Markus Zingg wrote:
>
> Dave,
>
> The pictures (and description) in the link you gave made the impression
> to me that the tank is molded as one piece. If now - acording to the
> experience others obviousely have made this turns out not to be true -
> you are IMHO right that its similar to doing your own then. If you also
> get the air pump heater etc. for just $49 I still think it's a very good
> offer but hearing that the tank is not made of one single piece is a
> bummer....
>
> Anyways, I do my tanks using polystyrene glass sheets that I cut into
> the shape I need using a fine circular table saw and "glue" them
> together. I use Methylenchloride as the glue and this chemically welds
> the parts together. So this is not really the same as glueing in the
> traditional sense. In fact, the this way chemically welded parts are so
> strong that if you mechanically try to break such an area, it usually
> breaks elsewhere. The key here is that if you cut the sheets into shape
> you use a fine saw so as the areas which are glued together are even
> with no unregularities or such. The nice part about the polystyrene
> glass is that you can see the "glued" area all through the material like
> if you would X-ray it if it were a different material and as such you
> can optically check if it will hold forever or if there are areas where
> it did not worked out well.
>
> Obviousely, for a pure etching tank, using a redy made available
> container is not wrong. I must admitt that the tanks I do are for the
> trough plating station where space is constrained and where bigger
> tanks mean spending partially lots of money more for pricey chemistry
> just because the tank is not optimally sized. For the first incarnation
> of the tanks about four years ago, I welded the plastic using a hot air
> gun because I too was afraid of leakage back then. Now with the
> experience of using Methylenchloride I definately don't want to go back
> to this hassle.
>
> Btw, I always fill the tanks of my machines only for relatively short
> periodes of time. I don't care leaving the fluids in there for a couple
> of weeks if I'm in a phase where I do a couple of PCBs in a row but once
> this phase is over, I always fill the fluids back into containers that
> can be air sealed and which are made of one piece of plastics (Sorry,
> don't know the propper term for them cause english is not my native
> language, but I hope you know what I mean). I do so to avoid loss of the
> partially pricey stuff (it otherwise vaporizes over time) and also for
> security reasons. There are cheap (about 1$ a piece) hand pumps
> available in flower/gardening stores which are excellent tools to fill
> such fluids back and forth withouth ever spoiling a single drop.
>
> Markus
Markus,
Thanks for the follow up info. Its all good. I have seen other people
use a similar, if not the same method gluing plastic like plexiglass
into molds (boxes) and it produces excellent results. As you said, the
key here is to be able to cut accurately so the chemical can weld the
plastic together. Usually easier said then done unless you have the
correct tools. I have a workshop and some wood working tools so maybe
some day I will try it. :) I think the term you were looking for when
sealing the bottles is "vacuum sealed" maybe? I like all the ideas so
far and this seems to be a friendly group. Just remember, I am a
beginner so even though the ideas are great, I may have to start with
simple ideas and methods until I get going...
:)
Thanks,
Dave