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TOPIC: Turtle's ABS blade scheme

keithturtle

Senior Member

Posts: 173
Date: Feb 12, 2010

RE: Turtle's ABS blade scheme

Excellent. Now to determine the strength and longevity of these two versatile materials Turtle __________________ Soli Deo Gloria

Caleb

Senior Member

Posts: 473
Date: Feb 12, 2010

RE: Turtle's ABS blade scheme

Pretty! __________________ - Bryan Mechanical Engineer turned stay-at-home dad.

Bernd
Senior Member

Posts: 224
Date: Feb 11, 2010

RE: Turtle's ABS blade scheme

Hello Turtle Ich had made my 50cm Test C-Rotor from PVC foam plates. This material gets soft around 80 degree celsius. I put it into the oven in kitchen and heat it to 100 - 150 degree. After a few minutes i put i on a form and pressed it with a towel until it got cold. Bernd

keithturtle

Senior Member

Posts: 173
Date: Feb 11, 2010

RE: Turtle's ABS blade scheme

What I've experienced with the heat gun is that to have the whole piece hot enough to form, some areas of that piece necessarily get hotter than they should for forming, and gross distortion occurs. That's why the oven; even heat ramped up slowly, at least in theory and much of praxis. Heat gun is fine for smallish pieces, but a whole 36" or 48" blade? Not feasable; turtle is too slow <groan> I do have a 6' PVC "hot box" with enough capacity, but it cannot be temp-controlled. All or nuthin', and all is way too much. I spent some time searching the topic, and came up with some good guidance. I know of an infra-red bulb I can use, 4' long, and may fashion a box for same. Distance and volume is everything. There is hope Turtle __________________ Soli Deo Gloria

wiboater
Senior Member

Posts: 242
Date: Feb 10, 2010

RE: Turtle's ABS blade scheme

You might be able to use a heat gun.

Caleb

Senior Member

Posts: 473
Date: Feb 10, 2010

RE: Turtle's ABS blade scheme

Would it be any smoother if you heated the plastic and then laid a warm sand bag over it so the pressure would be distributed and let it cool? I've tried heating plastic in my oven before and got wavy results too. (And a smelly kitchen) __________________ - Bryan Mechanical Engineer turned stay-at-home dad.

keithturtle

Senior Member

Posts: 173
Date: Feb 10, 2010

RE: Turtle's ABS blade scheme

One-piece Lenz blades is another option. They make this stuff in all colors; I just grabbed what was in stock. Thicker may be better as well- 0.090" is next on the list, in white. One factor for heat forming- the more bends you put in it, the more rigid it is, like the floor pan of a car. Bends that are aerodynamically friendly will only make it stronger. I have no idea about the flexor- tension fatigue factor. ABS is surprisingly cheap- paid 22 turtlebucks for 4' x 8' of the 0.065" stuff. Turtle, still at it __________________ Soli Deo Gloria

sjh7132

Guru

Posts: 1231
Date: Feb 9, 2010

RE: Turtle's ABS blade scheme

Very cool! We could maybe make 1 piece lenz blades. 250F doesn't seem that hot. I wonder if the plastic sitting in the sun with no wind could hit that temp and start to deform. I guess a coating of white paint might help that. __________________ Steve

keithturtle

Senior Member

Posts: 173
Date: Feb 9, 2010

Turtle's ABS blade scheme

Well, then, here are the results of trying to heat-form the 0.065" ABS sheet into the leading edge of a c-rotor. As I learned earlier with forming the "c" part around a pipe, there must needs be a form AND a corresponding reverse form, to compress the malleable plastic into the definitive shape.

Once that is done, it retains its shape well. Going to try the glue / assembly task later.

I think that vacuum forming, whilst accurate in its finished product, would stretch the film too thin and compromise structural integrity. In this approach, I merely centered a flat sheet on the pins and stuck it in a 250* F oven till it collapsed, then coaxed it around the curve with a pair of flat plates. Not very good results.

I am glad the learning curve has guard rails

Turtle, still at it

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