Problem Bending sides Ukulele Soprano

Joined
Nov 15, 2010
Messages
6
Reaction score
0
Location
Germany
Hi everybody,

I am trying to built a soprano uke.
When I bend sides with a bending iron the wood (Mahagony) slivers. The sides are 2,5mm thick. I had the wood in water over night.

You got any advises or recommendations for me?:eek:

Thanx in advance & best

Johnny
 
It's a long time since I built a soprano but I would reduce the thickness to 1.5mm and use some fabric softener in the water for soaking. When bending, support the back of the wood with some thin metal sheet (eg aluminium flashing)
Ken Timms (Timbuck) is the mahogany soprano expert. Hopefully he will see this post and comment.
Miguel
 
Your sides are WAY too thick especially for a soprano. I build mine at 1.6 to 1.8mm thick depending on the species. You'll find that timber will bend way easier at that dimension.

I would never soak timber even for 10 minutes let alone overnight.

For really stubborn or likely to cause problem timber like highly figured species then you can also use Veneer Softener.
 
Oh, ok. So the wood is too thick. Make kinda sense.
Will also use a metal plate on the back.

I will try it next week and report my results.

Thank you so much :cool::cool:

Johnny
 
Thin is definitely the main answer.

Mahogany can be tricky, especially as there are many different species sold as "mahogany", and even then two boards of the same species might bend very differently.

I find that, in general, the 'mahoganies' need higher heat than many other woods. This creates a real risk of scorching, and a damp rag between the wood and the bending iron helps prevent this and also speeds up the heating by adding a small dose of steam.

The other thing I find is that it's best to complete the bend in one go. If allowed to cool after bending, some mahogany can be very resistant to touching up the bend again - it feels as if the wood has set rigid.
 
Wow!!
So many things to think of...
Which I of course didn't have had before.

Great having experienced people who help that much.

Thanx!
:worship:
 
Didn't really expect to get that great response...

First of all I must reduce the thickness from 2,5 to 1,8/1,5.
That's gonna be an issue to get the same thickness all over the place.
Not sure if I do it better with my belt sander or the stewmac safe t planner...

Thanks for the Vid, Ken!

Best

Johnny
 
Didn't really expect to get that great response...

First of all I must reduce the thickness from 2,5 to 1,8/1,5.
That's gonna be an issue to get the same thickness all over the place.
Not sure if I do it better with my belt sander or the stewmac safe t planner...

Thanks for the Vid, Ken!

Best

Johnny

You might want to try a simple cabinet scraper (takes a little practice to sharpen, but not much).

Clamp one end of the side and scrape down the half furthest away from the clamp, switch the clamp to the other end and scrape the remaining half. It's not that fast, and some physical effort on your thumbs, but it's very controllable and you can actually feel the thick spots.

A belt sander is likely to catch and destroy the side, unless you stick it firmly down to some MDF or similar.

Another option, which I use quite a lot, is to take a flat board (I use the white melamine-faced chipboard) and stick two strips of something to it just a little further apart than the width of the side. Clamp the side down at one end, between the strips, and then plane away from the clamp. You angle the plane so its heel and toe are over the strips, which stops you planing deeper than those strips. I use 1.5mm plywood, but plastic strips might be even better if you can get them the thickness you want. This method takes just a few minutes per side, but you have to know how to set the cap iron if your have challenging grain.
 
My main problem is time.
So I have to find a way to do it as fast as possible.
Otherwise it will take forever :uhoh:

So the first option doesn't suit for me.
To be honest, I didn't really understand your other option.

Iam also thinking of planing the wood.
clamp one side and plan the opposite and vice versa...
 
What tools do you have? I have been thicknessing tops, backs and sides on a 6”x 48” belt sander for 37 years. It can be done that way fast and accurately provided you are skillful with the tool.
Brad


Could you tell me how do you do it exactly?

I have a Metabo belt sander.
 
Top Bottom