Cmdrted's method for vacuumforming canopies

Discussion in 'Tips, Tutorials & Tools' started by Renaud, Dec 19, 2005.

  1. Renaud

    Renaud Member

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    Last January, I downloaded this three pages report but I have just realized that all the pictures, page 1, are missing. And now, no picture is available at all regarding this report as I was looking in "tips and techniques". Help, please!
  2. cmdrted

    cmdrted Active Member

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    Renaud, I wrote that piece awhile ago but I'll be happy to update it and resupply the pics in the next day. I also wrote an article for lighthouses, emagazine awhile back but haven't seen the 2nd issue with the article on it. In short(as short as I can), 1. You need a copy of the kits canopy pattern. Xerox it or scan it and the build the copy. You donot need to glue the canopy framing to this part, this piece is going to be used to mold the "master" that you'll use in the vacuformer. 2. Get some bakeable clay, I use "sculpey" and follow the directions, press a generous piece inside the paper former and press it into all the nooks and crannies. when you do this do not make the form solid but only a few mm thick, as the bakeing instructions change unpridictablely. I usually make a pancake the thickness that sculpey suggests as the max thickness and press this in, also leave @ 3-4mm over lap beyound the edges of the canopy, this will allow a better vacuform and give you sometrimming room. 3. Bake according to the instructions. Let this cool and gently pry the paper off the now hardened cast piece. 4. sand this piece gently to remove any seams that the paper piece imprints on the hardened sculpey, if you don't they will show up in your vacuformed part. I use 400 to 600 grit wet dry and get the piece smooth.
  3. cmdrted

    cmdrted Active Member

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    The previous steps including the baking should take @20-30 minutes tops. Now the fun part, 5. If you don't have one of the commercial vacuform machines you can build one for pennies, if you have some scraps of wood and some stuff laying about. The machine is basically a box, @ the size of a cigar box with one hole in the side @ the size of your wife's vacuum cleaner accessary hose usually 1 1/2 inches, and the top (the working area) should be the size of your projected largest canopy with a little margin around the perimeter. make the box as airtight as possible around the seams, I used 1/2" plywood I had around the house and used tube and tile sealer from a bathroom project. My working area is @4x6". this area should be drilled every 1/4 inch with an 1/8 " drill pattern.(when I get home I'll show you a picture of this). This is where the master casting you made of sculpey will fit. 6. The plastic holder. This I feel is the hardest part of the project. You need to make something that basically sandwhiches the plastic in a frame like holder that you can heat up and allow the plastic to get soft enough to vacuform. I used 2 of the masonite clipboards "borrowed" from work. The type with the huge bulldog clamp. You need 2 clamps, as this will hold the plastic firmly enough so as not to allow it to pull from the edges of the frame when it is heated. You need to see the picture of this, it has to be smooth enough on one side to provide a tight fit with the vacuformer working surface.
  4. cmdrted

    cmdrted Active Member

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    7. The plastic. I usually use the plastics from various toy wrappings, blister packs etc. I did break down and actually bought a 4x8 foot .020 thick pvc plastic sheet. It was fairly cheap and will last 2 more lifetimes. The micromark company out of new jersey has some sheets of .015 that actually makes a much thinner canopy, and I have a pack of it and haven't run out of that either. I did a cost breakdown a few years back and useing the large sheet pieces it came out to @07-8c a canopy, including the sculpey. If you buy the sheets from micro mark, the cost jumps up to @ 15-23cents US a canopy. I must admit the .015 makes a much better scale thickness canopy and for 25c it doesn't really break the bank, I just can't let that huge sheet go to waste! 8. The heat source. This is the simplest I came up with, works great if you have an electric stove, especially the flat surface type. I use 2 scrap pieces of 2x3x @ 12" and straddle the smallest burner so as not to have them sitting on the heating element. This provides a rest to place the plastic holder on from the previous post. You need to experiment with what setting to place the burner to heat the plastic. This is not the time to do other things, you need to watch closely, the danger being 2 fold, the plastic catching fire(not too dangerous) but worse, it melts and covers the stove top and burners, usually a hanging offense according to housewives!
  5. cmdrted

    cmdrted Active Member

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    Here are some of the pics that I saved from the old article, The first set is the machine itself. It is a box with a 1 1/2" hole (green arrow) for the hose /accessary fitting of your everyday vacuum cleaner, the other arrorws shows a rubber gasket I glued around the periphery to make it more airtight. In practice it doesn't have to be that airtight. Note the work surface with the rows of tiny 1/8" drilled holes. They do not have to be drill team precision lined up. The second pic is the machine set up with the hose attached ready to vacuform.

