Vacuforming canopies

Discussion in 'Tips, Tutorials & Tools' started by cmdrted, Jan 20, 2005.

  1. cmdrted

    cmdrted Active Member

    Leif, this is for you, and the rest of us. Bear with me I'm trying to organize these ideas logically, but 2 night shifts in a row have me dazed. There is a time in aircraft building that flat sheets of clear acetate just won't do it and we want the full bubble. Especially on modern jets. I took the plunge last year and built a vacuform machine. It is not fancy at all just a box with little holes in the top and one big one on the side for your spouses vacuum cleaner hose attachment. I put some gasket material around the edges to get a little better seal, but this thing works ok without it. The box doesn't have to stand up to the vacuum of space and I think you can build one out of a study cigar box as long as you can get the hose attachment to fit fairley snug. make your work surface about 1/2" to 3/4" bigger than your anticipated largest project. Then drill 1/8" holes on the top, mine is a piece of 1/4" masonite in a fairly regular pattern. It doesn't need to be exact. I sealed the inside with tub and tile caulk I had laying around, but you can use about anything. The trick is to minimize as many leaks as possible. You want all the air sucked thru those 1/8" holes on the working surface.
  2. cmdrted

    cmdrted Active Member

    The" vacuform machine experience", part 2. Having built the box the hardest "moving" part is some sort of holder for the plastic. This has to stand up to about 200-300 degrees F. but for a few seconds. I made mine from 2 standard masonite clipboards. The 2 bulldog clamps are needed to hold a frame sandwhiching the plastic between. I tried not using a frame around the clamp assembly, sometimes it worked sometimes not. Unfortunately my small frame broke while movingso it needs to be rebuilt. It is nothing more than a 1" wide frame that matches the frame of the holder with the clamps. I drilled out one of the clipboard clamps drilled holes and bolted it to a single clipboard. I didn't have a cutoff wheel for the dremel so I drilled out the center opening with a drill. The opening should be about the same size as the work surface for the box. Mount the clamps so the bolts underside doesn't interfere with the seal on the work surface. Alot of words but see the pics
  3. cmdrted

    cmdrted Active Member

    Follow up on part two, the frame piece is in highlited arrows and is a piece of the clipboard cut to fit the frame with clamps with the opening @ same size as the frame with the clamps. My 1st one broke while moving and my son age 12 who doesn't do any chores except under duress in a totally unexpected out of character move threw the broken pieces away. Points for coming around but his timeing is a little off. (Patriots fan) :!:
  4. cmdrted

    cmdrted Active Member

    trying to upload pic............... :? Ok last post explains pic, frame made out of 2nd clipboard used to sandwhich plastic. This keeps it from pulling loose when heating.
  5. Leif Oh

    Leif Oh Member

    Great Ted, thanks. You've convinced me. This is obviously the path down which one has to tread eventually. Principle behind box and the making of it very clear. Top frame with clips equally so.

    Have I got it right, that there should be a second frame, the size of the purple lines, now sadly extinct in your case and thus only outlined? Yes, I think so. In that case, everything very clear.

    Thanks again! - L.

    PS. Fortunately, between the two of us in our relationship, I'm the one in control of the vacuum cleaner. I am however under strict restrictions as how to use household applicance for non-regular purposes since the time I decided to defrost the freezer using a hair-dryer lying inside going full blast and the door closed to just a chink. Resulted in the whole plastic interior melting down and me having to obtain very expensive and big spare plastic parts, no doubt vacuum-formed as well. The process involved in vacuum-forming involves a couple of sensitive elements, like heating plastic in the oven until it deforms at the point of almost melting, and then appying the vacuum cleaner, so we'll see how it goes. After all, it was twenty-five years ago, and some sins ought to fall under the statute of limitations after that time...
  6. Tonino

    Tonino Member

    This is a very interesting subject.
    I look forward to the following posts holding my many questions until the process description will be completed....

    This is a thing I've been thinking about for a long time.

    Perhaps this is the occasion to have a try on this.


