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Custom Made: Light Weight Doors


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#1 Benoit_Dupont

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Posted 10 August 2019 - 07:14 PM

hi guys,

 

So here is the story: I am making lightweight doors, just because. the constraints are:

- I don't want flappy fibres doors

- I want the windows to slides up and down as normal because I live in the montains, and well, it gets cold up here and very warm in summer. so I want air in the car.

 

basically, I got my hands on extra crispy doors, I have stripped the outer skin, will be replaced by aluminium sheet. and I will strip as well the interior panels.

 

Now here is the catch: if I get rid of most of the interior panel, I have to get rid of the winder mechanism, which by the way weights a metric ton, more or less.

 

So I am making leather pull strap, and in this post, I'll detail how I get there.

 

first thing first, got 2 sacrificial windows for a few bucks, scratched and all, but they will do fine for the purpose of the experiment:

 

Attached File  IMG_20190810_165019-W600.jpg   35.91K   0 downloads

 

the first thing to do with leather strap is to engineer a stop at the bottom of the window. if by any chance you let go of the strap, it will get at the bottom and potentially damage your door skin.

 

so I made little aluminium brackets:

 

Attached File  IMG_20190810_172351-W600.jpg   42.44K   0 downloads

 

and they will sit at the bottom of the door, like that. pay attention, there is not much clearance between the bottom of the window and the outerskin, so keep a few mils, but that's it.

 

here it is: 

 

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now since I got rig of the gutters under the window, i have to make a new one. here aluminium sheet and profile are your friends and I found one that just fit well. it's however very thin (5x5x5mm outer dimension) so it will not stand much traction without help. so, I made captive screws  to attach thicker aluminum plates to attach a leather strap.

Attached File  IMG_20190810_183146-W600.jpg   35.99K   0 downloads

 

so here is how it looks when all assembled:

 

Attached File  IMG_20190810_202944-W600.jpg   35.52K   0 downloads

 

there are 3 sections attached to the thin gutter: the main one is the one with the strap attached. Since I did not have the strap, well, humm, I used my own belt for the purpose of demonstration.  :D

 

the central one will thus have as final the leather strap rivetted (here I used shorted screws and washers. I do like that belt. 

 

Attached File  IMG_20190810_202145-W600.jpg   41.94K   0 downloads

 

the external triangle are there to compensate torsion on the gutter:

when the strap is pulled, it pulls on one side of the gutter. the counter plate in the center helps, but if you have extra pad pressing on the inside of the window (so, the same side that pulls), interior of the car, so to speak, it will compensate torsion.

 

and here is how it looks window up!

 

Attached File  IMG_20190810_202944-W600.jpg   35.52K   0 downloads

 

Now if you want to do it too, there is a catch that need to be addressed: the window in not balanced: it has a triangle shape. so originally, i aligned the pull with the center of gravity (and yes, I'm a nerd). turned out it's a bad idea:

the friction with the seal on the rear hand of the window is much worse. as result, if you align on the center of mass, the window falls forward. so it is better to align it to the middle of the large section of the window. then it is balanced and works well:

 

Attached File  IMG_20190810_203320-W600.jpg   32.72K   0 downloads

 

and finally here it is from the inside!

 

window up:

 

Attached File  IMG_20190810_203623-W600.jpg   37.71K   1 downloads

 

and window down:

 

Attached File  IMG_20190810_203032-W600.jpg   34.54K   0 downloads

 

ok now what's left to do:

- repair the crusty bits of the doors for sure

- cut the interior panel

- but insert a diagonal aluminum section to get more rigidity

- and insert a vertical strap that will old 2 nuts for the final belt.

 

those nuts will have to go through the door card. so i have to figure out a way to make it elegantly.

 

a couple of final tips:

there is a company that makes door cards similar to stock one, but you can ask them not to put the hole for the winder manivelle, so this is sorted out :)

 

there are door strap kits available for Porsche 911 that I can use but I might do my own, I havent' decided yet.

 

you have to replace the inner top door lip but something that looks more like a sheet metal seak (similar to the one you find on edge of metal to avoid cutting yourself, not sure how it's called) it's a rubber with metal inside anyway. the reason is that the strap will tear the inner lip. the good news is that the strap do apply pressure on the window and therefore, even if half open, I don't expect it to flap.

 

Not sure I will keep the windows. the guys from plastic4 make apparently decent poly window and it might be easier to pull.

 

that's it for today, hope you like it ! :)


Edited by Benoit_Dupont, 10 August 2019 - 07:18 PM.


#2 Curley

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Posted 10 August 2019 - 08:45 PM

excellent work as always, look forward to seeing more



#3 Avtovaz

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Posted 10 August 2019 - 08:46 PM

thats kinda one idea i had for my bmw rally car, but, i was going to put a quarter window at the front so the window is square not pointed. I was thinking of using elastic on the bottom of the window to help it go down too.

 

On the bmw e36 compact the windows are rubbish



#4 Benoit_Dupont

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Posted 10 August 2019 - 09:33 PM

excellent work as always, look forward to seeing more


Thanks ! I try my best

#5 Benoit_Dupont

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Posted 10 August 2019 - 09:40 PM

thats kinda one idea i had for my bmw rally car, but, i was going to put a quarter window at the front so the window is square not pointed. I was thinking of using elastic on the bottom of the window to help it go down too.

On the bmw e36 compact the windows are rubbish


Interesting Idea! Indeed an Innocenti door would be ideal but given the rarity i would not start with an Innocenti door.

