I had the same trouble with Bubinga and scrapped two sets, it's a ich to bend and it ripples across the grain too. I tried repairing the cracks with CA but it didn't look good and it would have looked better sticking on band aids....
. Bill S.
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| Author: | sparksod [ Thu Jul 09, 2009 11:13 pm ] |
| Post subject: | Cracked Bubinga sides during bending |
I'm looking for some guidance on what to do now.... I bent some bubinga sides on a lamp bender and have a few unexpected cracks in the upper bouts of both (outside) and in the waists of both (insides). I have checked to see if I can acquire another matching set of sides for my back without success. I'm trying to get a feel for what you pros would do if this were to happen to you. Are these sides salvageable? This guitar needs to turn out as perfect as possible (not that they all don't) as I'm building it for a close friend. Thanks for any input/recommendations/advice.... Jay |
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| Author: | peterm [ Fri Jul 10, 2009 1:38 am ] |
| Post subject: | Re: Cracked Bubinga sides during bending |
Bubinga can be one of the trickiest woods to bend. Definitely would recommend SuperSoft and using a heat blanket for better temperature control. How thick are the sides? |
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| Author: | bill stewart [ Fri Jul 10, 2009 2:44 am ] |
| Post subject: | Re: Cracked Bubinga sides during bending |
I had the same trouble with Bubinga and scrapped two sets, it's a ich to bend and it ripples across the grain too. I tried repairing the cracks with CA but it didn't look good and it would have looked better sticking on band aids.... . Bill S. |
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| Author: | bluescreek [ Fri Jul 10, 2009 6:56 am ] |
| Post subject: | Re: Cracked Bubinga sides during bending |
This is where the blanket is indeed an investment. I have been using them for 8 years. The light bulb will work on nice even wood but your off fall is much higher than with a blanket. With light bulbs the heat is refractive and you can not control the heat . With the blanket you can control this variable in the process. I use a higher heat , while I don't use Super Soft I don't think it will hurt. Todd is correct in that you need more heat and get it bent fast. I will bend this in about 4 minutes on the bender. Bubinga also will have a tendency to facet at the figure so let the sides a bit heavy .095 so you have some sanding out room . Todd has a video on You Tube http://www.youtube.com/watch?v=Q7vd9wGG4LM you will find this technique very useful. There are many techniques out there to bend wood . Find the one that works for you . Most people that have bending issues are often bending too slow. Once the wood hardens , you won't get it to bend. That window is dependent on the species and the individual board . I seldom take more than 6 minutes to get the wood onto the pattern . Another point of interest is that the hold downs are there to do the bending on the press. The spring pressure is designed to bend the wood by pressing. Pulling down on the ends of the slats will often cause more cracking than anything . Good luck and have fun with this hobby. There are a lucky few that are making a living doing this and we all started at the bottom |
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| Author: | Edward Taylor [ Fri Jul 10, 2009 2:10 pm ] |
| Post subject: | Re: Cracked Bubinga sides during bending |
Yikes! I didnt realize bubinga was so tricky to bend when I just ordered a set. Did you soak it or just spray it? I am going to be using a bending iron. |
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| Author: | Steve Brown [ Fri Jul 10, 2009 5:13 pm ] |
| Post subject: | Re: Cracked Bubinga sides during bending |
I broke a set even with John's bender and blanket. I was not bending it as hot as John suggests. That's the bad news. Now for the good news: I had some very well quartered bubinga and resawed new sides with much less wild figure. This bend went well and I have an extra set of sides that you can have for free. PM me if you want them. Steve Brown |
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| Author: | sparksod [ Fri Jul 10, 2009 6:56 pm ] |
| Post subject: | Re: Cracked Bubinga sides during bending |
