Homebrew PCBs

Hi Adam

Sorry for the late reply - terribly busy times here.

>Thanks for the descriptions. What are the internal 
>dimensions of the tanks. 

They are made to contain 2 and 4.5 liters respectively with a certain
"security" zone so as I don't have to fill them completely up. The
dimensions are therefore 4x25x29 cm with side pannels sized 9x30. The
bigger tank is identical except that it's 9 cm wide. All these
measures are internal dimesions.

>From your web pages I can see 4 
>smaller ones and one larger one for the copper 
>electroplating. From your pictures the tanks look like they 
>were made from 3 mm sheet. 

Uhmmm they are actually just 2mm :)

>Did you consider putting an outer 
>lip on the tops of the tanks ?

Yes, but it turned out that it's not necesairly needed. I WILL replace
the tanks though but mostly only because I want to try to build them
with a faster & easier method. I'm thinking of makeing the side
pannels from 4mm sheets and then mill a "U shaped track" into them
where I can sink the 'U' formed sheets into. This should make the
welder process easier and also make it more rigid. An outer lip seems
like a good idea. 

I must say that I like the fact that the tanks are "clear". You can
see a lot better what's going on and of course if a tank should ever
start to leak this would be seen much faster.

My "next generation" tanks also will have a tube inside that allows to
pump the liquid out of the tanks into a dedicated bottle per bath.
Like this I can further minimize that something happens to the
chemicals, overall, keep them cleaner and also avoid that parts of the
liquids vaporize. Especially the cleaning bath (#1) and also the
activator bath (#4) show this tendency. Well, #1 is really almost
behaves like water. Luckyly this is also the cheapest bath.

I definately will try this milling thing as soon as my CNC drilling
machine gets ready. The material is all ready for long (you may can
imagine how hot I am to start puting it together) but as mentioned,
terribly busy times here. I'm working 18+ hours at 7 days for now 9
months or so.. Luckyly there is meanwhile a silver stripe on the
horizon.

>I found that using lots of spring clamps are VERY helpful 
>when welding. I clamp a large piece of chipboard to the 
>bench so it hung out about 40 cm, I then could do all my 
>work on this board and easily clamp things from underneath 
>using sliding G clamps.

Hmmm, I unfortunately don't understand english good enough to know
what you mean. If you could make a picuture of that process I'm sure
it would become much clearer.

Markus

>Markus Zingg wrote:
>> 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
>> 
>> 
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>
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