Acoustic Guitar Construction

Something is wrong -- 600 watts should be above 250 in about 10 minutes.

Form lined with foil? Base lined with foil? Is there a reflector over sockets? Is that reflector covered with foil? And I do recommend enclosed forms like Kevin's for bulb heated benders

ken cierp wrote:Something is wrong -- 600 watts should be above 250 in about 10 minutes.

Form lined with foil? Base lined with foil? Is there a reflector over sockets? Is that reflector covered with foil? And I do recommend enclosed forms like Kevin's for bulb heated benders

400 watts: 2x150+1x100=400

Base lined with 24 ga aluminum sheet. I can make a reflector to fit right at the top of the sockets the if that's what is needed. What do you mean by an enclosed form?

All our benders are 600 watts running full power. Total cycle time 30 minutes including warm up. The reflector over the sockets is also an important safety feature to protect the wire insulation and bulb bases. In addition I used high temperature silicone wire throughout.

Enclosed form can be seen here:

viewtopic.php?f=8&t=4

ken cierp wrote:All our benders are 600 watts running full power. Total cycle time 30 minutes including warm up. The reflector over the sockets is also an important safety feature to protect the wire insulation and bulb bases. In addition I used high temperature silicone wire throughout.

Enclosed form can be seen here:

viewtopic.php?f=8&t=4

I used industrial oven wire (Nickel/copper core, fiberglass insulation) rated to 250 deg C.

The bender did reach 250 degrees fairly quickly, but the rate of increase slowed as it climbed toward 285.

Yeah I have 3 x 150 watt bulbs and mine gets to 300 in less than 15 minutes. I have everything lined with reflective aluminum tape, and my forms are totally enclosed. Plenty of heat transfers up into the wood through the covered form.

I think I'm satisfied with the bender's performance for now. I may change out the 100 watt bulb for a 150 watt, and may add a raised reflector, but I do not see the need to make any other major changes right now.

I'm following the Bogdanovich book & DVD instructions, so the guitars I'll make using his methods will have laminated sides. I made a couple of practice sides out of common Maple. Bogdanovich instructs that the sides be made to 0.065" thickness. That's what I made the Maple practice pieces. They bent very easy and required almost no preheating. Bogdanovich actually puts the sides into his bender cold & dry, then applies heat.

The practice sides were given 20 minutes of heat, then allowed to cool before being removed from the bending machine. As can be seen, they fit right into the (unfinished) Solera with no problems. Laminated sides, which have been glued up, then clamped and cured in the side mold, would fit even easier.

Nice, I was just looking through his book again last night. I am gearing up to do my first classical, but for the most part I'll be following the way Robbie O'brien builds his as I have his video course to follow as needed. Just cut the pieces and made master side for the mold yesterday afternoon. Glad your bender worked for you.