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| Homemade bender...bulbs or blanket? http://w-ww.luthiersforum.com/forum/viewtopic.php?f=10102&t=10752 |
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| Author: | jsimpson [ Mon Feb 05, 2007 5:46 am ] |
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Hey gang, budding luthier here. Recently built a Fox-style bender (a conglomeration of versions I'd seen on the web) and anxious to try my hand at it. Wondering what sort of temp is actually required...are lightbulbs really hot enough, or should I not even bother and just buy a blanket? Thanks in advance. |
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| Author: | crazymanmichael [ Mon Feb 05, 2007 5:53 am ] |
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bulbs have been working for a very long while. that being said, heating blankets are better. they get the wood up to bending temperature quicker with a more even heat, albeit at a higher cost. as for the temperature required, it varies between the different species, but as a general range, somewhere between 280f to 325f will bend most woods. |
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| Author: | peterm [ Mon Feb 05, 2007 6:05 am ] |
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blanket for sure and make sure you get a digital thermometer to keep your eye on the temps.... |
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| Author: | JJ Donohue [ Mon Feb 05, 2007 6:12 am ] |
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If you built it to accept bulbs then you can have heat on the bottom from bulbs and on top from a heat blanket. I have that combo and it works MUCH better than bulbs alone. Get the heat blanket...you'll love it! |
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| Author: | Rod True [ Mon Feb 05, 2007 6:23 am ] |
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Jon, Welcome to the OLF. Nice website and nice looking furniture you make there. I'm sure your guitars will turn out great with the attention to detail you work to. You've been given good advise already as to your question, but I can add one thing to the post. Take a look over at the 13th fret where John Mayes (another OLF member) has a great article on side bending. The article has detailed instructions regarding blankets and also a good list of bending temperatures for various common woods. |
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| Author: | Bob Long [ Mon Feb 05, 2007 7:20 am ] |
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Hi Jon, Welcome. All good advice above. I went from bending over a pipe to using a blanket, so I've never used bulbs, but the blanket has worked flawlessly for me. Bulbs vs. Blankets I think is like a lot of other choices in luthery... That is, are you going to build one guitar or many? If you think you are going to build more than one... then I'd recommend the blanket. Also Jon... you should find several other discussions about bending that are still current on this forum, and even more that are archived. Long |
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| Author: | Mattia Valente [ Mon Feb 05, 2007 9:18 am ] |
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Blanket. Seriously, break one set of moderately pricey sides because you didn't get perfectly even bending because you were using light bulbs, and you've more than paid for the price difference between bulbs and a blanket. |
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| Author: | Serge Poirier [ Mon Feb 05, 2007 9:25 am ] |
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Welcome to the OLF Jon! I'd say that with the woodworking skills that you undeniably have, you're likely to build more than one instrument and also because building instruments is really addictive so, you've been warned!  I'd advise using both the bulbs and blanket for these 2 reasons and if you can afford it, i'd buy 2 blankets.
have fun! Serge |
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| Author: | Greg [ Mon Feb 05, 2007 9:46 am ] |
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Blankets are much more expensive say $125 Compared with 3 Electrical boxes and sockets for $10-15. Add in a bathroom fan timer for $20 so you never forget to turn it off. I'm a bulb man, tho i've never tried a heating blanket. |
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| Author: | Arnt Rian [ Mon Feb 05, 2007 9:58 am ] |
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I built mine for bulbs and it worked well, never broke a side. Then I got a blanket because that's what everybody else has, and I now use it together with the bulbs. Soooo; bulbs work, blanket works better 
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| Author: | Dave Rector [ Mon Feb 05, 2007 10:22 am ] |
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I started with bulbs then switched to blankets. Seems to me that the blankets get the sides hotter a lot faster. This, at least in my case, helps prevent drying the sides out too much before bending, which can cause breakage. |
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| Author: | TonyKarol [ Mon Feb 05, 2007 10:49 am ] |
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Welcome Jon .. for a second there I thought Jessica Simpson had joined .... who'd a thunk it ... I built a lot with bulbs, but a blanket really rocks -much better heat control, more even, infinitely better if you are going to attempt to bend a cutaway in a Fox. |
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| Author: | tippie53 [ Mon Feb 05, 2007 11:27 am ] |
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I bend alot of wood and I can tell you that heating blankets are more efficient and will out do light bulbs anyday. Yes light bulbs work but you CANNOT control heat. The light bulbs work with radiant heat and you don't get the control you need to have consitent bends. Yes if you have perfect wood you may get good results but you will have a hard time getting repeatable results. Scorching and warping are often a problem with light bulbs. Heat blankets will cost up to $140 depending on the controls . Light bulbs may cost less in application but one set of wood broken , well you can add that to your cost. If you are looking for the best results and controllable results you need to consider a blanket. Now with that said you must look at what is available. Not all heat blankets are the same. I recommend a 4 watt per inch blanket. They can get to 450 degrees and are very controllable . They are also strong enough to overcome the thermal loss at the start of the bending process. Check out this link to see how I bend wood. I bend aboue 6 sets a week and have lost only 1 set in the last 3 years of bending. http://www.bluescreekguitars.com/tutorial10.php this should get you going and beninding wood with few problems. Once you get some confidence you will be bending like a pro in no time. good luck john hall blues creek guitars |
