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Or have I found the only d#*n piece?
Trying to bend a venetian cutaway, and I just could not get it to bend - virtually nothing.
It was thinned to 1.8mm, spritzed, held up against a hot iron (305 - 310F surface temperature) using a backing strap, and eventually it just cracked.
Then tried bending another place further up on the same cutaway portion (broken), almost nothing at all! Like steel plate.
I bent a different (trial) piece of EIR before hand, on the same iron - same temperature, no real problem at all.
After above problem, I was then able to straighten that piece, and reverse the bend.
And to add insult to injury, I was then able to then reverse it again. (all this against an Inside radius of 22,25mm.)
Given this, I don't think it's technique.
Perhaps the givaway with this set was the substantial springback I got back out of the sidebender, despite two additional cycles to set the bends.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Put rag or folded paper towel on the pipe and keep it wet -- it should bend eventually. Might need a lot of pressure on the backing slat, if the wood develops ripples it becomes very difficult to bend because the cupped area adds structural resistance. Generally I don't think adding a lot of water and steam "when working EIR" is a problem but rather helps the process.

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Ken Cierp

http://www.kennethmichaelguitars.com/

Must have spend at least 20 minutes on the same bend each time, spritzed the wood 8/9+ times each try.
I started testing the iron with bubinga at 2.3mm, and had less problems....

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

I've seen sapele and bubinga that were like that. They just preferred to break before they bent. It kind of sounds like the old story of the oak and the willow.....

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Joe Beaver
Maker of Sawdust

On those tough bends I do more than spritz, I keep them soaking wet and let the steam do its thing. Whats the grain pattern? EIR way off the 1/4 can be prone to cracks caused by delamination.

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Ken Cierp

http://www.kennethmichaelguitars.com/

Colin, did you try heating up a lager section of wood or did you concentrate just on the immediate cut-away section? Say 3 or inches on either side of the cut away. I find this helps. Just curious.
I've also noticed that wood I overworked on the bending iron becomes difficult, almost like I'm heat treating it. When that happens I re-wet the wood over night to try to re-hydrate the cells the have another go at it, that seems to help. Anyone else notice this?

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Jim Watts
http://jameswattsguitars.com

I'm with Ken on the need to soak some wood. Normally a spritz is all I need but some I've had to soak in hot tap water for an hour and then it the bend like butter.

Thanks for the feedback guys, I have had some success.
To outline the whole process I used, I originally bend the lower section of the side in a side bender, without any bending of the cutaway portion at the top, just the area of the upper bout close to the waist was bent.
The side was left in the bender 24 hrs, removed, and I had a fair bit of spring-back - I suspect the side wasn't wet enough originally.
I kept the blanket "portion" of the sandwich away from the unbent portion of the side, but it looks like actually a fair bit of heat got into it, as oils came to the surface all over it.
Yesterday I took the broken part of the side, sanded off the oils on the surface with 180 grit and soaked it, left for couple of hours, then sprayed it again before going back tho the iron.
With much re-wetting as required, I was able to bend it (slowly and reluctantly) to the tight radis of the cutaway point.
It looks like the overall proceedure in my case was flawed.
Perhaps the effect of the heat on the wood (heat treating? - Jim) and possibly the oils on the surface were stopping the water/steam penetrating the wood.
Just ordered a "professional" bending Iron and will try the next set on that one.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

I have seen wood take a set from heat such that previously bendable wood became very brittle.

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http://www.Harvestmoonguitars.com

Soak it in 70/30 water/fabric softener for 20 mins.

It'll bend.

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nigel

http://www.theluthierblog.com

how thin .075 is where martin bends. Rosewood usually bends like butter

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Thanks for the suggestion Nigel. I have some Supersoft II veneer softener. Don't like the idea of glycerine on my sides
As I said in the second post, looks like the problem may have been caused by heat from previous bending in the side bender.
Your videos have encouraged me to try another set by hand on a "bought" bending iron.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

A lot of folk avoid Supersoft or fabric softener (are they the same thing?) because they don't like the idea of chemicals in the wood or wonder about lingering after effects etc...but these worries should be added to the long list of "theoretical" concerns and questions that have little relation to reality. I've bent hundreds of sides using fabric softener and have had no glueing/finishing/strength issues whatsoever. I wouldn't consider bending BRW without it. Then, who does like snapping £1000's worth of wood that took hundreds of years to grow?...Yes, they will smell a bit of the stuff, but that fades.

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nigel

http://www.theluthierblog.com

Not the same Nigel, SS II is Diethylene Glycol Monoethyl Ether, classed as a wood plasticiser for this purpose, fabric conditioner contains mainly cationic surfactants, (soaps or detergents) - glycerine was my mistake, apologies - and sometimes silicones apparently.
Might try some comparison trials as my supply of SS II wil not last forever.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

I don't care for perchloroethylene and I don't like glychol ether. - Amy Farrah Fowler

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Insta - https://www.instagram.com/cbcguitars/
Facebook - https://www.facebook.com/cbcguitars

Big Bang fan house here!

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

Home brews have been the down fall of countless wood working projects. SS is engineered and marketed for our specific purpose ---- why take a chance?

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Ken Cierp

http://www.kennethmichaelguitars.com/

I hear ya! And I have SS II.
But when a respected professional like Nigel Foster tells me it's got to be worth a couple of quick test pieces at the very least.
My curiousity is piqued.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

No disrespect for Nigel at all -- but his science applies to the adhesives and coating he uses. I have seen long term failures caused by chemical incompatibilty --- not pretty, not fun. $.02

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Ken Cierp

http://www.kennethmichaelguitars.com/

That wood will bend at all (especially tight venetian curves) remains an amazing thing to me. SSII. Never had an issue.

-Mike

Couple of things. I probably have one of the tightest venetians out there. So here goes.

lay out a sheet of aluminum foil
prepare two pieces of craft paper the full width and length of the side
soak the craft paper and lay it out lined up with one edge of the foil-- be sure to smooth it out
wet the side thoroughly
align the side on the craft paper
put another soaked piece of craft paper on top and smooth it out
fold the foil over and trim it to the ends and along its long side
use a razor knife to cut open the folded side to allow steam to escape
let it sit 1 hour
put it in your bender and heat it up for five minutes
set the waist, then the cutaway then the lower bout
with the cutaway do a 1/4 turn every 10 seconds or so -- you'll have to learn how your cutaway behaves with bends

I have a pair of springs that pulls the cutaway arm toward the waist so it maintains contact on the horn as it is pressed. My sandwich is spring steel, silicone blanket, wood wrapped in foil with craft paper.

I have had some sides that just won't bend-no how, no way, ain't happening they just wont!

I have had it happen a few times with brazilian rosewood (ouch), curly maple and a few others.
I move on to another set of the same wood and it bends like butter.
No rhyme or reason

That's why they call it wood......

Sorry?

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

So when does this bender arrive so I can be in to sign for it?

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.

So I tried 3 test pieces of this side which cracked, one soaked in water, one in 70/30 fabric conditioner, one in SSII, 20 minutes each.
Then took them to the hot iron - not one of them bent. At all!
Looks like it may have been "over-cooked" in the bender prior to attempting the cutaway, so I'll try another set from scratch when my new bending iron https://www.luthiersbench.co.uk/bending-irons arrives, just using the iron.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.