Fire Extinguisher, do not forget that before you get going, and know how to use it! Heat blankets or Blow torch, you are playing with fire. I bend my sides outside with the heat blanket. Fear the flame, or at least respect it.
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| Side bending set up http://luthiersforum.com/forum/viewtopic.php?f=10101&t=30621 |
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| Author: | Goodin [ Fri Jan 07, 2011 3:34 pm ] |
| Post subject: | Side bending set up |
I am ready to bend sides on #1 and #2, and I am trying to get everything I need to do so. My luthier friend suggested I get 1.5" dia. pipe for mandolins and 4" dia. for guitars. Using a blowtorch centered at one end of the pipe and a tin can lid at the other end custom fitted with holes to let air pass through but hold heat in. I am having a hard time finding 4" pipe and Im not sure the material I should use. I have been told galvanized is not suitable because it emits harmful vapors when heated. Copper is expensive and may bend too easy. I was suggested to get aluminum in 4" at an electrical supply house but they only sells it in 10' lengths and it would be way expensive. So, I got a 2 3/8" diameter black iron pipe to try out. It was only a few bucks at the hardware store. Any other suggestions for what material pipe to use, where to obtain the pipe? Any other suggested methods for bending sides? thanks for any help! |
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| Author: | Dave Stewart [ Fri Jan 07, 2011 3:51 pm ] |
| Post subject: | Re: Side bending set up |
I made one years ago using black pipe. Worked ok. (Be careful where you stand!) On a more recent one, heated with an electric BBQ starter, I got a small piece of seamless 4" alum. pipe from "Metal Supermarket" (if you have them in your area). |
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| Author: | Darrel Friesen [ Fri Jan 07, 2011 4:00 pm ] |
| Post subject: | Re: Side bending set up |
Goodin wrote: I am ready to bend sides on #1 and #2, and I am trying to get everything I need to do so. My luthier friend suggested I get 1.5" dia. pipe for mandolins and 4" dia. for guitars. Using a blowtorch centered at one end of the pipe and a tin can lid at the other end custom fitted with holes to let air pass through but hold heat in. I am having a hard time finding 4" pipe and Im not sure the material I should use. I have been told galvanized is not suitable because it emits harmful vapors when heated. Copper is expensive and may bend too easy. I was suggested to get aluminum in 4" at an electrical supply house but they only sells it in 10' lengths and it would be way expensive. So, I got a 2 3/8" diameter black iron pipe to try out. It was only a few bucks at the hardware store. Any other suggestions for what material pipe to use, where to obtain the pipe? Any other suggested methods for bending sides? thanks for any help! 4" pipe is fine if you have the means to bend into an oval or teardrop shape, otherwise it's too big for most waist bends and certainly for cut-aways. I use a piece of 4" sch 40 A106 that I scavenged from an oilfield site. I bent it into a teardrop shape using an oxy acetylene torch, a vise, button jack and various persuasion tools. It works for most everything except cut-aways. A 300 watt light bulb and dimmer provides the heat source. For cut-aways, I use an 1 1/2" ID galvanized piece of the same grade pipe with a 300 watt halogen light for heat. Galvanized pipe is fine at the heat required for bending as the zinc won't melt until you're close to 1000 degrees F and vaporizes at 1650 F. If you're using a torch for heat, it's probably safer for you to stick to black pipe or aluminum unless you closely monitor your temperature. I use a magnetic 500F surface thermometer to monitor things. Plumbing supply stores will have black sch. 40 pipe up to 2" ID normally. For 4", a scrap dealer is usually a good source. Carbon steel, aluminum. stainless, copper, inconel, hastelloy, titanium. All will work fine, but carbon steel will be the cheapest generally. There are many ways to skin this cat. Search this site for "pipe bender". |
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| Author: | WaddyThomson [ Fri Jan 07, 2011 4:05 pm ] |
| Post subject: | Re: Side bending set up |
I used 3" truck tail pipe, doubled up, by splitting a section and squeezing it inside the other section. Electric Charcoal starter for heat. Grill Thermometer for temp. HF Router speed control for temp control. Works great. Attachment: P1030715 (Large).JPG
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| Author: | Bill Bounds [ Fri Jan 07, 2011 5:42 pm ] |
| Post subject: | Re: Side bending set up |
Hey There: I get pipe from scrap yards, welding shops. the welding shop can weld a mount bracket on your selection for a few bucks. A word of safty added. if you use the torch for heat, and have a small shop. use a CO monitor, you can kill yourself by running a torch in a small enclosed space for an extended amount of time. I've set off a monitor in the next room before. Bill |
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| Author: | Michael Smith [ Sat Jan 08, 2011 3:59 am ] |
