L-29 Delphin "Tigermeet" by Modelart

Discussion in 'Aircraft & Aviation' started by cmdrted, Nov 5, 2006.

  1. cmdrted

    cmdrted Active Member

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    The next thing is a heat source. The web search has you doing all kinds of unnatural things with ovens and oven toasters. I lucked out with the simplest approach possible. I used 2 2x3s @ 1 foot long and straddled the electric burner. The holder assembly from the last step sits on top of this. nothing could be simpler. I haven't done this on an open flame stove so experimenters out there be aware! It probably can be done but the height of the 2x3s would have to be a bit higher I would think. You wouldn't want the flames to hit the plastic.

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  2. cmdrted

    cmdrted Active Member

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    Which brings us to the next thing you need and that is plastic. I use some hobby shop stuff I ordered from Micromart out of New Jersey. They are a great source for all sorts of modeling tools. Just google micromart or mark. I use the .015 clear they have but I also used a differant stuff. I bought a 4x8 foot sheet of vivak .020 in thickness. They cut it in half for me and shipped it was @ 20.00 or so a few years ago. I haved even touched the bulk of the stuff yet. It makes great clear canopies, a little thick but if you are careful you can let it melt and droop pretty long and the glass thins out nicely. This was the stuff I used on the F-20. Today I didn't feel like going downstairs to cut a piece so I used the .015. Price wise I worked this out a couple years ago, for the hobby shop plastic, the canopies were coming out to @ 29c US. The big sheet came out to @ 10c a canopy.

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  3. cmdrted

    cmdrted Active Member

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    The next step is relatively simple. Cut your plastic to the size of the bracket frame sized thing. Then you sandwhich this inbetween frame with clamps-plastic-frame/bracket. You are ready to form your part. But what part? This is coming up next,... how to make a mold of your kits canopy.

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  4. cmdrted

    cmdrted Active Member

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    The next step, or actually the 1st if you have your machine built, is to make a mold for your aircraft. You start with a copy of your kits canopy. You have to build this inside out. I'll explain, you need to put the connecting strips on the outside. You want a very smooth inside free from as many blemishes as possible. When you have this built up, fit it to your fuselage. This is the time to custom fit it to any corrections, fitting abnormalities you or the kit put in there during constuction. You should have a piece that looks alot like this...

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  5. cmdrted

    cmdrted Active Member

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    Next is the kinda cool part. I use stuff called sculpey clay. It comes in a variety of colors and packages, but the cheapest and most useful for this is plain jane white. This stuff molds like clay dough and then with a little oven heat 275F for 15 minutes you have an almost ceramic hard male mold that you can carve sand and grind. It is fairly tough stuff, but be a little careful with it, it can shatter if you drop it! I bought this box a few years ago and it still is 3/4 full! They also sell it in little blocks in a variety of colors. One year I tried a few of the blues etc to sort of color code the canopies, I gave up after blue and turquiose. They have a metallic set but do not use them! I tried and they sort of crumple easier than the plain solids.

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  6. cmdrted

    cmdrted Active Member

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    Next you want a hunk of sculpey, well rolled and smoothed out to a little bigger than your paper. The instructions caution you about going thicker than 1/4" or 6mm. This will affect your bake times and it is just easier to use it in 1/4 ". Now press the stuff into the canopy pressing it into every nook and cranny. The idea is to have a nice smooth surface when it hardens to polish and use as a mold. Experiment with the feel of how much you have to press the stuff in. Trim any excess off from around the card former. It's easier to do it while the stuff is soft. If you wait until You bake it you have a lot of carving and sanding to do.

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  7. cmdrted

    cmdrted Active Member

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    Now I don't want to be a bigger bore than usual but I have to point out to non bakers and cooks. You need to preheat your oven to 275F. This means turning it on before you put in the mold and letting it come up to 275 before placeing the mold in the oven. Duh! but yours truly didn't know that. My 1st attempt came out very rubbery. The other caution is time the stuff! It says 15 minutes, not 14 0r 16! The stuff comes out very wierd feeling and brittle 1 minute either way! Very odd stuff but still better than mixing resins pouring and hardening. The following pic shows the baked mold and the card former alongside it. Some advanced techniques that hep fit your galss better in the long run. Give the card canopy with the sculpey in it a little squeeze before the bake. The stuff tend to slightly expand makeing your mold a little wider than you'd want. You can always sand this down latter, but I've found that the glass fits easier if it is exactly the same size as the fuselage or even a little narrower so that you gently have to pry the glass open to fit on the fuselage. I've tried it wider and have to squeeze the glass to stay on and the glue to set but it never looked quite right that way.

