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Robbins Guitars Thread


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Hey guys! It certainly has been awhile. Im not sure how many will remember me but hopefully there are some and other new friends who I will be glad to meet. I started building and posting on hear a few years ago but took an extended break after atending the Galoup school of lutherie for their 2 month Journeyman program. With the skills I had developed through trial and alot of error as well as alot of help and advice from this forum, I was able to impress my instructors enough to have been offered a 2 year apprenticeship. I am about a year and a half through it and I love what I do. Every two months we receive a new batch of students from all over the world (England, Iceland, Australia, Canada, China, just to name a few) that I help teach how to build and repair guitars! Its very awesome and I would like to thank those of you who offered your help when I was just starting out.

I have shifted my interests to acoustic guitars and although I was not allowed to build them for myself for quite some time, I have recently begun a build which is progressing nicely. Please let me know what you think!

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Both the back and sides are laminated bloodwood to add strength to the otherwise unstable species. it love to crack and chip if youre not careful.

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I have been experimenting with creating my own material for accent pieces to stand out a bit. It is lovingly call dangus wood at the shop :rolleyes:

Here it is utilized in my rosette!

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As well as the headstock overlay. If the parts are not perfect I wont put them on the guitar, third time was the charm with this one.

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Close up of the miters

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The link at the end of the last post was a video of the sound port

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perfling

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I made the end wedge on this and when I sanded it flush I ended up with a poor miter and a large gap so I cut it out and gave it a second go

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I was much happier with this one

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Next it was time to bind...in ebony!

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Detail shot

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That's all I have for ya at the moment but thanks for looking, I should have this finished up in a few weeks so stay tuned!

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I was envisaging something like an 8mm x 4-6mm neodymium mag set into the bottom of a wooden button. That would ride in a (curved) guide slot on the outside. Internally the corresponding magnet does the coupling. You're right in that the external button would be prone to loss. The idea I had in my head was based purely off not having a through slot in the side. Nothing but an aesthetic trick rather than a practical addition.

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It sure is good to have you back and sharing builds with us again Tyler. Your stuff has always been very creative and well executed. I expect the school increased your knowlege a fair bit, but you took solid skills in with you. This acoustic build is super impressive. The detail work that you and guys like psikoT and Chris Verhoeven do in your builds always amazes me. I never had the slightest desire to try all those layered bindings and laminates and inlays--the mere thought of it gives me a headache, I'm more of a shapes guy. But I love looking at that kind of stuff and your work is top notch.

Tell us more about dangus wood. It has a striking look.

SR

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Thanks for the kind words Scott!

The dangus wood is a variation of resin wood turning blanks. Wood craft sells them as fijiwood. I found a dealer that was making nice stuff so I asked about buying some to use in my guitars. He saw my work and said something along the lines of trading material for a guitar, so I light heartedly said that would be a lot of material. Well he didn't like that answer and stopped responding to my emails and wouldn't let me buy anything so out of spite I made a pressure chamber and now make my own material using various wood/ resin combos and use them in my guitars as a way to stand out from traditional wood or shell adornments.

This guitar used a peice of blood wood that was shattered under 12 tons of force and placed in the pressure chamber with black pearl resin to create a block of material to be cut up as needed.

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Really nice having you back here. Great stuff. I already liked what you were doing before but it is evident that you have evolved even further.

I gotta ask: I have been getting more and more interested in building acoustics myself. However I have a hard time bending bloodwood. OK, easiest would to step away from that wood, but I have already an intricately inlayed bloodwood fretboard with a a neck that has some bloodwood stringers and stuff and I have also already made the sound hole ring and the bridge... yeah you get it. The question is, at what temperature are you bending the bloodwood? And do you laminate the sides first and bend them laminated? Or bend three sets of sides (bloodwood, maple(?), bloodwood and glue them together after they are bent?

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I've never done anything like that myself Peter, however I would suspect that support is the big key. Cracking occurs where stress forces are concentrated and locally exceed the limits of plastic deformation leading to rupture. Woods like Ziricote and Bloodwood probably have much smaller plasticity zones meaning support throughout the bend has to be near perfect. Heat is what increases the yield within the plasticity range.

