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Stu

Posts: 1843
Joined: Jan. 30 2007
From: London (the South of it), England

cooked my sides 

First side bend on my jig and all went well.
however I gave one of the sides a second visit as it had sprung back quite a lot.

ended up burning the two curves. waist is fine.

shape is great but the wood is brown. (worse on the inside obvs) I tried to sand out but not very successfully

I didnt go too hot.

The only things i can think that may have caused it are
1. I didnt spray enough water on
2. I used some sealand on the jig when i made it. could that have heated up?

will try to add pics
  REPORT THIS POST AS INAPPROPRIATE |  Date Oct. 21 2020 21:00:30
 
ernandez R

Posts: 351
Joined: Mar. 25 2019
From: Alaska USA

RE: cooked my sides (in reply to Stu

Foto of the jig, heating element, and sides.

A short discreption of your process, dwell times etc too.

I cooked a few here and there on the pipe but mostly on the inside of the upper bought.

I've sence made up a side bender using a touch of Anders here and a bit of Paublo R. there, 250wt IR bulbs... So far no smoke. I always told my minions in the shop: this is not a wood burning class ;)

I did drill a few holes in the side bender to slide in a couple meat thermometers to get an idea of the temps, not exact but more of a baseline to use from one cook to the next.

I keep notes also and keep them with the bending jig.

Forgot to add, I wet the wood as required and then wrap with parchment paper stollen from the Boss's bakery whilst her back is turned ;) I've had the brown paper brown just a little more. I listen for the sizzle and while keeping notes on the time which I have sence used to repeat with successes.

HR

_____________________________

I prefer my flamenco guitar spicy,
doesn't have to be fast,
should have some meat on the bones,
can be raw or well done,
as long as it doesn't sound like it's turning green on an elevator floor.

www.instagram.com/threeriversguitars
  REPORT THIS POST AS INAPPROPRIATE |  Date Oct. 22 2020 2:54:38
 
Stu

Posts: 1843
Joined: Jan. 30 2007
From: London (the South of it), England

RE: cooked my sides (in reply to ernandez R

Hey!

Yeah my jig and process is exactly the same as pablos. with all relevant pieces. blanket, metal sheets etc

I have a keenovo heat blanket with digital timer and temp guage.

I've had smoke on every bend. sides and purfling.
(I thought the initial purfling/binding bend was just the blanlets first cobwebs being blown out.) then thought some was steam??


Perhaps I need to read the temperature manually to make sure things arent off on the digi one.

I will try some photos but I find the photo process on here tedious to say the least.
resizing etc
  REPORT THIS POST AS INAPPROPRIATE |  Date Oct. 22 2020 9:55:00
 
estebanana

Posts: 7999
Joined: Oct. 16 2009
 

RE: cooked my sides (in reply to Stu

If you have smoke on bending ribs, probably too hot.

_____________________________

https://www.stephenfaulkguitars.com
  REPORT THIS POST AS INAPPROPRIATE |  Date Oct. 22 2020 15:41:58
 
JasonM

Posts: 1565
Joined: Dec. 8 2005
From: Baltimore

RE: cooked my sides (in reply to Stu

I burnt one of mine, the one I didn’t bother wrapping in foil. How much meat do you have on your ribs? Could you card scrape it the burned wood out? That’s what I did with mine and a LOT of sanding.
  REPORT THIS POST AS INAPPROPRIATE |  Date Oct. 22 2020 16:26:01
 
RobF

Posts: 947
Joined: Aug. 24 2017
 

RE: cooked my sides (in reply to Stu

Hi Stu. Pictures really would help, or a more detailed description of your setup and what you did, also what type of wood you were bending.

If it was cypress, it can stain from the water/steam when the wet wood is heated. Basically, resins mix with the water and burn and then settle back onto the wood when the water evaporates. The stain will be dark brown and can look like a burn, but it’s really a stain. This generally can be sanded out without too much effort. Of course, it can also be a burn, but even if so, it often won’t go too deep and can still be sanded out.