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  8. cmdrted

    cmdrted Active Member

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    The next step is to polish the mold. You need to sand out any and all blemishes that will show up on the clear parts of your glass. If you have a ding or 2 on the parts covered by paper this is ok. I use 220 wet dry and sand down to using 600 grit. Now your mold is ready for the forming process. You need to place the mold on your vacuform machines top working surface. This needs to be raised as the forming process tents to tent at the bottom, if you don't allow for this the bottoms won't be properly formed. I use my son's leggo blocks and a piece of soft sculpey holds the mold to the leggos.

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  9. cmdrted

    cmdrted Active Member

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    Next gather up your stuff! You should have at least 2-3 precut pieces of plastic, I usually make 2-3 canopies as you sometimes mess one up trimming it. Get you vacuum cleaner and hook up the accessary hose to the port. Place the mold on the surface, heating blocks to the stove top, vent fan on. A #11 scalpel is an invaluable tool for cutting the plastic from the molds. This is not the time to be distracted. Send the family out for ice cream or something. A distraction could spell a disaster. In the pic is the "Mega-Suck 2000", the vacuform machine, the heating blocks with the plastic holder frame on top, the mold on the machine top and a handy beverage to quench the thirst of a man's work to be done. (don't drink alcohol and do this,, wait until you are done!!!).

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  10. cmdrted

    cmdrted Active Member

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    Next turn on the machine, turn on the burner, I use medium setting. Now is the part that has to have your undivided attention. Watch the plastic as it starts to heat up. It first gently sags then abruptly contracts and is taunt. This is why you need the heavy duty clamping set up in the frame holder. Itried using only one clamp and the heated plastic pulled out from under it and almost hit the stove top! I would've been busted for sure! Pay attention after the first sag then tauntness, theplastic will now start to melt and if you look under the frame you will see it start to sag down. This is the art part of vacuforming. You need to let it sag/melt enough to be pliable and form over the mold but not enough and you have a impartially formed part, too much and you risk melting a hole in the plastic. Just watch and experiment. The melting part takes @1 minute at most, alot of times much much less! When the plastic has sagged enough, IMMEDIATELY grab the frame and place it over the vacuform machine and place the frame over the mold. The plastic will be sucked around the mold and formed in less than 2-3 seconds! Mind the hot burner. I usually shut both the vac and the burner off eject the mold vac part. Let it cool and then cut it from the mold with the #11 knife. In pic arrow shows plastic starting to sag, I waited until it was @ 3/4 inch.

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  11. cmdrted

    cmdrted Active Member

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    The formed glass ready to be cut from the molds. This is another satisfying part. Gently go around the edge with the knife blade and gently remove the palstic from the mold. Then form up another just as a spare.

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  12. cmdrted

    cmdrted Active Member

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    2 pieces ready to be trimmed. At this point I have to continue tomorrow as my "other job" is calling. More tomorrow.......

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  13. cmdrted

    cmdrted Active Member

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    One last, rough trimmed ready to be fitted... now truly I must go for now!

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  14. cmdrted

    cmdrted Active Member

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    Canopy with rails and framing ready to install. The trick is to have the plastic @ 1mm smaller than the surrounding paper framing. This allows for an easy attachment to the fuselage, ie; paper to paper. Paper to plastic is ok but it sometimes gives to unrealistic a bulge when placed on the fuselage. I bond the paper to the glass canopy with Gemtac, a whitish glue found in craft stores to glue sequins and rhinestones to clothing. Caution, it is very tacky and leaves annoying prints on anything if you are not careful!

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  15. cmdrted

    cmdrted Active Member

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    And the canopy attached to the aircraft,

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  16. GT5500

    GT5500 Member

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    What a great plane and what a great tutorial, the only question I have is how do you make the plastic 1mm smaller then the frame?
  17. cmdrted

    cmdrted Active Member

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    Gt thanks, the answer is relatively simple. Take a magic marker and using the template you used for the mold mark the bottom where the paper meets the plastic. when you cut out the plastic mentally guesstimate @ 1 mm and cut it just that much shorter all around the plastic. Takes a little practice, that's why I usually make 2-3 canopies when vacuforming. This time I was lucky and got it in one!
  18. cmdrted

    cmdrted Active Member

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    Finito!

    Well finally, had enough time to finish her up! Here are some pics (Ad Nauseum). Hope you like them!

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  19. cmdrted

    cmdrted Active Member

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    And more...

    Some walk around pics...

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  20. cmdrted

    cmdrted Active Member

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    The End!

    Last of the tarmac pics, now on to something else!

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