Winter Build Off 2020 - Kuun Space

[Jisch]

This is one very, very sexy build.

thanks! still early, plenty of time for me to mess something up :-D

 

[kesslari]

thanks! still early, plenty of time for me to mess something up :-D

When I look at bass builds my internal responses tend to run from "good idea..." to "hey, that's cool!" to (very rarely) "I'd rock that!" The latter includes "5 strings, fretless, well made and beautiful". You've hit it, thus far.

 

[Jisch]

When I look at bass builds my internal responses tend to run from "good idea..." to "hey, that's cool!" to (very rarely) "I'd rock that!" The latter includes "5 strings, fretless, well made and beautiful". You've hit it, thus far.

Nice, thanks for the comment. I'll try to keep it going!

 

[Reedt2000]

Are you gonna work a bevel across the sound hole opening after it's all glued up. Kinda blend it in?

 

[washjayb]

Lunch was productive. I started out by calling around to the local wood places, really there are only two I can think of that might have finger planes and neither had them in stock. I took out my gouge and started removing material, it went well on the walnut, except I did get a couple of spots where it grabbed the grain and pulled up more material than I was happy with. Given the swirling grain on birds eye, it didn't work well there at all.

I remembered I have an angle grinder with a flap disc, so I figured I'd try that. I tried both 80 and 120 grits, the 80 was much better, it removed material slowly enough that it was comfortable and it didn't burn, the 120 tended to burn easily. I got the first round all the way done and took a measurement, it was still too thick. I did another round of drill holes in the body area (not in the horns) and repeated with the angle grinder then ROS. At this point it's just a little under 3/16" (5mm) thick. I think I'm going to leave it there.

If anyone has suggestions on whether I should go thinner, I'm open to ideas, I have very little experience here. I will be using a tailpiece with a floating bridge, if that helps.
View attachment 3652323

Beautiful!

What is your overall thickness?

 

[Jisch]

Are you gonna work a bevel across the sound hole opening after it's all glued up. Kinda blend it in?

Funny, I was just looking at that. It's definitely in "rough" form right now, a bevel that continues across both pieces is what I was thinking. I will probably finalize that once I have the top glued on and the shape finalized. I'm working on the inside of the body cavity now, even as it stands you can see quite a bit of it, so it has to be good inside there. I dislike sanding inside a box like this.

 

[washjayb]

Beautiful!

What is your overall thickness?

Sorry.

I see you indicated a target of ~1/8

 

[Jisch]

Sorry.

I see you indicated a target of ~1/8

I've updated that target a little. I'm at 3/16" now, I'm not going any thinner unless someone says I should. I can cause the top to deflect a bit by pressing down on it. I mean it takes a lot of pressure, but I can move it.

 

[Jisch]

I clamped the top on with three clamps and thumped the top and it definitely resonates, I think this is thin enough.

 

[washjayb]

I've updated that target a little. I'm at 3/16" now, I'm not going any thinner unless someone says I should. I can cause the top to deflect a bit by pressing down on it. I mean it takes a lot of pressure, but I can move it.

I feel you.

I was hoping to carve my top but seeing how gnarly the burl is has given me pause. I'm at ~9/16 and don't trust that I'll get any thinner while remaining structurally sound.

I'm leaning towards doing a more subtle shaping now... and some sort of an angled access. I'm using chakte viga bending sides as a central laminate on the body (unsure of thickness). Going to play with a soundhole from this central layer during over a chambered back.

Really love what you are doing with this.

 

[Jisch]

I feel you.

I was hoping to carve my top but seeing how gnarly the burl is has given me pause. I'm at ~9/16 and don't trust that I'll get any thinner while remaining structurally sound.

I'm leaning towards doing a more subtle shaping now... and some sort of an angled access. I'm using chakte viga bending sides as a central laminate on the body (unsure of thickness). Going to play with a soundhole from this central layer during over a chambered back.

Really love what you are doing with this.

Thanks! That burl is very cool. I haven't ever worked with burl, but it always intrigues me, I love the way it looks.

I wish there was some way to test things out beforehand! I'm not trying to get acoustic volume out, but I'm unsure how much movement is needed for the transducer. I guess worst case scenario I have the magnetic pickup! It will get thinner with final sanding, but not much.

 

[Jisch]

I got the control cover cut out. I use my dad's scroll saw for this, he has a really nice pinless one. I always just use the blade that's in it when I go over there, apparently it's usually a more aggressive one than the one that was in it today. I had to go very slowly, like crawling slow, but I got the most accurate cut I've ever done. The curves are never a problem, if they get a little more curvy it's no big deal. The straight line is always the problem, keeping that cut going 100% straight can be tough. Today the straight line came out dead straight, I guess I'll have to use that super fine blade every time. I'm going to try to put Tru Oil on the inside of the cavity in the morning, maybe get the front glued on tomorrow.

It's a little hard to see the grain through the sander marks, but it lines up perfectly, trust me :-D

 

[dwizum]

I haven't ever worked with burl

Imagine if someone drizzled wood glue all over a pile of popcorn and made a board out of it. That's about what burl feels like when you're working it. It can be really frustrating because it has no regular grain or structure and it's usually littered with little low density pockets that just crumble.

 

[Reedt2000]

I'm unsure how much movement is needed for the transducer

Are you putting the transducer under the top? Or fishing it through to underneath the bridge?

 

[washjayb]

Imagine if someone drizzled wood glue all over a pile of popcorn and made a board out of it. That's about what burl feels like when you're working it. It can be really frustrating because it has no regular grain or structure and it's usually littered with little low density pockets that just crumble.

My top is littered with voids running at a ~30° angle to its surface. Still solid somehow but very flexible.

I need a fill in solution.

 

[Jisch]

Are you putting the transducer under the top? Or fishing it through to underneath the bridge?

My plan is to put it under the top, any suggestions?

 

[Slidlow]

I considered which drill to use - the reason I picked a brad point was because it would cut easier and therefore require less pressure. That experience of putting dings all of the front of my last one has me spooked, I guess.

I do spruce tops for archtops and haven't had that issue?

 

[Reedt2000]

My plan is to put it under the top, any suggestions?

If the base of your floating bridge makes contact with the top across it's full length, I wonder if you could stick the transducer under it (kind held in place with the pressure of the strings). You might even be able to position the transducer to favor one side or the other to "tune" its response. Your bridge base would have to be wide enough to cover the pickup.

 

[Jisch]

I do spruce tops for archtops and haven't had that issue?

I probably over compensated for my past experience, all good.

 

[Jisch]

If the base of your floating bridge makes contact with the top across it's full length, I wonder if you could stick the transducer under it (kind held in place with the pressure of the strings). You might even be able to position the transducer to favor one side or the other to "tune" its response. Your bridge base would have to be wide enough to cover the pickup.

Hmm, I'll have to think about that. I used the K&K system before, I mounted it underneath, so that's just what I thought I'd do here. There are three transducers in the JJB system I bought. I'll have to look at the size of the transducers to see what the bridge would look like.