Otterblog

A record of the renovation of a
Wooden Drascombe Longboat 'Otter'


17th January 2007. Glued some ply and retested Git-Rot

After cutting out all the 9mm ply I then assessed how I was going to use the 12mm ply. This is used for bulkheads and the sides, front and back of the cabin. As it looked like I might need a little more than the two sheets of 12mm ply that I had bought I economised by doubling up a sheet of 6mm ply that I already had to make the parts for the transom and outboard well.

I used the Phenolic resin glue, Prefere 750/405M (formally known as Aerodux), -a 2 Part wood glue for use on gliders from Severn Valley Sailplanes where you can buy it in smaller quantities. (Thanks, Doug.)

After finding the instructions for Git-Rot I followed them precisely. I used two pieces of rotted ply and one piece of rotted Iroko.

I drilled holes as suggested at 5cm intervals along the grain with offset holes so that all the endgrain is covered.

Ply A has the three 4mm holes drilled at an angle as if it were a vertical face.

Ply B has three 4mm holes.

The solid Iroko has three 4mm holes and two 8mm holes to the right.

After mixing the Git-Rot thoroughly I applied it to the holes.

I kept topping up the Git-Rot to keep the holes full as it soaked into the grain.

Ply A and the Iroko didn't take much but I had to top up Ply B for two hours. Wait and see.

I said that I followed the instructions but they weren't that clear. They said "Where rot is deep into a large member it is advisable to drill a staggered series of overlapping holes approximately 4mm to 8mm in diameter slanting downwards." The diagram shows them staggered across the grain but it doesn't say what pitch they should be along the grain. How far will Git-Rot penetrate along the grain?

I drilled two 4mm holes 5cm apart along the grain and one offset in between.

It also says to work at lower temperatures as this will allow more time for penetration before it begins to gel which I did.

 

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Unless stated otherwise, Colin Watt 2006, 2007

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Last updated: 18 January, 2007