Stich'n'glue?

[9D280]

Don't panic - I'm not building a Mirror dinghy!

Anyone used this technique before? I am building an instrument pod to replace the upturned ice cream tub that has been the home for my tacho for way too long, and decided that S&G was the most cost effective method. Only one panel left to cut, then it's time to stick it together.

Now, everything I have read implies I need to remove the stitching once the initial "glueing" of the joint has taken place, but it strikes me that if left in place it should result in a stronger joint. (Plan is to cover the whole thing in a carefully cut sheet of fibre matt & flowcat it to match the rest of the console)

So, has anyone left the stitching in, and if so what did you use? I am thinking of using whipping twine (thin & strong) or thin fishing line.

[HughN]

Yep. Built a canoe using several hundred nylon cable ties for the 'stitch' part. These were easy to cut once the joint had been glued an easily sanded down before I use glass tape over the join. They also allowed the degree of force between the parts to be controlled - I started with them all loose and tightened them up gradually as the shape built up.

Getting correct the relationship between the holes in the different pieces was fairly influential - large mismatches tended to want to pull in every direction other than 'together'.

TBH, once glued and taped it was so strong that it could have been stitched with cotton or human hair!

[chewy]

Not tried that but I've made moulds out of cardboard and then waxed the area to be glassed, works fine.

[9D280]

Hugh , thanks - It did strike me I'd never seen a Mirror with "stiching" still in place. But good tip regarding the stiches. Lining the holes up should be reasonably easy - I can clamp & drill each pair of panels at the same time, as there are no curved joints.

I may also modify the "glue" bit of the theory slightly in order to get rounded corners. Plan being to insdtead of using tape on the inside of the joint, (the Acute angle side) use a "deep fillet" of resin / fibre mix, then once dry slowly & carefully file a rounded corner on the outside. Once that is at the radius required, add the outside tape.

I did an experiment with a scrap bit of ply / tape etc, and now reckon that a careful painting & fine grade sanding of resin followed by a couple of coats of International's "gloss rescue orange" will give a very gelcoat-esque finish that is as good as the console below. Will post a "how I built it" photo story when it's finished.

[HughN]

Various sources advocate degreasing the ply (with acetone usually) before gluing. Apparently sheets of plywood are given a very thin coat of wax so that they don't stick together when they are in a big stack.