Finally managed to come up with a working bending iron that is both quick to get up to temperature and silent, unlike my hot air blowing one, couldn’t hear myself think when that was running.
So to explain how this one works and that it costs no more than the price of a couple of pints of beer.
Tesco sell a standard clothing iron for £3.78, it is a “Tesco Value IR08 Steam Iron”, with free delivery! Anyway I never bought one because I just pinched the wife’s iron and told her to get herself a new one, which she did. The iron is a 1440Watt steam iron. I stripped it down until I just had the aluminium base with the heating element inside. I cut off all the surrounding aluminium right back to the edge of the heating element. I tried using the iron with the thermostat it came with but the thermostat itself was a bit big and bulky, besides it was not possible to keep the aluminium pipe I had added to the base to the temperature I require, 350 to 400°C. I don’t have a thermometer that can measure those high temperatures so I use a water spray on the pipe and if the drops of water just bounce off without sizzling then that is close to bending temperature as far as I know. These irons are NOT designed to have the element drawing current continuously and being as I have a mains 13amp foot switch I started running a few tests and here is what I found.
Turn the power on for 10 seconds and then off for 20 seconds for 4 minutes and it is ready to use, once it is up to temperature keeping it there requires much less effort, I have fixed the “on time” to 10 seconds and the “off time” gets extended to about 2 minutes, I don’t have an exact off time yet as I do not have any sides to bend, so I will get it more accurate once it is being used.
I am controlling the on and off times of the power with a solid state mains relay rated at 10 amp. I am controlling the relay with a micro controller(PIC Chip), I have 3 BCD switches that I set the “off time” with, from 1 to 999 seconds.
Here is a picture of the whole thing.
In the background is the small power supply to run the micro controller that is in a small black box with the BCD switches on it. The chip I used is a PIC16F876 and the software is pretty trivial. I will report further on how this performs once I get to using it properly. I did have a small piece of mahogany to do a quick test, it had already been badly bent with my old hot air bending system, I managed to put two more bends in it that came out perfect. So I am well pleased so far.
Here is a picture of the mahogany looking like an ampersand.
I still have more work to do on my tools such as sharpening chisels and the plane. I will be starting to build two more guitars in about a week or so. It will all be placed on the blog here so keep popping back to see what is happening.
I have just bought the £3.78 iron from Tesco and it is being delivered free on Thursday. It will make a good backup plan if the current one fails for some reason and at £3.78 I just couldn’t resist especially as it would cost me about £5.00 in fuel just to drive to their store and back, so god know what it costs one of their trucks. What a crazy world!