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That looks like it is getting way too wet. How wet is the rag you have placed on the iron? I ask because it also sounds like your iron is using all its energy to boil a all that water out of the rag and not able to stay at a good temp. Try it without the rag and don't worry about the thermometer. When drops of water dance on the iron as they sizzle off, you are at a good temp. Get a spray bottle and spritz the side in the area you are trying to bend. Not dripping wet but a little more than damp. Keep the side rocking or sliding across the hot iron as the wood warms up. When it starts to relax, add some pressure to get the bend. When you see the face up side of the rib start to dry, you can spritz both sides again. This is how I do it on most woods. I can usually get into a groove on the bouts where I am chassing the wet/dry boundary down the side as I get the bend (I am always bending the part that just dried bending as I move down. Less water causes less rippling but the trade off is you have to be more careful to avoid scorching. Give it a try and see if it works for you. Eventually, we all find a slightly different path to success.

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

I agree with Bryan, too much water, I had some Zebrawood do that when I first starting building. This was before I joined the OLF. I had watched a video of someone soaking the sides overnight before bending. They turned out just like what you have there. Sorry that happened, what a bummer. Kudos to you for pushing on with the bending on a pipe. I'm still working on that skill as well.

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I agree on the water causing ripples issue; too much water can make the wood go wonky. But, I still express concern over the inability to keep the temperature high enough and steady enough.

There’s a lot to be said for a blanket and a bending form if you are excessively frustrated with the bending iron. Lots of folks never use a bending iron. But, just so it doesn’t remain a permanent bad experience, know that it can be really satisfying to use a bending iron and have things go well.

Thanks for the help and support, guys. I'm not ready to give up on the iron yet!

I've been working on my "dilemma" all afternoon. First thing I did was dismantle the bending iron to take a look under the hood. I took a multimeter to the controller and found nothing out of whack. Seemed to work fine. Next was to take cutoffs from #1 and thin it to .080-.085 while the iron was heating up. It was maybe 20-25 minutes and water was dancing off the iron.

I spritzed one side and took it straight to the iron. No steaming but after a couple of minutes it began to soften. I rocked it back and forth and when it hit about 30 degrees it stiffened up. When I went to spritz it, I saw some of the wood had bulged. I kept going.. Once it hit 45 degrees I checked it again. The wood was now scorched where the bulges were.

Next I tried a dry run. A few seconds of contact and the wood cupped, pulling the center of the slat up off the iron. I could also feel it cup further down, 2-3 inches from the iron. This wood doesn't like heat or water.

I've had that iron for about 5 years. I've bent curly maple and curly sapele and a few other woods with success. The woods were thinner though, not for guitar sides. But this sipo isn't liking me (if that's what it is). I'm terribly allergic to it and have to wrap myself hermetically when working with it. When I bought it, I needed countertop edging and since it was so cheap, I picked up a couple more boards. The boards were 6/4 x 12 x 9' and I only used one for the countertop. I thought it would be perfect for the first acoustic. Milling it up went pretty well. The back glued up fine. Then came the bending...

Maybe it's the wood. Maybe it's me. Maybe I need to mill a walnut slab I have and see how that goes.

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Julie Moriarty
http://JulimorCreations.com

First, Jules, this looks like a bad test for reasons of un-even grain, and grain running out the rib instead of following the length of the rib. For sides, (especially for a beginner), it's good to have straight running grain and also would be good to pre-cut the shape of the sides (rough) to eliminate having to bend a full 5" of rib. With that, a stainless slat on top of the side to aid in bending and help keep the moisture in the wood will help. So will Super Soft 2. Quarter sawn sides are a big help at the beginning.
That test looks unreal. I never had that much of a problem boiling the sides. A better photo would be to hold a straight edge to show us how deformed it is, though.
If this is going to be your 1 off, personal guitar with no others in the future, mahogany is not the best bending wood (especially with ribbon grain), and you might consider another wood.
Still, if you plan on building more than a few, the John Hall type bending jig and heat blankets might just be a better way to go. The bending jig could also be hand built if you are strapped for cash. It's not a very complex build. Rather than continue with a system that is seemingly not working for you might lead you to think about a different system completely.
Whatever you do, be thoughtful and don't give up. This kind of thing is just not easy as it seems as you have found out. However, once you have figured it out, you will look back at it all with amazement and realize how "easy" it is after you know the tricks...

