I have a VERY small project that I am working on and I could use some experience.
I need to make a few vac-formed canopies. I had a friend make the plug out of heat cured plaster...I have the lexan....I have a high powered shop vac....a commercial heating gun capable of 500+ degees.
NOW I JUST NEED TO MAKE THE BOX.
Anyone have a step, by step tutorial...I have seen a few websites...but they leave me with many questions and the sites are so old that the administrators will never email back (they may be dead!).
I built a vacformer for my scale model canopies, trial and error was the name of the game. The most important part in my opinion is a good frame for holding the plastic. My frame held 8"x8" which would be rather small for RC stuff as you need, depending on scale you probably want something at least12"x12". You probably want to "vent the plug" at larger scales so the vacuum can pull throught the plug and the vacforming platform. I would carve it out of basswood, hollow out the inside of the plug and drill 1/16" holes through the outer surface to the cavity. My table was 7"x7" or so, I just used a had drill and had 1/16" holes on 1/4 " centers, it was made of 1/4" lexan glued to a tupperware container, which held the vacuum hose. I heated my PETG plastic in the oven on broil, I made a handle about 18 inches long that use a 1/4"-20 bolt and 2 pieces of scrap birch plywood. Heat the plastic till it starts to droop and looks liquid, with the vacforming on the oven door suction on. Pull the frame out of the oven and swiftly and smoothly pull down over the plug. If you have a good many to make you might want to hinge the frame on the vacforming box. I dont think you will get enough even heat with a heat gun, but I might be wrong. I was using .020 or thinner so if you go thicker your milage may vary.
Good luck,
Hague
The problem with doing these out of basswood is that they are shaped to the contour of the tip of the nose (it is a flying delta)....I had some cores cut of HARD EPS and he literally sanded into the core beds to nail the shape. I did a fiberlass model from the plug and it is perfection. It is only about 8 inches long by 2.75 inches wide (at it widest point).
Thanks for the help! Any other ideas are appreciated....I had posted elsewhere with little help...but a bunch of PMs offering Vac-forming services. This project is too small for me to lay out a minimum run of 50 as I will need 5 max.
I did some figures in my head and on paper...looks like it will cost upwards of about 150 for materials...and 'billable time' (whatever my labor amounts to! )
Is there a supplier of pre-made vac boxes that you guys know of in the 40-80 dollar range for a 12X12 or something like that?
I made my own a while back and it is not hard if you have some materials laying around. My problem for the size was the elements as one would not cover a large enough area. I purchased the elements at a farm supply (1500w at 120v). Originally I used my shop vac but also scrounged a couple of old vac motors and mounted them underneath for a dual setup. The last time I ran it with the shop vac hooked up it sucked all the dirt out shop vac. Now I just use the 2 internal motors.
If you can scrounge or have some stuff laying around I can give you more info. Enclosed is a picture of mine and a diagram I made for another fellow on an RC forum.
John
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