Official Luthiers Forum!

Excellent insight into stress risers- something I need to consider more in the future. I've used a few DA HotRods with the sharp, heavy brass corners and never gave it a thought. I didn't much consider SRs in wood but wow, I will now.

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Measure Twice,

Karl Borum

A newbie question about Bobʻs early post... Whatʻs the story with rattles and caulk? Since Iʻm just in the process of installing a StewMac double rod, this is the time to ask...

Some rod designs have spaces between the components that allow them to vibrate against each other or against the channel they are in. When the tension on the rod and the distances are just right, playing particular notes on the guitar can make the truss rod seem to sing. A couple of small dabs of silicone caulk along the length of the rod can help damp that vibration. Just use little dabs, not enough to squeeze out and mess up any glue joints. The soft caulk is flexible and won’t interfere with the action of the rod. Don’t use anything that cures hard.

I'll add silicon is a huge enemy of lutherie and what we do. If your shop gets contaminated with it, say a bench top, etc and that comes in contact with the wood of the guitar you are working on it can result in a finishing nightmare with fisheyes.

So try to contain anything with silicon to only where you want it to be and clean up well after using it and never, ever let it get on wood that you intend to finish.

I elected to not use any silicon in any of my builds and instead to use a file on the sides of my Blanchard truss rods to make for a precise fit in the truss rod channel. All of mine were snug as a bug in a truss rod channel and now nearly 20 years later no issues reported. I did put a top strip over the rod too but that was all I did.

I agree, silicone is the enemy of any finishing process. I’ve never had any problem with silicone escaping from the little bit of caulk that I’ve used. But, if you ever wax your car, change your clothes and shower before you go into your shop. Just a little fingerprint on your wood will ruin your day.