Thread: First build Pick no laughing !!

Next we have a 2 piece Tas myrtle Back blank. It was to have myrtle sided but 1 exploded in the last pass through the thicknesser so am now using Blackwood for the sides.
Couple of picks of the back bracing
Last pic is neck blank with scarf cut in a piece of 100 year old Qld Maple.



Ross

First couple of pics are of rosette. Inner ring is solid timber figured Merrango
Second ring is solid Myrtle
Outer ring is 4 layers of Qld Silky Oak all were prebent on the hot pipe. Veneer was easy the solids timber ones were a bit harder!!!
Next fer pics are soundboard bracing which I finished today next this is carving them then on to side bending.


Ross

No laughing here. Looks amazing to me? But I think the pics in the last post took a left at Albuquerque.



Oh! There they are now.

Looking good Ross! Nothing to laugh at there. How did you make your pipe bender?

Originally Posted by Sebastiaan56

Looking good Ross! Nothing to laugh at there. How did you make your pipe bender?

A bone of contention there! You can buy the electric kind for under $200 or cobble together a propane torch, gas cylinder and tube for something like $120 plus $650 for every small cylinder of gas but I just didny have $200 and the torch will come in handy for other stuff.
The Stainless pipe was donated & I am still waiting on a 75mm section. I used stainless because I thought it would be easy to keep clean and rust free and not contaminate the surface of pale timbers. I blocked the outer end of each pipe with a piece of brick. Works OK but like anything takes some practice.

I made an interesting observation yesterday that you are probably all aware of. Before bracing my soundboard tapping produced a quiet low tome of just under 3 sec in duration now fully braced but un carved the duration is shorter at about 2.5 sec but pitch is much higher. I think there is a lesson to be learned here.


Ross

Originally Posted by Different

I made an interesting observation yesterday that you are probably all aware of. Before bracing my soundboard tapping produced a quiet low tome of just under 3 sec in duration now fully braced but un carved the duration is shorter at about 2.5 sec but pitch is much higher. I think there is a lesson to be learned here.

Absolutely, as you brace the soundboard you increase the stiffness and therefore the resonant frequency. Some builders will keep tuning the braces till they hit a specific note eg I know "D" is used in some F5 style Mandolins. More important is to get the whole soundboard working efficiently. Hold it at 10o'clock and tap at 4 o'clock. Then at 2 and tap at 8. Compare the length and the note. Turn the sounboard upside down and repeat. Ideally the notes should ring for the same length of time. If not trim the brace that is a bit dull in sound or short in length of ring, either in the middle or the edge. You may want to do the same in the centre of the plate as well. Tuning your soundboard is a major component of an instruments sound and its one step that factory built instruments dont do.

Originally Posted by Sebastiaan56

Absolutely, as you brace the soundboard you increase the stiffness and therefore the resonant frequency. Some builders will keep tuning the braces till they hit a specific note eg I know "D" is used in some F5 style Mandolins. More important is to get the whole soundboard working efficiently. Hold it at 10o'clock and tap at 4 o'clock. Then at 2 and tap at 8. Compare the length and the note. Turn the sounboard upside down and repeat. Ideally the notes should ring for the same length of time. If not trim the brace that is a bit dull in sound or short in length of ring, either in the middle or the edge. You may want to do the same in the centre of the plate as well. Tuning your soundboard is a major component of an instruments sound and its one step that factory built instruments dont do.

Yes I plan to get more involved in the tuning and reducing of the top but the materials of this build (WRC top and bracing) give me serious concern about strength so I worry about removing much material. In fact I expect this build will fold up like a house of cards when it is first strung up. I dont care if it does because the intention of thei s first build was to identify the parts of the process and methodology that can be improved and how like dished forms rather than workboard and shims.
I suspect there is a lot of advantage in the heat blanket and bending for method but if you are yet to decide on a particular shape and size that you want to make more of then the hot pipe method is more flexible and less expensive.
On another forum someone showed a method of making your own dished forms by covering the surface of a flat disk with radiused slats and then fixing a 3mm top sheet creating a dished form. Do you know how you would draw the radius to be cut without using a compas or tramel 15 to 30 feet long?


