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bigdog1002
02-18-2011, 04:31 AM
Good morning experts,

After weeks of building templates, forms, jigs and dishes I am ready to actually start building my ukulele.

I have a quick question on bending the sides. My bender is made with a halogen lamp heater source. Should I
a. Attach one sheet of steel to the form and let it heat up them use the top sheet to help bend the wood into the form ?
b. Sandwich the wood between the two sheets and wait for it to heat up then bend it to the form ?

Thanks in advance.

The Curious Kid
02-18-2011, 06:31 AM
I have never heard of using two sheets of steel. I've only seen benders with one sheet that is fixed to the mold, and which the workpiece is bent around. I have heard of heated neoprene sheets being used to help the piece bend around the mold... In my opinion, though, that is verging on the ridiculous, and unnecessarily expensive, especially for hobbyists.

I bent my own ukulele's sides with a wood mold I made out of glue and a 110-year-old board I found in my basement. I just soaked the boards in a clean tub with clean water for a day and clamped them in the molds at night, took them out in the morning and glued head and heel blocks to them in a jig and got zero springback when the glue set.

Keep in mind that your first build WILL NOT be beautiful or perfect, and that its purpose is to learn the art. There is no absolute right or wrong way to make a ukulele. Make some extra parts and experiment with what you have, and from there edit your methods until you you have the art down to a science, but don't let it get boring.

I'm far from being an expert myself, but I think that is good enough advice. Sorry if it is unhelpful.

Good luck.

Pete Howlett
02-18-2011, 06:37 AM
Just a thought about your form. How do you intend to use it? If it is just for holding and gluing the sides to the end blocks then great. However, since it doesn't split through the centre you are going to have problems getting the body out when you glue the top and back in place... or have I missed something here? When I put together a uke using this method (http://www.youtube.com/watch?v=X28QCMjQ4qw) I had to grind off the overhang with a router, hence the removable parts. You might want to make a few mods on your excellent form?

I was typing this while curious kid was making his negative and fairly unhelpful comments. There have been many 'first' ukes shown on this forum which have put established makers to shame. To assume everyone is going to have your experience is arrogant and unhelpful. As a builder of ukulele of 16 years now going on 17 I am constantly finding new ways of doing things. However, because I started from a secure knowledge base and not simply an overabundance of enthusiasm, it has all been good. Furthermore, judging by the build quality apparent in the thumbnail I am sure bigdog is going to get it right because the ethic behind it looks right. All the best - I'll leave it to others to answer your heat bending question since I don't use this method and have nothing helpful to add in this regard

The Curious Kid
02-18-2011, 07:36 AM
I didn't say Bigdog had done anything wrong. His set-up looks well thought out and sophisticated, certainly better and more effective than my own ugly glued board board method. I just wanted to give an example of my own experimentation. I personally plan to alter it significantly for future builds into something more alike to what bigdog has made. So I am enthusiastic to see how he works it out. What I meant is that I am unfamiliar with his method and think it is very different from others I have seen like it, and that perhaps his best hope to make his invention effective for his purpose is to experiment with it on scrap pieces and learn from experience, and also like you said you do, to keep on experimenting. I know you are experienced, and I have great respect for you and your work Pete. I too am an enemy of arrogance, but I wanted to help. So I posted what I know, with the note appended that I know little. I even apologized in advance for it.

thanks for keeping me in check.

BobN
02-18-2011, 07:38 AM
Should I
a. Attach one sheet of steel to the form and let it heat up them use the top sheet to help bend the wood into the form ?
b. Sandwich the wood between the two sheets and wait for it to heat up then bend it to the form ?
.

A thin aluminum sheet on the outside of the wood helps hold in & distribute the moisture and heat. I use aluminium flashing.

bigdog1002
02-18-2011, 08:35 AM
After going back over my research I found.
http://www.ukuleles.com/BuildingHowTo/sidebend.html
In picture three they show that the steel sheet is tacked to the form. I think I will go with that approach. I also might do a initial bend with a pipe to get the waist to fit in first.

I got my timer, dimmer and fire extinguisher standing by so wish me luck.

Pete, Thanks for catching my mistake on the body form. I think I will make something similar to what you made in the video for the glue up

Timbuck
02-18-2011, 08:50 AM
I got my timer, dimmer and fire extinguisher standing by so wish me luck.

OK! I wish you luck..please show pic's afterwards of first attempt... no matter how it works out...for a de-briefing session.:)

Moore Bettah Ukuleles
02-18-2011, 09:42 AM
I have never heard of using two sheets of steel.

Hmmm... I use three sheets of spring steel. Four if you count the one that makes up the top the mold.

One sheet on either side of the wood slat and another on top of the blanket to protect it from the bender.

Allen
02-18-2011, 10:19 AM
I use a solid bending form with 2 pieces of aluminium flashing. Wood is spritzed with water. Wrapped in Al-Foil to keep the steam in and then slipped between the two slats along with a silicon heat blanket. The bottom piece of flashing helps support the waist durning the bend. The upper supports the upper and lower bouts. Besides helping to distribute heat evenly through the entire side. My bender takes both sides at a time.

When I first started building I used l50 watt light bulbs in a hollow bending form and laid the alloy / wood / alloy package on top of the bender to start to absorb heat and then gently try and bend it around the form. Took quite some time and not as effective as I liked. Others might have had better success at this, but it wasn't working for me.

There is a picture of the set up on my website here (http://www.brguitars.com/blog/files/a_tenor_for_paul.html) if you are interested.

ukulele-melee
02-18-2011, 02:25 PM
I've only built 2 ukes using a similar setup so take this with a gain of salt.
I have a 500watt halogen bulb on a rheostat and use a digital instant read thermometer.

