Repairing cracked frames

[srp]

When I did the repairs to my gaffer I laminated some replacement pieces from oak and epoxy. I chopped out the broken ribs with a mallet and chisel and then used a sanding disc in an angle grinder to form the scarphs themselves. It's quite easy to make a neat job with a little care. Because I was on my own I used silicon bronze screws, screwing them into the rib from the outside using the original holes. Epoxy again to join the scarhs. On a clinker boat you can use some cling film or polythene under the ribs to stop the epoxy sticking to the plank.
I also 'staggered' the length of the new sections of rib - I had to do several in a row and I didn't want all the scarhs to line up.

 

[gloriana]

An option i have used on a regular basis is, using a fit for purpose thin film and gap filling epoxy adhesive, bond in a carbon fibre plate into a pre cut slot. When the installation is complete bond in a timber fillet to match the existing timber. If you want too know some more i will gladly put a sketch together for you. /forums/images/graemlins/confused.gif

 

[KenMcCulloch]

Interesting idea. I was talking to my friendly local shipwright the other day and he suggested yet another method (apparently like so many clever things, an American invention). One takes an angle grinder and carefully grinds away the timber in the damaged area leaving an even curved scallop cut out of the frame, with its greatest depth equal to or just less than the full thickness of the frame, at the point where the crack was. Epoxy and thin strips of suitable wood, each shorter than its neighbour are then laminated into this scallop until the full thickness is built up. You then plane away the excess and have a very strong repair without having to spend ages getting a scarphed piece to fit exactly.

Sounds like a cunning plan to me.

 

[Lakesailor]

That sounds brilliant. I have a couple of lightly cracked ribs in my dinghy which may get that treatment as summer comes along. Also rather good as it's a 1 or 2 day job so doesn't keep you off the water.

 

[gloriana]

We laminate like that all the time, but ideally put some bonded in dowels / connectors through the laminates - gives it that extra omph! that's chippy speak! As i am new to this how do i tell you about the adhesive and carbon fibre plate? Don't be fooled into thinking American technology is best - they missed Mars.