Transom epoxy joins complete

Thanks to all those who gave me feedback after the near disaster, joining the two transom planks, the last remaining piece, to complete the transom blank, went smoothly.
This time I only thickened the epoxy to a ketchup consistency and was able to push the spline in by hand. The pieces then went together with little pressure on the clamps.
Lots of squeeze out. I cleaned the squeeze out from the aft face with a putty knife and then gave it a wipe with a rag dampened with acetone.
A gentle wind on the clamp then gave a whisper of squeeze out, ensuring there will be no gap in the join.
This time I don't need a single malt. But I deserved one.
Cheers to all who gave me advice.
Pete.

Epoxying the Transom

Well, this was nearly a disaster.

I had dry-joined the planks numerous times to ensure that the join was close to perfect.

The splines were a little tight, so I did a couple of fine runs with a plane until they were a slip fit. Then, as advised by JB and West Systems, I planed a little more off the back of the splines to leave room for the required epoxy bed.

But thinning the splines down from a tight fit allowed the two planks to come together with one just proud of the other. However, I found with judicious placing of wedges, clamps and heavy straight edges, everything came back flush.

So I donned the biological warfare gear again and mixed the epoxy. I had watched my fibre-glass-boat-renovating son mix the epoxy for the laminated stems and so imitating Tim’s technique, all went well. You taught me well Tim.

With a brush I wetted out the spline groove and faces. 

I then added the filler and saw dust to the epoxy to get a good peanut butter viscosity. I found a putty knife easy to get the epoxy into the spline grooves. A test run showed that I didn’t get complete squeeze out, so I removed the splines and added more epoxy. A lot more. Squeeze out is good, so I’m told. I then refitted the splines into the groove, but found I could only push them a little way into the groove by hand, (because you can’t have to much epoxy) but never mind the clamps would pull the planks together and there would be fabulous squeeze out.

So with the two planks pushed together flat on the bench I started winding up my new Veritas Surface Clamps. Well, the planks just would not go together. This was when I realised that verities surface clamps are for holding pieces on the bench while you work on them. Not for clamping transoms. Wind as hard as I could, there was still a 2-3mm gap between the planks. But there was no need to panic, as the epoxy wouldn’t go off for another 20 minutes. Not enough time to rush out and buy some decent clamps, the ones I discounted as not being needed.

Fiddling and winding, the epoxy slowly, very slowly, oozed out of the end of the splines and a mist from between the faces. More clamping and then . . . the two planks started to pop up off the bench at the join. This was looking like a disaster in the making and I could see myself having to saw the joint section off my precious Huon and start again.

But then I noticed that as the planks rose, the epoxy started to find an escape route between them and I could wind the clamps in a little more. So I Clamped a section of aluminium square tube across the planks, spaced so that it would stop them rising more than about one cm, and wound the clamps in until the planks rose to just touched the aluminium square tube. I then clamped the aluminium square tube down to push the planks back flat on the bench. The surface clamps held. The tremendous leverage applied by the aluminium square tube pushed the planks down and they slowly came together . . . with a huge squeeze out from the end of the splines. Yes. I did put a lot of epoxy in there.

Repeating the procedure I finally had the planks snugged up tight.

A couple of more bits of square tube across the planks ensured the result would be a nice flat transom.

The rest was a breeze, watching the squeeze, which got me thinking about the advice, “do not over tighten the clamps, so as to leave some epoxy on the faces.” But if you leave a bed on epoxy on the faces, you you will have a gap and not a flush tight join. Hmmmm.

So I adopted the rationale that the space I left around the splines for the epoxy would do the ‘adhesive’ job and the thin epoxy between the visible face edges was only cosmetic.

I think I need a single malt.

Transom FSP overlay

Ooops.
I overlooked posting the FSP Overlay.

Transom Continues . . . slowly

World’s thickest transom.

Having spent half my retirement funds on the Huon for the transom, I have been reading and re-reading the plans, sleeping on it and re-reading again. I can’t afford to get this wrong.

In order to ensure that my transom blank was large enough for the job, I had the FSP scanned and printed on transparent paper. I then flipped the transparent copy, laid it on the transom FSP and traced the Starboard section, giving me a FSP of the whole Transom. see pic.

As luck would have it, a sharp, fellow Somes builder spied my last blog entry and kindly emailed me, pointing out that my 38mm plank was the same thickness as the design Transom plus Transom Cheeks. Quite insightful, as he is an inches man from the Good Ole . . .

“Leave your plank thickness as it is Pete, and dispense with the cheeks.” he suggested.

So having mulled over that one for a couple of weeks, I decide it was a good idea. The reason I had to mull over it was that it means the inside face of my transom is going to be further forward than on the plans and I needed to work out if that could be accommodated. Conflicts as the engineers say! With some fiddling, I think it can. I’ll need to move the transom support forward on the jig, route out for the Transom Knee and do a fiddle where the Keel meets the Transom.

The good side is that the forward face of my transom will lie on the line of the forward face of the transom cheeks, so I will only need to mark the Transom with that set of lines and the rear face lines.

July 9th. Routing the Transom Joins.

Having managed to get the transom planks flat and sanded smooth, I played around with the two planks to find the most attractive faces and decide which way they looked best together. It was a bit of a compromise, as there is so much birds-eye and marbling in them. But there was an obvious pair of faces that matched. They did come out of the same log.

I then gave the faces a coat of varnish in the hope of protecting them from any epoxy squeeze out. I did this before routing the edges so any varnish dribbles on the edges will be removed by the router before epoxying them together.

To ensure the planks met well, I set up a routing jig as per JB’s advice and took a mm off both planks. What a brilliant technique.

JB's Routing Jig.

However, the boards did not sit together well and I diagnosed the problem was due to my bench having developed a warp . . . despite having flattened it with my router a couple of years ago. Obviously the bench timber is still drying. The wood is Murray Valley Pine (commonly called Cypress Pine, which is a ludicrous names as Cupressaceae [Cypress family] are different to the Pinaceae [Pine family]. It can’t be both!)

So I made up a sled and set about flattening the bench again. Starting at one end, with the router just skimming the surface, I found the router taking of 3mm in the centre reducing to zero at the other end. You can see the cutout in the pic below.

Routing Sled for bench flattening

Now it’s flat. What a difference. And the planks meet with hardly a visible line.

Routed Join. It's there somewhere.

13th July Splining the Transom Joins.

My gorgeous Veritas Plough plane, which I bought to cut the spine dados, arrived. I practiced cutting dados on a piece of pine. It took a while to get the technique right, but the real break through was adding a relatively large piece of 10mm ply to the fence to give a much deeper face.

I then bit the bullet and started on the Huon. All went very well, largely, I suspect because the Huon is so much easier to work then pine.

Veritas Plough Plan cutting dado for spline

Having cut the 3/8” grooves 6mm deep (The plane came with imperial size blades. Come on America, it’s time to change gears), I ran a piece of Celery Top Pine through the thicknesser and made a batch of splines.

How delighted I was when I slid in the splines, pulled the planks together and found the splines took the slight bend in the planks out and the faces came together almost invisibly.

Beer O’Clock.

Transom. Splined but not glued.

Transom Spline

Now for the Epoxy.