completelycharged said:
Is the vacuum just to prevent oxidisation of the cell surface ? If the two windows are sealed around the edge and then filled with Argon (cheap welding gas small bottle or a friend with a welder...) would that not do the same job ?
Just throwing some unconventional ideas around....
In the professional machine the prepared panel is put inside ... this is glass / eva /cells /eva / white backing plastic ...
It is put inside a heavy duty plastic bag inside the machine , .... the air is suced out of the bag to make the vacuum , so atmospheric pressure is pushing the glass and the white backing sheet together attremendous pressure
10 tonnes per square meter of panel !! ...
so the vacuum is to make sure no air bubbles in the top layer of eva , they will scatter light away from the cell , and look unsightly ... but also the vacuum pushes the whole sandwich together , making sure the now hot liquid eva gets into every crevice.
This is not easy for the DIYer to replicate without considerable investment , vacuum pump , heating chamber , ..
I built a heating element composed of a lattice of wire sandwiched between two glass sheets , epoxy fixing theglass sheets together . Passing current through the wire heats it up evenly , pressed hard onto the panel it melts the eva and does the job ...sort of ... some air bubbles ...
If trying to use eva , I would advise not to make the panels too large ...very difficult ...
Remember even if all goes well , it's still cheaper to buy the panelsfrom the manufacturer ..
In CBlacks case , where he already has bought the cells , unless very technically minded with a good workshop, liquid encapsulant might be a better choice.
The trouble with the idea above from compleatlycharged ofjust sealing between two glass plates with silicon , is that as the panel gets hot in the sun the argon will expand , build up pressureand find a way out , then cooling will suck in moist air .... I think it's humidity which destroys cells ...
I would advise CBlack first to try soldering the buggers (6x3s) together !!...this puts of most DIYers before even getting to encapsulation!!
CBlack said:
.... The backing will be a super soaked small plywood that has been treated.
I'm not sure the eva will bond well with plywood , also essential the backing is not permeable to any extent ...
I used glass as a backing on mostpanels I made , so that's glass/eva /cell/eva/glass ... you can normallyget glass free from your glass shop , they scrap glass 400mm wide ... for the front glass try to get
low iron glass , it lets more light through , most glass shops stockit ...
My advice is keep the panel size very small, it's much better to have a small suckcess than try to make a big panel and lose many cells in a disaster ....
Good Luck ... you will get an education doing this!