MIMF

Ive always bought solid composite rods from stewmac and LMI,then someone mentioned dragon plate.they have tons of items.id like to know if anyone hase used the composite tubes in place of the solid rod to stiffen our necks. The cost of the tubes is less than half the cost of solid rods. Time and technology move on so im wondering if the tubes are useable for guitar builders. Im starting a limited run of 9 guitars so cost is very important.what say you alll? Part numbers?

I have actually not found tubes cheaper in those dimensions than rods. If you do find 1/4"OD tubes at a good price, please share the source. On Ebay small tubes are usually just as expensive as pultrouded rods, and harder to find.

From an engineering standpoint, a hollow rod is less stiff than a solid bar for a given space. Let me explain: In an application like a kite a hollow rod is a better choice because it is stiffer when compared to weight. But in a neck, weight is not the deciding factor. Space is the limiting factor. You want to remove as little wood as possible when installing the reinforcement. And a solid bar makes maximum use of that space and adds the maximum stiffness available, even though it adds a bit more weight than the hollow rod.

Now if you are using carbon fiber rods inside an hollow body for flying buttresses, a hollow rod is a better choice. But this is not the case in a neck.

I like to use relatively small solid bars from Dragon Plate. I use two bars that are 3/32" wide and a bit less than 1/4" tall. These are MUCH smaller than the normal bars sold by Stew-Mac or LMII, yet they definitely add stiffness to a neck. But they don't overtax the truss rod as much as the larger bars. They are relatively cheap too.

Edit: best way to summarize all of the above is to say that a 1/4" diameter solid rod is much stiffer than a 1/4" hollow tube.

I hope he pops in, but I believe Mark Swanson uses hollow tubes from http://intothewind.com/kitemaking-and-repair
I have some, but I haven't gotten around to actually using them in anything yet.

I have used those tubes, and they do work just fine. They have a thicker wall than the ones I have seen from Dragon Plate, but I stopped using the round tubes from this source because I haven't had good luck finding decent round router bits to match the round tubes. I now use the square tubes from Dragon Plate.

This is not an element where I'd be trying to save a few bucks. Really!