Matthew's cornerless bass project

**Matthew Tucker** · #1 10-07-2007, 07:26 AM

This is to be a copy of Stefano Sciascia's bass, made from Tasmanian oak (eucalyptus regnans) back and sides, and a western red cedar top again.

I'm using a combination of heat blanket and bending iron. You can see the heat blanket on the mold, on the upper bout. I'm using aluminium sheet cut from old offset printing plates. Best thing I did was to add an inline switch within easy reach.

Here's my bending iron:

Yes that's a stove element in there. The 1mm stainless sheet is bent and bolted to a piece of galv lintel which is clamped to the bench when I need it. Gets bloody hot, and works really well.

ctregan · #2 10-07-2007, 02:56 PM

Thats a serious bending iron, does it have a temperature control?

**Matthew Tucker** · #3 10-07-2007, 04:09 PM

It has an off switch! But actually, until/unless I enclose the front part, I don't think I need one. It works well with the ON setting.

Actually, one big plus for the thermal blanket is that it's much more pleasant to work with, and very controlled.

I find the bending iron is necessary to touch up the curves, as bending using the heat blanket directly onto the mold means there is some springback. However it's a hot and burny process - need asbestos fingers.

ctregan · #4 10-08-2007, 06:17 AM

Two settings; off and bloody hot.

**Matthew Tucker** · #5 10-26-2007, 08:23 AM

Here's some progress pics. This bass is coming along a lot faster than #1 'cos I know what to do.

Rib garland nearly complete:

Hogging tools. That's one mother of a gouge.

Shaping the top. I've filled up two big bins with shavings so far.

This last pic is a bit ugly but it shows how much wood has to come off.

John Wentzien · #6 10-26-2007, 08:28 AM

That's gonna look good!

**Damon Rondeau** · #7 10-26-2007, 08:29 AM

Looking grand.

You moved recently, didn't you, Matt? Is that therefore a new shop space? Looks like a great place to work. Looks a lot like the vision I'm slowly working towards with my basement shop....

**Matthew Tucker** · #8 10-26-2007, 08:35 AM

I didn't move, we built a bit of an extension on the back and I got to replace my open air hell with a brick garage. But it will never see a car as long as I am here ...

In my workshop, I am as happy as a pig in 5hit

**Damon Rondeau** · #9 10-26-2007, 08:42 AM

Quote:

Originally Posted by Matthew Tucker

In my workshop, I am as happy as a pig in 5hit

I think I know exactly what you mean. Oink oink!

Don Harris · #10 10-26-2007, 09:43 AM

Looks great Matthew. Thanks for posting the pics. I'm already thinking hard about number two. It's going to be fun to move quicker and with more confidence. And to not have to stop along the way to make as many tools or jigs. I'm just finishing my spool clamps, made a double bladed purfling marking knife for doing the non-edge/free hand stuff, and need to put a wooden handle on my jeweler's screwdriver/purfling channel pick (my palm still smarts from doing the test purfling).

Where did you get your western red cedar? From a regular lumber yard? A tonewood supplyer?

I like the big handles on your gouges. I like using a scrub plane for the serious hogging. Makes quick work of roughly getting the edge to proper thickness.

Jake deVilliers · #11 10-26-2007, 01:29 PM

Gee, that's an awfully big guitar!!!

But seriously Matthew, way to go - I am so envious. TWO of your own basses!

Right on.

**Matthew Tucker** · #12 11-09-2007, 02:07 PM

Darren Molnar · #13 11-09-2007, 02:59 PM

Oh man, how I wish I was building a flat back. Looks like you're gearing up for a very pleasureable week-end Matthew. Cheers to you.

**Matthew Tucker** · #14 11-09-2007, 04:06 PM

Now I'm thinking about the design of the braces.

The original bass I am copying has "normal" transverse bracing but I don't have exact measures so anything I put in there will only be guesswork based on other basses.

But somehow I'm drawn to "jakstadt" style X crossbracing, and I note that Solano is doing the same sort of thing. From a "strengthen and prevent splitting" perpective it seems to make sense. But I wonder how they hold up over time, and whether there's any acoustic advantage or disadvantage. Anyone got any comments on this?

Peck_Time · #15 11-09-2007, 04:12 PM

My Christopher flatback has X crossbracing. My luthier noted that there was less room to adjust the soundpost compared to normal bracing,

**Adrian Cho** · #16 11-09-2007, 04:16 PM

Isn't Tassie Oak really soft?

**Matthew Tucker** · #17 11-09-2007, 04:18 PM

Tassy oak is quite hard. Ruins tools!

Solano's X bracing joins two transverse braces. I wonder if he "laps" the centre joint, or is it just butted together (looks butted to me)

I have drafted my X bracing so that the "normal" soundpost position is centred on the brace. This will give me at least 2cm in any direction. Should be enough, I guess.

Has anyone got any pics of Jackstadt bracing?

Ken McKay · #18 11-09-2007, 05:06 PM

I would half lap the joint and put a little pad over the joint if I were doing an X. But I think good old cross braces would suit you fine.

If you could get Arnold to spill the beans about his back bracing you would have a proven design. I looked in but I am not going to tell what I saw, because it is all his. I have seen guitar bracing similar though.

Supposedly, a flat back with cross braces vibrates more like a viol than a violin but most can't tell the difference in a listening test. There is a lot more to it than just the sound from a listener. For example, response from the bow might be much different with X versus cross. It could be worse. Cross braces are proven.

**Adrian Cho** · #19 11-09-2007, 05:20 PM

My Shen has X bracing and they also put a bit of an arch in the back so in theory it's sort of a flatback with a bit of the roundback strength and stability. Seems to work very well. Mine is new and even with the seasons we have here in Ottawa, it has been very, very stable.

Don Harris · #20 11-09-2007, 07:20 PM

I remember seeing a post awhile back about Robertson's replacing the X brace in a Jakstadt with a traditional bracing system and it made the bass lighter and more responsive if I remember right. I've got a Jakstadt and love the sound and have had no problems with the back. I think that Aaron at Robertson's has little respect for Jakstadts and I'm not sure why. Just my impression from a few comments he's made.