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Hi me with all the questions again.... :D jst wondering...I have a mahogany uke at the moment and the top is 1.8mm thick....

Would the sides and back be this same thickness? I just ordered some wood today and the guy is going to sand it to the correct thickness. I just need to tell him what thats going to be

Thanks heaps

Shimmy

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Hi me with all the questions again.... :D jst wondering...I have a mahogany uke at the moment and the top is 1.8mm thick....

Would the sides and back be this same thickness? I just ordered some wood today and the guy is going to sand it to the correct thickness. I just need to tell him what thats going to be

Thanks heaps

Shimmy

When I thickness my tops, sides and back for my acoustics thickness varies with the type of wood. My tops range from about 3.25mm(thick) to 2.25mm(thin), and sides are usually 2.5mm(thick) to 1.8mm(thin). As a rule I thin the sides until I feel them start to soften a bit. Woods like Mahogany tend to be a bit thicker, and woods like Ebony tends to do better thinner. If I were you I would probably take the wood no thinner than 2-2.5 mm and sand it yourself from there.

Good Luck,Rich

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The wood Im using for the front back and sides is Black Acacia (blackwood) which I believe is quite hard and dense.

I think it would be good to have all the boards 1.8 mm....so I guess if I get it thicknessed to 2mm I could hand sand it from there

Thanks for the tips Rich

Shimmy

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I've got plans for a Martin uke (early Style 1). The drawing shows the sides as 1.8mm and the back is 2.3mm, both in mahogany.

That sounds about right. Sides are usually a bit thicker than the top. Really though I don't use a set rule for thickness on the sides. You will feel the difference when the sides are ready(they become much more flexable at the right point). As for Blackwood, if it is the African Blackwood I am thinking of it is somewhere between Ebony and a hard Rosewood. It will give somewhere between .085" and .075" most likely. Best of luck! I really want to build a Uke in the next year or two.

Peace,Rich

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Hmm

Apparently the wood im using is nearly idenitcal to Koa

how does it affect the sound? having the top thicker or thinner?

Oh, Australian Blackwood. That will give at about the same thickness as Mahogany(sides). As far as the top goes. Your goal with a top is to get it as light and thin as possible without it structurally being to weak to resist the strings pull(without warping or deforming). The lighter it is the better it will respond to string energy. It is really a balancing act, and stiffer/stronger woods can go thinner. This is why we look for the strongest weight to strength/stiffness ratio in woods(Sitka Spruce has great numbers- thus it is used a lot for acoustics). Now the demands on a Uke top will be much less than an acoustic guitar. It will not need to be as thick, and bracing would be minimized. I would tell you to look to other builders that make Ukes with this kind of wood to get your "ballpark" thickness. Your thickness will be similar(you may adjust depending on the actual piece you recieve- every piece has slightly different stiffness). That sounds a bit wishy washy as a responce, but we are talking about +/- .025" at the most. As an example. I use Red Cedar for tops. I have read it shoud be about .130-.140" thick for tops(baseline). The wood that I have is old growth and a very strong example of this wood. I find it is best around .110" generally. Again that is acoustic guitar tops(thicker than Ukes). It is really something you have to get used to when you work with the material. You should lean to the thicker side if you are unsure(it will produce sound just fine).

Peace,Rich

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I see..unreal..thanks alot.my wood arrives next week so let the fun begin....although im still in several minds about what to do about a bender..hmmmmm

The other thing is I am building a concert size uke but Im not sure what the traditional scale length is...i have seen them range from 14.75 to 15.5 inches

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I see..unreal..thanks alot.my wood arrives next week so let the fun begin....although im still in several minds about what to do about a bender..hmmmmm

The other thing is I am building a concert size uke but Im not sure what the traditional scale length is...i have seen them range from 14.75 to 15.5 inches

I am not sure what the trditional scale lengths for Ukes are. I am sure a quick search will provide you with that info.

However you go on the bender(pipe or simple machine). Be sure to make a nice mold so you can get a good final product(especially if you only use a pipe).

P.S I make molds by taking the two sides and cutting the pattern on my bansaw. After I cut them I check them for square(important) and smooth the edges. Then I attach them with wood blocks and screws at each end. It makes for a nice mirror image. Some people also cut out a removable piece in the neck area. I don't because I prefer to fit the neck with the box free. Save the trimmed wood from the inside of the sides. You can use it to make your spreader bar ends(I add a bit of cork to the side that presses against the side wood).

Peace,Rich

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Thanks alot rich...

