Wood for Falcate Braces in UK

[Mitch Lees]

This a question for UK-based members. I am building my first falcate braced steel string as per the plans from the 'books'. Which wood have you used for the braces, and where have you sourced it please? My preliminary experiments with the Sitka and European Spruce I have to hand have not gone well!

Grateful for any guidance.

Mitch

[johnparchem]

Not in Europe, but I use sitka and englemann spruce. I thickness to 1.7 mm strips and bend them to form on a hot pipe before laying them up. What issues have you had with spruce.

[Dave M]

As with John I use spruce and could not bend thick strips so ended up with more, thinner laminations. Even then I wasn't particularly pleased and some snapped during bending but eventually got acceptable results.

Hot pipe bend then the primaries clamped to an inside caul for glueing and for the secondarys I have made inner and outer moulds to squeeze that tight bend.

Oh and while you are at it do several sets while you have all the gear out - you know you'll be making another one or two!

[kiwigeo]

My experience the same as Dave's.

[Trevor Gore]

Some spruce will heat bend and some won't. And you can't tell until you try. That's just how it is. None of the spruce I had would bend when I first tried making falcates. But I'd heard that spruce was heat bendable and without too much trouble. When I replenished my supplies, the new stuff would bend. Ostensibly the same wood. The wood that won't bend makes good back braces and transverse braces!

[Mitch Lees]

Thank you for your responses. It seems the spruce I have been trying to use was of the 'will not bend without breaking' variety. Because of this very limited experience, I had assumed all spruce was like this. However, I have another batch of spruce brace wood which I will now try - hopefully it will be more cooperative!

Many Thanks

[AKEric]

I have had 100% good luck with sitka. I use very precise male/female forms that clamp together and support the wood well. I use three, 1/16" thick plys. The forms were made using a 3/16" diameter, bearing guided straight router bit so they exactly match the width of the three finished plys.

I glue with TiteBond, and because the forms clamp so tightly there is no warping across the width; little if any spring-back.

For the primary braces, I bend and glue them dry with good luck.

The tightly curved secondary braces are a bit more finicky. I made a small steam chamber and steam the three strips for about 5 minutes. They bend in the form without any issue. Of course, they need to cure and dry out before gluing together.

I've done a lot of steam bending over the years, so I have the steam generator. You can easily use a kettle and a hose as well.

Falcate brace bending forms. Dowels slide in slot for precise alignment.

Secondary brace bending form.

Steam generator and steam chamber.

[kiwigeo]

Nice looking jigs Erik. My brace bending jig is a bit more "agricultural" I use epoxy resin to glue up strips that are around 2.2mm thick. The strips are held against the form with a picture framing band clamp with additional clamping pressure supplied by spring clamps. Paste wax is applied to the form before glue up to stop the braces sticking to the jig.

[Steve.Toscano]

I use engelmann (and at times also use King Billy Pine).
3x 1.9mm laminates.
I've had pretty good success with finding engelmann that bends well, the trick is to dunk it in water that is straight off the boil - very hot, then straight onto the iron.

Below is my 'bondage' clamp for the primaries, same for the secondaries.
The jig is 30mm wide, i glue up my falcates at 25mm then slice down the middle to get to 2x matching halves.

The black rubber is bike tyre tube kindly donated by the guys in lycra who were having breakfast at the table next to me at the local cafe one sunday morning.

2019-03-26 22.36.19.jpg (215.33 KiB) Viewed 24696 times

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[AKEric]

Thanks Martin,

Yours is great too. The ingenuity of the luthier bunch never fails to amaze me. Anyone else want to share their process?

[Mitch Lees]

Thanks all for going to the trouble.

This will be a great help - particularly the pics

Mitch

[Woodsy23]

I must have been lucky with the spruce I got for my first falcate built as it bent easily. I clamped the end of each 1.7mm strip to a form of the appropriate shape, draped a damp cloth over it then ran a hot clothes iron over it to press it onto the form. Then I clamped the piece in place for a short time. There was some spring back but that was eliminated when the pieces were laminated together. That system worked and was really simple so I continued to use it.

[gerryt]

Just bent my first falcate primaries and secondaries using Sitka from Timberline in the UK and it bent no problem. Thicknessed to 1.7mm and clamped to a form. The triple ply laminate was glued with West Systems epoxy.

[jamtor]

fast forward to 12:10 . what kind of wood does this?


youtu.be/6YCBJQ3MF5Q

[kiwigeo]

fast forward to 12:10 . what kind of wood does this?

Looks like spruce. With a bit of coaxing you can get it to bend around a tight radius.

Not sure about the logic behind that "extra" brace going across the lower bout.....one benefit of Trevor's falcate bracing design is the sound board gets divided up into roughly equal inter-brace areas.