Weissenborn teardrop style

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Weissenborn teardrop style

Postby ricbleu » Wed Jun 09, 2010 4:28 am

Ok, well here goes. The three pics I've attached are all the preparatory stuff. The teardrop shape, bout size and scale length were determined by the size and shape of the piece of figured oak that I had for the back. Bout size was 310mm (sorry guys, but we've been metric here since 1975 so I'd struggle to reconvert for you). Scale length 600mm (nominal 24"). After looking at dozens of sites on the web I decided to make my braces all 12mmx6mm (X section area 72 sq mm). Original Weissys and modern plans say 10x10 (X section 100 sq mm) but tall and narrow is proportionately a lot stronger than square thus allowing lighter bracing with greater strength. All bracing was Western Red Cedar orientated so that the growth rings were at right angles to the top & back. This is v important to maximise strength. Set out for soundhole and exact placing of braces was judged from pics off the net. Check out Tony Francis' blog site showing his restoration of one of these. I also guesstimated the bridgeplate from those photos. There were changes from the plan in the final product due to the need for me to shorten the Weissy by 15mm to let it fit into a previously made wooden case - I pinched those 15mm from the peghead which is why it's a little stubby in the final guitar. Next pic is the form. This took ages. I was using all bits & pieces from my woodstack hence the glued on bits to widen one piece of the 18mm ply. Those two plys are separated by 40mm blocks glued & screwed flush with the inside line of the form and the whole thing is lined with some 2.5mm white ash that I sawed from some leftover laminated flooring. The lining probably wasn't necessary but I wanted absolutely true curves on both sides and top & bottom of the form. You need to make the form in halves so that it can come apart down the centre. Do not overlook to keep a TRUE CENTRE marked at each end and top & bottom on your form. You'll need that reference again and again. For marking out the guitar shape from the plan onto the pieces of ply, I traced one half of the guitar to a piece of 3mm MDF, cut & shaped that with precision, then used that to draw an outline onto the ply then flipped it to draw the other side. Again maybe not a necessary step but I wanted everything to be symmetrical and a half template flipped over will reproduce itself exactly. The third pic is my high tech bending pipe which is self explanatory. I want to stress that if you've got a good base of woodworking tools, you don't need to be out buying expensive equipment which you might only use once or twice. Please feel free to ask anything you want to and PM me for my email if you want more. I have to thank Terry Buddell from Australia who changed my mind on starting this project when I'd decided I wasn't up to it. Terry also sent me his dvd and although it arrived during the 3rd week of the 4 week project, the more information one can gather the better. Thanks, Tel.
Attachments
05 bending pipe.JPG
04 the form.JPG
02 the plan.JPG
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Re: Weissenborn teardrop style

Postby zhyla » Wed Jun 09, 2010 3:43 pm

ricbleu wrote:The third pic is my high tech bending pipe which is self explanatory.


Hang on there, that's the part I didn't understand! Is this for curving the sides? I get why a round pipe would make a handy mandrel for that. But what is with the drill?
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Re: Weissenborn teardrop style

Postby ricbleu » Wed Jun 09, 2010 9:25 pm

Sorry to be confusing, zhyla. It's a paint stripping gun. I aimed it at the approximate working point and turned it on full whammy while I was working the sides. I spritzed the sides (rims) frequently with water and sometimes the pipe and worked slowly slowly. I tried, but didn't feel the need for a cloth over the pipe to prevent scorching the wood because an electric heat gun isn't as fierce as a gas one. On the teardrop there's only one tight curve - on its "hip" but that's a tighter curve than it looks especially when you are near the very tail (cut overlength) and there's not much "leverage" at that point. As the water turns to steam you start to see it bubble through to the surface and you feel the wood go plastic. But slowly slowly, moving the piece backwards and forwards, KEEP IT SQUARE WITH THE PIPE otherwise it's twisted in its length. And refer the work frequently to the shape of the form/mould and then as it cooled I held the rim in my hands and eased a bit more into the curve (overcurving it so to speak) to counter springback. You want to end up with as close to a perfect match with the form as possible so that there are no stresses on the guitar when you come to glue up. I didn't wear gloves because you really need to be working by feel - just a touch too much force while you're working the bend into the piece and you've got a broken rim. The third degree burns soon healed. When you are satisfied with the shape, clamp it into the mould and leave it overnight to cool and dry. If more work is then needed, then just resume the process. By sighting down the curves you can spot the lumps and flat spots. Repeat the process for second rim. Zyhla, I'm really pleased to be able to do this thread, but do let me know if I'm going astray ie too much detail, too little detail, pics too small (I can't find where it says maximum size for uploads), too boring etc etc. And feel free to contact me at rln@ihug.co.nz for better resolution pics or if you want to move the whole thing out of the forum. Let me know as soon as or if you want the next installment. :D
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06 side 1 in form.JPG
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Re: Weissenborn teardrop style

Postby zhyla » Wed Jun 09, 2010 10:22 pm

That clears it up. I love build threads, I've got no problem with the volume of info you're giving us. Not everyone here is into building guitars but I'm sure most like to see DIY kind of threads.

