html

Rear Spoiler Pick Up Truck
http://forums.pelicanparts.com/off-t...xperiment.html

Roof Wing
http://ecomodder.com/forum/showthrea...1-a-19525.html
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Old 10-11-2019, 04:56 PM   #6 (permalink)
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If you work with a narrow strip it will fight you. Start with a sheet and cut two nested C-shaped [J-shaped?] and join them at the center top?

I have some scraps of 1/8" ABS that seem suitable.

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