Yea I planned on making a plywood mold....If I wanted to make it 2 layes thick, I guess another way to do it would be to make one perfect one, then use a router to do the other 3?

Yeah, That can work. You just have to be sure that the routed replicas wind up perfectly square when you stack them. The mold will keep the sides square and true to the shape if you build it well. It is a huge help when you are setting tops/backs and kerfing.

Peace,Rich

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Ive seen a mold made a few ways...Some are made to be deeper than the sides, and others are made just a few inches shallower than the sides....

any idea what the reasons for this would be?

I figured if I keep the mould, I could use it for bending my timber bindings as well....I wanted to use ebony an maple for bindings..ive heard ebony can be quite tricky to bend...

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Leave the mold shy of the full side height. You want to be able to sand the edge of the rim. You also want to be able to have the top and back overlap when you glue them down, and so on(it is just better to leave it shy of full height).

As far as bending your binding. I bend them using my side bending machine. I have bent the binding and sides at the same time in the machine, but it is a little slow(so I do them seperately now). I tell you those side bending machines are the ticket. Flexable too. You just cut a pair if sides for the machine and you are off and running on a different size/style body. Well worth the time to build.

Peace,Rich

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The bending machines really do sound good..I just dont fully understand how do make one. The main bit the the sides get bent on are metal yea? when ever it comes to metal I tend to shy away because its not something I can normally do myself. How do you get the metal/aluminium the perfect shape of the side of the guitar youre trying to make?

I saw a good way of heating it tho. with a few powerful light bulbs underneath.....

I bet using the machine would give you a more accurate bend as well...I am actually starting to want to build one now.....

hmmm...any pointers? :D

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The bending machines really do sound good..I just dont fully understand how do make one. The main bit the the sides get bent on are metal yea? when ever it comes to metal I tend to shy away because its not something I can normally do myself. How do you get the metal/aluminium the perfect shape of the side of the guitar youre trying to make?

I saw a good way of heating it tho. with a few powerful light bulbs underneath.....

I bet using the machine would give you a more accurate bend as well...I am actually starting to want to build one now.....

hmmm...any pointers? :D

No, The machine is wood(1/2" ply would do just fine, 3/4" for the main frame that holds the screw would be a nice touch). The rest is hardware(screws, nuts & blts, springs). Oh, the wood itself should be sandwiched between two strips of sheet metal(you can cut withsheers). Some people also use heat blankets on top of the sheet metal/side sandwich(personally I tent a little with tin foil to regulate heat, and it works just fine).

Peace,Rich

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Hi Rich,

so how does one get the 1/2 inch ply bent into the perfect shape that you want your side to be?

And whats the spring for?

Sorry mate...Ill do some research on these.....I havent looked into them really hard...

Thanks

Shimmy

Uhh... I hope we are talking about the same thing.Here is a pic. of the one I built.

bender

Peace,Rich

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ahh

sorry my putes been down for a few days

So....would it be possible to get a back shot of that bender?

I can see the ply sides.....so whats in the middle of it? do you just bend the stips of metal over the sides? or is there an acutal solid peice imbetween those sides for the woodto bend across?

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Unreal...

Im definately sold on the bending machine....so whats the technical term for the metal to use for the top? thickness and what not?

Thanks alot for taking the time to help me out Rich..I appreciate it....

That jig page is great too..Ill read up on those...

Shimmy

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Unreal...

Im definately sold on the bending machine....so whats the technical term for the metal to use for the top? thickness and what not?

Thanks alot for taking the time to help me out Rich..I appreciate it....

That jig page is great too..Ill read up on those...

Shimmy

Boy, The thickness I used. It was just a piece of ductwork sheet metal I picked up. Light gauge is good for the pieces you use to sandwich the wood. I didn't make the bender you are probably refering to that uses a heat blanket on top of a jig with a sheet metal top. The metal that sandwiches the sides sets on the machine(exposed to the lights). It is supported by pins(believe it or not large nails will do the trick- you just drill out holes for them to slide in along the top of the form/ use enough to provide good even support). I think the one I built is refered to as a Fox style bender(I am not totally sure of that though- Mattia knows the names better than me). Using a heat blanket would be nice( I have heard its praises by others). I personally have good success tenting over the top and around the sides a bit with tin foil as needed to control the heat. One thing that also works really well. Seal up the wood and sheet metal sandwich with some tinfoil and masking tape. It seals in the moisture(so you can use less water). It seems to bend smoother and more evenly this way.

Peace,Rich

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