Given everything you outlined above, Julie, if I were you, I would switch to different pieces of wood (i.e., different species, with all the characteristics Haans mentioned), even if that means using a different back to match. Life’s too short to spend it wrestling with a little plank of wood that won’t cooperate.

I own both a regular bending iron (like yours) and a Fox bender I built myself, for blanket use. I prefer using the bending iron, but I usually bend easy woods like East Indian rosewood, and I like boring, quartersawn, straight grain wood. If I were to work with wood that was more challenging, I would not hesitate to switch to the Fox bender.

After reading everything here, several times, and reading the chapters on bending in both the Cumpiano and Kinkade books, also several times, where I am at now is only regarding the movement and swelling of the sipo once water is introduced. I can't see anything I did on the shaped piece that is patently wrong, except maybe my choice of wood.

However, I did some research to see if sipo has ever been used in acoustic guitars and read that Martin now uses sipo on their 15 series guitars. So it can be done.

But I'm not even sure what I have is sipo. Sipo, like sapele, is in the entandrophragma family. I've worked a lot with sapele and know it just by smell. It's smell is very different than the sipo I have in the shop. But by weight, what I have falls in line with where it should be, compared to sapele.

Whatever the case, I've have three more sets of sides of sipo planed and sanded to .085". Lots to at least experiment with. I just need to know if I can smooth out the undulations after shaping. Time will tell...

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Julie Moriarty
http://JulimorCreations.com

I sanded the side from the earlier picture to see how it turned out. I tried to get the sunlight to rake off it like the first pic but this was the best I could do.


I'm going to hit it with lacquer and see what shows through. Then I'll have some idea if this wood is usable. I've got 3 more sets of sipo sides already planed and sanded to .085" so I'm going to try to make this work.

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Julie Moriarty
http://JulimorCreations.com

I sprayed a few light coats of lacquer. After that dried, I sanded with 320 and sprayed one more coat.




It's not all that bad. Probably good enough for that first guitar. Since I intended to name it "El Kabong!", might as well proceed.

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Julie Moriarty
http://JulimorCreations.com

Yesterday I bent two book-matched sides. I learned sipo does not like a lot of moisture.

By the time I got to the second half, I developed a technique for sipo (at least the sipo I have):

1. Use a wet rag on the iron to bend the waist to keep the wood wet and prevent scorching. As the water evaporates, move the rag to keep steaming the wood.
2. Spritz the inside of the piece and begin bending the upper bout. As the steaming stops, spritz again. As you progress, check the progress against a template.
3. Repeat #2 on the lower bout.
4. Once the piece is properly bent, put it in a form and let it sit, under pressure, overnight.

The first half I did yesterday took me a little over an hour, mostly because I was stingy with spritzing. The second half took about 20 minutes. I didn't notice any rippling.

What looks like scorching is a stain from spring steel. I used it only for the waist on the second half as it seemed to speed things up.



For the end blocks, I'm getting mixed messages. Cumpiano says to orient the grain the same as the neck, so you'd see end grain when looking at the face of the block. Kinkead shows the grain running top to bottom of the case, so you'd see long grain on the face. Who is right? It doesn't seem like it would even matter.

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Julie Moriarty
http://JulimorCreations.com

I'm glad you tamed the beast. Bending on the pipe is just one of those things you have to put in some time and effort to nail down what works for you. Usually, once you figure it out you are golden.

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

"Who is right? It doesn't seem like it would even matter."

I use multi-ply plywood and face it with mahogany.

