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Vacu-forming

Posted: Tue Aug 30, 2011 5:22 pm
by gburch
I'm pretty sure I've posted about this before. Some of the projects I'm looking at for future exploration as possible 3D printed kits will likely need some vacu-formed parts -- especially and obviously canopies. So, here's a question. Do we have board members who have experience with doing vacu-forming? If so, I'd really like some pointers about how to get started doing some experiments to see if I can master vacu-forming.

Re: Vacu-forming

Posted: Tue Aug 30, 2011 5:31 pm
by normandy
You might want to talk with Pickelhaube.

Re: Vacu-forming

Posted: Tue Aug 30, 2011 8:58 pm
by maritime96
A few years ago a friend and I tried our hand at Vacu-forming. I felt it was a lot tougher then I thought it would be and we kind of gave up on it after quite a number of tries. I am not an expert and I am sure we made many mistakes but here is what I found out:
1) If you make your own vacu-form box (table) make sure you seal it up real well so that air is only being sucked down through the holes in the top, small side holes that you dont even realize robbed us of alot more suction than you would think. ( we made our box out of wood with peg board on top as the "form area" with the many air holes and one connector on the bottom for the shop vac we used.)
2) You need to decided what standard side of plastic your going to do most of your stuff on. (i.e 12 inchs by 12 inches, etc) the importance of this is that you need to make a "jig" the size of your table to hold the plastic while you heat it and then to press over the mold you use. You should make the jig so it has holes at the edge to go onto guide posts on the top of the table. The jig is what you use to give you the seal around the edge of the plastic to suck it down onto the mold of the piece you are looking to vacu form. Whatever you make this out of, also needs to survive the heat of the oven.
3) The Oven - we used an old kitchen oven. It needs to get the plastic very hot. You should heat the plastic till it bows down in the middle it is so super soft. Have the vaccume table sucking with the mold form in the middle ready to go - take the jig with the plastic in it out of the oven and get it immediately on the Vacu table - cool plastic is a big enemy to making this work.
4) The mold or form - this was our biggest issue as we found out we weren't the greatest sculptors in the world - and the mold also needs to be made of something that will not melt to / or becuase of the super hot plastic. Any mistakes we made in sculpting the mold that we thought we had fixed really seemed to show in the vac plastic. Also this mold cant have any major under cuts or idents as the plastic will form around it or into it and you will ruin your piece trying to get it off the mold.

Hope this helps you out a little. I know there are professional machies built with much of what I said already worked into them, but I don't know what kind of money you are looking to spend. Like I said we were two rank amatures at the process, just seeing if we could make it work. There are also many sites on the internet that can give you tips and ideas on the vacu form process. Good luck with your attempts.

Re: Vacu-forming

Posted: Wed Aug 31, 2011 1:16 am
by Jay
If you want to keep things simple, you might also want to have a look at "Plunge Moulding". It depends on what shape you actually want to replicate. Were you thinking of your V2 or possible X plane project?

Re: Vacu-forming

Posted: Wed Aug 31, 2011 8:27 am
by gburch
maritime96 wrote:A few years ago a friend and I tried our hand at Vacu-forming. I felt it was a lot tougher then I thought it would be and we kind of gave up on it after quite a number of tries. I am not an expert and I am sure we made many mistakes but here is what I found out:

-- snip --
Thanks for that -- it confirms much of what I'm seeing through research on the web and looking at just about every youtube video of home vac-form work.
Jay wrote:If you want to keep things simple, you might also want to have a look at "Plunge Moulding". It depends on what shape you actually want to replicate. Were you thinking of your V2 or possible X plane project?
Not for the V-2, at least not for the first version I'm calling "complete." One of the reasons I picked the V-2 was that it was something that could turn out pretty well just with the printer and modeling skills I (barely) have.

Based on the Pegasus rumor of them being interested in the X-15, I've sadly put that completely on ice, along with the dozens of hours of pretty intense 3D modeling I'd already done on it.

Believe it or not, I'm thinking about at least sketching out a pathway that could lead to two of my favorite 3rd-gen fighters, the Skyhawk and the A-7. Both of those concepts are just in the stage of looking at lots and lots of high-res photos online and trying to think about how I could approach the projects. But I'd need vacu-forming for at least the canopies on something like that, and maybe more ...