Are you bending by hand or using a bending frame and heat mat? I'd imagine that bending by hand is a nightmare since temps and pressure will vary over smaller areas in shorter timeframes, resulting in smaller areas of plasticity.

Again. Not my region of expertise. Gut feeling. My terminology is probably totally wrong too....hahaha....that doesn't help....

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Good questions Carl. Not to distract from Tylers thread, but here we go: I'm using a fox style bender with electronic temperature controller, silicone heating blankets and double spring steel slats. I always break at the same point, the very start of the cutaway bend, first bending the waist, then the butt end and then moving to the cut awe section. the wood breaks at that apex of the cut away "tip", actually several breaks after each other. The last time I removed the cutaway press and used a wooden block to carefully pressing the sandwich down towards the cutaway, being extremely careful to not pressing to hard. That part itself took maybe 15 minutes! Then I hooked up the cutaway press and still got crack in the initial ben, were I did it manually. This is freaking me out.

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Blood wood is a b****, plain and simple. It's absolutely gorgeous and explodes when any finish is applied but getting it to the spray booth can be a nightmare. I was forced to do a laminated back because the plates had slight cups and when trying to flatten them out to join, I heard the crack of doom. Blood wood is dense, heavy, a pain to work with, and not ideal for back and sides. I'm worried that my back will dampen some energy in the system because of its physical properties. I will definitely avoid this wood for the body on future builds.

All that being said, I totally get the desire to push through the difficulties and get to the spray booth. I didn't have any issues with bending the sides. I used a fox style bender with nicely quartered grain cooking at about 300 degrees until I could hear the water boil rapidly and then I bent as slow as I could. I also used a double layer of spring steel to support the bend. As for the cut away I have no experience bending that tight of a radius with this wood although it sounds like it's as difficult as I would expect. I suppose my advice would be to go the non cutaway route if possible or to consider a pieced cut away such a a flourintine variation. These would change your plans a bit but might be the only way to get the blood wood to cooperate short of soaking and cooking the hell out of it and hoping for the best when you pull that tricky bend.

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Florentine sounds like the simplest solution. I'm constantly amazed at the confidence of some people bending sides when they get to that part....especially after seeing them fail too! Has any experimentation been done using glycol ether-based plasticisers, such as those used for vacuum veneer presses (Super Soft, etc.)? I'm sure that altering the properties of Bloodwood temporarily using some method like that might be a worthwhile consideration in addition to the application of heat to relax the lignin.

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I just ordered a gallon of super-soft 2. Shipping is probably going to be as high or higher than the product itself, couldn't find it here in Europe. Some builders have had so-so results and some have excellent result using it. I just know I need to do something different. Please do not let me derail this whole thread now...

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Tyler's call.

Without discussion there is only the trade of information; not the generation and evolution of new ideas. :D

I hate to think of what you're going to do with all that Super Soft. Boat making?

I stumbled across a post on Lumberjocks about Bloodwood and just spent ages hunting it back down. This might provide useful information on the whys, and the reasons for its brittleness. In many ways, this also explains the nature of Ziricote.

Okay: bloodwood is a relatively new species, given the evolutionary history of trees. It does not produce oils like most other tropical woods as it is not a wet soil growing species.. it is an acidic soil dweller. In the forest succession.. it is a “nurse” tree and in the same family as mulberry trees, but can become monodominant and crowd out shade intolerant species. It seems to be a tree that is switching from utilizing vascular tracheid cells in favor of forming short vessels and lots of axial Parenchyma cells which spread out like wings and then interlock to form a open mesh of cells …. supported by thick walled and elongated fibers. It does allow for crystal growth within their parenchyma cells, which is why it also dulls tools. What this means is that the wood is very brittle and heavy and prone to checking and twisting during the drying process. Thus I agree the wood was improperly dried. Most bloodwood is farmed and licensed harvested, because the species is easily climate affected and several endangered monkey species (e.g. Brown Titi) live off this tree … eating it’s leaves, bark and fruit.