I soaked for ~15 minutes on both. After cracking the 1st side, I added a damp paper envelope around the second with the stainless steel slats I use every time outside that. More moisture the second time (sounds like I should have rather had less moisture)... live and learn. I appreciate all the quick responses. It has been very helpful. I think you guys are right. I took too long in bending (closer to 10 minutes in total per side), and I was thinking I didn't have enough heat after reading some other posts. I had just bent some EIR before this set using essentially the same technique and Walnut before that and they both bent like butter. I think its time to get a blanket.... Thanks for the guidance. |
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| Author: | Joe Beaver [ Sun Jul 12, 2009 1:10 am ] |
| Post subject: | Re: Cracked Bubinga sides during bending |
I'm just learning how to bend different woods. Haven't tried bubinga yet but in general it is like John says. You need to heat the wood quickly and bend it quickly. I was trying to get the wood to 300 or so and then bend. It was to late by then. Wood seems to get hot, become bendable, followed by brittle. The less oily woods seem to make the transistion quickly. Figured wood is difficult. |
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| Author: | Brock Poling [ Tue Jul 14, 2009 8:52 pm ] |
| Post subject: | Re: Cracked Bubinga sides during bending |
I just threw up my hands and walked away from Bubinga never to look back. I just can't get it to bend clean. It facets like crazy. |
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| Author: | peterm [ Tue Jul 14, 2009 8:58 pm ] |
| Post subject: | Re: Cracked Bubinga sides during bending |
Brock Poling wrote: I just threw up my hands and walked away from Bubinga never to look back. I just can't get it to bend clean. It facets like crazy. I did the same thing you did... why bother!!  But now I may give it a try with super soft. |
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| Author: | Christian Schmid [ Tue Jul 14, 2009 9:02 pm ] |
| Post subject: | Re: Cracked Bubinga sides during bending |
Brock Poling wrote: I just threw up my hands and walked away from Bubinga never to look back. I just can't get it to bend clean. It facets like crazy. Ahhh...that's why you sold all that waterfall bubinga binding at the swap meet... and me fool bought some of it  As long as I get 4 from the 10 into shape, I'll be happy...Christian |
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| Author: | old man [ Tue Jul 14, 2009 9:54 pm ] |
| Post subject: | Re: Cracked Bubinga sides during bending |
Got me worried, too. I bought the really wild set from uncle Bob. I only have the one set, so it is scary to contemplate what may happen.  The worst part is all the conflicting advice in the archives. One says soak it and one says bend it dry. One says bend at 220, the other says get it as hot as you can get it. One says bend it fast, the other says go slow and careful. At least I have four guitars ahead of it, so by then, maybe I'll screw up the courage to do it. It'll be a dread, so the curve isn't too severe.Ron |
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| Author: | SteveSmith [ Tue Jul 14, 2009 10:06 pm ] |
| Post subject: | Re: Cracked Bubinga sides during bending |
I've got a set from Uncle Bob too. I'll try it with Supersoft and if I bust the sides trying to bend it I'll use the rest for headstocks or something. 
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| Author: | Paul Burner [ Thu Nov 12, 2009 9:27 am ] |
| Post subject: | Re: Cracked Bubinga sides during bending |
I'm pulling up this thread from a few months ago because I'd like to know if any of you tried the SuperSoft II on your Bubinga sides. And if so - how did it work? I need to bend some in the not to distant future and like others, I'm concerned about cracking or faceting. Also - John Hall said in his thread to leave the sides at .095 and bend at that thickness. Is this what others of you have tried? As always - thanks! |
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| Author: | Fred Tellier [ Thu Nov 12, 2009 10:03 am ] |
| Post subject: | Re: Cracked Bubinga sides during bending |
I did a cutaway Bubinga set ( Uncle Bob ) last month with no issues. sanded to .085, Supersoft 2 overnight, heat blanket ( John Hall ) wet and wrapped in Kraft paper and bent with the same temperatures I used with EIR, but waited until it got a little warmer before starting the bend. I found it bent with the same forces as with the EIR after it was to temperature, I opened the slats and sprayed extra water into the cutaway before bending that area. I could not believe how much the supersoft affected the flex of the wood, I could flex it at least 3 times as much by hand after the overnight treatment than before. For problem woods supersoft will be my method from now on. Now I just have to figure out how to get the product in Canada without paying more for shipping than the cost of the product. I was lucky forum member PaulK from my side of the border had some that we worked out a trade on and I have enough for a few more bends. At the rate I build that will give me lots of time to get more. Fred |
