[igor_throw_the_switch]

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[igor_throw_the_switch]

Ben: glad you got her up and going! I do wish you'd used an idiot friendly box to keep fingers away from live parts tho. Sayal sells strain reliefs for cords, and binding posts as well (handy for temp hook-up of your bow.

The 600 watt dimmer isn't exactly happy dealing with an inductive load, but it's rated highly enough that inrush current won't hurt it (you are pulling about 50 watts of power - less than 10% of it's rated capacity. That's why I spec'ed the 600 watt dimmer).

I tried using NiCr wire at first and hated it. I couldn't get it to tension without snapping. I'm using the Sig .018" control line wire (stranded), although other guys have bee reporting good things with SS fishing leader (also stranded) in the 35 to 40 pound test area. Remember to scrape of the plastic coating where you are gonna hook up your wires or you will have no joy.

I used an H frame for two of my bows (I also have a vertical "scroll saw") and i used turnbuckles on all 3 to crank in the tension. My long bow - 54" - is tightened to between a D and G on a guitar (the 2 middle strings). If I pick the bow up in the middle of the cutting wire, it will deflect maybe 1/8" - and my bow weighs a few pounds! It's made of oak flooring strips that are 2 1/2" by 1/2".

I "stole" some sand off the beach strip and double baggied it for my weights, and I have a few jigs for squaring up things as well. Jigs ain't rocket science, and make the job a whole lot easier. Invest the time in them.

I have an old thread on foam slicing over in RCG - here's the link: http://www.rcgroups.com/forums/showp...7&postcount=32


Brad Kacer

PS to Don H - I'd love to see your rig sometime - I'm in Burlington too - right behind the YMCA

[igor_throw_the_switch]

As Spitball has pointed out, an AC ammeter would be a very handy thing (try Sayal for this as well). We vary the pressure (voltage) to account for different wire lengths, but the current needed will almost always be the same. You just need to establish benchmarks on what works *for you* I suggest 1.5 amps for white "beadboard" styrofoam, 2 amps (maybe a tad less) for pink or blue foam, and 2.5 amps for EPP. I have no scientific proof of these numbers, but they feel *right* The ammeter should be directly in line with the output of the transformer on one of the leads. If in doubt about how to hook it up, shoot me a PM.

Brad

[Ken Currell]

Originally Posted by igor_throw_the_switch

As Spitball has pointed out, an AC ammeter would be a very handy thing. We vary the pressure (voltage) to account for different wire lengths, but the current needed will almost always be the same. You just need to establish benchmarks on what works *for you* I suggest 1.5 amps for white "beadboard" styrofoam, 2 amps (maybe a tad less) for pink or blue foam, and 2.5 amps for EPP. I have no scientific proof of these numbers, but they feel *right*

Brad

How does the diameter of the wire affect it?
I use wire that is 30 - 31 thou.

[igor_throw_the_switch]

Originally Posted by Gary Maker

I happen to have a roll of, I believe it's Sig, control line wire but didn't think you could use braided wire! It's not too thick?? The stuff I have comes on a red plastic spool and the wire is not shinny but a darkish colour - Does that sound similar to what you use??

Gary: The wire I've been using is silver coloured, but it is braided. I think braided can handle more tension than a single strand can. Like I said, scrape off the plastic covering first where you are going to hook up your power leads, turn it on, and let the heat cook off the rest of the plastic coating.

Brad

[igor_throw_the_switch]

Originally Posted by Ken Currell

How does the diameter of the wire affect it?
I use wire that is 30 - 31 thou.

Thicker wire = more heat (current). NiCr has more resistance than SS as well - more voltage?. Mebbe we should try for a group buy on some 0-5 amp meters?

[Ken Currell]

Here is a photos of the wire tensioner on my 5 foot bow. The heavy spring takes up the slack on the wire. The brass tubing ensures that the rod will slide smoothly.

My next bow will move the spring to the top end where there is no electricity. To date it has never caused a problem but the new one will allow for easier tensioning of the wire.

[benjhind]

Thanks for the input Brad!

I'm keeping my eyes out for a safer box. The unit will sit for a while as it is until I have time to do some cutting. Everyone please note the disclaimer that the box I have constructed is unsafe.

Thanks,
Ben

[Ken Currell]

Originally Posted by igor_throw_the_switch

Thicker wire = more heat (current). NiCr has more resistance than SS as well - more voltage?. Mebbe we should try for a group buy on some 0-5 amp meters?

FMA has a meter combo on sale at a good price. I was thinking of getting one for myself. I do have a 120 amp alternator test meter but it is a bit bulky.

The other meter from FMA has a 20 amp onboard along with a 60 amp shunt.

http://www.fmadirect.com/products.htm?cat=57&nid=37

Look at the bottom of the page.

Does the price look OK to you? $24.95 U.S.

[igor_throw_the_switch]

Ken: I bought a Sperry Rand meter in Colorado a few yrs back - paid $60us for it. And I'm an electrician. I just couldn't figure paying for a Fluke - as good as they are. I don't need precision on a scale like that, and this meter is pretty good. I've seen places selling meters for as little as a few bucks. The choice as to quality/price is yours - how much precision do *you* need? I could get by fine in my job with a $20 meter. Playing with home made balancers requires a bit more accuracy than that tho......

Brad