Side bending crack. Can this be fixed?

I was doing a bit of hot pipe bending last night and I cracked the side in the middle. I think my pipe wasn't hot enough and I pushed it too hard.
Is it possible to shore up the crack and continue, or am I pretty much done?

That's a nasty crack. Across the grain and virtually full width. It is possible to glue it and it will hold up if glued correctly. You won't be able to hide the 'joint' though. It will always show.
I'd put it down to experience and start a new set. Side bending takes a bit of practice.
Those sides look a little on the thick side, although it's difficult to say with any certainty going by a picture.
Make sure the iron is hot enough.
Try bending with a spring steel 'backing' and/or try my foil wrap technique.

Since the shape is not complete, you're SOL. There's no glue I know of that you could use to repair the crack and then go back and complete the bend.

If the bend were complete, I'd suggest hot hide glue which makes for the least visible repairs of any glue, takes stain and finish well, and is fun to work with.

How thick is that side?
OK, I see Michael asked the same thing. I believe that's probably part of the problem. And if the bend were completed it would be up to you if you wanted to repair it and use it but I've got a nice piece of ambrosia maple with a crack in it that looks very similar to that one and it's being used for scrap, I tried to bend it knowing it was on the thick side... ergo having to "push too hard"... I hate when things like that happen.

I was afraid you guys would say that.
I think I will save up my $ and invest in a heat blanket before I bend the next set.
Thanks for the advice!

~Fred

Vic D said:

How thick is that side?

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Just a bit shy of 3/32".

finkdaddy said:

Just a bit shy of 3/32".

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That's a bit thick. On my sopranos the sides usually run around .70" ( or less )before final sanding...

What type of wood is that?

3/32 is 2.5 mm's in metric. I think you should be able to go quite a bit thinner than that. On my big Guitars I go as thin as 1.6 mm. Knock at least 0.5 mm off. You will be surprised how much of a difference that makes.
You don't really need a heat blanket. That suggests that you are blaming the tools. Anyone should be able to bend sides on a hot iron. They were doing it 400 years ago, quite literally hundreds of thousands of instruments have been done on a hot pipe.

I find that 2mm / 1/16 is usually too thick for the bends in soprano sides. For tight bends I might take it down to as little as 1.5mm. Of course, woods vary, but it would want to be very easy bending for 2mm to work.

I've not used a heat blanket, but I suspect that at 2.5mm it would quite likely crack anyway at least on a soprano side..

Dont get upset..it's only a bit of wood...Have look at this wood bending job..if this one cracks thats serious
http://www.youtube.com/watch?v=QspGC1_bhHw&feature=related
And there is more on this style of Compression bending here.
http://www.inventables.com/technologies/bendable-wood--2

ProfChris said:

I find that 2mm / 1/16 is usually too thick for the bends in soprano sides. For tight bends I might take it down to as little as 1.5mm. Of course, woods vary, but it would want to be very easy bending for 2mm to work.

I've not used a heat blanket, but I suspect that at 2.5mm it would quite likely crack anyway at least on a soprano side..

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I concur. On harder woods such as mahogany or zebrawood, .06" or a tad over is where I start with my sopranos.. and although I've yet to build a tenor, evidently they're not much thicker from what others have said. Of course that's just a starting point and feeling the give of the wood and listening to the tap as it's brought down has to be considered. I build with poplar a lot so I tend to relate my experience with it which I shouldn't do. I go a hair thicker with the poplar due to its properties.

Yeah, it's mahogany. I'll go thinner next time and take it easy on the bends.
I appreciate the advice.

I like stiff sides. I bend everything, including cutaways at .08" (2mm) without a problem.
BTW, 2mm in considerably thicker than 1/16".

I have bent hardwoods for soprano uke sides for years with over 250 and counting and the only time I have ever had a side crack like that is when the wood was crap. I don't use the hot pipe method, only the heat blanket with formed side jig. The normal thickness for sides that I use is at least 2mm and sometimes thicker depending on the stiffness of the wood. I like the sides a little thicker because then they don't get wavy and they are easier to sand without fear of getting them too thin which in turn will make them more wavy. Mahogany and koa are very easy to bend, even at 3mm, using a heat blanket and a little care.

