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Discussion Starter · #1 · (Edited)
Some months ago i was approached by a freind of mine to solve a problem for him. Basicly he needed a box to put a particular item in, so any old box just wouldnt do, it had to be a special.

Originaly i thought fiberglass, quick, fairly easy to lay up and reasonable price, i was wrong, GRP is more of a pain when making small items than i first thought, it is also fairly expensive. The box that i made from grp cost around £5.00 each to make.

So having a rethink, i stumbled upon vacuum forming plastic. Sounds technical but in reality its fairly basic stuff, you have a table with lots of holes in it, under the table top there is a void to which a vacuum cleaner is inserted.
There is a hinged frame connected to the table that clamps the flat sheet of plastic.
Lastly there is a heater to heat the plastic until it is flexible enough to form over the moulds.

So i decided to build my own vacuum forming table.
Got the table done in about a day, loads of tiny holes to drill, all at 1" spacings (having tested the thing, i will add more holes)
Then it was time to design and build the heater. I chose electric as i thought gas would be too harsh on the plastic with a greater risk of completley melting the sheet.

Eventually got the heater built, sheet steel core, insulated with fiberglass wool, then a wooden outer. The heater element is a chrome/nickel resistance wire rated at 1200 degrees centigrade.
The wire is insulated from the metal core with fiberglass posts, these are failing and will be swopped out for ceramic material.
The heater also has a removable lid, which is also insulated.

First test pull was a few days ago, first test was appauling and i started to worry, but loaded up another sheet and heated more and for a second ever test it was outstanding (ecstatic would be a understatment :laughing: ), but i thought i could get an even better result, so last night my mate came over and we done another test, this time with 2 vacuums attached to the table, heated the plastic even more, and yeeeeeeeee haaaaaaaarrrrrrr, we were vacumm forming plastic boxes :thumbsup: with a very tight detail indeed.

Jobs a gooden ;)

Now before i post the pictures up that you have all been waiting for :laughing:
let me just point out that the project was not to make the machinery look loverly, but to produce a plastic box that looks loverly. Also we didnt know if the project would work or not, so didnt worry about the athsetics.

That said, here is the oven



The table with the wooden moulds still on it



All the little holes that i had to drill and still have more to do



Thats all folks :thumbsup:
 

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Discussion Starter · #3 ·
I'm not allowed to divuldge the info on what the boxes are used for, just yet ;) or i would have posted a piccy up of them.

Yep the plastic comes in allsorts of colours and thicknesses, ranging from % of an inch up to 6mm thick. I was using 1.5mm thick sheets 2' * 4'
 
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