  7. cmdrted

    cmdrted Active Member

    Guys, you can question at any step, The process for me has become sort of routine, so I may forget to add some important thing that "just happens". Leif the vacuum cleaner never is in any danger, it doesn't go near any hot parts. I used a hole saw to cut the vacuum cleaner attachment hole in the box. Most of the attachment ends like the drapey piece has a delicate taper so you can just sort of push it in with no trouble. Don't worry about domestic mishaps, I used to build target rifles years ago and applied a bake on finish that required me spraying this stuff on with my airbrush in the kitchen, bakeing the damn thing in the oven and removing it and spraying with WD-40. Well I got some intesting "durable finish" on the kitchen floor with a "embossed/branded shape" imbedded into the floor as well. My wife banished the airbrush and any other such nonsense hobbies to the garage and basement. I vacuform when she goes shopping. The whole process takes @30-45 minutes. more later....
  8. cmdrted

    cmdrted Active Member

    Now having built up the box and frame, the 2 most important parts of your machine, you need a heat source. Luckily this comes in the form of your garden variety stove top or oven. If you have an electric stove top this is ideal. Do Not use a gas/flame top to heat the plastic. :!: I haven't tried this source but I feel it in my bones that the plastic will ignite and leave all sorts of decorative strings about the place. :( . I use 2 pieces of 2x3 pine to straddle the hot area on the stove. Don't place them on the burning surface. Have your fume extractor/fan going as this will reduce the tell tale smell. This step is way ahead of the process but my son asked to put it in. You won't need the oven/ burner just yet...
  9. cmdrted

    cmdrted Active Member

    A follow on from last series, The views show the relationship between frame with clips, plastic and frame (just a mock-up made of cardboard), piece "sandwhiched" and ready for heating. This is out of sequence with the whole process, but as the sunlight is up my wife isn't around, the series was ripe.....
  10. cmdrted

    cmdrted Active Member

    Back to the actual sequence, you need to make the mold for the vacubox. The first step is to build the canopy parts that came with the kit, including the parts that fit to the fuselage. Here is one for Marek's P-40E. You have to build the canopy "inside out" so the seam strips/flaps are on the outside and the inside is fairly smooth. This allows the sculpy clay to be fit inside and when baked have a relatively smooth surface. and cut down on finish sanding.
  11. cmdrted

    cmdrted Active Member

    Another follow-up. You need to copy the canopy parts if your kit is not on disc. As you are just building a mold for the Sculpey clay you can just xerox the parts from a printed kit. Just make sure you get the pieces that actually attach the canopy to the fuselage, be it rails or the frame pieces. Adjust this mold former to fit the fuselage as if it was the actual part. This allows the finished canopy to attach easily with little fuss. In Halinski's kits the glazing pieces are separate from the attaching frames. You have to cut them out and assemble them inside out to cut down on interior seems, then attach the rails or canopy framework. You need to experiment with copies to get the best overall set-up. As for the Sculpey, this is great stuff, The instructions are straight forward, you aren't going to make the mold thicker than 6mm so the bake time is 15 minutes, no more and no less. More and the stuff is superbrittle and rubbery and useless, less than 15 minutes and you still have clay. This stuff is durable, I've used the A4 skyhawk mold about 3-4 x with little wear. It is baked clay though so be somewhat gentle :!: The neat thing is you don't have to wait for ever with fiberglass or resin molds to dry you don't have to carve wood, if you flub it just start another and bake, 15 minutes
  12. FlintknapperGene

    FlintknapperGene New Member

    Hi All
    Great information, & some good ideas on using available resources--I like clipboard bit a lot.
    A couple comments from some other directions (& forgive me if I'm redundant, I don't keep up on the forum):
    If your canopy shape doesn't undercut, such as the F-16 canopy, you might try plunge-forming before you go to the effort of making up the vacuum box. Basically, you just set your form on a sturdy mount that's high enough to get your hands under & around, heat your plastic stock in its carrier (an electric skillet is the best thing to use, the temperature control helps a lot) and just push the stock over the form. Making your carrier just a bit larger than the form will help pull the canopy over the sides of the form and not splay out.
    You can improve the clarity of your canopy with a little work. Roughness & small waves can be sanded out with wet/dry sandpaper, sanding wet. Start with 600gr and work down to 1200, then polish with plastic polishing compound--um, if you didn't pick this up at the hobby store when you got the sandpaper, you can try CD/DVD polish, it's a finer grade of the same stuff. At the last, apply a wash of Future floor polish and let it dry.
  13. Leif Oh

    Leif Oh Member

    Again, we should help out to save those invaluable tips that occur in diverse threads.