| Post subject: | Re: Side bending set up |
I think with the black iron you might get some staining so you may want to wrap some aluminum flashing around it. I don't like bending on a pipe and love my warm heating blanket. |
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| Author: | Michael Smith [ Sat Jan 08, 2011 4:00 am ] |
| Post subject: | Re: Side bending set up |
I think with the black iron you might get some staining so you may want to wrap some aluminum flashing around it. I don't like bending on a pipe and lover my warm cozy heading blanket. |
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| Author: | Goodin [ Sat Jan 08, 2011 11:10 am ] |
| Post subject: | Re: Side bending set up |
thanks guys. these are great ideas. i have a large basement shop with windows so i should be ok, but i will get a CO monitor for added safety. I can't build guitars too well if I kill myself! Bill, what kind of fuel do you use? I got propane because it was the cheapest, but they also had oxygen for much more cost, and one other kind I cant remember right in between in cost. Is any one safer than the other, or more suited for our needs? |
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| Author: | Quine [ Mon Jan 10, 2011 2:06 pm ] |
| Post subject: | Re: Side bending set up |
I use a 1.5" pipe and a heat gun for everything....guitars and ukuleles anyway. I have a 3" pipe but I'm just used to the smaller one I guess. I haven't found any problems using the small diameter for large radii. |
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| Author: | Ian Cunningham [ Mon Jan 10, 2011 5:06 pm ] |
| Post subject: | Re: Side bending set up |
I love Quine's idea, just get a hand held heating device and stick it where you need. My own pipe is 2" black iron. I can't see any problem using it for a guitar if I change my mounting technique (too close to the base). Just got to be patient and way more picky. |
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| Author: | Goodin [ Mon Jan 10, 2011 9:36 pm ] |
| Post subject: | Re: Side bending set up |
Hi Ian - did you find it necessary to wrap aluminum flashing or something similar around the black iron pipe to prevent marks on the sides? Here is my set up. I just finished rigging it up this evening... |
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| Author: | Frei [ Tue Jan 11, 2011 12:51 am ] |
| Post subject: | Re: Side bending set up |
Fire Extinguisher, do not forget that before you get going, and know how to use it! Heat blankets or Blow torch, you are playing with fire. I bend my sides outside with the heat blanket. Fear the flame, or at least respect it.
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| Author: | TomDl [ Tue Jan 11, 2011 4:26 am ] |
| Post subject: | Re: Side bending set up |
The gasses you are most likely to come across are propane, Mapp, and O2. O2 is not a fuel gas, it won't burn, but it will sure help things along! It is run with any of the fuel gasses to dramatically increase heat to welding or cutting temps, and therefore is not needed here. Mapp smells bad is dirtier, but allows hotter temps with aspirated burners, so it is useful for situations where propane is borderline. Propane is the relatively safer gas, though not really indoors safe ATMO. But it is your best bet here. |
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| Author: | Corky Long [ Tue Jan 11, 2011 9:25 am ] |
| Post subject: | Re: Side bending set up |
Goodin wrote: Hi Ian - did you find it necessary to wrap aluminum flashing or something similar around the black iron pipe to prevent marks on the sides? Here is my set up. I just finished rigging it up this evening... Goodin, you might find that that setup doesn't allow you to apply the force necessary to bend. I've found that the line between too much and not enough is a fine line, but a certain amount of force is necessary to get the wood moving. At the level of force I'm exerting, I'd be afraid of those clamps 1) chewing up the table, or 2) those circular clamps (forget what they're called) snapping over time. I've never snapped a side while bending, so I don't think I'm pushing too hard. I dont have a picture, but my simple setup consists of a large table vice, which clamps two chock of scrap wood, as a cawl to hold onto a piece of plumbers 3" pipe which is in an L shape. The Mapp torch fits up inside the vertical part of the pipe, and the heat and flame bends at a right angle to provide the horizontal bending surface. Galvanized pipe and harmful vapors? Uh oh. Don't know whether I'm using galvanized pipe or not... How do I know? And how hot is too hot? |
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| Author: | Goodin [ Wed Jan 12, 2011 8:47 pm ] |
| Post subject: | Re: Side bending set up |