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| Author: | Jim Kirby [ Thu Nov 12, 2009 3:07 pm ] |
| Post subject: | Re: Cracked Bubinga sides during bending |
Lucky here too - no problems so far, using a blanket and bender and a little more heat-up time before bending (not terribly hot compared to other bends though. No SS II either. Attachment: sides-1.JPG Attachment: sides-3.JPG
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| Author: | Flo [ Thu Nov 12, 2009 3:20 pm ] |
| Post subject: | Re: Cracked Bubinga sides during bending |
hi guys, I'd never heard about Supersoft before. I guess it's a stuff that could help softing the wood before bending. Where do you get it ? Thanks |
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| Author: | SteveSmith [ Thu Nov 12, 2009 3:28 pm ] |
| Post subject: | Re: Cracked Bubinga sides during bending |
I got mine from veenersupplies.com: http://www.veneersupplies.com/advanced_search_result.php?keywords=super-soft&image.x=0&image.y=0&image=Find |
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| Author: | Michael Dale Payne [ Thu Nov 12, 2009 4:13 pm ] |
| Post subject: | Re: Cracked Bubinga sides during bending |
Facet brakes like this are due mostly in large part to the grain run-out caused by the figure. Bubinga is notorious for this. One critical thing when dealing with hard to bend woods is to properly support the waist bend. This means the lower and upper slat of your sandwich must make constant contact with the wood through out the bend. You need a spring loaded bar pulling the lower slat into the bottom of the wood and the press caul will push the upper slat and blanket (if you use a blanket) into the upper side of the wood. When this happens properly the wood is fully supported and faceting is greatly diminished. Without a spring loaded caul or bar on the lower slat the lower slat pulls away from the wood as you start to bend. When this happen; if the stress on the waist bend exceeds the woods elasticity the wood will crack because there is room in the sandwich for it to relieve the stress by cracking. If the sandwich is drawn tight from both sides of the waist the wood is supported equally and the wood has nowhere to go thereby reducing its ability to relive the stress by cracking or faceting. All so SS2 is great stuff Spray generously by not drenchingly (not really a word)on both sides wrap in craft paper and allow the SS2 to dry off for at least one day 2-3 is better. The affects last for 5-7 days so there is no rush to get it in the bender you never want to go to the bender prior to the SS2 completely drying. The heat will cause the SS2 to stain the wood deeply if you do not allow it to dry first. I have bent many sets of bubinga with various different figure from bees-wing to near quilt figure the key is supporting the sandwich during the bending. Especially the waist or a cutaway |
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| Author: | Ken C [ Thu Nov 12, 2009 9:51 pm ] |
| Post subject: | Re: Cracked Bubinga sides during bending |
Michael, are you using a form fitting waist caul as well? Ken Michael Dale Payne wrote: Facet brakes like this are due mostly in large part to the grain run-out caused by the figure. Bubinga is notorious for this. One critical thing when dealing with hard to bend woods is to properly support the waist bend. This means the lower and upper slat of your sandwich must make constant contact with the wood through out the bend. You need a spring loaded bar pulling the lower slat into the bottom of the wood and the press caul will push the upper slat and blanket (if you use a blanket) into the upper side of the wood. When this happens properly the wood is fully supported and faceting is greatly diminished. Without a spring loaded caul or bar on the lower slat the lower slat pulls away from the wood as you start to bend. When this happen; if the stress on the waist bend exceeds the woods elasticity the wood will crack because there is room in the sandwich for it to relieve the stress by cracking. If the sandwich is drawn tight from both sides of the waist the wood is supported equally and the wood has nowhere to go thereby reducing its ability to relive the stress by cracking or faceting.
