Boiling sides?

[Dekka]

When I'm bending sides, I seem to have no trouble initially and then all of a sudden....C_R_A_C_K! This then brings on a wobbly that ends in something being smashed and me shouting at pieces of wood.
Anyway, on my side-bending google journey I came across a classical maker boiling sides in a trough. The way it came out of the water and virtually sagged onto the form without much resistance made me wonder why everyone doesn't do it that way.
What are the cons to boiling sides?
Is there too much moisture held in the fibres afterwards? Are some woods unsuitable?
Do any ANZLFers do it?

PS I haven't tried veneer softener yet but I intend to on the next set I trash.

[DarwinStrings]

Not sure why you are breaking them Derick, K Yairi seems to use a similar method to the one you described. The wood will dry out again no worries, not sure about cons. I use the heat blanket and don't have any troubles, maybe you could try one. It does seems that some wood doesn't like water as much as other wood though like curly stuff.

Jim

[Bob Connor]

Dekka

There's absolutely no need to boil sides.

Can I ask a few questions?

What wood are you trying to bend?
What thickness is the wood?
What method are you using? Bending iron, mold with lamps or mold with heat blanket.
At what temperature are you starting the bend?

Regards

[Dekka]

I've got a home-made bending iron but I'm half-way through making a bender with an internal heat-source.
The iron gets hot enough to scorch if I overdo it. I soak the timber prior and spray as I go.
Thickness is around 2.6mm.
Woods I've tried include :- Fijian Mahogany, curly Red Shorea, Tassie Oak, Silky (Grevillea) Oak, Rock Maple, and Spotted Gum which was the only one that bent easily without cracking but it was flatsawn and did cup afterwards.
The woods are certainly not premium but I want to get my method right before I start having a crack at any really good stuff.
It's forming around the horn of the cutaway that gives me the most grief. Bouts and waist is easy enough.

[ozwood]

Hi Dekka,

you probably need to be around 1.5 - 1.8 around the cutaway to bend that tight , if it's a nice porous timber , wood softener works well, I use the Carbatec stuff, But I believe Trevor has found a better one, If that helps.

I have learnt by exp that if the sides are to wet they can do funny cupping things across the grain that can be a real bitch to get out.

Just my thoughts.

Cheers,

[simso]

I think yours are a tad still to thick for easy bending

I occasionally boil sides for bending, things to consider, boiling makes the wood limp it also removes some of the woods tannins.

The wood remains limp for very short period of time, the moment the woods celluloid starts to cool of which is about 30 seconds then you loose that bending ability and have to reheat again

Steve

[Trevor Gore]

Yep, 2.6mm is rather thick for just about any sides. Typical is no more than 2.2mm, then down to 1.8mm or a bit less on cutaways, thinner on stuff like bloodwood (brosimum rubescens). Torres was famous for really thin sides, in the 1mm range. No idea why he went so thin, but the air resonance certainly drops with thinner sides.

I tried the Carbatec veneer softener. Didn't think much of it. I've found that domestic fabric softeners do at least as good a job, but don't use either much at all. The more wood I bend, the less water I use. I keep sides at ambient humidity (rather than dry room), so probably about 12% EMC and I've bent sides without further water, but found free water on the SS slats after bending and cooling. So I reckon you don't need any more on most woods! The less water you use the flatter (widthwise) your sides stay.

I bend cutaways by hand on a pipe. For difficult woods I use a wet paper towel between the pipe and the wood, which forces steam into the wood, so you get better heat transfer with less risk of "cooking" it. It generally pays not to wet the outside of the bend on figured woods, especially things like figured maple. Try to bend dry and you don't need much heat on maple.

[Lutherie Gervais]

Yep, 2.6mm is rather thick for just about any sides. Typical is no more than 2.2mm, then down to 1.8mm or a bit less on cutaways, thinner on stuff like bloodwood (brosimum rubescens). Torres was famous for really thin sides, in the 1mm range. No idea why he went so thin, but the air resonance certainly drops with thinner sides.

