2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

umm plexi glass under the hood?

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Old 05-20-03 | 09:19 PM
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umm plexi glass under the hood?

what temp do you think under hood this whould be subjected to?

I have loads of plexi glass, im thinking of making a cold air box... it seems that plexi would be a good way to keep heat out of the box... but im not sure at what temp the plexi will become soft. maybe more important at what temp does it start to break down and release fumes/gas.
It would be a bad *** looking cold air box.. but if its not gonna last but one summer day then it may not be worth the trouble.

so here is the question...

plexi glass or not to plexi glass.

Remember now i have it. so it would be free.

jaared
Old 05-20-03 | 09:20 PM
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I would think plexiglass would melt pretty fast.. but I don't know for sure.
Old 05-20-03 | 09:24 PM
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guess ill have to do the oven test...
Old 05-20-03 | 09:34 PM
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Lol I guess... be sure to set it on like... I don't know in an old pan or something so it doesn't drip everywhere.
Old 05-20-03 | 09:41 PM
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plexi should be fine, but it is very heavy when compaired to alum sheet
Old 05-20-03 | 09:51 PM
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not the plexi iv got... its 1/8 inch..

im doing the "oven test" now

ill post the results in a few more min

jaared
Old 05-20-03 | 09:52 PM
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how hot will it get in there?
Old 05-20-03 | 09:57 PM
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i made one out of plexi. It was actually Rhino Glass that I nabbed from the factory I worked at for the summer. It didn't come close to melting or getting soft, however it is a BITCH to work with. Cutting it sucked, drilling it sucked, getting it to fit sucked.
Old 05-20-03 | 09:58 PM
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umm how hot?
Old 05-20-03 | 10:04 PM
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maybe 200* F? more for a turbo car maybe.
Old 05-20-03 | 10:09 PM
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I had a Mechanical Temp gauge that was sitting just under my hood for a while, it never went over 150F in my N/A
Old 05-20-03 | 10:26 PM
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lexan would be much better if you want something clear
Old 05-20-03 | 10:33 PM
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HA! ok new idea...

umm ok so the oven test proved to me that i need to save the plexi for something more useful.

ok here is the result of a single layer @ 200 degrees. i set the timer for 10 min.. but i took it out after 6 min.


-------------------------------------------------------

ok here is the doubble layer with support @ 200 degrees.. it lasted fine for the 10 min! (just a lil' soft)


---------------------------------------------------------

so I upped the temp to 300 and had to take it out after about 5 min. (started to smell and turned white)


--------------------------------------------------------


Now it didnt melt and go to **** at 200... but it hazed.. then at 300 it turned white and was very soft once i took it out.... it stayed bendable for a good 10 min after it was out!

So ill use some metal, well it was worth a try!


jaared
Old 05-20-03 | 11:13 PM
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Re: HA! ok new idea...

Originally posted by Jaared
umm ok so the oven test proved to me that i need to save the plexi for something more useful.

ok here is the result of a single layer @ 200 degrees. i set the timer for 10 min.. but i took it out after 6 min.


-------------------------------------------------------

ok here is the doubble layer with support @ 200 degrees.. it lasted fine for the 10 min! (just a lil' soft)


---------------------------------------------------------

so I upped the temp to 300 and had to take it out after about 5 min. (started to smell and turned white)


--------------------------------------------------------


Now it didnt melt and go to **** at 200... but it hazed.. then at 300 it turned white and was very soft once i took it out.... it stayed bendable for a good 10 min after it was out!

So ill use some metal, well it was worth a try!


jaared
here is just a guess, but try that with a stock air box and see what happens....

I would guess it melts.

Anyone dare me?

I'll bet the plexi works fine
Old 05-20-03 | 11:27 PM
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i got enouf of this stuff to try makin one...

i guess it is worth a try... it sure would look nice clear and all...

im gonna keep the stock intake/scoop thingie over the fan shroud, and make a ram air thing from the F.T.P. hole too.

hella air is good!

jaared
Old 05-20-03 | 11:46 PM
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i knew a guy who tried to make a hood out of acrylic sign material with steel supports. it melted after 1 autocross run.

since "PLEXIGLAS" is juat a tradmarked name for clear acrylic then I am afraid it might melt.
Old 05-21-03 | 12:15 AM
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So I tried to follow your work

200 Degrees



here is the oven at 200 insert stock air box. 200 For 10 min not much it was warm smelled a bit, but felt strong for the most part

300 Degrees


A new game it was all soft. Not as bad as your plexi, but soft none the less

When was the last time you put your hand on the stock air box and it burned?

Draw your own con conculutions(sp?)

Last edited by seveninphilly; 05-21-03 at 12:19 AM.
Old 05-21-03 | 12:29 AM
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lexan is the ****, a friend of mine worked at a aircraft assembly plant (small time) he nabbed me like 20 sheets of 15x15 inch lexan and a few aircraft alumiun sheets
Old 05-21-03 | 12:37 AM
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lexan hatch window.... mm... yummy..... hood made of all lexan... yummier.....


-Kanaida
Old 05-21-03 | 01:48 AM
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I think the air box should be alright. Unlike the rest of the engine which is heated by ambient air and rising heat from the engine, the airbox has a constant supply of new cool air from outside. The air is constantly moving through the box touching all the inside surface area to keep it cool. Just my two cents. I'd say it wouldn't reach above 175 unless using some massively thick plexi, in which case the moving air inside the box may not be enough to keep cool the outside of the plexi.

Remember in science class when you put the match under dixie cup filled with water and it wouldn't burn. Same theory, just distorted and shorted a great length since air is xx times less dense than water.
Old 05-21-03 | 01:51 AM
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a better question to ask is why does it take longer for cars to warm up in -10 degree weather. Its not because of the ambient air, its because of the moving air hitting the radiator.

This of course saying you have a stuck open thermostat or something illogical like that.

Moving air cools greatly, thats why we make air to air intercoolers.
Old 05-21-03 | 02:26 AM
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holy sheet man!!! you did it.. HA! stock airbox in tha oven...

well lookin that the result of that... im gonna make a airbox out of my "plexi".. its not the plexi brand.. when i went to buy the sheet, they had plexi and a better brand (more shatter resistant) so i upgraded to it...

Ill post pics of it in the different stages... im gonna work on the car all weekend. I hope i get it runnin too.. my starter went bad.

with all this talk im gonna heve to make it look good...

Does any body want me to save the measurements? maybe make a template? i guess i will just incase someone wants it later.

jaared
Old 05-21-03 | 02:39 AM
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Plexiglass(Acrylic) or Lexan(Polycarbonate) can be painted from the inside of the box that youre making and it looks really shiny from the outside.
Just look at a R/C racecar body which is lexan painted from the inside.
Kim
Old 05-21-03 | 02:44 AM
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im gonna rock the clear.... thinkin of some custom ingraved something... ideas are flowing like crazy... man i WAS bored... but i found a cure.

jaared
Old 05-21-03 | 02:55 AM
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You got me thinking, I work with plastic injection moulding so at work we have alot of scrap lexan that could be used for an C.A.B.
Thanks




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