All so SS2 is great stuff Spray generously by not drenchingly (not really a word)on both sides wrap in craft paper and allow the SS2 to dry off for at least one day 2-3 is better. The affects last for 5-7 days so there is no rush to get it in the bender you never want to go to the bender prior to the SS2 completely drying. The heat will cause the SS2 to stain the wood deeply if you do not allow it to dry first. I have bent many sets of bubinga with various different figure from bees-wing to near quilt figure the key is supporting the sandwich during the bending. Especially the waist or a cutaway |
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| Author: | Steve Saville [ Thu Nov 12, 2009 10:35 pm ] |
| Post subject: | Re: Cracked Bubinga sides during bending |
Bubinga is no problem with SS2, a nice bender and with sides thinned to .070" Here is my recent bubinga. Nice figure, no cracks! Maybe I got lucky. I really like bubinga!  
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| Author: | Mike OMelia [ Fri Nov 13, 2009 12:15 am ] |
| Post subject: | Re: Cracked Bubinga sides during bending |
Bubinga is a fantabulously beautiful tone wood. Take your time. Figure in any wood presents bending problems, but as the above pics show, its worth the effort. Go with slightly thicker sides. Let the wood soak up the moisture and bend with patience. Then, sand out any facets etc. It has wonderfully small pores and is easy to size (pore fill). Mike Steve, is that lacewood binding?!? |
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| Author: | Michael Dale Payne [ Fri Nov 13, 2009 2:15 pm ] |
| Post subject: | Re: Cracked Bubinga sides during bending |
Ken C wrote: Michael, are you using a form fitting waist caul as well? Ken Michael Dale Payne wrote: Facet brakes like this are due mostly in large part to the grain run-out caused by the figure. Bubinga is notorious for this. One critical thing when dealing with hard to bend woods is to properly support the waist bend. This means the lower and upper slat of your sandwich must make constant contact with the wood through out the bend. You need a spring loaded bar pulling the lower slat into the bottom of the wood and the press caul will push the upper slat and blanket (if you use a blanket) into the upper side of the wood. When this happens properly the wood is fully supported and faceting is greatly diminished. Without a spring loaded caul or bar on the lower slat the lower slat pulls away from the wood as you start to bend. When this happen; if the stress on the waist bend exceeds the woods elasticity the wood will crack because there is room in the sandwich for it to relieve the stress by cracking. If the sandwich is drawn tight from both sides of the waist the wood is supported equally and the wood has nowhere to go thereby reducing its ability to relive the stress by cracking or faceting. All so SS2 is great stuff Spray generously by not drenchingly (not really a word)on both sides wrap in craft paper and allow the SS2 to dry off for at least one day 2-3 is better. The affects last for 5-7 days so there is no rush to get it in the bender you never want to go to the bender prior to the SS2 completely drying. The heat will cause the SS2 to stain the wood deeply if you do not allow it to dry first. I have bent many sets of bubinga with various different figure from bees-wing to near quilt figure the key is supporting the sandwich during the bending. Especially the waist or a cutaway My upper waist caul is a 1/2 round piece of 2" diameter aluminum tubing attached to my screw press. The lower spring loaded caul is a ½” wide aluminum bar located on center of the waist bend with the springs on each end to keep the bar pulled tight to the sandwich. All my forms have a relief slot in them for the bar to set in as the bend is completes. The springs are attached to the outside of the press screw tower in line with the guide slot for the upper caul. If you keep the bottom slat pulled tight to the wood at the center of the waist bend the slat will stay tight around the full bend. If the bottom slat is not pulled tight to wood at the center of the bend the lower slat can bend at a different rate causing a small gap between the wood and bottom slat. This allows the wood to relive stress by cracking. A true form fitting caul on either top or bottom does not work as well as one may think. This is especially true on the bottom because at the first of the bend the wood is not ready to take the full waist bend profile. It needs to take shape in a gradual manner. If you used a form fitting caul you would create pinch points or stress points at the edge of the caul during the early stages of bending that could lead to depressed areas in the wood. I found a simple half round upper caul equal to the smallest radii of the waist bend and a 1/2" wide bar for the lower caul works best |
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