Joining and fixing 1.5mm polycarbonate (Thien top-hat wall)

[baldpate]

Hi all,

I'm in the process of building a small 'top-hat' Thien separator (chamber approx 300mm diameter x say, 80 mm high) - it's small, but so is my workshop (loft of terraced house), my vac (Earlex 1100W), and my needs (hand power tools + router table, dinky home-made table saw, and SCMS).

The only (well main) area I have doubts about is the construction of the chamber walls. Sheet material is my only real option, I think. Having read this previous thread https://www.ukworkshop.co.uk/forums/post678708.html?hilit=thien separator#p678708
I'm currently thinking 1.5mm polycarbonate, cold bent, might meet my needs. But I have only very limited experience with working, joining and fixing sheet plastic, specifically polycarbonate.

So my questions are these:
1) can I cold-bend 80mm width x 1.5mm poly to a radius of 300mm ?
2) the most economical way to make the wall would be to buy an A3-sized sheet, cut it into 80mm strips and butt-joint the strips : would glue-weld joints stand up to bending to 300mm radius? (buying a single piece of the necessary would be quite expensive)
3) assuming I could do (1) & (2), what glue should I use to fix the poly walls into routed slots in the top & bottom of the 'hat'? Polyurethane? Epoxy?

I'd be interested in any suggestions for other wall material, particularly if you can recommend a suitable thickness which isn't too difficult to work. My plan 'B' is to use two layers of 1.5mm baltic ply; I haven't really got a plan 'C' yet (aluminium? thickness? workability?)

Thanks for any specific answers/info you can give.

Regards

Chris

 

[alan895]

When I built my Thien separator I used hot glue to bond the plastic I was using (1mm PETG), admittedly it was a bit bigger in diameter at around 450mm but it worked very well. All I did was route out a groove around 3mm deep, put a few dabs in and after ran a bead around the perimeter to get a good airtight seal.

PETG is easy to work with and the measurements you are stating it should do the trick, I got a 1000x1000mm sheet relatively cheaply but you can get them in varying sizes judging by a quick Google search. I'm looking to build another for my Numatic and chanced upon a 250x100mm round plastic cake container which I thought would make an ideal second unit fixed to a 10L bucket so once I get some free time I'll be modding this into another separator.

 

[Limey Lurker]

I'd use metal; aluminium or steel, and join the ends with hollow rivets or silicon mastic,which I would also use to seal into the top and bottom.

 

[baldpate]

When I built my Thien separator I used hot glue to bond the plastic I was using (1mm PETG), admittedly it was a bit bigger in diameter at around 450mm but it worked very well. All I did was route out a groove around 3mm deep, put a few dabs in and after ran a bead around the perimeter to get a good airtight seal.
...

Thanks for pointing me towards PETG. I've bought a small sheet of 1mm to experiment with before buying anything larger. Good idea about hot-melt glue, too - can't think why I overlooked that.

 

[Graham Orm]

Here's mine http://www.youtube.com/watch?v=UopsGH-Yzf4