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  6. cmdrted

    cmdrted Active Member

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    The next series is the frame for holding the plastic to be melted. It is basically a clipboard with an area cut out that cooresponds to the size of the work surface of the machine. I then used a second clipboard's bulldog clamp and bolted it to the othe side. A 3rd piece is a small frame that has an opening the same size as the clamp pieces but is big enough to fit under the bulldog clamps. This piece is used to sandwhich the plastic between the clipboard and itself. When you heat plastic, it 1st tends to shrink on itself and it pulls with a pretty good force, that's why you need to really secure the plastic in this double clamp setup. In one of the pics the underside of the clipboard shows the screws/rivets used to secure the clamps. Make sure these are located outside the work area of the vacuform box.

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  7. cmdrted

    cmdrted Active Member

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    The canopy build pics. I'm using Marek's P40E that I recolored to a US bird. When you build the paper mold, any connecting strips or tabs ahould be on the outside of the canopy. If you build it from the otherside it will show up in the sculpey mold and have to be polished out. It usually makes the canopy a bunch smaller. Image one shows this process. Image 7 shows the basic sculpey that I use. Donot get the metallic colors, neat though they seem they seem more brittle than plain white. Image 3a shows the sculpey squeezed into the proper thickness pancake ready to press into the canopy underside. Image numbered 2 shows the sculpey pressed into the canopy "mold" with an extra bit extending past the bottom for trimming later

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  8. cmdrted

    cmdrted Active Member

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    This will be enough for tonight, I need to find the rest of the pics etc. In the next 2 pics are 2 baked canopy forms that I removed from the oven and sanded them down for use. They aren't the P40 molds but an A4 skyhawk and an Iar 80 mold from a few years back. You can see the line that is cast into the sculpey from the bottom edge of the canopy frames. You will actually get this line in you finished product and marks the rough border you need to trim down to. The paper frames cover the irregularitys but try to get them as smoothed out as possible. The last 2 pics are the packaged plastic sheets from micro mark, and a piece of the huge 4x8' sheet I bought. I prefer the .015 from micro mark for smaller canopies and turrets etc. But the thicker .020 is ok. Just make sure you remove the thin paper or plastic protective covering before you heat this up. I bought a piece of this stuff and thought it wasn't very clear, heated it up and found out the hard way that the plastic wasn't cloudy my kitchen was!

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  9. cmdrted

    cmdrted Active Member

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    A few more steps... here are some pics of the setup used to heat the plastic on the stove. It involves some very sophisticated, highly detailed engineereed pieces of equiptment found only in the finest dumpsters/construction sites worldwide... yes 2 scrap pieces of 2x4 or 2x3... In the 1st pic you can see the limits of the heating element and the small "safety distance" that the 2x3 pieces are from the element. You will still get scorching sometime but it is only for a few moments and as said before you need to do this undistracted, The 2nd pic is how I balance the plastic holder on the 2x3s. When I "designed" this I didn't know the specific dimensions of my Wife's new stove so I had to have it balance like it is in the pics, but asa I said this heating part lasts only moments. In the last pic you can see the plastic heated up and properly sagging. This is the "art part" of when it is quite ready to be vacu-formed. I read in an article that you can test the plastic's readiness by gently probeing with the eraser end of a pencil. The point is if it isn't hot enough the form will not fill in, too hot and it sometimes will poke a hole in the high spots or be too brittle. Take heart if it isn't hot enough and the plastic hasn't torn you can reheat it and you can try again. This process take only a few seconds sometime so once again , pay attention!

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  10. cmdrted

    cmdrted Active Member

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    The last bits... I need to mention that before you are heating the plastic the mold must be setup on the forming box. There are a bunch of technical reasons for why it has to be set up the way I'll mention but suffice it to say you need to have the mold a bit higher so the heated plastic forms around it and has enough area too cover the entire mold and alittle below so you have a completely formed piece with all the detail and some trimming area. I use my sons "lost pieces" of his lego set and a bit of unhardened sculpy to properly set up the mold for casting height. The pics show this best. Also after the mold is set on your machine you should hook the vacuum hose up and have it running, because the time from when you have the plastic heated up and when you have to put it over the mold is only 2-3 seconds. No time to fumble with switches etc.

