www.KitGuitarsForum.com

what I use is a VSI switch
this is not a resistor but allows control of the voltage by short bursts at full power. I can control the voltage withing about 2 degrees and that is good enough for bending wood. I also use a cooking thermometer so I know the heat of the blanket at the point of bending.
When I first started I had a pid set up and still lost sides at the upper bout. Once I started using a thermometer I found that the heat could vary depending on heat load and wattage. I now only use and sell 5 watts per in blankets . I also learned to check the moisture.
Water can act as a refrigerant . I always place the probe between the slat and the blanker. The VAR setting on the controller comes in after I attain my heat usually about 325 to 350 F then use the 15 min at 220 to 250 F to release the water and set the bends.
A router speed controller is the same thing

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John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com

The blankets that John sells are made in the U.S., high quality, and backed by a warranty. I have seen blankets delaminate. Don't clamp directly to the rubber on the blanket and don't let a lot of the blanket hang over the end of your mold. If they run wild, without the heat sink that the mold makes, that's not good for the blanket.

I think that no matter what kind of temp checker you use, as long as you use it in the same way, your experience will soon lead you to the right path for your set-up. I use, and really, like those little mechanical surface temp gauges that Stew Mac sells. Since I sell parts and supplies myself, I'm always tempted to see if I can buy the product directly from the manufacturer. I did that with those units and the company said no problem, as long as I buy them in 1000 piece lots. Another million dollar idea shot!

Got my heat blanket and tried it out. The thing heats up muy pronto and hold the temp with in a fraction either side of the set point. I like it!!!

Digging around, I found a 5x30-inch 110v Keenovo heating pad 750 watt - - - that sounds like it fits guitarmaking nicely. Any ideas from anyone about using a pad that size instead of the usual 6x36-inch pads?

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peter havriluk

Should be plenty wide enough except when you place some bindings in along with a side you are bending, then you may not get heat evenly. The length should be okay as that is plenty long enough to heat the areas of the side that are going to bend. I almost ordered one just that size as it was about half the price....

Simultaneously bending bindings with sides...in the future. Appreciate the response. Time to order. Now to deal with temperature control.

Much obliged.

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peter havriluk

the Kenovo is a 2 1/2 watt per inch you should have a 5 also they are not warrantied . I tried one and it failed after 20 bends

_________________
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
president of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com