That you cooked the bouts instead of the waist makes me think you might have made a sandwich out of the spring steel, blanket, and side and then held it firm at each end with clothespins or small clamps to be able to put it all into the form without stuff moving around too much. If you then turned on the blanket without releasing the ends, the bouts would be cooking away while the waist was being clamped down. The solution to that is to start clamping the waist and, once it is secure, release the end clamps on the sandwich and let the bottom spring steel and blanket portion of the sandwich fall away from the side. Once the waist is 70-80% formed, start bringing the sides into play, slowly, gently, but with some haste, and alternate completing the waist clamping with forming the bouts until the bouts are fully down. Leave the last 5% or so of the waist until last, that way the final waist clamping will pull any portion of the bouts that may have risen off the form back snug onto it.

If the sides are soaked and wrapped in foil then try lowering the heat, as well. The temperatures sometimes suggested online can be pretty high. If you’re careful, you should be able to get the whole thing done without exceeding 280-290F. Just be gentle, but also don’t linger.

Parchment can also be used instead of foil. I think the idea there is to aid evaporation. Some forms use perforated spring steel, also for that purpose. Then you can get a nice polka-dot pattern cooked into the cypress..which, of course, is muy flamenco.
  REPORT THIS POST AS INAPPROPRIATE |  Date Oct. 22 2020 16:56:46
 
RobF

Posts: 947
Joined: Aug. 24 2017
 

RE: cooked my sides (in reply to Stu

I forgot to mention, you can start bending before everything hits final temperature. If you don’t have an actual temperature readout, the sound and presence of steam will indicate when it’s passing 212F. It will sit at boiling for a bit then start going to final temp after that, fairly quickly. I generally will have a large amount of the operation completed by the time it reaches final temperature.

I use a handheld digital thermometer with thermo couple as a backup against a thermocoupled controller which operates in a closed loop with the blanket (the LMI rig). The handheld thermometer looks like a multimeter and can be found online for pretty reasonable prices, I think I paid about $25 for mine. If I see the blanket controller’s reading moving much higher than my handheld’s I shut everything down and check my setup. I do all this because I’ve cooked the odd side in the past, too, lol.

P.S. I also think it’s a good idea to practice bending sides by hand on a pipe to get a feel for how wood reacts under heat before using a bending form. Having that experience seems to give one a better sense of it when using the form.
  REPORT THIS POST AS INAPPROPRIATE |  Date Oct. 23 2020 12:34:06
 
JasonM

Posts: 1565
Joined: Dec. 8 2005
From: Baltimore

RE: cooked my sides (in reply to RobF

Roberto, what are your thoughts on soaking the sides in water before bending? I heard Maria Conde say in one of their YouTube vids that they soak them for a “while”. Maybe this is good for burn prevention. But I would be worried that the extra water would not cook off and the side would cup and distort as it fully dries. Any opinions on soaking vs spraying ?
  REPORT THIS POST AS INAPPROPRIATE |  Date Oct. 23 2020 14:50:15
 
Stu

Posts: 1843
Joined: Jan. 30 2007
From: London (the South of it), England

RE: cooked my sides (in reply to RobF

Thanks guys.

The resin coloration thing is interesting. Thanks.
Also thanks for the tips about the two bouts cooking before actually bending.

Stuff to think about.

At work now and can't resize the pictures on my phone. Will try later.

I'll also be able to see some strange light marks on there too.
Sanding hasnt really changed things.
And my initial 1.8 mm thickness is looking a lot thinner.



Images are resized automatically to a maximum width of 800px

Attachment (1)
  REPORT THIS POST AS INAPPROPRIATE |  Date Oct. 23 2020 14:58:57
 
estebanana

Posts: 7999
Joined: Oct. 16 2009
 

RE: cooked my sides (in reply to RobF

Rob,
I'm so glad your here explaining all the stuff that I've lost patience with. It's funny maybe not lost patience, but not enough time to diligently handle it.

_____________________________

https://www.stephenfaulkguitars.com
  REPORT THIS POST AS INAPPROPRIATE |  Date Oct. 23 2020 15:18:06
 
Stu

Posts: 1843
Joined: Jan. 30 2007
From: London (the South of it), England

RE: cooked my sides (in reply to Stu

Another pic.

