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Discussion in 'Tele Home Depot' started by richa, Jun 19, 2017.
Me: Honey do we have a hot pot around here somewhere?
Wife: Yeah up in the loft. What do you need it for?
Me: ...Um...melting some gelatin - you know kinda like that Knox stuff - practically food.
Wife: Will it ruin the hot pot?
Me: ...Um...probably not.
I used the discussion of hide glue on FRETS.COM as a guide. I think I should have used more water. It was thin enough to run off the brush, but in retrospect I think it should have flowed a lot more freely. The biggest issue I encountered is that gluing the braces sort of exposes all the places where the fit wasn't as good as it seemed (uneven squeeze-out etc.). Going to have to rethink my approach to fitting the braces. I think just using planes and chalk (or something) to find the high spots might work better than sandpaper. The ends of the braces wanted to gap slightly (from getting rubbed into the steepening arch) and there was a little more side-to-side rounding than ideal (even with the guide blocks). Not sure it's catastrophic and in the end everything seems fairly sound.
Then shaved the braces. I think this is close to being done. I didn't say right - just done. Might taper the ends out just a bit more.
Here's a comparison of the "bound" plate (clamping to edges to the form) from some point before adding the braces and again with the shaved braces. There is a more consistent plateau from about 150 Hz to 600 Hz. Before it was from 150Hz to 400Hz with more gaps. I'm given to believe this is a good thing. On the whole I wouldn't mind seeing a tad more LF response. But I'm only willing to shave so much off the brace. But maybe just a leeeetle bit more.
Looks like a nice tight glue joint from where I'm sitting. This is coming along nicely.
I'll admit... your sound graph thingy doesn't mean much to me, I like to think of it as a particularly challenging Tour de France stage profile.
Hah! I'll admit that it doesn't mean much to me either. In fact I forgot the last line of my post which should have been "So what does all this mean? Ah dang...I don't know."
I mean I can interpret the frequency response but without a baseline I have no way to know if it's good or bad except broadly. And it's only a slice of the story anyway. My prediction is...it will sound lime a guitar.
Fussed and fiddled a bit more - tapering the ends of the braces a bit more. Domed and smoothed them. This is what I believe will be the final brace profile. I wonder if there's a reason you don't seem to see a tall thin brace on archtops? As a beam they have higher strength to weight ratio so ought to be more responsive. But then in the physics of the archtop plate "light and responsive" don't seem to be where the juju is. A few minutes with google really didn't turn up much about why arched plates do what they do. humpf. Lots of stuff about what they do - just not why.
Didn't change the low-end respond much. Might have strengthened the upper midrange a bit.
Just for grins here's what the back plate looks like. I don't have any basis to know if thinning it a bit would be a good thing or a bad thing - so I'll probably just leave it.
If anyone was wondering why I'm capturing these when they don't seem to do much good - well a baseline has to start somewhere right? You have all been wondering that right?
Another thing to note is that the response curves really are repeatable - meaning the peaks and valleys are consistent from one impulse to the next. But even small changes to the plate change the smaller peaks a lot which indicates that trying to control them is not really meaningful. But the knees and broad peaks of the overall response are well behaved and seem like an actual "signal" that can be used.
From your latest graphs, it seems like they're pretty well in a similar ballpark(I think that's what I get from them) which to me could mean that's a good thing? Though understanding tap tones/frequencies has never been my strong point.
I've enjoyed following along so far and can't wait to see the finished product. Hopefully it works out well for you!
Thanks Robert. From what I understand having a strong resonance peak at exactly the same place would be bad...but having them close is good or at least ok. The top is not that peaky and the back is so hard to say what will happen. I'll just have to wait and see.
It's kind of interesting to compare what my ears tell compared to what the graphs say. My ears say the back sounds lower than the top and my ears seem to be zeroing in on that lower peak. The ears want to zero in on something and that something isn't as well defined on the top but it sounds higher. But what I find interesting is that my ear wants to turn the impulse response into a simple tone and clearly there's more going on than that.
