On 01/06/14 10:27, T Blake wrote:
We want to make a Cloche with hoops of bent-over plastic water pipe, covered
in Plastic sheeting; to end up like a minature Polytunnel for the allotment.

We dont know where to get a large sheet of plastic from here in North West
London,

The internet.

http://www.firsttunnels.co.uk/polythene-covers.asp


so we are going to stick together 'cut-open' clear plastic bags.

What would be the simplest way to stick the bags together, and if glue is
the answer;

You won't glue polythene - the usual option is tape.

Plastic bags will be too weak as well - plastic comes in gauges - you'll
want something reasonable heavy.