Post by David Mitcham on Dec 7, 2014 4:07:41 GMT -5
I'm thinking of making a small 'machine' for vac forming windscreens and maybe some small body parts - car that is. There are several designs on the web for such devices most of which look too big, and therefore wasteful of material, for making the occasional screen but I'd be really interested in any advice Forum members have. For example would a small device, say 6' square, work and is using suction from a household vacuum cleaner (Dyson) sufficient? I'd be grateful for any suggestions!
Post by Phil Kalbfell on Dec 7, 2014 6:39:52 GMT -5
David This is the smallest of my machines, this one is used for screen and testing moulds. Saves firing up the bigger machines and waiting for the heater to warm up.
It is made from a cast project box To heat the small size plastic I use a grill oven sitting on the bench. You can cheaply make one and try using you vacuum for the source. PVC is relative easy to vac form,so the vacuum should provide enough vacuum for simple moulding.
Post by David Mitcham on Dec 7, 2014 14:53:12 GMT -5
Many thanks Phil and David. Both your posts are really helpful and just what I was hoping for. I think this will be a Christmas break project. Incidentally where do you get your clear sheet from, please?
Not sure if this is helpful or not, but I have a small 5" × 5 " dental vacuum former. It was new and cost about £60.00. MicroMark offer them.
I also made a larger one which takes a 12 x 12 sheet over 10 x 10 plate.
The suction is provided by a simple shop vac of 4.5 peak hp. The key is making sure all the joints to the vac box are sealed tight. I used my hot glue gun.
I get my plastic in 4ft x 8ft sheets, 30 thou, and it's called PETG. It takes a little less heat than other plastics such as pvc.
The nice thing about the little one is you can quickly do windscreens and other windows, as it is a one piece unit. The heating element is in the top and swings aside, the vacuum is in the bottom, and the controls are side by side. I wait until I have a sag in the middle of about 1.5 inches.
The one I made uses a hot plate for the heater, and I made a box around it covered in tin foil to reflect the heat. The 12 x 12 tray sits on top of the box and the plastic is held to a light alum frame with binder clips. Once I get the sag, I simply turn on the shop vac and take the plastic and frame over to the former, and the shop vac sucks it down in a snap. I leave the vac on for a bit as the plastic cools, and after about 20 seconds turn the vac off.
Its actually a lot of fun to make your own. I've seen some made using a cookie sheet drilled full of small holes and fit to a box.
Post by David Mitcham on Dec 9, 2014 6:24:31 GMT -5
That's really helpful, thanks. I have seen the dental type vac machines advertised on e-Bay and wondered how good they are. I think I'll have a go at making something first based on all the advice I've had from you, Phil and David. I think I've got all the materials I need in my workshop and garage.