After years of repairing vintage mahogany and koa ukes, I've learned that the thinner the sides are, the more problematic they are down the road. I have 4 vintage Hawaiian ukes (1920's and earlier) in my shop right now for repairs and every one of them has wavy sides because the wood is so thin. Just some thoughts!

BlackBearUkes said:

I've learned that the thinner the sides are, the more problematic they are down the road. I have 4 vintage Hawaiian ukes (1920's and earlier) in my shop right now for repairs and every one of them has wavy sides because the wood is so thin. Just some thoughts!

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I bet they sound great too, probably why they're in your shop getting a checkup after 90 years. I tend to go with Martin's philosophy when it comes to building and their vintage sopranos are built fairly thin. Tone and volume are much more important to me than aesthetics, second of importance is longevity. When all of that has been taken care of I'll put more bling into the thing. Everyone builds differently. I played a 300 dollar factory uke lately with all the shell and trim you could fit on it... it was quiet and pretty lackluster.

They are in my shop because they have cracks and are barely playable, bad intonation, etc. They do not sound great, only OK. They are collectable ukes, not players. I too like vintage Martin ukes because they sound good and were built with care. I do not believe making the sides (we are only considering the sides now) a little thicker will inhibit the sound at all. In fact, I believe the uke will hold up better with less body distortion. Import factory ukes with all the bling are in my opinion pure crap and a waste of resources and not worthy of much discussion.

In terms of longevity, I suspect climate plays a huge part. Here in the UK we don't have climate, just weather, and also not much in the way of central heating. Thus my 20s (I guess, 30s at the latest) Kumalae still has non-wavy sides. It's definitely a player - no cracks, really sweet sound with big volume, and weighs in at a mere 225 gm, which I think means its sides must be wafer-thin. The best I've managed (in mahogany) is 305 gm, with top/sides/back a fraction over 1/16 (yes Chuck, apologies, this is about 1.5mm), though with metal pegs. If I'd used wooden pegs it might be 275 gm. So the Kumalae is silly light, but has survived 90 years or so without distortion.

I accept that, sonically, thicker sides might be a good thing. But for playing, there's something really appealing about a uke which vibrates so much all over that it's hard to hold on to. Plus, if you're a hobby builder like me, thin sides are easier to bend. If it falls apart after 10 years I'll just have to build another, which is what I like doing in the first place. If it were going to a customer I'd be more concerned about its lifespan, and have to learn to bend thicker sides.

BlackBearUkes said:

They are in my shop because they have cracks and are barely playable, bad intonation, etc. They do not sound great, only OK. They are collectable ukes, not players. I too like vintage Martin ukes because they sound good and were built with care. I do not believe making the sides (we are only considering the sides now) a little thicker will inhibit the sound at all. In fact, I believe the uke will hold up better with less body distortion. Import factory ukes with all the bling are in my opinion pure crap and a waste of resources and not worthy of much discussion.

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I trust your opinion more than mine since I've never played a vintage Hawaiian uke. The only source I've got to go by are the reviews from others who say they were built right and sound awesome. Of course the topic is subjective in many ways, from different builders to the way the ukes were maintained and so on. I'm still sticking with certain dimensions found in certain ukes for now but may go a little thicker with the sides in the future... on SOME woods.

As far as import factory ukes go I agree wholeheartedly about their worth but I disagree that they're not worth discussion, the waste of resources is important to talk about. Unfortunately, in this system companies cannot produce the best product. If they did make things that last as long as possible, out of the best material and with the hands of the most skilled artisans they would simply go out of business. Companies, corporations, won't admit to it but intrinsic and planned obsolescence are an integral part of maintaining profit in our current so called economic system. I say "so called" because our current system really has nothing to do with an "economy" in the literal sense, the Greek root of the word means to conservatively manage a household, something far from this model of ultra-consumerism that we're part of today. In order for a company to maintain production and increase profit it must cut corners and to build a product that would outlast their warranty by a large margin would be to insure their demise in the future. Which brings me back to intrinsic and planned obsolescence. The market system requires "cost efficiency" and that means cutting corners at every stage of production, from labor to the materials used etc... As the global "economy" pulls down the purchasing power of those in the more consumerism oriented countries we see the need for cheaper and cheaper products. Technological unemployment is creeping up, advancements in technology and automation are going to do away with the laborer and this is happening at an exponentially quickening rate, the purchasing power is not coming back. This is a system which has just about run its course and a planet with finite resources just will not support a system which requires infinite consumption... nature is truly the only dictator who will not be unseated. This trend will continue as long as we're stuck in a monetary system or until the last tree is felled and the last drink of clean water has been drank... or until we extinct ourselves.

