Thread: Clear hood

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Does anybody know how to minipulate either plexiglass or Lexan to make it bend and shape it? I remember the car in the movie Greese Lightening and the car the guys made for the race had a clear hood. I want to do that to my rod. Any suggestions would be helpful. Thanks! K9

Here's the readerz' digest condensed version. > Make a mold out of your hood. Beef it up to withstand the pressures of a vacuum pump. Drill pressure release holes in your hood in selected areas. Fabricate a vacuum system ..... install on the underside of your hood/mold. Heat up a large sheet of acrylic. Lay it over the mold a vacuu-form it to the mold. When it cools, pull it off, N' trim the edges.

And no ............... it's not that easy.

Not that practical either ....... remember you saw it in a movie.

Rodger that! Thanks. Now I have to try and do it. I'm thinking another hood for the mold, I need the nose piece off an old hood anyway. Not sure what to use for a vacuum yet. Thanks for the idea. I'll let ya knwo how it turns out. K9

Once you get the vacuuform machine & mold operational you might wanna' make several. Acrylic won't stay clear very long with road grime - hot engine - etc..

K, I don't have any practical or technical information to offer, but I just wanted to say that I think that would look cool as heck!!! Have fun with it...an like Pro said, make some extra ha ha!!!

Originally posted by techinspector1
and also this.....you can bend Lexan, but you can't bend acrylic.

With a vacuform machine you don't really bend it you heat it to a nearly liquid state and then suck it down to the mold before it cools. Works with PVC, plexiglass, lexan. etc. The machines I've experienced hold the sheet suspended over the mold, Heat lamps heat the plastic until it starts to sag, then it's lowered over the mold and vacuumed to the mold and held there until iit's cooled to a solid state .... a matter of a few seconds.

A friend of mine usta' make vacuform costume heads for Enesco (makers of the ''Precious Moments Figurines''). The costumes were worn by people at trade shows, etc. to promote the figurines. He would vucuform 2 halves and then plastic weld them together, then paint and decorate em' Those were made from styrene or maybe expanded PVC tho. They had to be light and somewhat flexible.

Sweet! What I plan on doing is taking an old hood and making that the mold. I then want to take the old hood and cut the front part off to where it covers the radiator core and make the rest of the hood clear. Maybe make it two halves and run a rod down the center to hinge it to so it opens like the old hoods or "lambo doors" We'll see. I know i can do the nose piece of teh hood and maybe just have to have an "open air ride" I'm a long way from that. Thanks!

Originally posted by techinspector1
thanks pro, I didn't know how it worked. I was just saying not to try to bend acrylic cold.

Yea, the bad news is once it cools it's brittle again. I don't think it would be a very durable material for a hood. But hey, nothin' ventured nothin' gained.

An expensive undertaking to do a part of that size. K9, I think I would do a small vacuform project first to see if it's something you really want to tackle.

post some pix of your set-up your go'nA build..........
let us all see how you do it .......

maybe you'll start your own brand .........

Originally posted by K9 48 Chevy
Sweet! What I plan on doing is taking an old hood and making that the mold. I then want to take the old hood and cut the front part off to where it covers the radiator core and make the rest of the hood clear. Maybe make it two halves and run a rod down the center to hinge it to so it opens like the old hoods or "lambo doors" We'll see. I know i can do the nose piece of teh hood and maybe just have to have an "open air ride" I'm a long way from that. Thanks!

The hood will have to be REALLY reinforced. Most likely completely filling the underside with a material that chemically hardens. Any weakness will cause the mold to distort or fold like a Pepsi can from the vacuum pressure.

Originally posted by DennyW
Well, I suppose if he wants to try it, I would go with Lexan 9034. It has a heat deflection of 270*@264psi, and it's UV stabilized. 4x8 sheet, 1/4" thick, with discount is 226.56, not counting shop fees, hahaha.

.................... and multiply that by however many sheets of material that will be ruined until the machine and technique are perfected. ooooouuuuuchhhh.

Originally posted by DennyW
Yes, I thought I would just show him a sample of the cost for just the lexan.

A more cost effective plan, and just as visual would B no hood. .............. And it never needs cleaning.

http://phx.corporate-ir.net/phoenix....1114&highlight

Here's a site for Polypropylene-Ethylene resin if you want to do an injection mold. Then you could make it as thick as you like so it might hold up to the beating from vibration.

I don't know why I'm postin' this site. Lyondell shut the R&D pilot plant down & laid my Wife off a year ago and after nearly 20 years. .................................... Oh, but that's another story.

What about taking a good donor hood, removing the middle panel section and making a replacement out of a sheet of lexan. I would stiffen the hidden, underside edge of the hood with some good quality steel and cut away as much of the middle panel as possible. Perhaps the lexan panel could then be inset into the opening and screwed into place. I would probably put a rubber gasket between the lexan and the hood edge to keep water from getting into the engine bay. If the idea of foggable, stainable lexan doesn't appeal, you could try the same idea with tempered glass. Some tasteful and subdued colored lighting in the engine bay would make this kind of modified hood really POP! Especially at night. Just my thoughts...

I have used Lexan before on my stock car. I'm aware of the expense, thats why I was hopeing maybe plexiglass would work. I know when Lexan gets a lot of heat (like when I crashed and the car caught fire) it turnes white. I have to get some things under teh hood to be able to show it off first. Thansk for the info. I think I'll get in touch with my racin budd's back in Alabama and see if one will send me an old windshield, God knows we always kept the junk around just in case. I'll do a test and let ya know.