Time to hit the hardwood store...
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Re: Weissenborn teardrop style

Postby ricbleu » Thu Jun 10, 2010 3:52 am

I hope I caught you in time, zhyla. Before you come out of the hardware store with a wheelbarrow full of clamps, check out the ones in the pic. These are easy to make. I used 6mm (1/4) threaded rods with a nut & washer for one end and a wingnut & washer for the other. I cut the rods into appropriate lengths for my job and then sliced a 40mm diameter dowel into 25mm lengths, drilled a 7mm centre hole with a drill press and cut some felt from an old hat for padding. I made 20 of them and could have done with about four more. For a traditional shaped Weissy you'd need more rather than less. They are used as the pic shows. Likewise don't buy one of those reverse acting clamps often seen in luthiers' shops. More useful if you are into production runs, but for one or two offs there are costless alternatives.
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13 back being glued.JPG
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Re: Weissenborn teardrop style

Postby Django1 » Thu Jun 10, 2010 6:22 am

Hi Rick
nice piece of "Book Matching" on the back of the instrument, as far as I can see
cheers jim.
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Re: Weissenborn teardrop style

Postby zhyla » Thu Jun 10, 2010 2:40 pm

Thanks for the tip on the clamps. I have seen those before, definitely the way to go. I'm a very thrifty guy so I dig cheap solutions, especially for things I won't use every day.
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Re: Weissenborn teardrop style

Postby ricbleu » Wed Jun 16, 2010 3:44 am

Thanks for the compliment, Jim. It really bookmatched itself, the figure was so strong. I couldn't get a perfect match all the way along though because my table saw has a 3mm kerf and then there was about another 1mm lost on each slice in the initial dressing and probably another 1mm each in the final scraping and sanding. A bandsaw would have been a better tool, but I've never owned one.

I'll post another couple of construction pics and if they throw up any more queries, I'm happy to answer, as always.

But, zhyla, you asked how I cut the soundhole. I still hadn't finalised my method as I approached it on the morning I did it. But I had a sudden realisation that I was dealing with a piece of timber only about 2.75mm thick. So in brief I made a jig - a short piece of timber (about 10mmx10mm and about 30mm longer than the radius of the soundhole) with a screw through one end which would be screwed down through the centre of the circular soundhole mark (school compass and pencil) into a piece of waste ply. The guitar top was clamped to the bench with the ply underneath. Then at the point of the circumference, I drilled a small hole (1.5mm) in the jig and tapped through a piece hacksaw blade ground down to about 2mm wide (not far from matchstick width) and sharpened razorsharp in a curved "point" at the end which would protrude. I tapped it through until about 2mm protruded. Then with the screw screwed through the centre point of the soundhole but not so tight that it would resist the jig being rotated, I simply worked my way round the circle, cutting deeper and deeper until I knew I was more than half way through, then unscrewed the centre screw, inverted the work and repeated the operation until the soundhole came free. There was a tiny disparity in the middle of the cut where my cutter blade had approached at a minutely different angle, but it cleaned up with 280 paper in about 30 secs. If anyone is familiar with the very old fashioned homemade tool called a scratch stock, it was the "scratch stock" principle which gave me this idea. And if I was doing more than one, I'd make something which was more durable. Mine was essentially a single use device.

I do hope you press on, zhyla. This was my first and I am more than pleased with it. It certainly isn't perfect and I took a lot of risk with timber choice and self drawn plans but when I strum her open strings and hear the sustain slowly decay in a sort of throbbing manner... well, it feels good. :D
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12 top bracing.JPG
08 back braces glued.JPG
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Re: Weissenborn teardrop style

Postby zhyla » Wed Jun 16, 2010 5:12 pm

Thanks for the explanation. I haven't committed my brain to doing one of these yet, I'm about to get started on a couple lap steels that will keep me busy for a while. Hopefully by the time I'm done I'll have some woodworking skills down.
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Re: Weissenborn teardrop style

Postby Freeman » Wed Jun 16, 2010 7:30 pm

Please keep it up - I like build thread, particularly when the instrument is a bit esoteric. I learn something from every one of them and a Wessenborn build is somewhere in my future
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Re: Weissenborn teardrop style

Postby dralla » Wed Apr 18, 2012 2:41 pm

hi ¸is there a way to have copy of your plan your plan with more detail than on the picture? and can you tell how large was the guitar?
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