Cello Back freshly purfled

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One-piece Cello back purfling complete.

Narrow (violin-style) purfling, like the original

Today I completed the back plate purfling. Though this is a cello, I purfled it with violin-style purfling, as it was pointed out to me by Jacobus van Soelen that the original instrument (1712 Davidov Stradivarius) had narrow purfling, like a violin, not the wide purfling I used on my first cello (and which I actually like to use on violins and violas, as well.) I just like the eye-catching appeal of the larger purfling as a rule. In this particular case, I must concede that the wood is so beautiful that it really does not need additional “eye-candy”.

The job starts with layout and measuring

Last night I laid out the corners, and marked the whole purfling channel using a purfling marker (sometimes called a purfling cutter— but I only use it for marking– I use a knife to actually cut out the slot for the purfling).

Then cutting and fitting

This morning I incised the whole purfling slot, using a small, home-made knife, and then cleaned the waste wood out of it with a purfling pick.

While I fitted purfling into the slot, and carefully fitted the corner miters, the glue-pot was heating up.

Gluing the purfling

When all the purfling seemed to fit correctly, I tipped each center-bout purfling strip up out of its respective slot, so that it pivoted up and out on the two corner miters, but left the ends in the slots, unmoved. I slipped hot hide-glue (quite thin) into the slot, using a palette knife, brushed hot water to flow the glue, and pressed the purfling strip back into the slot, forcing it deep into the groove with a special tool. (Sometimes I use my purfling pick for that job. Today I remembered that I have a plastic wheel on a sturdy handle,  actually designed for forcing the rubber trim into screen window frames. It worked perfectly. :-)) Then I repeated the above process for the upper and lower bouts.

If I start toward the middle of a section of purfling, and work toward the ends, the glue is forced along under the purfling, and squirts out along the edges and, finally, out the ends, and the miters. The result is that all of the piece has adequate glue, even if some spots had been a little skimpy. Then I brushed more hot water to re-flow the glue, and wiped off the excess with a rag.

So– here is the completed back, ready for final arching, and for having the edge channel cut, etc. It will look pretty rough until the gouge slices along the channel, and trims that excess glue and damaged fibers off the top of the purfling strip. Then it will look very nice. (Purfling isn’t only for looks, by the way, on violins– it also helps stop a split from the edge from moving up into the plate…supposedly.) Anyway, this is how it looks for now:

Completed purfling on one-piece cello back, before carving the channel.

The channel still needs to be cut, but the purfling is complete.

Lower treble cello-back corner, freshly purfled

Lower treble corner, freshly purfled

The next step will be to mark an edge margin all the way around, locating the crest of the finished edges, after which I can use a gouge to carve the channel, and begin the final arching.

But, for today, I have a bow to re-hair, so this is as far as I am going with the cello.

 

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One Response to “Cello Back freshly purfled”
  1. 03.03.2013

    Pretty uneventful day today. Delivered a couple of bows I had rehaired, and a fiddle I’d restored. No work on the cello at all. Maybe tomorrow, depending on how tired I am after classes are over.

    I’m glad folks are enjoying the build. I had a really frustrating thing happen: I had finally decided that the spruce I had in stock was not going to be suitable for a cello top, so I ordered two Sitka tops from a local tonewood company. I quoted the price from their website, and they agreed that was right. I waited while they checked their stock, and called me back, telling me it was in stock…talked with three people before I was done, but got off the phone satisfied that my plates were on the way. Expected them Friday…Saturday at the latest.

    So…Friday, mid-morning, I got a call (a fourth individual), saying they did NOT have any of that grade, and I had to take the next grade up, and that the prices on the website were out of date, so, I was not only going to be getting my plates a week later, but would be paying half again as much for the privilege. I ended up cancelling the order, and calling International Violin Co. and getting three European spruce cello tops from them for the price of the two they wanted to sell me at the other place…including shipping from Baltimore. Still will be the end of this week before the wood is here, but at least I am not getting the run-around. Too bad. I have dealt with that local company in the past…not sure I want to, anymore.

    So…I guess the goal now is to see how much I can get done on the back, scroll and neck, and plan on joining the spruce plates next weekend. Best I can do, I guess.

    Be patient…it will come together eventually. But I really need it to be done by mid April…really.


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