Ross

Its looking good Ross.
As far as radius dishes go ... Pythagoris. Is that how you spell it? anyway ,.he's your best friend for working out the maths behind making some rails for your router to run on ..I found a little program somewhere on the OLF that did the maths for you ..I'll see if I can find it in my travels.
I did have some photos of making my dishes but i can't find them..
Basically I made the rails for the router.
Glued 2 pieces of 18mm mdf together and cut them to a 24" diameter disk.
I drilled a hole in the centre of the disk so I could spin the disk..
I made the rails about 30" long so it would fit over the disks and enough travel for the router to get to the edge of the disk.
clamped it all up on a workhorse bench and do a pass ...swivel it a couple of mm ...do another pass....hours later and a lot of mdf dust and you have some radius dishes..
I hope that makes some sense.

Originally Posted by Different

Next we have a 2 piece Tas myrtle Back blank. It was to have myrtle sided but 1 exploded in the last pass through the thicknesser so am now using Blackwood for the sides.

Ross,

If you want to take some meat of sides, backs or tops stick 'em through a thickness sander not a thicknesser...but I guess you know that now. The buggered sides will come in handy as headplate veneer so all is not lost.

All looking good and bringing back memories of my first build. Keep the pics and reports coming.

Cheers Martin

Ross,

Looking at your top bracing I have one question. You appear to have two meaty looking braces immediately forward of your soundhole and no patch under your upper bout.

Normal convention is to have the UTB immediately north of the soundhole and then an upper bout patch north of that and functions to stiffen up the upper bout.

I know youre not a great fan of convention but IMO the upper bout needs some form of bracing, especially since your top is a three piece job. Last night I was looking at pics of a Martin with a failed three piece top. The thing had failed along one of the joints in the upper bout area....food for thought.

Cheers Martin

Originally Posted by kiwigeo

Ross,

If you want to take some meat of sides, backs or tops stick 'em through a thickness sander not a thicknesser...but I guess you know that now. The buggered sides will come in handy as headplate veneer so all is not lost.

All looking good and bringing back memories of my first build. Keep the pics and reports coming.

Cheers Martin

Oh I know that but dont have one available. I often manage to thickness down to 2 or 3 mm with use of a backing board but this time was not to be!
Yes headplate and bending practice is exactly the use it is being put to.

Ross

Originally Posted by kiwigeo

Ross,

Looking at your top bracing I have one question. You appear to have two meaty looking braces immediately forward of your soundhole and no patch under your upper bout.

Normal convention is to have the UTB immediately north of the soundhole and then an upper bout patch north of that and functions to stiffen up the upper bout.

I know youre not a great fan of convention but IMO the upper bout needs some form of bracing, especially since your top is a three piece job. Last night I was looking at pics of a Martin with a failed three piece top. The thing had failed along one of the joints in the upper bout area....food for thought.

Cheers Martin

Martin
I have an Upper Transverse Graft ahead of the Upper Face Brace (as yet uncarved) as per Cumpiano book.
I have been toying with the idea of adding a couple of extra bracing diamonds along the 2 top joints do you think this is a good idea?
Will try to post a better pic of the bracing once I have carved and sanded.


Ross

Ross,

I run reinforcing diamonds along my top plate seams in the lower bout area on all my steel strings. I usually add at least two diamonds along each seam. Think of it as insurance against fiddly repairs further down the track.


Cheers Martin

Originally Posted by Different

Martin
I have an Upper Transverse Graft ahead of the Upper Face Brace (as yet uncarved) as per Cumpiano book.
I have been toying with the idea of adding a couple of extra bracing diamonds along the 2 top joints do you think this is a good idea?
Will try to post a better pic of the bracing once I have carved and sanded.


Ross

Ross,

One thing I forgot to mention. If youre planning to shape and scallop your braces then I'd hold off gluing in your finger braces until youve shaped and scalloped your X brace. I glue in and shape the X brace and then glue in and shape the finger braces and tone bars. If you glue in all your braces at the same time its a pain getting a plane and/or chisel in to shape the X brace....the finger braces get in the way.

Cheers Martin