Vacuum forming Lexan

[Kevin_Mc 411]

does anyone on here make their own shells or know of anyone who does? I know a lot of rockcrawler guys do it so they don't damage an original Bruiser shell.

i've watched a few videos on Youtube and researched it on a few sites in the USA and it seems a fairly straightforward concept. Obviously, there is a lot more to it than making a mould and using a hoover to suck out the air which is why i would rather have someone with experience do it. I could build my own for a bit of expense but trying to get the right volume of air pulled out would be the downfall for me. this also seems to be the majority of the expense as it would need to be some form of controlable pump to stop the lexan being pulled apart when the air is taken out.

anyway, back to the question - does anyone on here do it or know of someone that can/will? I can supply the mould which i will make myself from moulding an existing pre-cut shell with plaster of paris and some balsa wood for added strength.

anyone able to help?

[Will16 45]

What shell do you have in mind? I've made a 2cv Rallycross body out of cardboard and I'm making it out of 1mm ally sheet. If its a complex shell contact Kamtec or Controlfreax.

[Kevin_Mc 411]

it's an Escort WRC one that i want to modify - i don't want it to be a WRC or a Cosworth but an Escort with a different bodykit. Cutting the shell and puting in parts from other shells won't work as its a custom kit. If it ever gets done, all will be explained (although you're far too young to know what its a replica of!)

i could use styrene but it would mean paint would be on the outside and with a paintjob like i have planned i don't want it to look rubbish

[Will16 45]

Is it the-Gabat Escort?

C'mon tell me!!

[VagabondStarJXF 350]

It's probably cheaper to do it yourself rather than get a pro to do the work for you. I saw a vid of someone's homebrew vacuum forming kit and there really isn't a lot more to it than heating the lexan then sucking the air out around the mould as you press the warmed lexan down. The guy in the vid used a standard vacuum cleaner aswell so you won't need to worry about getting a special pump or something. Obviously the setup will look a bit ghetto but I'm guessing the end results are what your after. This is something I've honestly been tempted to do myself but haven't had the time, money or simply just not been bothered to try. How are you making the mould and what are you making it out of?

[Mad Ax 9329]

It's probably worth getting in touch with Kamtec (http://www.kamtec.co.uk/) and see what they've got to say about it. Very detailed shells like Tamiya require a very complex multi-part molding process, but simple stuff can be done. Kamtec makes a big range of ABS and polycarb shells out of one-piece moulds. I know they've made a few shell designs based on moulds made by customers. I don't know if they'd be interested in making a single shell, but if it's a shell that can be mass-produced and re-sold as part of their stock line then it might be cheaper.

There are often unforseen consequences - vacuum moulded shells can "flange" at the bottom if they aren't designed properly. I remember this was a big problem with the Kamtec FTO bodyshell that seems to have disappeared from existence, possibly for this very reason. Kamtec may well be able to advise before spend too much time or money going down the wrong track. It's worth an email with an outline of your idea, at least.

Best of luck

[Kevin_Mc 411]

Is it the-Gabat Escort?

C'mon tell me!!

nah, it's not that extreme. Its staying quiet for now but if i can get it sorted i'll let you know

It's probably cheaper to do it yourself rather than get a pro to do the work for you. I saw a vid of someone's homebrew vacuum forming kit and there really isn't a lot more to it than heating the lexan then sucking the air out around the mould as you press the warmed lexan down. The guy in the vid used a standard vacuum cleaner aswell so you won't need to worry about getting a special pump or something. Obviously the setup will look a bit ghetto but I'm guessing the end results are what your after. This is something I've honestly been tempted to do myself but haven't had the time, money or simply just not been bothered to try. How are you making the mould and what are you making it out of?

the video i seen on Youtube looked a bit ghetto too but it seemed to work well. I planned on using plaster of paris to get the mould (by taking a mould of my own shell), letting it cure then making a rough shape out of balsa wood, put it in the mould and fill it out with more plaster of paris

[Will16 45]

OK but one last guess-The Reyland Escort?

[tonysmini 19]

it's an Escort WRC one that i want to modify - i don't want it to be a WRC or a Cosworth but an Escort with a different bodykit. Cutting the shell and puting in parts from other shells won't work as its a custom kit. If it ever gets done, all will be explained (although you're far too young to know what its a replica of!)

i could use styrene but it would mean paint would be on the outside and with a paintjob like i have planned i don't want it to look rubbish

Is it one of the Gartag rally cross motors or possibly an RS1700T? (Probably one of the maddest and best looking Mk 3 escorts ever)

[Will16 45]

Gartracs are awsome!!!!!!! I love The John Welch STP rallycross car. I've got meself a MK3 Frewer Escort shell it's great!!!

