STANDARD FLOOR BOLT PROCEDURE

[bob mitchell]

 It is a little ironic to be writing this, considering how proud I was to have discovered how the floors (the 2x 6's that are bolted to the apron, and the frames are bolted to them) were connected to the apron from a picture of Dennis Gaffney's - THERE IT IS, I SEE IT!. Anyway, its two years later and I am putting my 70th something new floor bolt in place through new floor 38 and a new apron for the length of the boat.

Looking back..........anyway, here is my standard procedure for floor bolts.

      

       First I clamp my hardwood drill jig, squarely centered , to the floor. That can be done in place (usually) or outside of the boat if other structure prevents it being done in the boat (as frame 38).     Next I clamp the floor in place on the apron, and use the new holes in the floor as a guide for drilling the apron. Now remove the floor. Then I take my "after the fact" counter sink hole saw, shown beside the vise in the above photo, and come from the the bottom of the apron. The hole saw pilot bit is anything with a shank cut down to go in the original pilot bit hole, and 1/2" on the other end so that the hole saw itself will remain centered. Drill the minimum to make the carriage bolt head below the surface, and clean with chisel. 

        Next, which I consider critical, is to plug the hole through the apron with the bolts, as shown in the photo, and fill the hole in the apron from the top with liquid epoxy. I add a little borax rot killer to mine in powdered form that may or may not get dissolved if water ever gets in there. But the point of the epoxy is complete encapsulation of the apron and electrolytic isolation of the bolt. If water did reach the apron hole it would be absorbed into the apron with no way to escape, so I seal the hole. While the hole is soaking paint the rest of the bolt with epoxy. Be especially careful to saturate the bottom of the hole (use a brush), ie the counter sunk part, because a carriage head surrounded by wood hardened with epoxy is just better all around. After a few minutes, but before the epoxy goes off, drive the bolt up through the apron and the floor, and bolt.       

[Hans Petrie]

I didn't know Borax killed rot!  This is good to know.  I did know that Ethylene Glycol Antifreeze is popular rot killer which is why I never complain when it accidentally spills into the bilge when I work on my cooling system.

[bob mitchell]

Actually this is the stuff I use - that 5 gallon bucket cost about $80 - I just mix it with water and spray away. The sprayer cost $14.95 at ACE and is still working well after a year. If I was in fresh water or had a deck leak I would throw some dry in the bilge. It is not borax, but in the borate family. The only thing is that, being water soluable, it does leach out over time. If you click on the photo you can read my original comment, ie I forget about stuff fast.

        Whether or not incorporating it into epoxy as a filler will allow to disperse is of course speculative, but I think a small amount might be on the edge of the epoxy penetration - I would expect a gradient from epoxy saturated to no epoxy where some of the borrate might dissolve and be effective if water ever got there. I would not bet on that process being effective, but I did it anyway.