Weissenborn Copy Build

[Bob Connor]

I have just received some very nice plans for Weissenborn copy from Gwenn.

I had them printed off during the week and have spent the last couple of days making templates and molds for both this Weissenborn and for a Size 5 (Terz) guitar.

Gwenn asked if I'd do a thread about constructing the Weissy so here it is. I've never built one of these beast before so it'll be an interesting exercise to say the least.

I have some Tasmanian Blackwood for the back and sides and some Surian (Toona Calanta - I think) that I got from Maurie Howlett for the top.

I'm not going to follow the bracing of the top from the plan but adapt it to the lattice bracing that I'm using in my normal guitars. So about all I'll use is the body outline and the x-brace position.

The sides will be double laminations and I'll use some carbon fibre in the area under the end of the fingerboard.

Should be an interesting project and I'm really looking forward to it.

Here are the first pics of the completed mold and almost complete side bending form.

[Gwenn]

Hi Bob,

I'll be following this thread with a lot of interest! I feel quite honoured to play a little role in your experiment as well! There are two things in your project I want to follow very closely: side double lamination and your lattice bracing design...

As I told you in my email, my plan is the sum of the information I've been gathering on "orthodox" weissenborn construction, but in the future, I'd like to experiment other paths. In this regard, I find Tasmanian luthier Daniel Brauchli particularly inspirational..

anyways, I wish you a lot of fun with this project!


Gwenn

[ozziebluesman]

G'day Bob,

Thanks for sharing your weissenborn build with us. I'm looking very much forward to seeing your design.

Cheers

Alan

[Dave White]

Bob,

So you've finally given in

Treating it like any other guitar from the soundhole down is definitely the right way to go. Just wait until you get to the setup stage - getting the neck angle right is a real bitch

I'll be watching with interest.

[John Maddison]

Am gonna be watching this one with interest, Bob.
Maurice was very generous with the Surian that he re-sawed and I'm sitting on a few nice slices for using in ukes in the future. Be keen to find out how you eventually prep for finishing - the wood seems to be fairly open-pored. It looks to be stable enough to be used in cabinetry work and a trawl of Google images shows it's also used for boat building. Right, that's that done - I've joined the thread ... bring on the updates . Cheers!

[Bob Connor]

Thank you gentlemen.

Yes Dave - I've finally gone over to the dark side

I kind of suspected that the lower bout would stand up to the same treatment as a necked guitar but there would be a lot of stress in the area around the soundhole and particularly under the fingerboard in that area where it transitions from the boxed construction of the neck into the body.

A lot of the plans that I have seen and some of the bracing I have seen in photos indicate that these instruments should be massively braced. As I'm not trying to reproduce a vintage instrument I'll try a few things, but I'm wondering whether the lighter bracing will make it too lively for a slide guitar. Only one way to find out I guess

[jeffhigh]

I think the major flaw with the original weissenborn bracing is that the spread and positioning of the x brace does not allow the bridge wings to sit onto the x brace arms.
I have built two from the MIMF plans which have stood up well, but the next time i would be closing the braces a bit and moving the intersection a bit towards the tail.
The other problem is from builders using really high string height above fretboard and soundboard. The high torque from this is very damaging and unnecessary.

[Bob Connor]

I got the side bending form finished today so I thought I'd better bend some sides.

On the last couple of instruments I've built I left both laminations at aroung .070" so the sides were a very hefty .140". It certainly adds some weight to the instruments.

I decided to make these around .045"

Being so thin and flexible I saw no need to spray them with water so I wrapped them in paper and bent them dry. They actually didn't hold their shape that well but I expected that (being so thin). Once they are glued together they should be fine.
I've stopped using the thermostat on the heating blanket and don't bother with the thermometer any more. Plug it in, start the bend at 3.5 minutes and make sure you are finished at the 5 minute mark. Unplug and allow to cool. Pretty simple eh.

Also made a start on a headstock.

[Bob Connor]

I think the major flaw with the original weissenborn bracing is that the spread and positioning of the x brace does not allow the bridge wings to sit onto the x brace arms.
I have built two from the MIMF plans which have stood up well, but the next time i would be closing the braces a bit and moving the intersection a bit towards the tail.
The other problem is from builders using really high string height above fretboard and soundboard. The high torque from this is very damaging and unnecessary.

Gwenn has come up with a larger bridge plate design than that shown in the MIMF plans Jeff, which should improve stability in the bridge area. I agree though the the bridge is probably too far away from the main X-brace.

I haven't drawn up any bracing plans yet but I have noticed that there are only 19 frets on any of the designs that I have seen and the x-bracing does look forward shifted (at least from the point of view of a bloke who usually builds necked 6 strings)

I am thinking of adding another fret or two and moving the soundhole and X-brace south. I'm also adding a double layer of Surian around the soundhole. I think this is quite important in reducing the effect of the "rolling" bridge and it will also reduce the amount of belly in the lower bout, simply because the bridge will find it harder to depress that area around the soundhole. This (in conjunction with a larger bridge plate) allows you to lighten up all of the lower bout which is where most of the action is tonally. There's nothing wrong with adding some mass in the centre of the soundboard, particularly if it achieves this sort of outcome and particularly in this type of guitar where the soundboard will be pretty well loaded by virtue of the string height.