Can't upload together



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  REPORT THIS POST AS INAPPROPRIATE |  Date Oct. 23 2020 15:21:12
 
Stu

Posts: 1843
Joined: Jan. 30 2007
From: London (the South of it), England

RE: cooked my sides (in reply to Stu

Another



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  REPORT THIS POST AS INAPPROPRIATE |  Date Oct. 23 2020 15:23:48
 
RobF

Posts: 947
Joined: Aug. 24 2017
 

RE: cooked my sides (in reply to Stu

Stu, I can almost guarantee you that that will sand out. I’ve seen a lot worse go away without too much wood loss. On your picture of the inside of the bout, I believe the large dark area is a burn, but at the edge there’s a more yellowish discolouration that is likely a stain.

Jason, I do soak my sides, generally for about five minutes, depending on the wood. I’ve used parchment, but mostly use tin foil to wrap them. Once bent, I remove the side from the foil and return it to the mold with a sandwich of one spring steel sheet on the bottom, then the blanket, then a sheet of parchment, then the bare side. I bring that up to 240F, then immediately down to 220F and let it sit for a few minutes until I feel the wood is nice and dry, then shut off the heat and let it sit for a good hour or so after that. Even doing that I’ll still get some cupping around the waist area that needs to be sanded out. Not always, but more often than not.

I started soaking because I cracked some sides when doing it with just a misting. But there are plenty of makers who swear no more than a misting is needed and some who say it can be done dry. My first teacher (who’s made over 1000 guitars) advocates soaking, while my second advocated misting. They both make great guitars, so I don’t think there’s one magic solution to this.
  REPORT THIS POST AS INAPPROPRIATE |  Date Oct. 23 2020 15:38:25
 
Stu

Posts: 1843
Joined: Jan. 30 2007
From: London (the South of it), England

RE: cooked my sides (in reply to RobF

Thanks Rob. That's encouraging. I'll have another bash with sanding.
Any idea what causes the lighter marks?
  REPORT THIS POST AS INAPPROPRIATE |  Date Oct. 23 2020 15:48:15
 
RobF

Posts: 947
Joined: Aug. 24 2017
 

RE: cooked my sides (in reply to Stu

One thing you can do is take a shaving off the edge of the side with a plane or knife and see if it gives an indication of how deep the burn is. Just a fine shaving, which will be removed anyways once the binding channel is cut. I really doubt that it goes all the way through, but that was definitely a hot spot, so there is some cause for concern.
  REPORT THIS POST AS INAPPROPRIATE |  Date Oct. 23 2020 15:58:13
 
RobF

Posts: 947
Joined: Aug. 24 2017
 

RE: cooked my sides (in reply to estebanana

quote:

It's funny maybe not lost patience, but not enough time to diligently handle it.

I, on the other hand, have an abundance of time. So much so, that I’ve started playing bass again and just bought a Fender Strat so I can perfect my Flamenco Surf schtick. I feel like Dylan in the mid-sixties....going electric, man.
  REPORT THIS POST AS INAPPROPRIATE |  Date Oct. 23 2020 16:05:02
 
Stu

Posts: 1843
Joined: Jan. 30 2007
From: London (the South of it), England

RE: cooked my sides (in reply to RobF

Cool. Thanks for that idea.
What if it has gone right through?

Is that a structural concern?
Also even if this still is discolored... Could I just stain it with conde orange when I finish?

Ps. Thanks for all your help and patience with us novice builders. Nice to know not everyone is a jaded old sod. 😉
  REPORT THIS POST AS INAPPROPRIATE |  Date Oct. 23 2020 16:13:08
 
RobF

Posts: 947
Joined: Aug. 24 2017
 

RE: cooked my sides (in reply to Stu

If the burn is extremely deep the sides should be scrapped. You can save them and repurpose the wood, however. For instance, if you were to put in a soundport you already have some prebent side material that can be laminated to the inside of the port area of the bout for strength, etc...

But, remember, some of the old guitars can have what are considered to be extremely thin sides by today’s standards, and they’ve survived.

I still think you’ll be OK, it really doesn’t look that bad. If that were me, I’d probably clean up the inside and build with it, then clean the outside up when doing the cleanup of the box after assembly. But it’s good to actually handle the wood before making such a decision, so it’s prudent to advise a full cleanup, just to be safe.
  REPORT THIS POST AS INAPPROPRIATE |  Date Oct. 23 2020 16:31:49
 
ernandez R

Posts: 351
Joined: Mar. 25 2019
From: Alaska USA

RE: cooked my sides (in reply to Stu

Stu,
Couple more notes:

The last Pauble R. video I saw had him pulling both boughts down and the waist last. Was on an Instagram post not too long ago.

