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| Author: | Andy Zimmerman [ Sun Nov 27, 2005 1:38 am ] |
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This is being asked because I am a novice and I am getting mixed info and I want to see what your bending sequences are!! Thanks Andy |
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| Author: | BruceH [ Sun Nov 27, 2005 2:12 am ] |
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Actually, none of the above. I set my waist about halfway, then the lower, then the upper, and finish it off by setting the waist all of the way. |
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| Author: | Skip Beach [ Sun Nov 27, 2005 2:48 am ] |
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I just finished bending my third set of sides & do it mostly as BruceH does - except the waist goes down about 3/4's of the way before tackling the lower bout, then the upper bout, then the waist finished tight, finally the upper & lower bouts pulled extra tight. This is on a lightbulb-powered Fox-style bender. Seems to work fine. Skip |
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| Author: | Bobc [ Sun Nov 27, 2005 3:01 am ] |
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Pretty much the same way as Bruce. Leaving the waist for last maybe a bit less than halfway puts tension on the metal slats and keeps them really tight to the wood. |
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| Author: | Dave White [ Sun Nov 27, 2005 3:05 am ] |
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Andy, I've taken to bending the waists on the hot pipe and then putting it my Fox bender when I then do the lower bout followed by the upper bout. So I've polled with your first option. |
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| Author: | Shane Neifer [ Sun Nov 27, 2005 5:25 am ] |
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I have the experience of one set but what I did (using the fox bender that I built), after lots of reading was set the waist, then back it off a bit and then set the upper bout (it is tighter and things start to cool as the bender is opened up so you need to get those tight bends done first while things are at temperature) then the lower bout then tighten everything up with the waist again. My first is a venetian cut-away and went very well! Shane |
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| Author: | KiwiCraig [ Sun Nov 27, 2005 9:10 am ] |
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Waist first,to about 3/4 down ,lower bout ,then upper bout. Finally screw down waist all the way.I leave in the fox style bender overnight and recook the next day for a few minutes,and leave it again for several hours. Still get springback ,so end up on the hot pipe to touch up (particularly the waist) I do like Shanes method and will try that next time. KiwiCraig |
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| Author: | L. Presnall [ Sun Nov 27, 2005 9:13 am ] |
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John's method of 2 blankets, sequence just like Kiwi's...but I let the side cool to the touch, then out of the bender and into the mold...no spring back issues so far...I just try to get the kerfed linings on ASAP so the side holds it's shape out of the mold. |
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| Author: | Steve Saville [ Sun Nov 27, 2005 10:18 am ] |
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Please don't get the wrong idea, I don't think there is one right way to do this. I love bending by hand. It is my favorite part of building. There is nothing like the feel of wood bending in your hands. (OK, wood breaking in your hands is pretty bad  , but I've only had that happen when practicing.) I think I would miss it if I used a bending machine.
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| Author: | tippie53 [ Sun Nov 27, 2005 1:01 pm ] |
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I have been bending wood a few years. I bend on average 6-8 sets a week. I don't think that there is many species that I hadn't bent. I have learned much and will share. You do not need 2 blankets and if you do go that route all your patterns will need to be remade to accomadate the lower blanket. If you have to bend the waist on the iron then the machine you have a poor bending system or bad pattern. There a few considerations to consider when bending. 1st is it high risk , Highly figured brash or brackish? 2nd is this well quartered with minimal runout High risk bending : Anything that I feel is high risk I will use kraft paper that is well soaked in water for a few minutes. My sequence is set the wood into the machine and align. Then with the wet paper under and over the wood and heat blanket on the top of the slats. I start the heat. The waist cawl is pulled down just to contact the setup so I can have some friendly friction to aide in the alignment and such. As the heat gets to about 250-270 I will check to see that the paper and wood are still wet. If not I will add water with a spray bottle. I try not to exceed 325 at this point At this point the probe is under the blanket at the waist so it has good contact with the blanket. I am not too worried at the wood temp at this point as I am at heat generation. Once the lower bout is fixed I recheck alignment. The probe is now set between the slats at a void area. Never allow the probe to contact the wood. This will let a mark that is impossible to remove without alot of sanding. the steel disperses the heat more evenly and without marring the wood. Never set the blanket against the wood as the wood grain will raise in the pattern of the heating element in the blanket. I will do the upper bout and agian check for moisture. I want to see steam and hear sizzling. Once the bouts are set and alignment checked again I will set the waist. Only go till the cawl contacts the pattern. This works well to pull the slats and wood onto the pattern for a good repeatablily. This whole process will take about 3-5 minutes. The heat will seem to hold nice at about 270 to 300. I like to hold this for 2-3 minutes. Let cool , then blow out the excess water and reheat to dry out. The temp will usually do a sudden spike to 350 as the wood and paper dry. Again only a few minutes is needed. I am sure some will think the 2 blanket system is needed. Maybe if you have a low wattage blanket but I use at least 4 watts per inch and the blankets will go to 400 degrees. Wood can't tell how many blankets are there. Heat is heat and that is that. If you want more than one blanket I will be happy to sell you the set up but it really isn't needed. Once the sets are cool set into the mold or a drying rack to hold shape till the other side is done. Paduk