Picked the hottest day of the year to bend sides. But that's not saying much here in the Pacific Northwest so I guess I can't really complain.
I concluded that on the first side I must'a still been practicing because it was kind'a cantankerous. The waist was fighting back hard. The second side almost seemed to bend itself by comparison. I suspect one or more of the following:
a. The second side got extra soak time while I was fighting the first side.
b. Since you're bending opposite directions relative to any grain that ran through the two book-matched sides it's possible one just had a more favorable conjunction of celestial grain mojo.
c. I just got that much better at it.
All clamped up for the night. We'll see how much spring-back we get tomorrow.
Plan forward - I think. Maybe. Possibly:
Tail block and neck block.
Rough in neck enough to do the joint
Cut the neck joint
Decide if I'm going to do anything with a piezo pickup if any of it needs to be done before glue-up
Glue top and back
Bridge and tailpiece
String it up and try it out
Decide if I'm going to put a neck mount mag pickup and finger rest on it
And somewhere in there I still have to decide what I want to make the fretboard and bridge out of. I might have to break down and buy something. Maybe something dark. Maybe something that can be dyed black. Maybe something Katalox?
Not a lot of progress today. Seems to be holding shape just fine. Trimmed the excess from the ends of the sides. Cut the tail block and heel block. Still need to shape them. Heel block seems ridiculously large for the size of the body...but the neck is a full size 25.5" scale which seems like the more material element. Actually I just realized that it won't be quite as thick as shown in the picture below.
Anyone used Black Locust for a fretboard or neck? I have a beautiful one that needs major surgery. Harder than hard maple. Very durable. Hard on tools. Not especially pretty but not ugly. Thinking I might try to seal the ends on a log or so and season it. Pity it wouldn't do me any good for the fretboard on this build.
Shaped the blocks. Put a piece of tape down on the bench, clamped the sides firm against the mold where they butt together, and traced it. Then taped it to the block and cut it close to the curve on the bandsaw. Used a hand plane for final fit. Worked like a dream on one and took some fiddling on the other.
So somehow I had this idea that I could just bang a clamp or two on each block and glue them to the sides. But the sides do want to twist a bit. And my form is not full height so the bit of the sides that stick above it don't want to lay flat against the block. I ended up putting the whole thing on edge and letting the sides stick out a bit on each side and then whacking a clamp of some kind or other on just about every part of the thing that I could. No idea what the "right" way to do this is.
I think there are many ways to glue sides to end blocks depending on your forms and assembly procedure. I clamp mine down to the assembly board surface and then glue the sides to the endblocks while clamping them against the forms and down to the work board at the same time.
This makes sense.
For all the dubious clamping required to get there it came out ok. I'm just glad I dry clamped it first so could see I was going to have a problem ahead of time. Shudder to think what kind of mess I might have had if it would have been a panic'y kludge instead of a planned out kludge.
The blocks are a bit proud of the sides but aside from that everything seems square. I ended up leaving slight gaps where the sides butt together. Not sure what happened between the time I trimmed them and the time I clamped them. That form tends to move around a bit more than I would like. Not a big deal because the neck joint goes on one end and I was planning on doing an inlay piece on the other end. Decidedly don't like the MDF form - but it was cheap and easy.
Might add another layer of plywood to make it full thickness and try to stiffen things up a bit (assuming I use the same form for another build).
Started on the neck. If I had a plank big enough to cut three one piece neck profiles and laminate them I would have done it that way. But I don't so I'm doing it this way.
No need to add another thickness to your mould: it's helpful to have the sides protruding so you can glue on the linings. Gives space for all the clamps/clothes pegs. Do one side (top or back) then when dry, push through to do other side.
Cut the rebate for the fretboard extension with a bandsaw and cleaned it up with a chisel
Probably won't go much further on this for a while except to cut the neck joint.
And made a pile o' linings and side braces
That's a point. It would sort of be cutting my nose off to spite my face.
You never truly understand the prices companies charge for an acoustic guitar, til you build one.
Awesome job Richa.
That's no joke!