Am planning to use this to cut down a dacron Etchells jib to 6.25m luff length to use as a no3 jib on 1/4tonner. The leech will simply be cut straight from above the top of the clew patch to the luff, allowing for the 18mm overlap and also a small aluminium headboard rivetted to the top. Insert 2mm nylon leech line. The sail will always be rolled up when not hoisted.

embossingtapesupplies.com.au/crystal-clear-double-sided-tape-tesa-4965-red-liner.html

Technical advice from the above company is that it would be fine - clean the sail with isopropyl alcohol. This tape is a more cost effective type than 3M VHB.

Has anyone done this or similar and had success? I might take the finished sail to a canvas shop to run a line of stitching down it. Sailmakers costs are too much - apologies to them.

I would not tamper with the sail. I used an Etchells jib on my quarter tonner [mast head rigged] and it performed brilliantly. The only problem was returning to the mooring if I had the sail still hanked on. It was the jib with the press stud "hanks". The sail was very stiff resin filled and really caught the wind and would blow the nose down when trying to pick up the mooring. I eventually changed to a Dacron 16 foot skiff jib as the No 3. I removed the wire luff and replaced it with 4 mm Spectra and sewed extensions on to the head and tack to raise it off the deck a bit and give a good angle for the sheets. I used screw-on plastic hanks. It was very successful. The other choice is to pick up an old Kevlar onion bag headsail of eBay and get creative with that sticky back stuff.

I'm basically lazy so I just use sticky back on both sides and zig zag sew around the edges.