Homebrew PCBs

Hi Adam

>I can see the 3 mm sheet being bent that way say upto 300 mm 
>in length. I made a plastic bender because I was planing on 
>doing larger tanks  450 mm length on 4.5mm thick PVC. You 
>seem to have done things quite nicely with what you've got.
>
>What thickness material are you using ?

2mm and 4mm. 

>Did you have to reinforce all the welding zones with blocks 
>of wood before you started welding so that the "hobby glass" 
>sheets didn't bend under the heat ?

They too bend under heat. What I did was first (using the 9mm reducion
nozzle) bend a long sheet (25x65cm) to a 'U' shape. I did this by
first bending one side, placing the sheet on a table into a 90degree
angle and let it cool out, then bend the second side. I thereafter
palced a thick wood block on the table as a base (in order to prevent
burning the table) and also created a little peace of wood that fit's
into the 'U' measuring ~4.5cm x 3cm using 5mm think wood. I then could
put the 'U' onto the side part (9x30cm) and place the wood into the
'U' to prevent it from loosing shape. I then used one hand to hold the
'U' down and also feed the plastic into the welder (of course this
time unsing the welding nozzle) and the other to hold the hot air gun.
It takes some practice but onece you figured it out it works not that
bad. You somehow miss a third hand :))

>I found that I had to make special wooden frame inserted 
>into the tank so that during welding the pressure of the 
>welding rod didn't collapse the sheets.

See above, you probably did the same thing then.

> From your past posts on the "hobby glass" I get the feeling 
>this is ridged clear pvc sheeting. Try burning some and see 
>how it compares to flame color/smoke smell to some real PVC. 
>PVC is very difficult to get burning by its self and 
>produces a harsh smelling smoke, (HCl fumes).

I'm currently not at home, so can't try this right away. I happen to
know how PVC smells when burning. Some 22 years ago I happend to learn
tool maker as my first profession where we were building molds to
fabricate plastic parts. I have a collection of the diverse plastic
base materials somewhere. Have to grab that out and compare the
flames/fumes of them with the glass I'm using.  

Markus