I tried the Carbatec veneer softener. Didn't think much of it. I've found that domestic fabric softeners do at least as good a job, but don't use either much at all. The more wood I bend, the less water I use. I keep sides at ambient humidity (rather than dry room), so probably about 12% EMC and I've bent sides without further water, but found free water on the SS slats after bending and cooling. So I reckon you don't need any more on most woods! The less water you use the flatter (widthwise) your sides stay.

I bend cutaways by hand on a pipe. For difficult woods I use a wet paper towel between the pipe and the wood, which forces steam into the wood, so you get better heat transfer with less risk of "cooking" it. It generally pays not to wet the outside of the bend on figured woods, especially things like figured maple. Try to bend dry and you don't need much heat on maple.

Isnt Torres the first of doing laminated sides ? and that was the reason of having 1mm thick ...

[Nick]

I initially started bending using sides soaked/submerged in hot water for twenty minutes, it was a recommendation I think I read in the StewMac paper catalogue (this was in the days when there was no such thing as an internet!). As time's gone on and more sides have been bent (using my trusty bending iron) I've used less and less water, so much so that now I don't pre-wet at all and just use a spray bottle to spritz the sides before bending. As others have stated you want to start bending with your sides much thinner (I typically use 2mm as a starting point reducing it in the cutaway areas).
I don't know your bending technique at all and forgive me if you do do it the following way but one thing I recently noticed when I was helping/watching a guy bend his first set of sides is watch the amount of pressure you apply to the wood! Let the wood bend in it's own time, don't force it (this guy literally ended up wrestling the sides into shape, cracking both sides.... he didn't follow instruction too well & I gave up trying to tell him to ease up in the end) and don't rush it thinking it should bend within 10 seconds of hitting the heat! You are only applying enough pressure to help the wood, not forcing it to bend. One thing I love about hand bending is that moment you feel the wood go from stiff to it's plastic state.

[Dekka]

Thanks for the replies, blokes.
For some reason I had it in my head that thicker was better, e.g. 3mm, and that 2.6mm was a compromise.
I'm sure all will be revealed when I unwrap Trevor's books in a week and a half.

I'm thinking maybe I should do the cutaway first so I'm not having to adjust it in relation to the waist although the tightest curve is the upper bout.
What's most frustrating is that it's not even a very acute curve so it should be easy.

[Mark McLean]

Yep, 3mm thickness will be a struggle with a lot of woods, and you will be amazed how much easier it is at 2.5mm. For tight bits, like a cutaway, you can thin that part a bit more than the rest. Supersoft helps also.

[mqbernardo]

Isnt Torres the first of doing laminated sides ? and that was the reason of having 1mm thick ...

no, Torres´sides were solid wood. they were on the thin side, although i´m not sure every side was in the 1 mm ballpark. he did use side reinforcements, though.

[tippie53]

http://www.youtube.com/results?search_q ... oKMbBxX_i0
check this link
Here is how I bend. I do my sides at .085 inch.
I got rid of light bulbs as a heat source , they are not the best as you can't control the heat

[simonm]

I go for something in the 2.0 mm to 2.4 mm as a hobby builder I am not so bothered about consistent side thickness. I aim for the around 2.4mm and then keep flexing the wood with my fingers - when it flexes easily I am happy with that.

Alan Carruth (you'll come across him on other forums sooner or later) mentioned at some point the problem of over-working the sides. In other words the quicker you can bend the sides the better. If you keep worrying the same patch on the side especially if the iron is not hot enough you end up with the wood being dry and brittle or very resistant to bending.

The trick is to use only a light spritz of water and move the side back and forth a bit the warm up a section then concentrate more on one bit until you feel it bending but all the time trying to keep the area around it warm. The absolutely best thing you can do is thing down a stack of "sides" (i.e. any old timber) to about 2.2mm +/- a bit and bending that. Once you have bent maybe 10 "sides" in a go you will find you start developing a feel for it. Do that two or three time and you will be set for life. Once you get the hang of it, bending a set of sides (one the iron is hot enough) is a matter of about 10 mins.