I'm positive that given the advancements in technology today, we can create materials that mimic the tone woods Luthiers covet, not just mimic but far exceed the quality of the best material while being consistent, without the anomalies sometimes found in traditional woods that might cause structural problems down the road. Luthiers of the near future will design their instruments on a computer and feed the data to a 3D printer which will turn out a beautiful rosewood instrument in less time than it would take for a glue pot to heat up. And they will last much longer than any instruments of the past.

Intrinsic and planned obsolescence, market secrets, outdated institutional beliefs are holding us back as a species but that's going to change. For a good perspective on planned obsolescence Google "The Lightbulb Conspiracy"... a great documentary with an unfortunate name.

Namaste,
Vic

I wouldn't be too sure of that Vic. We have real life examples of instruments that are over 400 years old (Amati fiddles) and still very much playable. They may have been repaired down the line but 400 years and still going strong isn't my idea of built in obsolescence. We have Glue (Hide) that lasts thousands of years. We also have real life examples of relatively modern materials that are pretty much junk after 30 or 40 years - certain Plastics, Rubber, Nitro Cellulose. Take the example of Parchment and modern paper. It doesn't take a genius to work out that the former far outlasts the modern equivalent. There is just a huge difference in the cost.
You might just have to wait the best part of 200 years before passing judgement on the longevity of any modern material.

Michael N. said:

I wouldn't be too sure of that Vic. We have real life examples of instruments that are over 400 years old (Amati fiddles) and still very much playable. They may have been repaired down the line but 400 years and still going strong isn't my idea of built in obsolescence.

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And those are wonderful examples of fine instruments but not examples of planned obsolescence. Those instruments were made out of the finest materials available at the time by master artisans, albeit most likely only for the enjoyment of the aristocracy, in a time of feudalism and a nasty plague that wiped out a 3rd of France's population. Of course the monarchy to follow ended as expected. Someone once said, "History doesn't repeat itself, but it often rhymes."

"We have Glue (Hide) that lasts thousands of years. We also have real life examples of relatively modern materials that are pretty much junk after 30 or 40 years - certain Plastics, Rubber, Nitro Cellulose."

Bingo, planned obsolescence. There is no incentive to create the most scientifically advanced materials for production of consumer goods when a company has to insure profitability.

“Nothing produced can be allowed to maintain a lifespan longer than what can be endured in order to continue cyclical consumption.”

"Take the example of Parchment and modern paper. It doesn't take a genius to work out that the former far outlasts the modern equivalent. There is just a huge difference in the cost.
You might just have to wait the best part of 200 years before passing judgement on the longevity of any modern material."

Another great example would be hemp paper, a paper of the highest archival quality that was used to pen the ever so popular US Declaration of Independence. This paper was done away with in the 30s when a newspaper tycoon by the name of William Randolph Hearst saw its use as a paper product as competition to his 1000s of acres of timber to be used in his rags. Alcohol prohibition had just ended and there was a void in the bureaucracy that needed to be filled, so the war on hemp was started. A successful propaganda campaign ( with many racist overtones ) was waged by said newspapers and hemp was taxed out of existence, eliminating competition for wood pulp and bringing in the wonderful war on drugs and the growing industry of private prisons, prisons whose stock goes up with the increase of prison population...

As far as parchment goes, I'd hate to think about the goat massacre it would take to send out the next Grizzly catalog.

This is a good example of planned obsolescence. I found this half size guitar in the alley while walking to a cookout. From the looks of it, the young lady this belonged to wasn't impressed at all. lol

View attachment 29495

Look closely, staples screws and plywood. I'll use it as a template while changing the bracing and neck joint to make a real guitar of my own.