The elastic is a good Idea also: not necessary with Glass Windows. Gravity does the job. With lexan however it is a different story. Will think about it.

#6 Magneto

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Posted 10 August 2019 - 09:50 PM

so what keeps it up? Just the presure of the glass pressing the belt against the door frame? Cause I gotta think that a couple of good bumps and it will work it's way back down to the bottom of the door again. Maybe a small stud sticking up and holes in the belt to let you hook it over, that way it could be part down if you wanted.



#7 Benoit_Dupont

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Posted 10 August 2019 - 10:02 PM

so what keeps it up? Just the presure of the glass pressing the belt against the door frame? Cause I gotta think that a couple of good bumps and it will work it's way back down to the bottom of the door again. Maybe a small stud sticking up and holes in the belt to let you hook it over, that way it could be part down if you wanted.


To keep the window up you need buttons on the door card Indeed. I just did not fond exactly the one set for me

#8 Avtovaz

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Posted 10 August 2019 - 10:06 PM

 

thats kinda one idea i had for my bmw rally car, but, i was going to put a quarter window at the front so the window is square not pointed. I was thinking of using elastic on the bottom of the window to help it go down too.

On the bmw e36 compact the windows are rubbish


Interesting Idea! Indeed an Innocenti door would be ideal but given the rarity i would not start with an Innocenti door.

The elastic is a good Idea also: not necessary with Glass Windows. Gravity does the job. With lexan however it is a different story. Will think about it.

 

 

 

well, for the bmw, i can use the divider from a mk2 escort or a nova, apparently they work well as they curve the same as my glass. for the mini maybe you could cut 2 50mm strips, bolt them to the quarter window either side to make a holder?

 

the elastic i think would be good as instead of just the gravity, it may help pull the window down straight?

 

 

edit i mean two bits of elastic. one either side


Edited by Avtovaz, 10 August 2019 - 10:07 PM.


#9 Benoit_Dupont

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Posted 10 August 2019 - 10:10 PM

Indeed. Worth a try

#10 Avtovaz

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Posted 10 August 2019 - 10:11 PM

the windows in the queens carrage are the same idea LOL! that is why i though of it

 

DS080988-80493.jpeg?itok=MfTiTItq



#11 Benoit_Dupont

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Posted 10 August 2019 - 10:16 PM

God save the Queen then :)

#12 Ethel

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Posted 11 August 2019 - 09:00 AM

I reckon it could be back to the drawing board if you want to make the window to move parallel  ;D

 

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#13 Benoit_Dupont

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Posted 11 August 2019 - 09:11 AM

Ahahah. Well Indeed. Turned out that the middle of the long edge is a good fit. Should be good enough. :)

Will investigate the Spring/bungie cord thing however.

#14 Benoit_Dupont

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Posted 11 August 2019 - 10:46 AM

thats kinda one idea i had for my bmw rally car, but, i was going to put a quarter window at the front so the window is square not pointed. I was thinking of using elastic on the bottom of the window to help it go down too.

 

On the bmw e36 compact the windows are rubbish

 

Allright Avtovaz. comming back to your idea. I think I'm gonna try this: I'm not a big fan of elastic. but I do like a good spring. so considering the travel of the window, I found that:

 

https://www.industri...m/e05000374500s

 

good thing is: it comes in stainless steel :)

 

the travel is enough for the window.

 

now considering the displacement is maximum (357,38 mm), it brings us down to about 14.3N, so equivalent of 1.4kg down pull per spring.

 

it means that I would had 2.8 kg to the pull effort. it is actually quite significant if you use the standard windows (as they weight 3.45 kg).

 

however a lexan window would be approximatly half that. so it means that it would result in a weight pull of 4.5kg in the end.

 

Still a lot. I think

 

an alternative is this set:

 

https://www.industri...m/e05000375000s

 

it is longer and will have to be placed with an angle, which means the pull direction will change wrt to the travel.

 

they have a lower constant, thus the added effort weight is about 2.2kg.

 

it does not cost a fortune, and is definitely worth trying your idea, thanks Avtovaz !

 

regarding the pull straps, several options:

 

I can go for the porsche source:

http://www.gt-racing...straps-part-79/

together with:

http://www.gt-racing...straps-part-80/

 

and I need 2 of those (one at the bottom: closed, one at the bottom (open). you could do with one and only have the top button. but if you do that, than you end up with a strap dandling free in the air. so you need some kind of ring to keep it low. I'd rather use 2 buttons: one at the top, one at the bottom, well space, so when my window is close, the strap sits nice and flush to the door.

 

plus it adds safety. if you have only one button, and you take it off by accident the window could come down and guillotine-slam everything down the window and you probably don't want that. 

 

so grand total is 105$

 

or I could follow the DYI route and go for something like that (sorry, it's a french shop but quite sure there is an equivalent where you are)

https://www.decocuir...-cm-c2x13110253

 

and that:

https://www.decocuir...uir-c2x15934913

 

which is more or less the same thing with more sweat and tears, but grand total is somewhere around 30€

 

so, I guess I'll go for sweat and tears :)


Edited by Benoit_Dupont, 11 August 2019 - 10:49 AM.


#15 Avtovaz

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Posted 11 August 2019 - 10:59 AM

right, the springs should work, the elastic i was thinking of is this stuff though

 

CLICK HERE

 

we have that in work you see!






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