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Vacuum forming - Questions


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Since my son is 4'10, he can't wear kids armor, and adult ones are too big for him.  Last weekend I made a small vacuum forming table (12" x 16") to try to make some parts manually.  The problem is that it doesn't work well ...  I'm not sure where is the problem.  The plastic takes the form of the mold a bit, but that's it.  It doesn't go stick on the vacuum table, like it's not sucked enough.

 

It may be the pump ...  I used an old vacuum.  I don't want to buy a super big shop-vac just to do a test, it takes a lot of space !  If that's the problem I'll buy one, but I surely can't return to the store if it doesn't work enough to my taste. Is the vacuum source really important, or all vacuums can work ?

 

It may be the plastic ...  I used a styrene sheet from the hardware store that is used to do shower walls.  It stinks when heated ! (Is it really safe to put it in the oven that I use to cook ???)  Maybe I used one too thick, I don't remember the thickness.

 

It may be the support holding the styrene sheet.  The sheet is suspended at like 3/4"" over the vacuum table.  I put a plastic border around the top of the vacuum table, something that is used to seal windows borders, to seal a bit when sucking.

 

I heated it in the oven until it makes a balloon of like 3"-4" then pushed it on the vacuum table (with the vacuum already sucking) and maintained it for a minute.  It seemed so easy in the videos  :(

 

I'll post some pictures tonight.

 

Do you have an idea of what can be the problem ?

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Lol....i did enjoy your comment of ...it looked easy in the videos...

Well welcome to the wonderful world of vacforming...

Take note what i am saying here and now....

It costs a lot of money to do it. And it is a skill that takes time and lots of plastic thaEverythingoes to the trash......

Then the molds...time and money there....and just when you think your done....more time

 

Ok that said...i did worn you!!....lets get started

Everything you said could be the problem....get your self some .060 styrene....and then we can move on

But yes to a new vacuum

 

But i have to say...if you dont want to spend the money on a good vacuum dont go down this rabbit hole

 

You can get a small adult size and trim it down...you sound handy and creative..it can be done...a nice AP set..small and thin

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Alex,

Click on the link below. This is a vacuum table a friend and I made. All we use is a large shop vac, and you can see it pulls all the way to the table surface. The material we are using is 0.063" thick.

 

https://www.youtube.com/watch?v=DaMcdcUiWuQ

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Thanks !

 

@James : 900$, ouch !  Maybe not for the moment at that price ;)   The nearest Lowes is at about 8h from me, maybe I can check near stores what their return policies are.  For the moment I'm still trying small parts for testing, I don't want to invest big amounts.  I mainly want to test the procedure to see if I'll be able to make pieces for my kids costumes.

 

@Bryan : Mine is smaller, but looks like yours.  What did you use for the plastic seal on the top ?

 

@walt :

Buying an AP kit for a kid that will outgrown the armor in less than 2 years (after the trimming and adjustments) ...  I can do it for sure, but it would cost too much for me, I'll have to buy another one not too long after.  If I try vacforming I will be able to mold new pieces while my son is growing, and I can do some pieces for my daughters costumes.

Here what I bough (I think) : http://www.rona.ca/en/polystyrene-sheet/   It's 0.060, so it should be ok for that.  But styrene vs polystyrene ?

What would be an affordable vacuum that can work ?  I don't want to be fancy or do very big pieces, it must fit in my oven.  Or I should build a heater now ...

How much do you think it can cost to start from scratch ?

 

And I'm not too familiar with molds, I must read more on that subject ...

 

Here's some vacuums :




 

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@Bryan : Mine is smaller, but looks like yours.  What did you use for the plastic seal on the top ?

 

Alex,

We just used a small adhesive d-shaped neoprene weather strip around the frame's mating surface. It's not the most efficient seal. We lose a little vacuum pressure, but not enough to matter. We are looking to improve the design.

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Ohhhh, nice, thanks !  Great advices in there.  

 

So getting a second shop vac from Canadian Tire (wait for the rebate !), cover the unused holes with a styrene sheet.  Also maybe check for a rubber strip.  And make an opening frame.

 

Here are the pictures of my setup :

tQV44jL.jpg  s37ATln.jpg

 

 

My super duper effective vacuum ! :

 

2Y0patE.jpg

 

Oh, and what I saw on netflix while writing  :)  (HIMYM Season 5) :

 

aB8CbQf.jpg

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  • 1 month later...

It's on hold for the moment, I need to finish my armor, and I do a lot of overtime at work, so the free time is practically non existant :-) I plan to try it again with a second vacuum, and with a heat source other than the oven.

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Alex welcome to the world of plastic sucking fun :) might take a look at the wood frame for holding the plastic, seal up the seams with some double bubble (epoxy) the vacuum will escape through the un-joined 2x4's? (looks like in the pic)...WARNING it's like a drug...the better results you get... the more you want ..started out with a vacuum cleaner, and the oven ,then scavenged a toaster oven, (for the elements) then another, then went to a vacuum pump 8cfm and a 10 gal air tank used for surge, then...the gauges and regulators...then another tank, now I'm introducing compressed air to aid in releasing the mold, but what a ride.. :) like Walt says "It costs a lot of money to do it. And it is a skill that takes time and lots of plastic thaEverythingoes to the trash......

Then the molds...time and money there....and just when you think your done....more time"

 

here's a link to pic up hobbyist amounts of plastic http://www.widgetworksunlimited.com/Thermoform_Plastic_Sheets_s/36.htm

 

Good luck hope you get back to it soon :)

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