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Making a Cello #3: Working on flattening the plates.

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Blog entry by PhiltheLuthier posted 05-25-2012 03:33 PM 4431 reads 1 time favorited 7 comments Add to Favorites Watch
« Part 2: Day 2, the blocks. Part 3 of Making a Cello series Part 4: Finally a Joint! »

So I haven’t gotten to the ribs yet because I need a bending strap and they seem to be harder to get than they should be. First I tried ordering the sheet metal to make one from McMaster-Carr, but apparently I’m no longer considered an “established customer” so they canceled my order. It seems they don’t like to send stuff to Canada, go figure. Next I decided to order a ready made one from International Violin, but they’re back ordered, so I’ll just have to wait a few weeks and it’ll come, so until then I’ve moved on to the plates!

The back I’m using is some European (what ever that means) maple from Bois de Lutherie Aigrisse, it is far too expensive if you ask me, but lutherie wood always is, I guess I’m not a Luthier because I want to be filthy rich. At least it’s not more expensive than gold.

Okay enough ranting!

Thursday I finished my Big Shooting Board which you can see in the projects section. I then used that shooting board to shoot a square edge on the joint side, and the opposite side of the first maple plate. The reason I did both sides is that I’m not going to flatten the plates in the traditional manner, with a hand plane, but in a more production oriented manner, with a thickness planner. So after squaring up the two sides to the flat side of the plate I lay the flat side on the bench top and shimmed it to make the flat as level as possible. Then I glued on two sacrificial pieces of poplar, and it looked like so (actually this is an after flattening picture because I forgot to take a before):

These are needed to run the piece through the planner as the piece is wedge shaped. I glued them on in a temporary manner, a bunch of dots of hot hide glue along the length and let dry over night. I left the ends sticking out so they suffer the effects of planner “snipe” instead of my thousand dollar piece of wood. Action shot:

So after about 50 passes to make it flat I had a nice smooth board and surprisingly little effort exerted. On the next one I may try taking more wood at a time in the beginning, but this curly maple tears out something awful when you take too much wood… perhaps someday a helical cutter head will be a good investment. After the plate was flat I flipped it over an flattened the other side to a thickness of 32mm which gives me about 2mm extra.

Next I took my handy old butter knife and split off the sacrificial wood.

Once started you just pull and it comes right off.

And presto-chango! A nice flat piece of maple ready for the jointer, though it’ll need a sister first.

If at all along the way you have any specific questions, or things you’d like me to cover in more detail let me know, and I’ll do my best to comply.

That’s it for now, see you next week.



7 comments so far

View Bertha's profile

Bertha

12951 posts in 1447 days


#1 posted 05-25-2012 03:40 PM

That must be terrifying working with that ungodly expensive wood. It is spectacular to look at for me, since you paid for it:) The figure is so tight and the wood is so clear. When finish hits that stuff, it’s going to be orgasmic. I’m not a luthier (drummer) but are these typically French polished? If so, God Bless you, my friend;)

-- My dad and I built a 65 chev pick up.I killed trannys in that thing for some reason-Hog

View BTimmons's profile

BTimmons

2187 posts in 1239 days


#2 posted 05-25-2012 08:28 PM

Al,

I’m a cellist and I’ve worked in a violin shop before, mostly doing sales. The cello I now own is one that I finished myself from the bare wood on up. So while I can’t guess for sure what Phil’s recipe is, I have a little experience in that arena.

Here’s the typical procedure for violin family instruments. The the maple neck is unvarnished along its length, where the player’s fingers would otherwise stick during position changes. Usually the wood is rubbed smooth with mineral oil and steel wool or some other extremely fine abrasive. On the rest of the instrument, the wood is usually given what’s called a ground coat to provide some initial sealing, which also provides the carcass of the instrument with some additional stiffness. The ground coat is typically done with seedlac, which is basically shellac in a more raw form. After that dries, a few coats of oil varnish is the most common go-to finish. Some makers prefer a spirit (alcohol) varnish, which requires anywhere from 10-20 thin coats.

Not sure about French polish, I think that’s mostly done on older instruments as infrequent maintenance or repairs if I’m not mistaken.

-- Brian Timmons - http://www.BigTWoodworks.com

View PhiltheLuthier's profile

PhiltheLuthier

56 posts in 1523 days


#3 posted 05-27-2012 04:11 AM

Haha, it’s not that bad, I mostly know what I’m doing, and there’s lots of room to fix mistakes along the way. I suppose if I’d never made an instrument before I would probably be at least a scared by the cost.

Generally speaking violin family instruments are not finished with a French polish. In fact even what Brian refers to in his last paragraph will not be a true French polish as the varnish used is not shellac, though it likely contains some shellac. I did French polish a mandolin once, it is a very nice finish and is quite durable even though some people think shellac alone is not, and the color is amazing if you use orange or better yet garnet shellac… soo pretty… Any how! No I will not be French polishing this instrument, I have not decided on the whole finish process yet (it is a long ways off after all) but it will include a linseed oil based varnish, and probably some shellac too :D

View SirFatty's profile

SirFatty

472 posts in 966 days


#4 posted 06-08-2012 04:47 PM

Why is the wood so expensive?

-- Visit my blog at dave.spalla.com

View PhiltheLuthier's profile

PhiltheLuthier

56 posts in 1523 days


#5 posted 06-10-2012 02:41 PM

Well, I guess mostly it’s hoccus poccus… like anything they put the price as high as the market will support. But compared to normal lumber it is cut in quarters, so the yield for a given tree is less, they probably throw away any wood that has no figure at all, and it is supposedly air dried, which allegedly makes for a more stable piece of wood when it comes to shaping it, now I’ve found air dried wood to move a lot, I think the fact that it is figured means that there is a lot of tension in the wood, but I’ve never worked with kiln dried wood, so perhaps it is like a spring board, but I don’t know.

I have many opinions about the price of the wood, but nothing really to base them on… but here’s a link to the guys who harvested this particular back, it should open on a page with a table of contents briefly describing the process and pictures too!

Bois de Lutherie Aigrisse

View DS's profile

DS

2132 posts in 1174 days


#6 posted 06-11-2012 03:46 PM

Thoughts on why tonewood is so expensive:

From what I understand, the best tonewoods are usually from old growth stock, which, isn’t readily replaced and is in short supply worldwide.

A lot of the stands of old growth forest are protected and just not available for harvest. A few private stands are harvested and made available, but they also control supply to maintain prices.

The harvesting method for tonewoods varies from the methods used for standard lumber, so, those doing so are in more of a niche market as well and likely do not employ the same mass production methods that yield the economies of scale. Kinda’ like boutique beer breweries, to use an analogy.

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

View jackcamino's profile

jackcamino

20 posts in 1074 days


#7 posted 06-18-2012 09:21 AM

I’ve seen some violin necks and even soundboards that they are given with some kind of patina; How do you put this patina to a new instrument? Thanks.

-- When you think that I am buried and I will revive. (folio 59ii RECTO). Codex Atlanticus. Leonardo da Vinci. c.1490

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