Originally Posted by Bill Fitzmaurice
Possible, but not with longitudinal spline braces. Inch for inch, pound for pound, they're the least effective bracing method. Panel to panel cross bracing is no less than four times as effective, using 1/4 the material. Like so:
They're not as easy to install, but ease of installation should not be the primary concern.
I appreciate your input , Bill, and I can't disagree with your statement about the benefits of cross bracing. In terms of spline braces as least effective, well, now I do take issue. There are plenty of engineering examples of beams using a T configuration, most commonly in highway bridges and parking garages. So I doubt that spline bracing, which is a form of T-brace, is as inefficient as you claim. Here are two examples of what I am trying to discourage through this discussion (my apologies to you if this is your build, While the bracing shown is plenty strong, it just uses a lot more wood and adds a lot more weight than is needed):
Also, the repeated baffle brace typically places the thickest material in the corners where it is least required, and the thinnest material in the middle of the panel where it is most required (again my apologies if this is your build):
No Arny, I don't own a lumber yard, but I do have to buy my wood from one, notably Home Depot ("HD"). Intuitively, it would seem that you are right, but if you actually do the math in terms of board feet of lumber, the cross bracing method with 2x2 vs 1x4 splines comes out to be nearly equal. If you look at the cost of 1" dowels at HD, cross bracing with dowels would cost 2-3x more than 1x4 splines. Likewise, 2x2 lumber cost nearly twice as much as 1x4 boards. The cheapest material is 2x4 studs, but making your cross braces out of 2x4 lumber would still cost more than 1x4 splines and would weigh twice as much. The only way to make less expensive cross bracing than 1x4 splines is to rip 2x4's into 2x2's.
But now we are getting into significant woodworking skills. It is not easy to rip cut a 2x4 with a circular saw. Nor is it easy to make a dozen or more precision cuts to get cross braces to perfectly fit between panels. The MartySub was conceived as a minimalist build in terms of woodworking skills, tools and build time. Ripping 2x4 lumber and making a few dozen cuts to exact dimensions is starting to move away from the essence of the MartySub, at least as I understood the project. Having said that, I admit that making a bunch of lap joints, and roundovers and other details of my build was a significant departure from a minimalist build, but all of that is optional for someone with limited circumstances (be it time, money, tools, skills, facilities or some combination) that still wants a kick ass sub that can really dig deep into the teens with lots of output.
I hope I haven't offended anyone with my comments or examples. My goal has been to stimulate discussion and get us all thinking about efficient bracing, and in the case of the MartySub, easy to build as well. I look forward to spring so I can open up the garage and do more building and less talking. . .