Category Archives: pressure forming

Blowing Arcylic Canopies Using Stuff From Around The Shop

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Blowing an acrylic sheet after heating it is an easy way to make a smooth and transparent canopy or bubble for anything from clams to light fixtures. [Michael Barton-Sweeney] does it using plastic blow ovens he made cheaply, mainly from stuff which most of us already have in our workshops.

All you need is a way to heat the plastic, to then clamp it down around the edges, and finally to blow air into it as you would when blowing up a balloon. Of course, there are things to watch out for such as making sure the plastic is heated …read more

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Pressure-formed Parabolic Mirror from a Mylar Blanket

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Parabolic reflectors are pretty handy devices. Whether you’re building a microwave antenna or a long-distance directional microphone, suitable commercial dishes aren’t that hard to come by. But a big, shiny mirror for your solar death-ray needs is another matter, which is where this pressure-formed space blanket mirror might come in handy.

Pressure-forming was a great choice for [NighthawkInLight]’s mirror. We’ve covered pressure-formed plastic domes before, and this process is similar. A sheet of PVC with a recessed air fitting forms the platen. The metallized Mylar space blanket, stretched across a wooden frame to pull out the wrinkles and folds, is applied to …read more

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Quick and Easy Pressure Forming Makes Plexiglas Domes

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Thermoplastics are amazingly versatile materials. Apply some heat, add a little force, and within seconds you’ve got a part. It’s not always quite that simple, but as [maxelrad] discovered, sometimes thermoforming can be as easy as blowing up a balloon.

In need of a cowling for an exterior light fixture on an experimental aircraft, [maxelrad] turned to pressure forming of Plexiglas for the hemispherical shape he needed. His DIY forming rig was a plumbing-aisle special: PVC pipe and caps, some air hose and fittings, and a toilet flange for the pressure chamber. The Plexiglas was softened in a toaster oven, …read more

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