Show full size 924Board.org
Discussion Forum of 924.org
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
 Technical FAQ924 FAQ (Technical)   Technical924 Technical Section   Jump to 924.org924.org   Jump to PCA 924 Registry924 Registry

924 / 944 rear spoiler
Goto page 1, 2, 3  Next
 
Post new topic   Reply to topic    924Board.org Forum Index -> Performance Upgrades
View previous topic :: View next topic  
Author Message
AppleBit  



Joined: 16 Nov 2002
Posts: 1516
Location: Minneapolis, MN

PostPosted: Tue Jan 22, 2002 4:17 am    Post subject: Reply with quote

I want to buy a gt-racing.com rear window that is only 17 lbs.... the way to do it is to take the frame off my window...

I want to do this...

Now, I also want to add a spoiler... Does the 924 spoiler mount into the window? I know the 944 one does... I can drill this window no problem since it is plexiglass....

Any answers would be nice

Tanx


_________________
Classic British Sports Car Restoration v6 + v8 Engine Conversion Swaps

Porsche 924 Wide Body LS1 Corvette 500 Horsepower Engine
Back to top
View user's profile Send private message Visit poster's website
Richard  
Guest





PostPosted: Tue Jan 22, 2002 3:07 pm    Post subject: Reply with quote

My experience is that the spoiler mounts in the frame, although it could mount in plexiglass, but then the two contors might not match and some plexi might show. I would also be concerned of the plexi cracking from the strain. What is also important is that there is two sizes of spoilers. The 924 Turbo and maybe the 924 S had a thiner lighter one. The 944 spoiler is almost twice as wide and weighs a ton! It could also be that early spoilers were thin and later ones are wide...so ask. I would get a junk one and mold a fiberglass spoiler from it and epoxy it to the plexiglass.
Back to top
Zuffen  



Joined: 31 Jul 2001
Posts: 1421
Location: Owasso, Oklahoma 74055

PostPosted: Tue Jan 22, 2002 4:15 pm    Post subject: Reply with quote

I would put the wing on the body it it were me.

I can get you a body mount wing for 80 bucks if interested. Made of th same stuff spoilers are made of.

_________________
Bob Dodd - 924turbo@cox.net
931 1982, 944 1982 euro, 924S 1988SE, 93 968 tip 06 Silver Cayenne S, 06 Black Cayenne S

I have Way too many cars, parts for the 931,944 and 951
Back to top
View user's profile Send private message Send e-mail
Peter_in_AU  



Joined: 29 Jul 2001
Posts: 2740
Location: Sydney, Australia

PostPosted: Tue Jan 22, 2002 8:50 pm    Post subject: Reply with quote

$600 for a sheet of polycarbonate?

Can anyone tell me why I can't take a rear hatch glass, cover it in plaster to make a mould then lay a piece of poly/lexan over the mould and heat it and push it into the mould. There are no "corners" so there shouldn't be too much distortion.

Another option. You can get fibreglass resin and mat which when cured is transparent.

Although large, the hatch glass really is a very simple shape.

Just a thought.
Back to top
View user's profile Send private message Send e-mail
ricomartinez  
Guest





PostPosted: Wed Jan 23, 2002 6:04 am    Post subject: Reply with quote

Peter,
Do it and sell them to us for $200! Yeah, I've thought about how to make one too. There's a plastic company here in San Diego that sells plastic in any form you want. There website says you can heat and shape. Acrylic requires 200deg F + for shaping.

The hatch seems more complex than I originally thought. There is a curve from front to rear. That combined with the curves on the sides makes for a seemingly difficult build. I figured I'd need an oven like that for pizzas to make it work. You can buy "line" heaters to bend sheets, but I think that would be difficult.
Back to top
Zuffen  



Joined: 31 Jul 2001
Posts: 1421
Location: Owasso, Oklahoma 74055

PostPosted: Wed Jan 23, 2002 6:30 am    Post subject: Reply with quote

what about two glass hatches with the lexan or plexiglas sandwiched between.