As for working it. I have had a board twist only once, i put it down for almost year and all the movement was out and it was fine from them on. As for veneers glue can easily squeeze through the open cells, so I had to use an epoxy.. west system because it blends well with varnish coats… DO NOT use alcohol as it will stain the wood darker permanently… acetone will make the fibers way to soft and easily dissolve any glue you might have used prior… causing bubbles and splits. I may never use bloodwood veneer again.. what a complete PITA. but it looks so awesome!

http://lumberjocks.com/topics/41970

Super Soft may relax the fibres and heat relax the lignin, however the intrinsic structure of the fibre cells isn't going to allow them to untangle easily. The fibres of happy woods simply slide past each other. Bloodwood is like combing spaghetti with a hammer.

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Good text on bloodwood. Thanks!

I hate to think of what you're going to do with all that Super Soft. Boat making?

I have a few ideas, moahahaha... No seriously I'm thinking multilaminated curved "sides" for Yamaha silent guitar type instruments, a bit like the electric cello I did a few years back. Or I'll just make furnitures instead. :lol:

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Please by all means continue with the discussion! This thread is just a spot for me to post all my pics and not clutter the forum. What ever discussions branch off from them is just an added bonus and they are more then welcome!

The super soft interests me a lot because I do have a cutaway design I would like to use but it involves a very tight radius and I want to stay away from a florentine if possible. I think I might give it a shot! I've got some black limba back and sides that I'm itchin to use so maybe I'll jump on that once I get this build in the booth.

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My interest in Super Soft comes from wanting to make a moulded top and back for an ES-175 style bass. I could couldn't find it here either. Cheers for having us here Tyler! haha

We should discuss steam bending of solid woods elsewhere though Peter. My casual mention of boat building wasn't far off the mark. You should look into a steam box for that. Marine ply works nicely as a box in conjunction with a wallpaper stripper to generate the steam. Again, I almost made one for the sides of the aforementioned project which would also have been used for bending the arms of my armchair. I opted for cold laminated arms in the end.

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You know, as I ordered a gallon, and if it works, I gan easily part with a litre or so and ship it to you. The "magic stuff" will arrive in about 10 days and I will try it on a rosewood and a bloodwood side I have left from cracking the other book matched half. I'll let you know how it works out

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Thanks for the offer Peter - I highly doubt I will anything to put it to good use on for a while now. I'm pouring my energies into the startup, so until that has its own feet I can't allow vanity projects to take hold....tempting though they might be at times....

It'll be good to see some useful information coming out of the experiment though. On the face of it, I would doubt that it'll be much easier. Seems that trees just don't want to be our friends any more :-(

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I have finally got around to test bending with supersoft. I tested on offcuts of bloodwood, from a set of sides I had previously cracked in the fox bender... I also got a Sloane bending Iron

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I might do a review of this as it has some obvious problems, even though it is almost the "industry standard". However, I tested three pieces, one only lightly sprayed with water, one treated with supersoft and one soaked in water over night (yeah, a bit too much, agreed). The result was a bit depressing as all of them cracked in one way or another. The one only sprayed with water snapped repeatedly, the one treated with supersoft started to bend before breaking so just a slight improvement with supersoft. One interesting thing is that the one soaked in water sheered lengthwise. Apart from that the piece actually kept together. My conclusion was to go thinner as it seemed that the bloodwood has a maximum thickness before the outer fibers break and the heat is never enough for the outer fibres to soften. So from the next experiment I pulled out the single remaining full bloodwood side I had yet not cracked and sanded it down a bit more, to roughly 1.7-1.8 mm thick (.070-.075"). Then I sprayed it with water when I started to heat up the iron as the iron takes about 20 minutes to reach full heat. I sprayed it a few times during that time. I also notched up the heat a bit to just below maximum. I sprayed the wood with more water during the bending. I think I have the technique down now:

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The trick is like drilling in stainless steel. Go very slow in the beginning, and increase the speed after a while. I had one outside split when I got too cocky on the third test bend (you know, when you get to: I have mastered this now! I cannot fail! Lets speed things up...). If this had been a side I was going to use I could have saved it with a outside steel slat and a bit of work to glue it back later on. I also got two small cracks at the perimeter, but not bad, being in the binding area of the side. This all got me confident enough to get back to trying yet another set of bloodwood sides.

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