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| Author: | Joel [ Mon Feb 05, 2007 3:42 pm ] |
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Alright, I'm convinced. Where can I get a 240V blanket, for use in Oz? I'm almost finished building my light bulb powered bending form, so now is a good time to look at adding a blanket to the mix. |
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| Author: | Joel [ Mon Feb 05, 2007 8:41 pm ] |
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I've found the answer to my own question. LMI have a 220V blanket. Looks like I've got some more saving up to do... |
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| Author: | Arnt Rian [ Mon Feb 05, 2007 9:05 pm ] |
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Joel, Blues Creek has them at a better price. Right John? |
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| Author: | jsimpson [ Tue Feb 06, 2007 12:16 am ] |
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[QUOTE=Rod True]Jon, Welcome to the OLF. Thanks for the input and kind words, Rod! Overall, from the number of replies this post has gotten, it sounds like I better save my pennies for a blanket. |
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| Author: | jsimpson [ Tue Feb 06, 2007 12:19 am ] |
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[QUOTE=Bob Long]Hi Jon, Welcome. All good advice above. I went from bending over a pipe Thanks for your insight, Bob! And many thanks for recommending this forum...I'm sure it'll become invaluable as things progress (?) here! |
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| Author: | crazymanmichael [ Tue Feb 06, 2007 12:56 am ] |
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i just ordered another blanket from omega, cost $67 and some change. even if need a transformer they are not that hard to find in oz. early in my time there i got one out of an old g.e. fridge which died. the transformer was fine and worked till i sold it. be careful using light dimmers and timers as heat controllers. 5w psi blankets can use over 1000 watts and excede residential dimmer/timer capacity in the us. 2.5w psi blankets are ok on domestic units but take longer to get the wood to bending temperatures. your best bet if you can't find a suitable router speed controller is probably a variac. suitable units can be had at very good prices on ebay. |
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| Author: | jsimpson [ Tue Feb 06, 2007 4:27 am ] |
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[QUOTE=crazymanmichael]your best bet if you can't find a suitable router speed controller is probably a variac. suitable units can be had at very good prices on ebay.[/QUOTE] Thanks, Michael. For those interested, Harbor Freight currently has router speed controllers at half price...$12.50 USD! Although I don't know if it's beefy enough to handle a heating blanket, it sure works great on my drum sander. |
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| Author: | crazymanmichael [ Tue Feb 06, 2007 4:53 am ] |
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most router speed controllers will handle 15 amps so yes they will handle a blanket. that is what john supplies with his fitted out blankets, though i don't know his source. my comment re the variac was directed to the poster in australia who has to cope with 240v as standard current on the grid. that being said i use variacs to control mine as well. |
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| Author: | JohnAbercrombie [ Tue Feb 06, 2007 5:17 am ] |
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[QUOTE=crazymanmichael] be careful using light dimmers and timers as heat controllers. 5w psi blankets can use over 1000 watts and excede residential dimmer/timer capacity in the us. [/QUOTE] Good points. I put together a control for a 1050W blanket a while back, using (mostly) parts from HDepot in Canada. You are correct that the 'basic' dimmer units are only rated for 600W, but you can buy 'heavy duty' units rated at 10A 117V and they are commonly available in NA, but more expensive. A router control would be a much cheaper alternative. Pre-wired Variacs are not particularly cheap on eBay once you include the shipping cost- or they weren't when I was looking for one. Wiring up a variac requires a bit of facility with electrical work. The standard timer units (wind-up type) seem to have 10A+ ratings (check the label) so that should not be a problem. A timer is VERY handy for a blanket (or bulb) system and is a definite safety feature if you have any tendency to 'multi-task' in the shop and get sidetracked. BTW, not all blankets out there are the same. The LMI blanket I got is 36x6 in and very smooth ; the BluesCreek blanket that came through the door yesterday is 32x6 and 'lumpy' with the wire pattern quite obvious. The plugs supplied are different as well- the LMI plug mates with a computer-style power cord, the BluesCreek blanket I bought used had a standard 3-prong NA plug. No doubt both are equally effective. BTW, I wouldn't put too much faith in tables of bending temps you see- most of the recommended temps are quite close to each other and the temp will change quite a bit when the wood/slats start soaking up heat. I find the 'drop of water dancing' test and the sound of steam to be as good an indicator as any digital thermometer. John |
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| Author: | JohnAbercrombie [ Tue Feb 06, 2007 5:19 am ] |
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Michael- I'd overlooked the Australian location for the original poster- sorry about that. My comments really apply mostly to North America. John |
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