I Want To Build A Vacuum Former And Am Looking For Advice

W Crow

New Member
Hey guys, I've been planing on building a vacuum former and i could use some advice. What i have in mind is something similar to what XRobots made and showed in his video https://www.youtube.com/watch?v=maH5Ech0wK8 and on his website http://www.xrobots.co.uk/vacuumtable/vacuum05/.

Now i have two questions about his setup:

1) can i use a vacuum surface with a larger internal volume? At the start of the video he shows the vacuum surface to be very thin. I can imagine how this would be a benefit but i wonder if it's strictly necessary. My thought is that i could get away with a vacuum surface made from peg board https://www.lowes.com/pd/Hardboard-Pegboard-Actual-47-75-in-x-95-75-in/3014321 and the rest of the frame made of particle board with a larger internal volume using a shop vac for suction.

2) Where can i get good thermo plastic from? What i'm looking for specifically is HIPS or ABS in a thickness around 2mm. I've manged to find a few places that sell what i'm looking for but not in the size i want ( the size i want being 15 to 25 cm squared).

Any advice on this project would be welcomed.

Thanks :)
 

swhite228

Well-Known Member
As your pulling the plastic over the buck it is cooling. The thin vacuum table allows the vacuum to remove the air quickly and produces a stronger suction than a table with a large area under the vacuum surface.

The quicker the plastic is sucked down over the buck the less chance the plastic will cool to the point it will effect the molding process. That is how it was explained to me by the owner of a plastic fabrication plant.
 

zorg

Master Member
RPF PREMIUM MEMBER
what are you going to make? it will have a factor on what thickness plastic you are going to use.

one very good bit of advise i can give is make sure your buck is totally dust and debris free, even the smallest bit of dust can blemish a part, trust me i know!

i usually give the bucks a once over with some talcum powder, it helps get the plastic off the buck if you have a lot of detail or undercuts
 

cavx

Master Member
RPF PREMIUM MEMBER
Are you planning on using the patio heater like shown in the video. My suggestion is to make a lid.

If it is the same video, he pulled 2mm black HIPS to make the C-3PO bottom.

Using white plastic will give you a different result as white tends to reflect heat back and black absorbs.

There are three essential parts to this -
1. Heat
2. Seal
3.Suction

If anyone part is not 100 percent, your vacuum formed parts will not work out 100 percent.

You want to be heating all the way to the edge, not just the centre. You will have to do some R&D to get the distance right for the materials you want to work with.
Materials like HIPS and ABS get soft at about 120 degrees Celsius, but you want the plastic closer to 150 for the best pulls.

Shop vacuum cleaners pull about 6"Hg but they do it continuously. A vacuum pump and surge tank can give full vacuum of 29.5". MDF is porus at 6"Hg, so you will need to have metal parts if you go to a vacuum pump.

Make your seals from a single part rather than having a join or joins. I found an affordable rubber at the local hardware store makes great seals but it can't handle high temps. High temp rubbers cost big dollars.

I modded my rig to address all of the fails. It is now something that can pull 6mm perspex. It also now uses a vacuum blanket.


First image : when I was using the full form size plastic to make the seal and I had a heap of waste.

Second image : the vacuum blanket provides the seal, so I can use much smaller pieces of plastic. As a result, my waste has gone from 1/3rd of a sheet to virtually 0.

If a pull is not quite right, I can reheat and pull the blanket to reform and I learned that I can heat through the blanket.
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Last edited:

Militicus

Member
RPF PREMIUM MEMBER
I built one years back, MDF insulated housing with a toaster oven as the heater and the suction bed was MDF drilled out like pegboard. Pegboard is too thin. It worked great, used a shopvac for the suction. No idea where the pics went but msg me if you have any questions.

Sent from my SM-G965U using Tapatalk
 

TK-326

Well-Known Member
RPF PREMIUM MEMBER
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