    Maurice, in Barry's thread on the Corsair had a very valuale tip on a site for vacuforming.

    Barry himself, later in the same thread gave an excellent example of how to practise the technique of plunge-forming.

    Please, guys, if you know that you have written something pertinent on a subject that crops up, do try to dig it up and make some cross-references. I'm really worried that all the knowledge collected on this site is getting buried in the very wealth of information availble, but increasingly hard to find again when it is best needed.

    Best, Leif
  14. RyanShort1

    RyanShort1 Member


    I couldn't agree more with you about doing the cross-referencing, etc... Perhaps these should all be extracted into articles as well.

    Also, the easiest way to start vac-u-forming is to find an old Mattel Vac-U-Form kit. ;-) That's how I do it!

  15. barry

    barry Active Member

    See the OV10 build 23/01/05 for what I think is about the biggest plunge pull you can get to

  16. Old Ranger

    Old Ranger New Member



    Please don't forget an important safety tip.

    We all know we should NEVER use our spouse's kitchen equipment - skillets, silverware, stove., etc. - for industrial, modelling, or experimental purposes!

    Right!! If you do - please make sure she is out of the house and there is enough time to dissipate the smoke, clean up the mess, and destroy the evidence!!

    If all else fails, it's: Honey, why don't we eat out tonite?!!!


    The Old Ranger
  17. cmdrted

    cmdrted Active Member

    Hi Guys, Sorry this is a lengthy thread, there are a lot of differant ways to do this, The thread and forming canopies, I'm just passing on a really easy way to make the molds that doesn't involve carving Although I haven't tried it yet the sculpey molds may even survive the "plunge" method also. Anyways to continue; Making the mold for the canopy using the sculpey clay is one of the fastest methods I stumbled across. My son was making some school project using this stuff and one of his "rocks" or something looked like a standard bubble canopy. I played with the thing and it held up to some"ruff" handling. You can sand this stuff smooth and it only takes 15 minutes to bake. You take a wad of it and flatten it to no more than 6mm thick. You then stuff it into the paper canopy former you built previously. Use a pencil eraser end to make sure it fills all the nooks and crannies. Leave a bunch beyound the paper edge/border. This will give you some excess plastic later to adjust to fit the fuselage.
  18. cmdrted

    cmdrted Active Member

    Canopies continued. Once you have the clay stuffed into the canopy follow the directions on the package, bake for 15 minutes at 275 F. You can leave the paper former on the clay it won't burst into flames until Fahrenheit 451. When this has baked remove it from the oven and let it cool. When you can hold it without burning your hands gently work the paper former off. At this point if it doen't come off easily you can soak the stuff off in water. When the clay mold comes out of the paper you may have to sand the new mold down to get rid of any seams or that jointed line thing you get if you piece the regular canopy together using strips of clear acetate. This is a must any big irregularities will show up in your vacuformed plastic. this series of pics shows the finished molds for an IAR-80 and an A4 skyhawk
  19. Gil

    Gil Active Member


    Great application for Sulpey! You're right about the stuff being durable.

    The following book is helpful for anyone wanting to build their own vacuum forming unit and is useful in determining the best types of plastic for vacuum forming.

    "Do It Youself Vacuum Forming for the hobbyist" by Douglas E. Waslsh, 1990. Vacuum Form, 272 Morganhill Dr., Lake Orion, MI 48360.

    The describes vacuum forming machines like the one described in this thread and some larger machines with available materials. You can find it on the net for around $14-15.00 U.S.

    Best regards, Gil
  20. robson

    robson Member


    Great work!
    What kind of plastic did you use?

Share This Page