About these sides, scrape or sand and use, or save them for later and when you are ready to build that 900gm 1mm thick sided Torres style lightweight.

Keep in mind the temp Sensing element of your device is not telling you how hot the whole sandwich is. Just lower the thermostat about 50-75f ( sorry for the yank units) and listen for the sizzle of the water. If your hear the water sizzling you know you are over 200f. And calibrate accordingly: it's a balance of tempature, tempeture rise rate, and dwell time.

I let mine cool down completely, then I do a second cook to set the wood but with less of a dwell time, then I leave the wood in the jig for 24 vary, vary long hours. Lutherie is teaching me patience, the main skill I lack :/

HR

_____________________________

I prefer my flamenco guitar spicy,
doesn't have to be fast,
should have some meat on the bones,
can be raw or well done,
as long as it doesn't sound like it's turning green on an elevator floor.

www.instagram.com/threeriversguitars
  REPORT THIS POST AS INAPPROPRIATE |  Date Oct. 23 2020 21:36:40
 
ernandez R

Posts: 351
Joined: Mar. 25 2019
From: Alaska USA

RE: cooked my sides (in reply to ernandez R

Ok, seems I miss remembered the Paublo R. video. Here is the link where he does the finel pressing of the waist, about 3/4" or so last.

https://www.instagram.com/p/CEH2w6hHJ9s/

One other note: I made my side bender double wide so I bend both sides at the same time. Also there is enough extra width that I can bend the bindings at the same time, my plan but hunt done it yet.

HR

_____________________________

I prefer my flamenco guitar spicy,
doesn't have to be fast,
should have some meat on the bones,
can be raw or well done,
as long as it doesn't sound like it's turning green on an elevator floor.

www.instagram.com/threeriversguitars
  REPORT THIS POST AS INAPPROPRIATE |  Date Oct. 23 2020 22:54:58
 
Stu

Posts: 1843
Joined: Jan. 30 2007
From: London (the South of it), England

RE: cooked my sides (in reply to ernandez R

quote:

Lutherie is teaching me patience, the main skill I lack :/


Haha.yes. I'm learning this too and it's nice when you accept it.
My shop time is always limited by the backdrop of young daughter and chronic illness wife.. So I used to go in for hr or two and try and do everything. And rush.And end up in a mess of tools n wood. And I hated it. I know have found peace in setting myself little goals. achievable in those sorts bursts of time. It's much more calming and productive! Remind myself there's always tomorrow! Haha.

Thanks for you added thoughts on the bending. Very helpful regarding temperature etc. I'll have a look at pablos Instagram.vid.
  REPORT THIS POST AS INAPPROPRIATE |  Date Oct. 24 2020 11:14:16
 
JasonM

Posts: 1565
Joined: Dec. 8 2005
From: Baltimore

RE: cooked my sides (in reply to Stu

Rob, thanks for sharing your method and tips for bending, and the info on soaking vs misting. Idk, I misted last time I might mist again next time!

Agreed on the patience. Master patience says if I want to disrespect, them that’s fine with him. I can look forward to throwing the part in the scrap bin each and every time. He doesn’t care lol
  REPORT THIS POST AS INAPPROPRIATE |  Date Oct. 24 2020 15:11:58
 
constructordeguitarras

Posts: 1439
Joined: Jan. 29 2012
From: Seattle, Washington, USA

RE: cooked my sides (in reply to Stu

So glad I use a bending iron the old fashioned way.

Why care about the burn on the inside? I wouldn't.

_____________________________

Ethan Deutsch
www.edluthier.com
www.facebook.com/ethandeutschguitars
www.youtube.com/marioamayaflamenco
I always have flamenco guitars available for sale.
  REPORT THIS POST AS INAPPROPRIATE |  Date Oct. 25 2020 0:39:50
 
Stu

Posts: 1843
Joined: Jan. 30 2007
From: London (the South of it), England

RE: cooked my sides (in reply to constructordeguitarras

That's good to hear.
I was worrying about whether I should be worried! 😄
From a structural point of view. Being a novice I wasn't sure if this kind of thing could end up causing splits or cracks later in in the guitars life.
But sounds like it's not an issue.

Cheers
  REPORT THIS POST AS INAPPROPRIATE |  Date Oct. 25 2020 8:44:22
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