expanding foam

4 Articles

Puttering Around In A Converted Golf Cart

April 16, 2020 by 16 Comments

Technically speaking, golf carts are already sports cars, they’re just not very sporty in themselves. When [rtkerth] went to trade in his old golf cart for a new one, he found that it would be more valuable to hang on to the old one and have a bit of fun with it. The result is retro-styled kart that would not look out of place at a micro car show.

Before getting to the really fun bits, he had to do a bit of prep work, such as relocating the six large batteries so that super cool stock seat can sit lower. Now the batteries are distributed throughout the vehicle, including one that’s been cleverly disguised as center console. Since the cart won’t be hitting the links anymore, there’s no need for a place to put clubs. Two of the batteries are now in the back, supported by a platform made from old bed frames.

We love the fiberglass fab work [rtkerth] did to the front and rear — it looks great, especially considering he’d never done it before. The rear is done more traditionally with a foam mold, but the front is fiberglassed directly over expanding foam insulation framed with cardboard. The local body shops refused to paint this baby roadster, so [rtkerth] did it himself before adding the killer touches — 1930s Brooklands-style windscreens and 1950s bullet mirrors that look great together.

Believe it or not, this isn’t the first amazing golf cart mod we’ve seen. Go see this baby DeLorean before you’re outta time.

Bubbly Filament Works Better Than You Think

February 17, 2020 by 22 Comments

Normally bubbles appearing in your extruded filament would be considered a bad sign, but it turns out you can now buy filament that has been specifically formulated to foam. [Stefan] from CNC Kitchen has doing some experiments with these bubbly filaments, and the results have been very interesting.

The filaments in question are VARIOSHORE TPU and LW-PLA, both by ColorFabb. Both filaments have a blowing agent added to the formulation, which releases gas as the temperature is increased. This causes bubbles to form, creating a cellular structure, which decreases the density and increases the flexibility of the printed part. This isn’t the first time that foaming is sold as a feature, but previously it was only done for aesthetic purposes in Polymaker’s Polywood filament.

Before putting the materials through his excellent test procedures, [Stefan] first goes through the process of tuning the print settings. This can be tricky because of the foaming, which increases the effective volume of the plastic, requiring careful adjustment of the extrusion rate. Foaming in the PLA filament reached its maximum foaming at 250 C, at which its density was 44% of the unfoamed filament.

In testing the physical properties, [Stefan] found that the tensile strength and stiffness of printed parts are reduced as foaming increases, but the impact strength is improved. He concludes that the lightweight PLA can have some interesting applications because of the reduced weight and increased impact strength, with 3D printed RC aircraft being an excellent example of this. It should also be possible to change the between layers, effectively sandwiching the foamed layers between solid skins.

[Stefan]’s videos are an excellent resource for those looking to master the finer points of 3D printing with different materials. He has reinforced prints with carbon fiber, played with extrusion widths and developed an ingenious gradient infill technique.

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Hackaday Podcast 016: 3D Printing With Steel, Molding With Expanded Foam, QUIP-Package Parts, And Aged Solder

April 26, 2019 by 3 Comments

Join Editors Elliot Williams and Mike Szczys to recap the week in hardware hacking. This episode looks at microfluidics using Shrinky Dinks, expanding foam to build airplane wings, the insidious effect of time on component solder points, and Airsoft BBs used in 3D printing. Finishing out the episode we have an interview with two brothers who started up a successful business in the Shenzhen electronics markets.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

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Making A Flying Wing With Expanding Foam

April 21, 2019 by 9 Comments

Many radio control aircraft modelers will be familiar with the process of cutting wings out of foam with the hot wire method. The tools are simple enough to build at home, and it’s an easy way of producing a lightweight set of wings without too much hassle. [IkyAlvin] walks a different path, however (YouTube link, embedded below).

Expanding foam is the key here – that wonderful sticky material in a can that never quite goes where you want it to. MDF and foam is used to create a mold to produce the wing forms. It’s then a simple matter of loading floor underlay into the mold to act as the outer skin, and then filling the mold with expanding foam and waiting for it to cure.

The final parts are assembled into a flying wing, and the first test flight is remarkably successful. Using foam overlay as a skin also has the added benefit of providing a sleek silver finish to the aircraft. It goes to show that there’s always room to explore alternative techniques outside of the mainstream. If you’d like to get more familiar with the classic hot wire technique, though, we can help there too. Video after the break.

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