She Aint The Purdiest Foam Cutter

[vawtman]

Happy New Years everyone

 The profiles were attached with Ghurds famous hot glue worked nice.

 Has you can hopefully see i got hungup going around the leading edge and overcooked it but the rest of profile went good.

 How was it made?

 The transformer is from an old pool robot 24v

 The wand has 1/2 emt on the inside to stiffen.

 The spring is from a dishwasher with about 2in pull.With insulater inside from heater.

 The element is the 200w booster element from a milkhouse heater. It straightend out to the perfect lenght.

 I used a fan to blow the VOCs away temporarily LOL

 All in all it is fun playing with.Need more practice has you can tell.

 Any suggestions to reduce my funtime are appeciated

 Thanks

 

[Norm]

  Okay this may sound chintzy, or whatever but...

if you cut the top and bottom from a 2 liter

pop bottle and made a profile that had about the

same circumference as the pop bottle circumference

...about 4 popbottles would give you enough

material for a 2ft.blade.

          ( :>) Norm.

[willib]

it looks ok!

where is your power switch?

how do you control the current?

[vawtman]

Hi Willib

 Where is the power switch?

I just unplug it for now,any suggestions for a pushbutton type that you use.

 How do you control the current?

I dont yet but would help.It would be nice to have switch and control right on the wand so when going around sharp corners one could throttle it down a bit.

 Thanks

[Experimental]

Hi Vawtman,

     This is almost exactly how we used to make wing components for aircraft composite wings, in leingths as long as 8 feet.

    You can use a variable resistor for your control, but we used toy train transformers -- the speed control acted as the "heat controller !!

We also used stainless safety wire, for the hot wire.

   If you put "stations" on your end patterns (devide them into, say ten sections)one thru ten -- have one person on each end and call out these stations as you proceed with the cut, they come out very uniform -- espically ,when you have a taper and twist in the prop !

    At the trailing edge, on one side, we left the edge very thick, then glassed from  about 1" back from the leading edge, wrapped the glass around the leading edge, to the "finished trailing edge -- leaving about 1/8th inch of glassed fabric sticking out the trailing edge -- after the glass has cured, you use the hot wire to finish cutting off that thick area, you left on the trailing edge, then glass the "unfinished side, by starting again about 1" back from the leading edge --wrap around the leading edge and end at the unfinished trailing edge again -- that 1/8th inch or so you left on the trailing the first time, gives you fabric to bond to, on the "second" glassing and a double thickness, on the leading edge.

   The reason we left the trailing edge "thick" was because, if you cut it to a sharp edge, before glassing -- it is very easily damaged and stays straight if left thick untill one side is done -- you also sand the starting edge, before glassing the second layer (carefully) or you will have a "bump" where the new layer is laid over the first.

   You can put as many layers on as you feel necessary, but on small props, one is often enough with that doubled leading edge !!

    Where you join the blades together, to form a "hub", I drilled oversize holes and glassed in wood dowels about 3/4" in diameter, then put several round pieces of fabric over the area (about 6") then drilled the 1/4" mounting holes, thru those 3/4 dowels -- this gives you hard points for your bolts, or you crush the foam core when mounting !!

   I used "West systems" epoxy and finished with a putty type slurry you make, by mixing the resin with, #410 microlite filler -- this is a nice sanding filler and then epoxy primer and paint...

    I hope all this is helpful -- Have fun, Bill H.......

   

[TomW]

vawt;

I have heard of folks using a light dimmer to control the A.C. in to the transformer, also. A cheap one probably be fine on intermittent use.

It can also shut it full "off". A savvy tinkerer could easily rig it to a foot pedal that turns off when foot is off it and varies the heat based on how far you push it down.

Just ideas.

Cheers.

TomW

[elt]

I've used a light dimmer running into a doorbell transformer but I was only heating about a foot of wire ... maybe something like that sized appropriately would work for you.

- Ed.

[RP]

Check your local flea market, for an old sewing machine pedal.  They're basically a 100watt variable resistor.

[vawtman]

Thanks for all the info Bill

 I did a test just using epoxy paint.Painted on one thick coat then layed the cloth on and added a second coat seemed to work.What do you think?

 The blades will have no twist or taper and will be supported on each end(vawt).The final profile im thinkin will be 2in thick with a chord around 1ft.

 I can see yours and Gordys suggestion about having a competent assistant on hand but cant find one.Trying to train my dog LOL

[vawtman]

Thats a good idea RP

 I think my mother in law has an old sewing machine,its gonna be missing a part.Fun

 Thanks

[Experimental]

  OK now I see what you are doing !!

   The epoxy paint works and being supported at each end, takes a lot of the strength issues out --- we often have to use what we have !!

   Have been working on a Diesel powered Suzuki Samurai, so haven,t had much time for the wind projects lately, but durring our recent power outages here in the North West -- was sure glad for my wind gen and 12volt inverter !!!

   You have fun and lets see more pictures,  Bill H........