Slide the first glass and plastic into a sealed plywood insulated plywood box, add wet heat (steam) or dry heat bring the temp up to spec slowly and let gravity and time do the rest. Then if necessary add the second glass to compress the shape further

The glass shouldn't alter at the temp required to flex soften the plastic. And you could always support the bottom glass and put it on a sliding tray with some wheels. So it goes in easy. And one guy could carefully do this job himself.

When it is done you trim the excess before removing the plastic piece and it should be a real close replica.

All this can be built outside.

You can use a propane heater or even an electric heater with a fan.

Just an idea. If it works I expect someone to make me a couple rear hatches, i'll pay for the materials.

_________________
Bob Dodd - 924turbo@cox.net
931 1982, 944 1982 euro, 924S 1988SE, 93 968 tip 06 Silver Cayenne S, 06 Black Cayenne S

I have Way too many cars, parts for the 931,944 and 951
Back to top
View user's profile Send private message Send e-mail
wdb  
Guest





PostPosted: Wed Jan 23, 2002 7:54 am    Post subject: Reply with quote

another option is acrylic, mix 2 lquids to make a solid. its used to make scientific submarine ,bubble and canopies because it is more transparent than glass when 4" thick .place 2 hatch glasses together with the desired space between them seal around the edges and pour the liquid between them,after it cures perfect dementions for your light weight hatch
read " POURED ACRYLICS " article scroll down
http://www.zeller-int.com/categories/moldmaking/clearcastsys.htm
difference between polyester,acrylic and epoxy
http://users.lanminds.com/~drewid/acrylic_vs_epoxy.htm
cheap acrylic
http://www.taxidermy.com/cat/18/artwater.html
mold making and casting tips
http://www.resin-supplies.co.uk/information_pages.htm

[ This Message was edited by: wdb on 2002-01-23 08:08 ]

[ This Message was edited by: wdb on 2002-01-23 08:38 ]

[ This Message was edited by: wdb on 2002-01-23 09:51 ]
Back to top
wdb  
Guest





PostPosted: Wed Jan 23, 2002 11:16 am    Post subject: Reply with quote

I think there might be a small problem with my idea (see above ). the acrylic is more viscous than water(thicker) and may not flow into a 1/8" tight space and fill the mold completely before it starts to cure and gets thicker. ( cure time about 45 minutes )maybe silicone a funnel to one end of a 2 1/2 foot piece of 4"( 0.d.)PVC tubing and on the other end a threaded cap with an air nozzle siliconed to it so air pressure can be used to force the acrylic gently into the mold (dont want to crack the glass and distort the mold)
Back to top
dwak  
Guest





PostPosted: Wed Jan 23, 2002 11:38 am    Post subject: Reply with quote

You bastards! I've just glued two of my hatches together.
dwak
Back to top
wdb  
Guest





PostPosted: Wed Jan 23, 2002 12:13 pm    Post subject: Reply with quote

LOL that was funny. did I leave out the header HOW TO MAKE BULLET PROOF GLASS by laminating alternate layers of glass and polycarbonate BY Clyde Barrows

[ This Message was edited by: wdb on 2002-01-23 15:32 ]
Back to top
Peter_in_AU  



Joined: 29 Jul 2001
Posts: 2740
Location: Sydney, Australia

PostPosted: Wed Jan 23, 2002 1:16 pm    Post subject: Reply with quote

could you not use fibreglass to take a mould of the outside and inside of the glass. You could then pour and brush the acrylic into the upside-down outside mould and then place the inside mould onto the acrylic and squish it down to the right thickness.

wdb, do you know how transparent the "translucent" resins and fabrics actually are? I know we're not talking glass but are we talking tinted glass or mud?
Back to top
View user's profile Send private message Send e-mail
wdb  
Guest





