The first thing I did was to carefully remove any parts I was not going to need on the line bender. When taking something like this apart to reuse it is a very good idea to do this carefully and methodically. I don't like throwing parts away and try where possible reuse as much as I can. Photos and drawings, paper and pen all help to record what parts are and where they came from originally.
Originally the rollers protected the electronics from some of the reflected heat but now they have been removed I will need to provide some insulation and protection for them and the transformer from any reflected heat. This will be done by building a metal shield and adding some form of thermal barrier. Alternatively I can reposition the heater module and transformer to where the motor and gear box used to be loacted and away from the heaters. With the donor stripped back I needed to reroute some wires to the heater using heat proof wire which I had rescued from something else.
The heater will need protection from anything that might come in contact with it and will also need a controller area for the heat to be directed onto the plastic to be heated. This is basically a variable width slot in a piece of metal. Where possible I have reused as much of the original case as I could.
There will also need to be some supporting structure to holder longer pieces of acrylic while it heats up. This has been done using some scrap sheet aluminium secured in place with some new pop rivets.
Acrylic needs to be heated to between 140 and 180c without over heating which causes the plastic to boil and then burn.
Hopefully the heater control will be able to provide sufficient control to do this. Devices I have used in the past have always been crude and the temperature control is very in accurate.
Other considerations are electrical safety and protection from heat. It goes without saying that any work on mains electrical parts should only be done by someone who knows what they are doing.
Step 1: Electrical Works.
The first thing to say about the electrical part of this project is you do need to know what you are doing. Electricity can kill. If you are incompetent then seek advice and help, don't guess.
The original mains lead was quite short so I am replacing this with a better lead. Any cable that goes through the metal case needs to be protected with a gland or strain relief device.
Originally there were two heaters but I only need one which mean that I had to cut the the original cables and refit. This was done using crimp connects and heat protected cable/wires.
ALL the wiring has been checked for safety.
The mains supply cable passes through the case using a strain gland. The cable is secure inside the case with zip ties to prevent snagging.
Step 2: Initial Testing.....
The casing was reassembled and a testing heat was undertaken. You can see in the pictures the heater coming on, stabilising and then turn off to regulate temperature. As the acrylic heats it tends to curve upwards, as soon as this stats it is best to turn it over to warm the other side. Once heated the acrylic can be bent and left to cool. I use a heavy machinists angle to get a 90 every time. What ever you do don't use water to cool the acrylic as this will make it brittle.
You can see my teat piece has bent very well and I am very pleased with the result.
Now that I have tested the heater I can go ahead and make some refinements. These will include some support for the material while it is heated, a front panel for the controls, and a name for my machine.
Step 3: Heater and Acrylic Support.
The heater needs to be protected from accidental damage and to control the heating area (width of heating). In addition there needs to be some physical support for the material being heated.
The plan is to make a variable width slot to allow the control of the heating area and to have some adjustable supports to holder the acrylic.
Having tested the heater and bent some plastic I decided it was not necessary to make the heater slot variable. However some flat supports were required. I had saved some sheet metal from a cabinet I had taken apart so this was measured marked out and cut using my slot cutter (the slot cutter was obtained free from a school that was closing down).
Two strips of the sheet were cut and laid in place while another test bend was created. I did this to determine the working width of the slot. Once this was done I marked out the fixing points. I decided to use pop rivets as they are almost flat. They are the only new items used in the entire project.
Once the holes are drilled in the supports they are secured temporarily with Cleco clips these are effectively clamps for sheet metal. Once a test fit was completed the supports were removed and the edges deburred and the outer corners rounded off. Finally the supports are secured with pop rivets.
The heater is fully functional and ready for use.
Step 4: Refinements.
As with all projects there are refinements that can be made. I know that I am going to make a control panel decal and think of a name for my heater. I am going run the heater and learn from my experience before making any other changes.
I hope you have enjoyed seeing how it is possible make an effect strip heater using all repurposed parts except 8 new rivets! Not bad!