and bubinga need a little more heat. I use about 25 degrees more for these 2 woods. Low Risk Wood : Low risk wood are done much in the same manner but without the paper and the 2nd heat. When I dampen the wood I spray it much in the same manner that you would in cleaning a window. In the last 3 years I have broken 3 sets. All were highly figured wood and only 1 was scrapped. The other 2 were repaired. I found the kraft paper is more friendly than foil but if you have a sysytem that works for you then use that. The beauty of this hobby is that we all build a slightly different way. That is what makes each guitar its own personality. Hope I helped john hall blues creek guitars. Rick Davis tought me the waist last and most of the people that I know that build high end guitars do it this way. Next time you bend try it this way and watch what happens as the waist pulls into the pattern. The "sandwich" will press the wood onto the pattern. This does 2 things , aside from the nice set and repeatablity , the slats help to keep side warp at bay. If you have not tried this system and you have been having trouble with the bends not matching the patter give it a try. |
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| Author: | RussellR [ Sun Nov 27, 2005 7:39 pm ] |
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Thanks John |
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| Author: | Michael Dale Payne [ Mon Nov 28, 2005 1:29 am ] |
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I can't answer the way the pole is written so here is my proceedure non- cutaway I set about 1/3 of the waist bend then bend the lower bout full, bend 1/2 the upper bout, finish the waist then finish the upper bout. This pull material around the radii of the upper and lower bouts in to the waist and makes a nice tight transition. |
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| Author: | Colin S [ Mon Nov 28, 2005 1:31 am ] |
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Waist to within 1/2" or so, the lower bout, upper bout, finish waist. I don't do cutaways, (cowardice). Colin |
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| Author: | Andy Zimmerman [ Mon Nov 28, 2005 3:57 am ] |
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Thanks for all the info Andy |
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| Author: | npalen [ Mon Nov 28, 2005 7:43 am ] |
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the steel disperses the heat more evenly and without marring the wood. John--You mention this in your post above but not sure which "steel" you're talking about. Thanks Nelson |
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| Author: | tippie53 [ Mon Nov 28, 2005 9:15 am ] |
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The steel slats will disprese the heat to the wood from the blankets very well |
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| Author: | Josh H [ Mon Nov 28, 2005 1:18 pm ] |
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It looks like I am one of the few who does all his bending by hand on a hot pipe. I am also the only person so far who does upper, lower and then waist. I will get the upper bout close to where I want it and then move to the lower bout. Once the lower is close I do the waist. Then I go back and make sure I have everything bent to where it needs to be. I clamp it in the mold and let it cool. I check it and if need be I will touch it up and let it cool again. Then it should be ready to go. Josh |
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| Author: | tippie53 [ Mon Nov 28, 2005 1:50 pm ] |
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The topic is on the bending machine and how you do the bending. I stopped the pipe years ago but do admire the art of it. I can bend a set in 3-5 minutes. It is for production more the anything. john |
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| Author: | npalen [ Tue Nov 29, 2005 2:59 am ] |
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John--Don't mean to be a pain here but wondering if you use steel slats on top and bottom of the wood? If so, how to you rewet the wood? I'm curious because I would like to stop halfway thru a tight cutaway bend, rewet the wood and then finish the bend. (without disassembling the sandwich) Thanks Nelson |
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| Author: | tippie53 [ Tue Nov 29, 2005 8:53 am ] |
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You check the wood before you start bending. Once you are doign the actual bending you keep going. Stoping and restarting is going to cause some problems. See wood is thermoplastic and when it gets hot enough to start to bend , stopping the process and restarting ins't a good thing to do. You can also spray water between the slats , the steam generated is what you are after more than anything. Steam heat will penetrate the wood faster than dryheat and the steam aids in the loosening of the wood fibers to compress and allow the bend. Wood will not stretch so you need to have the wood ready to compress. Once I turn on the blanket till I have the wood on the pattern is about 3-5 minutes tops. Once the wood is wet and to temp the actual bend time is less than 1 minute so the wood shouldn't be dry by the time I am done. Most people that have trouble with the machine often do it too slow and they over cook the wood to the point of drying it out and making it too brittle. Heat is heat and once you see that you are in the 275 range the wood is ready to go. |
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| Author: | Andy Zimmerman [ Tue Nov 29, 2005 9:59 am ] |
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John When at temp and you start the bending of the bouts, do you just pull the springs over quickly or do you slowly go around the pattern. (Using your bender) Andy |
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| Author: | Shane Neifer [ Tue Nov 29, 2005 10:41 am ] |
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LMI as a good cheap video on the process. It is poor quality but watching it gives you all you really need to know. Like they say, a picture is worth a thousand words, for me, it's the seeing that's leads to believing! Shane |
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| Author: | tippie53 [ Wed Nov 30, 2005 8:45 am ] |
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Once I see 275 I start bending. It will take about 15-20 seconds to bend the lower bout. I recheck the upper bout for moisture and then also bend taking about the same amount of time over the radius 15-20 seconds. Once the bouts are thrown I do the waist. hold the temp about 3 minutes and let it cool john hall |
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