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  11. cmdrted

    cmdrted Active Member

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    The forming process.. Now that the plastic is heated, the mold was set up, the vacuum turned on, you quickly, ie. 2-3 seconds take the plasic holder frame and place it over the mold pushing it down to the top of the machine and watch the "magic" take palce. It still fascinates me at how quick and how neat this is. The plastic whooshes over the mold and cools in seconds! Now all you have to do is release the canopy and mold from the frame and gently cut away the plastic to release the mold and start trimming to fit the plane. If you are reasonably gentle you can use the hardened sculpey molds for many years. The A4 skyhawk mold is the only one that broke and I still think it was because I used the metallic colored sculpey. None of the white sculpey molds ever broke. They may chip a few palces when you cut away the plastic but if it isn't in the actual canopy area it will be fine.

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  12. cmdrted

    cmdrted Active Member

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    The finish, this is a strange mix of me-109 canopies, A4 skyhawks, P40 etc. I couldn't find all the parts and pics but I think the pieces and explanations should do well. Any questions, let me know and I'll help anyone interested. This seems like alot of work but it actually takes @ 30 minutes start to finish, and you can form as many canopies as you want. There are a few of the original Mattel vacuform machines out there on ebay, etc. but I haven't used them for this. Also there is a company that makes vacuform machines, complete with frame holders etc. He wants 100+ USD for this. With the scraps I had around the garage, and pilfering the kids sculpey, and toys, this rig set me back @2-3 USD.

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  13. cmdrted

    cmdrted Active Member

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    Ps the finished P40 pics seem fuzzy due to the macro lens, fault finding lens. The important bit is make sure the insides are clean before glueing to the fuselage, also I use a glue found in craft stores to glue the paper frames to the plastic, it is called Gem-tac. Sorry I don't have a pic, I actually need to go and get another tube. It is the stuff used to glue gems to stuff. I also used the Uni-bond stuff in the red white and blue tube withsome success. Also some pics with the A4 Skyhawk canopy.

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  14. Willja67

    Willja67 Member

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    Excellent tutorial! I've always wanted to know how to do this. Thanks a bunch.
  15. Renaud

    Renaud Member

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    cmdrted's canopies

    With the exception of "la machine compl├Ęte" of course, I had to use my dictionnary here and there...and I am satisfied with killing so two birds with one stone. Thank you, cmtrted!
    But what's the meaning of cmdrted?
  16. dwgannon

    dwgannon Member

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    Outstanding. Thank you for sharing. I think I might give it a try. But I have to sweet talk the wife on the stove. I have the ceramic top and she would kill me if I melt the plastic and can not get it off.
  17. lizzienewell

    lizzienewell Member

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    I've got a gas stove. Would maybe a toaster oven work? Maybe a heat-gun? I'd like to see that frame made out of something that won't burn. A metal clipboard?
  18. cmdrted

    cmdrted Active Member

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    All good ideas, a metal frame might work but be careful it might transmit the heat around the edges faster there than the centre and cause the plastic to fall out into the oven/stove. As for the ceramic tops if you are not distracted and very attentive you can catch the plastic before reaching "critical meltdown". The original description from the "commercial makers of this machine" use a metallic type frame, and use the actual oven as the heat source, but from my experience with this contraption you need to move pretty fast from when the plastic is just right to form and placing it on the vacuformer. I think if you experiment with other heat sources and don't let the plastic touch any open flames it may work. You may have to stack the heating frame higher but it may work, ie use 2x4s stacked up to 8" or so. One observation I made while watching the plastic heat, is it takes a while before the plastic shows signs of melting, then there is a contraction phase where it tried to pull away from the frame sides, then it relaxes and starts to sag. The timing from contraction to relaxing is only seconds (sounds like a bizarre LaMaze to me), but once it sags it stays in that state for a little while.
  19. Willja67

    Willja67 Member

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    It's kinda coincidental that this thread poped up today. I work construction and there were some scrap 1x8's so I cut them up and stapled them together. The interior dimensions are about 7x7x7. I know that it's a little bigger than what you made yours so I'm wondering if it's okay?
  20. Bowdenja

    Bowdenja Active Member

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    Will,

    I think that's what makes Ted's machine so unique. It is very flexable as far as materials, size and such. As long as you can hook up the vac, seal it off and have the plastic hot and ready it'll work!

    john