For just end blocks or both neck and end?

I put the mahogany grain going the same as the sides and use mahogany on both the neck and end block. I'm tempted to go the plywood route on the end blocks and your solution of putting a mahogany face on it might be a good compromise. Of course, considering the fact you can't see the end block I guess it doesn't matter to anyone but a repair tech or an enthusiast player putting a camera down in there.

Edited to add: Nice work on the pipe, Jules!

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The only thing about the head and tail blocks, regarding grain orientation, that I can see mattering, is where the neck and headblock join. As long as the grain is orientated the same, you shouldn't have any issues. The wood will expand and contract the same, as long as the woods are the same.

This is just an average of wood movement. Some wood can move more than this.


If you glued the tangential of the neck to the radial of the block, there could be some separation that would cause the glue to fail. Cumpiano uses tapered pins - no glue - to connect the neck to the body, so this wouldn't be an issue, but he still goes so far as to recommend orientating the head block so end grain shows on the face. Whether it's end or face grain on the face of the block, as long as the tangential (or radial) faces are running the same, it shouldn't matter.

Anyway, I orientated both the head and tail blocks with the neck but chose to expose the face of the wood rather than the end grain. The acoustic guitar has all kinds of places where grain orientation is 90 degrees but as long as the wood is thin, it doesn't matter so much. But with the thicker wood of the neck and heel, I figured it's best to keep the grain going in the same direction.

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Julie Moriarty
http://JulimorCreations.com

If you haven't already, go to Cumpiano's website. He has made several clarifications and changes to his book. He no longer recommends the tapered pins for the neck joint, showing instead one of the many different ways to approach a bolt on neck joint. Those tapered pins are just too cumbersome to be practical (especially for beginners) when there are more modern ways of attaching the neck.

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Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

John Hall has recommended Windex as a spray to help in bending. He mentioned that they used to use ammonia. Has anyone tried this? I just used it on a set of sides of .08" Alaskan Yellow Cedar and they bent very nicely.

Ed

Julie—

A few thoughts for you about the orientation of the grain for the structural blocks inside the body of the guitar:

1. I suspect that the ways in which guitar builders and general woodworkers talk about grain orientation leads to communication failures a fair amount of the time, so I will try to talk about it in a slightly different way, hopefully to aid clarity.

2. When it comes to either of the structural blocks inside the body of the guitar, there are always three surfaces to which the blocks are glued: the sides, the top, and the back. This leaves three surfaces of each block exposed to the inside of the guitar.

3. I think many builders (and I am among them) prefer to orient the blocks such that all three of the glued surfaces of each block are something other than end grain. Some builders are OK with orienting one or both blocks such that the top and back are glued to the end grain of the block. Nobody that I know of orients either block such that the sides are glued to the end grain of the block.

4. Unless you are using a glued butt joint for the neck/body joint (and practically nobody thinks this is a good idea any more), the expansion differential between the neck wood and anything on the body is not something you need to worry about in terms of messing with the integrity of the glue in that joint. If the neck is bolted on, that’s obvious. But even with a dovetail, the integrity of that joint is not up to the glue; it is up to how well the joint fits together. The glue in a sliding tapered blind dovetail joint (I think that’s the right woodworking term for the traditional neck/body joint on a guitar) hardly does anything. The joint itself is what does the work.

If it wasn't for all the great information I've been getting here, this build would be like walking through a dark cave hoping I wouldn't get scraped and bruised too badly. Thank you again for all the help!

Bryan, that tapered pin idea looked good but everything you have to do to get it right, and the fact the only time I've seen it was in a 30 year old book, convinced me to follow more current methods. Still debating between the dovetail and the mortise and tenon though.

Don, what you say makes sense with guitars because most of the woods being glued together are pretty thin. If making a table with bread board ends (90 degrees from the table boards), you have to allow for expansion by slotting the mortises wider than the tenons and pinning them with dowels. The dowels sit in elongated holes to also allow for expansion. But in a guitar, there just isn't that kind of mass. Kinda like why it's okay to alternately glue laminates in plywood at 90 degrees.

