Side bend question...

[Joseph Jones]

Hi all,
Can anybody point me towards some posts that describe in detail how to bend sides with an iron?
Thanks
Joseph

[Allen]

Pretty simple.

Make sure that your side material is as thin as it needs to be. Different between ukes and guitars. Thinner is easier to bend.

I build my ukes at 1.7 - 1.8mm thick. Iron is on full wack. Spritz side with spray bottle and I use a piece of alumium flashing to back up the timber so helps keep some of the heat and steam in.

I mark the centre of the waist on both sides and start my bends there. Hold it on the flattest part of the iron to help get some heat into the material and you can rock it back and forth on the iron. Very gently start to apply some pressure. If you need to add some more water, spritz the timber again as required. Go easy and you will feel it start to give. You will need to work the timber on different parts of the iron to achieve the required shape most likely.

When shape is right for each of the bends I have a fan near by that I can hold the timber in front of while I hold tension on it so it cools quickly and sets the bend.

Some timber bends way easier than others

[kiwigeo]

For stuff like this check out Robbie Obrien's tute videos.
youtu.be/8fEhicNLgxo

[Joseph Jones]

Thanks Allen,
I find that very easy to understand.
I’ll be bending some figured mahogany for a 00 acoustic cutaway, so 2mm thick?

Video looks simple also.
Thanks Martin.


Joseph

[Allen]

2mm should be easy for a guitar.

Figured timber takes extra care as the short grain is very easy to fracture.

[Steve.Toscano]

I try to do most of my sides at 2.2 / 2.3 - depending on the timber, down to 2 for difficult stuff.
2mm should be fine for mahogany and with a first timers hands.
If doing a cutaway you might want to go down to 1.8mm in the cutaway area.

[Dave M]

As Steve suggests I go down to 1.8 mm for the cutaway side.

If this is really your first build it is perhaps worth noting that a cutaway is significantly harder to do than a straight build. Everything from bending the sides, shaping the linings, fitting the bindings, shaping the head block etc are all more difficult.

As a confirmed 12 fret joiner I now always build cutaways but there are challenges all the way that were not there for the ordinary shaped boxes that I built to start with.

Good luck

[simonm]

Any mahogany I have used (mainly Khaya) has bent very easily. I would advise you to make a bunch of sides from any kind of mahogany you can get your hands on. Thickness to between 1.8 and 2.2 mm and bent a bunch of sides. Thinnner is easier. In Europe one seller gets rid of reject wood this way. Some of it has worm holes or strange patterns, or are orphans and they sell it as practice wood. It doesn't really matter what you use.

I didn't do this until I had a half a dozen or maybe more made. It made a big difference when I finally did it. In fact I suppose it would do no harm if I repeated the exercise again despite having a good few more guitars under my belt. Expect to have to "touch up" the bends before you use them if you are not using them immediately.

A major mistake when beginning is spending too much time on a side - don't spend half an hour on one side. Depending on the wood type, the thickness and how accurately you want to follow a plan, something in the 3-10mins per side with the caveat that you might need to touch up before you use it. 3 x batches of 2-3 practice sets over a few days would teach you a lot. Walnut is another very easy wood to bend.

[Joseph Jones]

Thanks guys,
I’ll more than likely scrape the cutaway section thinner...
Also like the idea of some practice sets but I can’t see that becoming a reality.

Post some photos shall I?

Probably not what you guys call figured!

Made up a stencil with a center line and marks top and bottom to create the cutaway shape as the plan didn’t have one.

Joseph

[Fisherman]

Any mahogany I have used (mainly Khaya) has bent very easily. I would advise you to make a bunch of sides from any kind of mahogany you can get your hands on. Thickness to between 1.8 and 2.2 mm and bent a bunch of sides. Thinnner is easier. In Europe one seller gets rid of reject wood this way. Some of it has worm holes or strange patterns, or are orphans and they sell it as practice wood. It doesn't really matter what you use.

I didn't do this until I had a half a dozen or maybe more made. It made a big difference when I finally did it. In fact I suppose it would do no harm if I repeated the exercise again despite having a good few more guitars under my belt. Expect to have to "touch up" the bends before you use them if you are not using them immediately.

