Thursday, January 26, 2012

One step forward and two back

Removed the screws from the stringer I glued yesterday, some needed heat help but I did not break any today. Then it was time to look at the scarfs from yesterday, perhaps not perfect but hopefully good enough (yeah right!).

Not too bad in my opinion considering it was cut and glued while still on the boat.

I did not get a good picture of the other one but we will bring that one up more later. The stringer on the boat will most likely have to be towel steamed and since epoxy does not like heat (becomes soft) I strengthened the scarf with a pair of screws. I hope it will work, otherwise I will have to turn the stringer around so that the scarf is in the aft end.

Through bolts to keep it together while steaming

Time to fit the stringer that was scarfed on the work bench. Started aft and as I approached the second frame from the transom..... BANG!


The bloody thing broke at the joint. I think perhaps that the epoxy had not cured enough? Interestingly it broke between the glue, thickened epoxy, and the un-thickened epoxy that I put on the end grain to saturate it (all according to the book).

Ok, let's start over again. The original scarf was a 1:6 done with a handsaw and plane, so now I decided to go for a 1:9 on the table saw. I made a simple jig of plywood.

The plywood piece is screwed to the stringer

From the other side, 1:9

The fence is set at the same depth as the width of the ply piece and the saw will then cut the stringer at the correct angle

This is how they look after the table saw

I learnt a neat trick at the Boat Building Academy for planing scarfs. To get a sharp and square feather edge on the scarf you make a cut with a knife on the backside where you want the feather edge to stop. Then when you plane the scarf the excess wood will fall of and leave you with a nice square edge.

The knife cut was done on the back of this piece, the cut is aligned with the end of the table. Then you start planing the scarf and as you thin it out and approach the cut edge you get a clean square edge. 

Scarf glued up, again!

I will leave the scarfs for a day or two to gain some strength (a little colder now so they may need some more time).

Time today: 2h (Total time: 105h) [Could I be one quarter of the way........?]

No comments:

Post a Comment