space between plank butts

[Paul Silverman]

I've been on line a couple of times over the past months for help on a refastening project- replacing iron nails with bronze screws for cedar planking on oak frames. I'm getting ready to apply new seam sealant. I've used epoxy to fill old nail and screw holes and in a few cases where two planks butt have replaced butt blocks. The newest problem is that occassionally I've had epoxy essentially glue butt ends together as it filled a gap left by an old iron screw. I'm thinking that I need to remove the epoxy to allow for plank expansion where two planks butt. Assuming I do, the question is what tool to use? I've considered two options: (1) get a dremel tool with a small circular saw and use it to saw a new gap between the butt ends (but this will not remove all the epoxy); (2) buy a much more expensive Fein multimaster tool with either a segmented saw blade an E-cut blade to plunge cut a new gap between the planks. The latter seems the best, but the tool and blade is likely to set me back about $200. Alternatively, could I just leave the two plank ends essentially glued together and not worry about expansion with the grain?
Advice?

[Bob Smalser]

If I read you right, planks don't expand along their length any to speak of, just their width.....so something hard between the butted end grain isn't a good practice, but isn't catastrophic.

[ 06-15-2005, 08:40 AM: Message edited by: Bob Smalser ]

[Mrleft8]

Typically known as "Butt cracks", these are not really an issue. As Bob Smalser stated, the movement of wood in length is not a measurable amount.

[Paul Silverman]

Thanks for the help. She goes in the water in a couple of weeks.

[RGM]

I'm thinking that your planks are approx. 1 1/8" thick? You need to be able to cork the plank butts with at least a thread of calking cotton (not candle wicking). The cotton needs to be driven to the back of the seam, made tight and then the caulking/seam compound of your choice used to pay the seams. If the excess epoxy interfers with the corking then cut it out of the way with one of the tools/methods you have described. Here's the trick, try to do it with out removing any material from either end of the planks. Ideally the plank ends should be in contact with eachother over 100% of their interface, no spaces, no gaps. Otherwise it's like re-planking a boat with planks that have been cut too short. As the others have described your planks will not grow in length to any significant degree. Butts that are not tight and properly corked will leak, contribute to flexing of the hull, deteriorating plank ends and butt blocks, etc. A good, thorough corking job goes hand in hand with a re-fastening job. Besides helping with watertight integrity corking helps with structural integrity by stiffening up the boat. Good luck.

[Dan McCosh]

FWIW: I have areas where epoxy has completely filled the space between the butt ends, and they have been in place for 20 years with no problems. Areas where they have been properly caulked have caught water and rot on occasion. I would argue that sealing the end grain is more important than the caulking. The actual seam is backed up with the butt block and the caulking does little to keep water out; the wood doesn't expand lengthwise; but the raw wood ends and/or an improperly bedded butt block are rot traps.

[gaffman]

If you want to be fanatic about things, you could scarf back the ends of the two planks where they butt up and take out the butt block entirely with a scarfed piece connecting the two planks, making them one. That would solve your concerns. Also, instead of filling the nail holes on replanking, you could put a fastener in the old hole and scribe some arcs from it, above or below onto the plank above or below, and when you replace the fastener with bronze, just put your dividers on the arcs and scribe down and you'll be right in the same hole. Saves time and does a nice job.

[Dan McCosh]

In fact, I haven't used a butt block in decades, and do scarf planks rather than use butt blocks. Generally, however, the scarf placement is simlar to butt block placement, and I try not to use extremely short planks. The remaining blocks in place do encounter the above problem (where the two planks meet) accidentally filled with epoxy on occasion. Where it has, I have simply filled the remainder of the joint with epoxy, which has caused no problems.

[Paul Silverman]

Since I'm not replacing any of the planks that are butted, scarfing is unecessary, though I recognize that it is ideal in new construction or replacing butted planks. If the existing planks were initially corked, they still are, since I haven't disturbed them much, but it looks to me like they were simply fitted tightly together originally (65 years ago). Regarding, putting new screws precisely where the old nails are, I've done this, to some extent, by marking the nail position, drawing a straight line from the hole for about 3 inches, filling the nail hole with doweling and epoxy, and then measuring back from the end of the line to identify the place where the nail was before drilling for a screw. However, most of the nails were nailed at various angles to the planks (to increase their holding power). The result is that the new screws probably do not use precisely the same holes. Most of the screws have "grabbed" into the oak frames well, and those that don't get removed, holes filled, and are redrilled elsewhere. Someone in a previous thread wondered whether I was doing more harm than good. She'll go into the water soon, hang in the travel lift to swell enough so that my pumps can control the water, and then hopefully tighten up. We'll see!