A major mistake when beginning is spending too much time on a side - don't spend half an hour on one side. Depending on the wood type, the thickness and how accurately you want to follow a plan, something in the 3-10mins per side with the caveat that you might need to touch up before you use it. 3 x batches of 2-3 practice sets over a few days would teach you a lot. Walnut is another very easy wood to bend.

3-10 minutes is pretty good going! although i havent bent mahogany before... maybe its a piece of cake!!

im around the 15-20mins per side mark. a wet rag at the waist helps to avoid scorch marks. holding the shape after you take it off the iron so the bend holds is also recommended...

[Joseph Jones]

Thanks Fisherman,
I think I’ll go with wrapping it like Allen described.

Will definitely make some formers up though...
is there any harm in making just one, doing one side, and then cutting a cutaway shape in it for the other side? (I plan to make a solid shape from laminated marine ply)

Joseph

[simonm]

3-10 minutes is pretty good going! although i havent bent mahogany before... maybe its a piece of cake!!

im around the 15-20mins per side mark. a wet rag at the waist helps to avoid scorch marks. holding the shape after you take it off the iron so the bend holds is also recommended...

The trick is practice. Get a bunch of an old wood, thin it and practice as often as possible. After a number builds and some practice bending (3 x Khaya sets I think) I bent a bunch of sets of different woods one afternoon. I did either 5 or 6 sets in about an hour a few years back. One set (the last one) was extremely quick - it was ultra thin maple for a small guitar. As I was not using the sets immediately, they all needed a bit of touching up when I finally used them. Ever since then I am have way more confidence bending. The only wood I have cracked so has been cypress. Cracked two sides. The last time I did it, I used the good one and and the orphan from the last time I cracked one. I still had it lying around even thought was 5 or 6 years previously. Worked out nicely.

On one or other forum, Allan Carruth has posted about the problems when you spent too long trying to bend a side. I think it is called "case hardening" but I am not sure if I recall the term correctly. Essentially, the idea is that the longer wood is hot, the harder it gets to bend and the more likely it is to crack or at least that is my interpretation. My current aim is to do a set in 15 mins. I think it is always much better to bend a number of sets in one session as you need to get back into the swing of it. You can always adjust the shape a bit when you come to use them and need to touch up in any case due to inevitable spring back.

I think the trick is to thin until the wood feels bendy - don't worry too much about what your measurement says. Some historical guitars are apparently closer to 1mm than 2mm and the have survived.

[nkforster]

Here are a few videos I made on the subject:



youtu.be/9jf8J6rt6ng

youtu.be/1NMxMO93v8s

youtu.be/nm420mtesnU

[johnparchem]

Figured Mahogany, first time bender, a venetian cutaway ... what can go wrong? I have found some honduras Mahogany to be very brittle and resistant to bend. Other times it has bent OK. But please get some practice sides and bend them to your shape first. A venetian cutaway takes some practice as it is not always apparent where you need to start heating and bending in the cutaway section. Also feeling when the wood is plastic is a subtle thing. It is also possible to heat wood too long and set it.

[Joseph Jones]

Okay.

But I must say I’m a bit confused what you all mean by “Practice Sets” isn’t that a expensive... or do you mean from any hardwoods I have lying about??

Joseph

[nkforster]

If you've never bent sides before, or haven't bent many, you do need to practice first. Practice on any pieces of wood you can get your hands on.

[johnparchem]

Okay.

But I must say I’m a bit confused what you all mean by “Practice Sets” isn’t that a expensive... or do you mean from any hardwoods I have lying about??

Joseph

Many of the tonewood sellers have orphan sides, seconds and the likes; basically wood that they can not sell as part of a set for any number of reasons. These same vendors often sell off a stack sides cheap. I actually keep an eye out and buy them to cut out bindings. Or as you said if you have some appropriate wood lying around and can resaw it that works,.

[Petecane]

This thread has helped me along as well so big thanks for the inputs.
Bending them quickly whilst moisture is still in the wood is good sense.
I was wondering why I was cracking a few..
The obvious had not dawned on me.
My wood was burnt to a cinder ( scorched ) and of course didn't want to know any more...
.....Crack!!!...another one bites the dust.
Putting a wet cloth against the wood is a brilliant idea.
Thanks again

Pete

[simonm]

Noticed a typo in my last post above. It should read "any old wood" - not "an old wood".