I think I'm ready to glue in the kerfing but I'm having some reservations. Before I glued up the blocks to the sides, I made some minor alterations to the bends to take any stress out. In doing so I slightly relocated the waist. To get it to match the form perfectly I have to clamp it to the form. I'm thinking I might need to get the waist back in place before moving ahead. I'm concerned any pressure exerted on the plates by the sides might deform the plates.

Is this concern legitimate?

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Julie Moriarty
http://JulimorCreations.com

Julie--

Just so I don't mislead you to having a false sense of security, expansion and contraction is definitely something to worry about with acoustic guitars; however, the neck/body joint is not the place to worry about it. The main place to worry about it is with the top, and to a slightly lesser degree, the back. Brace a spruce top in high relative humidity, then allow the guitar to later live in a low relative humidity environment, and top cracks are likely to happen. That's why you see all sorts of chatter here on the OLF about relative humidity control, and keeping it in the low 40% range all the time during building. I figure you already know that, but better safe than sorry when sorry means a crack in the top.

Oh, and on the sides fitting in the form question: As long as you can get the sides to fit the form with finger pressure, it will be fine. That small amount of stress is not a big deal. Now, if you really have to wrestle the sides into their proper spot, that's not good, and could warrant some bending iron adjustment before gluing it all together.

I did not know or even think about the top cracking, Don. Thank you again! My brain has not yet become attuned to the intricacies of guitar wood in a given environment. In the woodworking I've done, I've never fussed over wood movement, just followed standard practices.

A few years ago I moved from Chicago, where humidity fluctuates greatly, to Florida, where it stays fairly high year around. I took three of the electric guitars I built up north with me in that move. It's been three years now and they are all still doing pretty well in this humid environment. And we have the house open a lot. But a solid body guitar isn't anywhere near as delicate as an acoustic. Thank you for the heads up.

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Julie Moriarty
http://JulimorCreations.com

Not sure you can see the deviation clearly but this is where I am right now with the shape.


I installed the top kerfing while in the mold. Not sure if that makes any real difference but I don't get much back pressure when I fit the sides to the top.

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Julie Moriarty
http://JulimorCreations.com

Julie—

Going from “built dry” to “living wet” is not as big a problem as going from “built wet” to “living dry”. When a guitar built in a dry environment goes to live in a wet environment, it just swells. That might affect action, but it doesn’t usually lead to cracks. The opposite, however, is a very real thing. Guitars that are built in a wet environment, and then go to live in a dry environment, are the ones at risk.

For your electrics, it doesn’t surprise me that they are fine. Acoustics making that move would have been mostly fine, too. But just keep an eye out for the acoustic you are building now. Since you are building it in a high humidity state in the summer, it will probably need to be humidified (via a soundhole humidifier) if you ever take it somewhere north in the winter, or else top cracks are a real threat.

On the body shape: it’s probably fine. Now that it is out of the mold, there are spots on the treble side (assuming a right handed guitar), in the upper bout near the block, and the wide part of the lower bout, that you would want to be closer to the planned body shape. But if it nudges back to the right shape when placed in the mold without too much pushing, it will be fine.

I've done the retire to Florida thing, Don, and I haven't yet had an itch to go back to those Chicago winters. The only way I see this (or any future guitar) end up north is if someone up north gets it after I've moved to the big workshop in the sky.

I was in the shop a few minutes ago working the kerfing to accommodate the X braces. I'm not completely happy with the quality of the work but I figured I only have about $40 in material invested here so far and I am learning along the way. So even if this ends up being my El Kabong, I will have honed some skills and learned a few lessons.

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Julie Moriarty
http://JulimorCreations.com

Julie, make sure to taper the end block top and bottom to the width of the the kerfing. Can get pretty ugly looking later if you don't...