[tonysmini 19]

the frewer shell should be quite easy to turn into a 1700T, and I thought I'd spelt Gartrac wrong once I posted it. A huge arched rallycross escort, mmmmmm

[Will16 45]

I would love to have a real Gartrac but they are sooooo rare. The road versions were pretty cool as well but they came witha 2.8 Colonge engine not the YB Cossie engine that mist people swapped to. I'd like to get another Frewer shell but theyy are soooo rare as well. Oh if you want a RS1700T style shell there is one one evilbay. I'll PM you the link.

[Kevin_Mc 411]

i'll give Kamtac an e-mail, i can't see it being a shell that many people will want though so it would be a one off

it's not a 1700T or a mk3 Gartrac and its not a Gabat Cosworth, although its the same shape of Escort. Martin's Reyland Escort could be done with a normal Cosworth or WRC shell and Repsol colours so it's not that either.

it's nothing exciting and tbh i can see me using a WRC shell and having a lookylike with all the hassle but i'll explore every avenue first.

[BeetleLover 4]

If you are doing a one off you should share what Escort you're making!

James

[Will16 45]

Well if a prototype gets made and looks good I'll have one as I love Fords.

[tamiyoman 2]

Its not quote as easy as cutting a sheet of plastic, heating it and switching on the vacuum lol.

Air is not "sucked out" the lack of pressure at the rear (Vacuum) causes the air pressure above to push down and "Push it out".

For Polycarbonate you have to "Pre-Dry" it at around 90c for around 4-6 hours (depends on how well spaced they are) as Lexan is Naturally Hydroscopic (it absorbs moisture fromt eh atmosphere), if you dont pre-heat/dry it before you form it you will end up with hundreds of tiny white bubbles in the lexan (which is the moisture turning to steam and trying to escape the lexan), you also have to add in shrinkage factor of around 3-5% during heating process.

Then there is the mould, which needs to be as smooth as.......... (think very smooth), it also need air evacuation holes in the mould for air to escape around areas where air would get trapped (I.E. Around windows and in middle of shell), otherwise you get poorly formed shells or lack of detail.

Once you have done all that, you have to experiment with heat settings, time in heater before forming etc etc and eventually you get a shell made, its not easy, in fact its a pain until you learn how to do it, but when you do the results can be great.

When your learning its waste waste waste and time time time, when you know how to do it, its heat for 60 seconds, heater back, mould up and vacuum on, then 10 secionds later release your new shell from the mould, bingo!

Cheers

[Kevin_Mc 411]

thats exactly why i don't want to do it myself, its all the time and expense thats involved in setting up the process.

i knew about the mould needing air holes to let the trapped stuff out already, the process seems like its going to be too much hassle just for one shell to be made.

[tamiyoman 2]

thats exactly why i don't want to do it myself, its all the time and expense thats involved in setting up the process.

i knew about the mould needing air holes to let the trapped stuff out already, the process seems like its going to be too much hassle just for one shell to be made.

IM sure someone would do it for you, but the costs involved would be too high i think, unless you can get another 50+ people wanting one them split the costs.

[Kevin_Mc 411]

yeah it looks like it, that's why i wanted to make the mould so that all that would be required would be the actual forming from lexan. I doubt anyone else would want the shell and tbh i don't think i would like them to as it wouldn't be as special as if it was my only one

[WillyChang 1814]

why don't u handbuild it out of sheet/tube/squaresection "Evergreen" styrene?

making a mold to make just 1 example does not make sense unless you're casting Faberge eggs or Ferrari V12 blocks...

[Kevin_Mc 411]

its too complex a shape to make out of styrene

sadly it seems like it's not worth the hassle and cost even with someone else doing the fabrication

[WillyChang 1814]

right... just don't tell Mike Villena that

alternately draw it up in 3D geekcode and get it 3D printed

[Kevin_Mc 411]

what i should have said was "its too complex a shape for me to build in styrene"!

that must have taken an insane amount of time, patience, skill and effort to make - none of which i have

[WillyChang 1814]

Yeah me neither... I'd have lasted long enough to make 1 valve - pity about the other 19

Dunno if youve used both media but IMHO styrene is easier to work on than

a hunk of PoP. Plaster is brittle, porous and heavy & can't weld on bits

to fix any accidents or rethoughts.

Is there a suitable doner shell you can base off?

Then you can just build the bits that's different.

[Kevin_Mc 411]

There is a suitable shell but I can't see how to remove bonnet vents without making it obvious that they've been covered over with styrene. Especially with it being polycarbonate and painted from the inside and the styrene being painted on the outside.

Any tips?