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ctviolin
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Joined: 07 May 2009
Posts: 961
Location: Roswell
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 Posted: Mon Aug 26, 2013 11:08 am Post subject: |
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| Michael Darnton wrote: | | Anyone mind if I change the name of this thread to "Cold Bending of Ribs", edit it a bit to reflect that, and make it sticky? |
I wouldn't mind at all - please, go ahead and change it.
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DonLeister
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Joined: 29 Mar 2007
Posts: 383
Location: Richmond, VA
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| Posted: Wed Aug 28, 2013 7:31 am Post subject: |
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I don't mind the editing and making it a new thread.
I should make it clear, in case it isn't, that I have to use my bending iron with considerable heat to make the ribs conform to the form.
Craig, I didn't realize until just now, are you bending your ribs without heat?
I just read the SCAVM article and it describes using an iron. |
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ctviolin
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Joined: 07 May 2009
Posts: 961
Location: Roswell
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| Posted: Wed Aug 28, 2013 9:48 am Post subject: |
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| DonLeister wrote: | I don't mind the editing and making it a new thread.
I should make it clear, in case it isn't, that I have to use my bending iron with considerable heat to make the ribs conform to the form.
Craig, I didn't realize until just now, are you bending your ribs without heat?
I just read the SCAVM article and it describes using an iron. |
Sorry that I didn't answer this sooner.
You're talking about the forms that I use to wet bend the ribs right? yes - no heat is used in that process. At least that's the way I learned, and the way I bend with the forms.
The ribs are bent with pressure and water only. The plastic I put between the upper and lower bout ribs - is that so I can bend two ribs to the correct form at one time. If I don't use a strip of plastic between them, the ribs tend to want to stick or bind a bit, one to the other. Otherwise, they could (or perhaps should) be bent separately, one at a time.
I'm going to bend the two C bout ribs, which are bent separately, and show that being done.
Please - ask away - to me this is an interesting process to do and to share, and I'm more that happy to answer any questions about it.
I'm also going to add a brief discussion about what I would consider the the weaker aspects of the process are, because there are some areas where a bending iron is really helpful.
Not strictly necessary, but helpful.
In particular, with people who like to use thicker and/or heavily figured ribs - I think that the cc bouts, in any case, can be formed much easier with the help of an iron... because the bends are much more "compact" or "curved" than the upper or lower bout ribs are.
Oh well - that's what I've found to be the case. Other opinions may vary on the different aspects of cold bending. I guess it would depend on how much you (meaning anyone) lean towards this as a primary method.
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byacey
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Joined: 29 Mar 2008
Posts: 105
Location: Edmonton, Alberta
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| Posted: Wed Jul 23, 2014 9:37 pm Post subject: Re: Ok you guy`s |
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| ctviolin wrote: |
First I wet them through, then I put a scrap of plastic in between them, so they do not grab one another and are able to slide past one another, thern I put them in the form, and slowly tighten the tight part of the curve that is where the block is, down, and put clamps on the large curve (which would bend around the mold fairly easily anyway), but what the heck, might as well get them curved now.
Then I let them dry in the mold for a day or two, or until I'm ready for them. Usually I'll put them outside in the New Mexico sun to dry... I believe that being outside helps the wood somehow - perhaps it simply helps things dry out completely.
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My mentor taught me something very similar.
He would throw the cut rib stock into a pan of boiling water for about five minutes, and then quickly pull them out with tongs and bend them on the forms. We used a stainless steel sheet metal backing, and clamp the ribs in the forms between the form and the backing. Then he would toss the whole thing into a 200F oven for an hour or so. The ribs had very little spring-back if any, after removed from the forms.
I mostly use a bending iron now, but for really highly figured rib stock, the hot water method works better.
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John Cadd
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Joined: 23 Jul 2009
Posts: 1344
Location: Hoylake
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| Posted: Wed Apr 09, 2025 5:45 pm Post subject: Cold bending ribs. |
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This topic may have been caused by using the wrong methods . None of the pictures worked for me btw.
The standard flexible brass strap is not necessary either .
My method today is a change from what I used to do . I don`t have the heater on maximum .About 75% avoids burns . The sharpest bend is the join at the centre bout .For the longest pieces allow about an inch spare to hold onto .That will be cut off . I use cold water brushed on the one side against the heater.Just a few inches directly where I want it to bend. I dont`t lay the wood along a wide area .Mostly I use the end of the aluminium heater block. I don`t keep the wood inn contact for long . The action is to rock the rib against the heater end. As that area dries ,I wet it again and continue in the same area. Mostly my forefingers control the rocking about two inches from the contact point. Very little pressure is needed . The less the better . Just enough to keep it in position . Just avoid trying to physically push it into shape . Keep checking the outline curve against the diagram or whatever shape you use. That produces a stable bend without any scorching or splitting . Any moisture left can be removed by gently brushing the rib against the heater .If you leave any moisture in place it will continue by itself to alter the corect shape again .
Doing the rocking action gently is not difficult.The brass strap is not needed . Do the rocking continuously . Use a minimum of water . |
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John Cadd
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Joined: 23 Jul 2009
Posts: 1344
Location: Hoylake
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| Posted: Sun Jun 08, 2025 10:21 am Post subject: cold bending ribs |
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The problem with a heated bender is the temperature of the metal part. If steam was the only thing used it would avoid scorching the wood . There must be a limit to how much highly figured wood will take sharp bends without turning black on a heater .Cutting the wood thinner gets you a bit closer .But that also makes scorching a bigger hazard .Doing the bending in stages with a resting period may be useful .
I have not tried the steamer jet I used to open the backs of guitars. That is ideal to release Hide glue one inch at a time with no splinters at all . The steam comes out faily dry (superheated under pressure ) in a forceful jet about i mm wide . |
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MikeCooper
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Joined: 08 Nov 2023
Posts: 181
Location: USA Georgia
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| Posted: Mon Jun 23, 2025 5:48 am Post subject: |
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I use an iron pipe heated with a propane torch. Iron is such a good heat sink it's almost impossible to get it too hot. Copper pipe on the other hand gets way too hot way to quick and will burn the wood.
I use an old leather belt for a bending strap. |
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