Corky Long wrote: Goodin wrote: Hi Ian - did you find it necessary to wrap aluminum flashing or something similar around the black iron pipe to prevent marks on the sides? Here is my set up. I just finished rigging it up this evening... Goodin, you might find that that setup doesn't allow you to apply the force necessary to bend. I've found that the line between too much and not enough is a fine line, but a certain amount of force is necessary to get the wood moving. At the level of force I'm exerting, I'd be afraid of those clamps 1) chewing up the table, or 2) those circular clamps (forget what they're called) snapping over time. I've never snapped a side while bending, so I don't think I'm pushing too hard. I dont have a picture, but my simple setup consists of a large table vice, which clamps two chock of scrap wood, as a cawl to hold onto a piece of plumbers 3" pipe which is in an L shape. The Mapp torch fits up inside the vertical part of the pipe, and the heat and flame bends at a right angle to provide the horizontal bending surface. Galvanized pipe and harmful vapors? Uh oh. Don't know whether I'm using galvanized pipe or not... How do I know? And how hot is too hot? My set up is much stronger than it appears in the pictures. I can put a good amount of weight on it and it wont budge. Besides, i thought it's not a good idea to push too hard when bending as you may break the wood? Here is a good article on heating galvanized pipe: http://blogs.popularwoodworking.com/edi ... d499b.aspx |
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| Author: | Ian Cunningham [ Thu Jan 13, 2011 8:40 am ] |
| Post subject: | Re: Side bending set up |
Goodin wrote: Hi Ian - did you find it necessary to wrap aluminum flashing or something similar around the black iron pipe to prevent marks on the sides? Here is my set up. I just finished rigging it up this evening... That's pretty much my setup! Just a propane torch and a pipe. I use the pipe bare. I haven't come across anything unusual on my sides yet so I don't think it's a problem. The only marks it makes are scorch. The lightest color wood I've used is Sapele though, so I may not be a good barometer. I always rinse my pipe before using it, too. I must agree with Corky though, even though your setup appears strong now, it will probably wear down eventually with tragic results. If one of those band clamps snaps then you might have a very hot pipe on the floor, perhaps even on your foot. Not good. Also, having bare wood contact with that pipe isn't a good idea either because the wood will burn, and that, coupled with the friction from pressing the pipe while bending will cause it to come loose. I would get some longish bolts and bolt the pipe to a workbench or workboard. My setup uses four long bolts attached to the pipe as "legs". The weight of the pipe is enough to keep it there steady, shallow holes in the workboard it rests on keep it in the same spot. While you're at it, find a way to incorporate a much bigger propane tank. I run out just about every project and can see it getting annoying when I find myself building more frequently. DEFINITELY get a good quality fire extinguisher too. |
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| Author: | Goodin [ Thu Jan 13, 2011 9:36 am ] |
| Post subject: | Re: Side bending set up |
Hey Ian - You might not be able to see it in the picture but the pipe is actually resting on two cut gutter nails and not directly on the wood. This set up is to bend sides for a dulcimer (and perhaps A body mandolins later). So the sides are only 2" thick and have gentle curves. I think this will be sufficient for my needs right now. When I start on guitars I will build a more robust set up. Do you care to post pics of your set up? |
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| Author: | Corky Long [ Fri Jan 14, 2011 1:38 pm ] |
| Post subject: | Re: Side bending set up |
Goodin wrote: Corky Long wrote: Goodin wrote: Hi Ian - did you find it necessary to wrap aluminum flashing or something similar around the black iron pipe to prevent marks on the sides? Here is my set up. I just finished rigging it up this evening... Goodin, you might find that that setup doesn't allow you to apply the force necessary to bend. I've found that the line between too much and not enough is a fine line, but a certain amount of force is necessary to get the wood moving. At the level of force I'm exerting, I'd be afraid of those clamps 1) chewing up the table, or 2) those circular clamps (forget what they're called) snapping over time. I've never snapped a side while bending, so I don't think I'm pushing too hard. I dont have a picture, but my simple setup consists of a large table vice, which clamps two chock of scrap wood, as a cawl to hold onto a piece of plumbers 3" pipe which is in an L shape. The Mapp torch fits up inside the vertical part of the pipe, and the heat and flame bends at a right angle to provide the horizontal bending surface. Galvanized pipe and harmful vapors? Uh oh. Don't know whether I'm using galvanized pipe or not... How do I know? And how hot is too hot? My set up is much stronger than it appears in the pictures. I can put a good amount of weight on it and it wont budge. Besides, i thought it's not a good idea to push too hard when bending as you may break the wood? Here is a good article on heating galvanized pipe: http://blogs.popularwoodworking.com/edi ... d499b.aspx Thanks for the article on heating the galvanized pipe. Sounds like soaking the pipe in a citric acid solution is a prudent measure if you're going to heat those pipes (as I've been doing on my last 7 builds  )
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