Prop makers?

Discussion in 'The light stuff area' started by ryanjames170, Sep 27, 2018.

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  1. Oct 1, 2018 #41

    Aesquire

    Aesquire

    Aesquire

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    You certainly don't need CNC or pantographs, or fancy anything to carve props.

    A band saw is really nice. But optional. Ditto digital protactor/level. ( I'd have loved one, but didn't )

    Draw knife is even optional, a band saw is more time saving.

    You do need clamps. Or a heavy clamp table, like two slabs of steel & a floor safe, but that's more work than It's worth, I know. Hit Harbor Freight with a 20% off coupon when clamps are on sale & buy a stupid amount of them in three sizes, too big, way too big, and just right. ( you will find a use for them all, but the too big will be the ones you need. )

    A disposable cup & brushes for the Resorcinol glue. Never mind space age epoxy. Ignore lies of waterproofing and ease of use. Resorcinol. Powder. You mix it with distilled water from the grocery store.

    First, you do math. Use the book above, or another, or both.

    Then you make plywood. That's what the clamps & glue are for. No, you can't buy it.

    While you wait for the glue to dry, use the math to draw, and cut out, templates for the airfoil and angles. "Shirt cardboard" ??? The back cover from spiral notebooks is fine. Buy a dozen notebooks at the back to school sale leftover sale. The front cover may work too.

    A flat work bench with a paper ruler glued down like a number line, zero in the middle.

    Sand paper. Rasps. A book on home made props.

    Go for it. ( How do you think Wilber & Orville did it? First they wrote the book........)
     
    fly2kads likes this.
  2. Oct 1, 2018 #42

    Aesquire

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    For commercial prop makers, I'd add Cato. He'll need the same info everyone else needs, including you. Power, size, anticipated speed, guess of drag.
     
  3. Oct 1, 2018 #43

    plncraze

    plncraze

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    Check out carving a prop with an electric chain saw. Goes stupid quick.
     
  4. Oct 1, 2018 #44

    TFF

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    The man that used to do the prop carving demo at Oshkosh used a chainsaw for roughing the cuts. He could probably get down to fine work in about two hours with nothing special. Used lead strips, stick on tire weights, to match the opposite side. He was fast. He was also missing some fingers; don't know if it was from the chainsaw.
     
  5. Oct 1, 2018 #45

    BJC

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    I think that you have confused resorcinol glue wilh something else. The prop maker that I know uses Weldwood Plastic Resin, which is a powder that gets mixed with water.


    BJC
     
  6. Oct 1, 2018 #46

    plncraze

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    Is this the same kind of Weldwood sold by Aircraft Spruce?
     
  7. Oct 1, 2018 #47

    BJC

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    Yes, sold by AC Spruce, and thousands of hardware stores.


    BJC
     
  8. Oct 1, 2018 #48

    Hot Wings

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  9. Oct 1, 2018 #49

    plncraze

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    That was why I asked. If you search for Weldwood it seems that it is a brand rather than a specific kind of glue.
     
  10. Oct 1, 2018 #50

    BJC

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    I’m not aware of any resorcoinol that is mixed with water; Weldwood Plastic Resin is mixed with water, and, as I indicated, is the product that a wooden prop maker that I know uses.


    BJC
     
  11. Oct 1, 2018 #51

    Aesquire

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    https://en.m.wikipedia.org/wiki/Resorcinol_glue

    My bad. It's been too many years. Use the right stuff, like the Weldwood brand mentioned above.

    There are other brand names.

    Despite decades of chemical engineering, this is the propeller preferred stuff.
     
  12. Oct 1, 2018 #52

    lr27

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    Better than resorcinol? Better than T88 or other epoxy?
     
  13. Oct 1, 2018 #53

    Hot Wings

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    True. But the "Weldwood" name was used interchangeably for both types of glue. Not proper, but it happened. Then we add in Aerolite glue where the powder is mixed with water....... it made for a lot of confusion.
     
  14. Oct 1, 2018 #54

    TFF

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    There are highly regarded prop makers using recorcinol, plastic resin, and epoxy right now. Every concept has pros and cons.
     
  15. Oct 1, 2018 #55

    pictsidhe

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    The powdered weldwood is urea-formaldehyde. Not as good as resorcinol-formaldehyde, but still good stuff. The UF I used needs lots of clamping pressure.
     
  16. Oct 1, 2018 #56

    Aesquire

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    use any decent brand of Resorcinol.

    I confused the water mixed glue, good stuff, but a bit fussy, with the Formeldahyd/Resorcinol glue that comes in a powder & a goo you mix. Red powder, brown goo, the Right Stuff.
     
  17. Oct 1, 2018 #57

    Aesquire

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    Resorcinol is considered the "only really waterproof glue" in part because nothing else has spent 60 years in the water, and still worked.

    Some new epoxy stuff might be even better, but doesn't have the decades of use. Get back to the question in a century.

    The layers in the prop must be as close to flat as you can make them, since the glue won't fill any gaps and the gap would be a weak spot. You need to use firm clamping to make the prop blank a solid piece, and don't rush anything.

    One time saving trick you can use ( from the book I can't find on my shelf today ) is to make the trailing edge of the prop a straight line. It costs a tiny fraction in efficiency, but makes the template matching a bit easier. It's one of those "tricks to use until you learn the other tricks" techniques, and not mandatory at all.

    I've only made less than a dozen props. The first one, I cut up and threw away. I didn't like the workmanship. The second worked, but was pitched wrong, and the third worked pretty good.... then Craig Catto started making better ones.... And yeah, I mis spelled his name above, didn't I? When I'm wrong I do it a lot.

    Not that I'm blaming Craig for putting me out of business. ;) Propellers are, still, a matter of science and intuition, no matter what NASA thinks, I was an amateur hack using a cook book approach and Catto was inspired and dedicated. I was happy not to spend hours with a rasp in terror I'd mess things up, and buy better, and cheaper if you figure man hours.
     
  18. Oct 1, 2018 #58

    BBerson

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    Catto said he uses Weldwood Plastic Resin (powder mixed with water but is strongly water resistant when cured)
    Not intended for underwater use.
     

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