PostPosted: Wed Jan 23, 2002 3:07 pm    Post subject: Reply with quote

when applied to and in contact with wood like on old mahogany boats, you cant tell there is fabric in the finnish, it looks like a deep rich varnish finnish, but i dont think fiberglass would be translucent enough for a window at least not if you want to see a 90 ton frieghtliner going 70 MPH. it could probably be polished to the point of removing all surface improfections so as not to scatter the light and be see through,but i think maintaining that finnish would out weigh any benefits of using fiberglass. the cheap acrylic i posted might be the best choice for windows,a further search may turn up acrylic cheaper than the one i posted .I suggested using the glass from the hatch,as the mold,because for me, making the molds seem to be,added expense and a involved process ,and the surface of the mold would have to be polished to be as smooth as glass,any surface irregularities would transfer to the acrylic and have to be polished out,the glass is already that way. but your idea of painting the acrylic on the surface of the glass sounds like a good idea,the brush marks will disaapear before it hardens ,allow the each coat to harden,and apply as many coats as necessary to build up to the required thickness,do not sand between coats,the thick acrylic will not fill the fine scratches,and you'll have white plastic. micrometers can be rented from a tool rental place to judge thickness. clean up the edges and if necessary,a polishing compound for the finnishing touches,or you could make a fiberglass hatch and a much smaller window.

[ This Message was edited by: wdb on 2002-01-23 15:45 ]
Back to top
Peter_in_AU  



Joined: 29 Jul 2001
Posts: 2740
Location: Sydney, Australia

PostPosted: Wed Jan 23, 2002 6:07 pm    Post subject: Reply with quote

the only reason for spending the time making a mould would be to end up with something the same size as the original glass.

If you used the glass as a mould you'd end up with something either too big or too small depending on whether you used the outside or the inside of the glass. Or am I missing something?
Back to top
View user's profile Send private message Send e-mail
924_fan  
Guest





PostPosted: Thu Jan 24, 2002 4:30 am    Post subject: Reply with quote

Peter - I think that you are correct in respect to the sizing of the glass. To use two rear windows as the mold would probably make the glass slightly smaller (based on using the inner side as the new outer). Whether or not it would work requires trial & error.

Also, the glass would need to be stripped clean of the defroster grid and frame. Molding is very sensitive; and, any imperfections will appear.

Glass fiber is not a suitable material for a rear window - it is translucent not transparent.

The way to form the rear window to maintain its dimensions is to 1) make a mold of the inside of the original glass. 2) Then to make a mold of that mold. Then use the second mold as a form for the plastic. If you are casting the window then, two molds will be needed - one inside and one outside.

The mold can be fiberglas reinforced resin or plaster formed on an armature. The armature is needed to maintain the shape.

For mold release you can use good quality car wax or PVA. I recommend PVA.

Don't forget that after all of this, you might want to have a decal made for the rear window with the safety standard numbers on it; since you don't want an inquisitive peace officer writing you a ticket for a non-DOT (in the USA) window.
Back to top
wdb  
Guest





PostPosted: Thu Jan 24, 2002 4:56 am    Post subject: Reply with quote

the dementions are not that critical,all body panels have a gap between them for fitting and centering...there is a gap between the outside edge of the haych frame and the inside of the opening prolly 3/16 or more on each side ,the glass by itsefl is smaller,so if your copy is slightly larger than the glass it should not be a problem, trying to anticipate what you will find when you start a project is good,but somethings you cant know until you open it up. I suspect the edge of the glass is rounded over,like this * ) * should you mold in that edge,it might be possible to pry the acrylic off without to much trouble,but will the new glass sit at the right hieght,if you dont add the edge to the new window,maybe you can just turn the frame upside down ,place the new glass in the frame and use body filler or silicone in the frame to hold the new window aginst the frame and to secure it in place,if the window turns out slightly to big,it can be trimed with a electric sander,saw, dremmel tool,the ede of the frame is about 3/8 of an inch wide on each side, 6/8 or 3/4 of an inch (1cm ?)to compensate if the new window is slightly smaller,or you could copy the glass with the frame still on it,and use silicone to smooth and fill the joint where the glass and frame meet and prevent the acrylic from getting between the frame and the glass. the only way to know what prolems may arise,and how your going to solve them, is to do it. have a spring get to gether,invite all your mates (friends and family ) two heads are better than one and 50 should do the trick. and last but not least a quote "scared money is crippled with doubt " just do it.



[ This Message was edited by: wdb on 2002-01-24 05:09 ]
Back to top
Display posts from previous:   
Post new topic   Reply to topic    924Board.org Forum Index -> Performance Upgrades All times are GMT + 11 Hours
Goto page 1, 2, 3  Next
Page 1 of 3

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group