Hi all I'm after a bit of advice on how to cut the plastic sheeting as I had some difficulty cutting and marking, It was ok as It wasn't really seen on this particular project, but I always like to know the correct method. First of all marking, I used tape as you can't pencil line on, and market didn't work great. And next how to cut, tried multi tool did the job but no finish. Any ideas?
I've cut a few sheets of this myself Measure down both sides, mark with a felt tip or sharpie, lay a straight edge across 2 marks and then you can mark the tops of the ridges Alternatively stick a length of making tape across width and mark with a pencil Cut mine with a fine tooth hand saw, can't remember tooth count and saw in garage and I'm far to lazy to look now Main thing is support the sheet really well, especially close to cut line, support off cut as well, you don't want any wobble at all. Gently clamp a length of timber on top of roof sheet and clamp to work bench Cut at a steady speed at a low angle. I got nice clean cuts, only had about 3 sheets to cut and no problems with mine If weather cold and roofing been stored outside, bring it in house night before to warm up a bit - cold makes it more brittle and again, support support support and NO wobble
A black marker marks most plastic sheeting. I've cut GRP corrugated sheeting with a serrated 12" diamond blade in a con saw and worked well. Festool have a range of blades designed to cut all sorts of plastics.
I never tried this, but how about sandwiching it between two pieces of ply, the ply having stuck to its end edge on both pieces(offset), that foam profile that is used for end blocking. Pressing on the ply at the cutting edge with just your cutting line on the corry sticking out, gotta be able to saw easily with normal handsaw! Innit? I normally cut it as DIYDave but with a more blunt handsaw, following the profile horizontally/vertically/angled as needed. Mr. HandyAndy - Really
Ye might be worth trying that Andy. Didn't have a fine tooth saw. Next time I'll get one! I'll tell you what the multi tool definetly doesn't work lol. Edges looked rough but luckily hidden.
SIAB has it right. It's easiest if the sheet is laying on an old piece of ply as it stops you from going to deep and hitting the sheet with the centre nut.
There is also these smaller circular saws that you can fit metal cutting blades to http://www.makitauk.com/products/saws/circular-saws/10-8v-cordless-circular-saw.html Some of the German mini marts occasionally have them cheap
A 4 1/2" grinder with a slitter blade is perfect. I had to cut loads last month and tried all sorts of methods and that was by far and away the quickest, easiest and most accurate.