Regards

[jeffhigh]

On the cheapo chinese weissenborn i saw the other day the top had actually warped between the end of the bridge and the X braces.
It wasn't just rolling the whole top structure forward, it was distorting the top between the braces.
And it had a full 1" string height above the soundboard.
I agree the bigger bridgeplate is worthwhile

[Dave White]

Bob,

This is the top bracing I used on Colin's:




The X brace angle is around 80° and the bridge plate not huge. Remember that although the string height is more than a normal guitar(but as Jeff says it doesn't have to be that high) the scale length is shorter and the tunings are "dropped" but with higher gauge strings.

[Bob Connor]

The X is closed quite a bit on that Dave.

I'll look forward to getting some paper out and drawing designs. Won't be for another couple of weeks though. I'm off to Tasmania next weekend to deliver a couple of instruments and pick up some more wood. (Possibly for the next couple of lap slides )

[Bob Connor]

I did some work today glueing one of the sides together. Photos aren't too flash as I only had my phone with me but they're good enough to give you the idea.

I have a vacuum setup but I haven't finished building it. When I do I'll use it for glueing the side laminations together but for the moment I'm doing it this way.

I drilled a heap of holes on the side bending mold with a hole saw.

Here are the sides ready to be glued. I know that a lot of builders in the US use epoxy for this step but it's messy, not that good for your health and I reckon Titebond does just as good a job. These sides at .040" were really floppy and didn't hold their shape coming out of the sides bender so it'll be interesting to see how they are when I take them out of the mold.

I laid a double layer of tinfoil under the sides so they won't stick to the mold and you can see why I drilled the holes in the mold.

[Bob Connor]

Joining the back. made up a rough jig to do this as my normal one isn't long enough.

[Bob Connor]

I've got the top marked out ready for braces. The X braces will be 8mm x 12mm. The other braces in the lower bout will be 3mm x 5mm.

I've shifted the centre of the X-brace south by 12.5mm and tightened the angle on it a bit so the wings of the bridge will sit over the braces.

The top itself is 2.4mm thick.

[Dave White]

Bob,

Looking good. That's an interesting bracing pattern. Are you going to have intersecting braces through the three finger braces - the lines parallel to the X braces on your top? I would have thought that this would make the lower bout edges on the stiff side given the proximity to the rim-set. Are you going to use a soundhole re-enforcement patch?

[Bob Connor]

Yes Dave the area where the finger braces usually live will have the intersecting lattice type brace. These braces are very delicate - only 3mm x 5mm but they are very stiff once you glue and cap them. This top is also not that stiff once I got it down to "fighting" thickness. It is very light and not at all like a hardwood. It actually reminds me more of cedar. It's my first one so I really don't know what to do or expect with it. Considering the bracing I've seen on the plans of the originals I think it might be OK.

It will have the soundhole patch, which I now use on all of my instruments.

I've been looking at your extra X brace in the area above the soundhole and I'm thinking I will do something to beef up the bracing in that area. I was going to cap the upper transverse braces with carbon fibre but as I don't have any at hand and I'll probably be wanting to glue the top on over the next weekend I'll probably do something different. Just haven't quite decided what yet.

Cheers

[Bob Connor]

On go the back braces.

[Bob Connor]

OK. Back's on.

The sides are so stiff with the double lamination and reverse kerf lining that I decided to glue outside of the mold.
These are the first of the pre-made Spanish Cedar linings that I bought from Bob C and I must say it was a pleasure not to have to make the bloody things

The centre strip as Blackwood as well. The same stuff that Steve Kinnaird is using on his King Billy OM.

[ozziebluesman]

G'day Bob,

Looks real good mate! Did you arch the back on this one?

Cheers

Alan

[Bob Connor]

No arching Alan, everything is going to be flat, top included.

I'm waiting for the glue to dry on the top braces so with a bit of good luck I'll have the top on tomorrow.

Which will leave binding and finishing. I'm hoping to have this done by Christmas

[Bob Connor]

This what the bracing ended up looking like.

[Bob Connor]

Top and back are on and the bindings completed.

[John Maddison]

Lookin' hot, Bob ... and that Surian top has come up a treat!!

[Bob Connor]

I'll be pore filling in the next couple of days John.

That Surian has pores like the grand canyon so I'll let you know how I get on.

I did put some shellac around the soundhole when I was putting in the rosette and it came up a lovely golden colour, a lot different from the pinkish tinge it's got now so I'm hoping that the Z-poxy will give it a nice vintage looking vibe.