I also use aluminum flashing and craftpaper/butcherpaper/grocerybag to prevent any staining from the aluminum.
I sandwich it as aluminum/paper/wood/paper/aluminum. I feel that the paper also helps retain some moisture.

Moore Bettah Ukuleles
02-18-2011, 03:17 PM
A canvas envelope, in which I insert the side, when wetted down and wrung out gives me the right amount of water I need and also keeps the wood from staining. And it can be used over and over and over.
For those who are interested and have access to the latest Guild of American Luthiers magazine, check out what Charles Fox has to say about bending with spring steel vs other metal slats.

Allen
02-18-2011, 07:52 PM
Just got my copy Chuck. Takes a bit of time to cross the last bit of the Pacific. I'm going to put that on the top of the list of things to do tonight.

I should have added that when I bend Koa or Tasmanian Blackwood, they always get wrapped in brown kraft paper, isolating the wood from any metal contact, or you get a really ugly green / black stain. Never noticed it on other woods, but there is always something that might surprise me some day.

thistle3585
02-19-2011, 03:12 AM
Check out "Factory Fridays" on the Taylor guitar website. They have some pretty impressive machinery but what really stood out to me was that they don't use water and only wrap the sides in kraft paper. http://www.youtube.com/watch?v=jxEqGqi4D-E

Pete Howlett
02-19-2011, 05:57 AM
I've tried the envelope Chuck but still get staining - you collect your water right? I think I'll have to go back to de-ionized water.

It took a year to develop that Taylor system and I've also used brown paper. However I still enjoy the relaxation I get from hand bending - I am conflicted. What I have found was that forms and bending blanket are good for setting hand bends.

Liam Ryan
02-19-2011, 12:16 PM
I can hand bend a nice easy bending set of soprano sides like Tas. Blackwood in about 10min. It takes me longer in a bending machine.

bigdog1002
02-20-2011, 01:04 PM
So I got my wood, sprayed it with unicorn tears and put it in the bender. The practice with pine worked great but the 1st real side of mahogany did not go so well. I got cracking in the waist on on the upper bout. The second attempt went a little better after I soaked the wood for about 20min. I wrapped the wood in parchment paper then used a thin sheet of aluminum on top.
Tomorrow I am going to prebend the waist with a pipe and use more heat.

Any more advice ?

The Curious Kid
02-20-2011, 05:15 PM
Yes, I realize now that my input was beyond useless. Four sheets of steel and a blanket, eh? that sounds like the ultimate in sophistication... Currently I'm just considering of graduating from my pathetic block mold to a pipe with a light bulb in it... I think that's about as far as I'll ever go though... or are such predictions always wrong?

Timbuck
02-20-2011, 09:35 PM
So I got my wood, sprayed it with unicorn tears and put it in the bender. The practice with pine worked great but the 1st real side of mahogany did not go so well. I got cracking in the waist on on the upper bout. The second attempt went a little better after I soaked the wood for about 20min. I wrapped the wood in parchment paper then used a thin sheet of aluminum on top.
Tomorrow I am going to prebend the waist with a pipe and use more heat. Any more advice ?

I drilled a 4mm X 50mm hole down the centre of one of the heat retaining rods..in this hole I place a Meat thermometer..
I take the heat up to about 325 F degrees....the Thermometer scale ends at about 200 F so I had to add my own graduations mostly by guessoligy..when I reach the green mark I put in the sides and slowly start bending and then clamp down solid...when I reach the red mark...I let the heat dwell at this point for about 5-10 mins..(If I go higher than the red then I burn the wood)..I then switch off...and let the bender cool right down..If I remove the components before it has cooled down and the material is still hot, then I get some springback and distortion...I notice in the Taylor Video they have holding jigs to keep the form in place after bending, I suppose this is to free up the hot bending machines for more production.
http://i219.photobucket.com/albums/cc143/shiregreenbod/PICT0055.jpg

bigdog1002
02-21-2011, 08:18 AM
Success !!!


The third try worked great. This time...

a. Soaked wood overnight
b. Wrapped in aluminum foil
c. Had a sheet of aluminum flashing on top and bottom.
d. I waited until I could hear the water sizzling then started pressing the wood into the form.
e. After it was all pressed into the form I turned down the heat and let it cook for 20 min. then turned off the heat and waited an hour or so until it was cool.

So the formula that worked for me was the Steel sheet on the Jig then a sandwich of flashing / aluminum foil/ wood / aluminum foil / flashing and more heat then I expected.

Thank you everyone for the advice. The hard part is done and everything else is easy right ?

Allen
02-21-2011, 09:00 AM
As you found out, if there is no sizzle, there's no steam. No steam....no bend.

Also that people new to this might not realise, Mahogany is actually quite difficult to bend compared to other woods. So while it's usually quite inexpensive and easy to get, it can be a steep learning curve on getting it to do what you want as a first time lesson.

Pete Howlett
02-22-2011, 05:01 AM
I love hand bending mahogany because of its resistance to bending - it takes on a very smooth curve, even figured stuff so long as it is fine.

cursley ukulele's
02-22-2011, 01:51 PM
im starting to think my pressure cooker chunk/heat gun might not be 'cool' anymore....

matrix12x
03-01-2011, 02:11 PM
Enjoyed following this thread. learned lots of good tips.

I just completed my fox style bender using a Watlow silicon blanket. This was my first time bending Imbuia, and my first time using a fox style bender.

I have used a piece of pipe with a propane torch primarily before. I wet the Imbuia mildly. It bent super easy. no problems. I used myself as a temperature controller, switching on and off the heatblanket to maintain temperature (300 deg).

https://lh4.googleusercontent.com/_YXaCDSxsqtI/TW2QknSEqFI/AAAAAAAAFU8/q5Ap_MKYQGk/s288/P1050095.JPG