Tag: how-to

The how and why of filling fastener holes with glue and toothpicks

Porcupined is surely the ugliest we make each boat during preservation. RJ and I spent many an hour sinking three round, maple toothpicks, dipped in Gorilla Glue each fasteners hole. How many? We opened and inserted 10 boxes containing 1,500 toothpicks each, and two pints of Gorilla Glue while filling every fastener hole from stem to stern and waterline to keel.

Now we are assured that the thousands of silicon bronze screws we will use to fasten the planking will bite into new wood.

We allow the glue to cure for 24 hours and then shave all the offending toothpicks off the hull using our Fein Multimaster. Next comes three coats of Clear Penetrating Epoxy Sealer and the bottom will be ready for the next steps.

Ahead of that moment, however, we must deal with the holes through which fasteners are sunk and fasten the intermediate frames – the battens – in place. All 32 of them must be degreased, toothpicked, sealed with CPES and installed, bedded in 3M5200.

Even more tedious is dealing with the hundreds of holes left when we removed the ½ – ¾ inch pan head brass screws that Chris-Craft sank into the bottom planking from inside the bilge. RJ teased the tips of #10 screws into each of these holes, lest we generate a forest of 5200 stalactites hanging from the bilge.

The bottom planking, which is in superb condition and remains eminently usable, must be scrubbed and sealed with three coats of CPES, at which time we will complete installation and the modified True 5200 bottom milestone will begin disappearing in our wake.

Don Danenberg’s seminal piece on 5200 bottoms, “What is a TRUE 5200 bottom,” Classic Boating, September/October 2014) is a must ready for anyone undertaking replacing an antique or classic wood boat’s bottom. The section on fasteners is particularly apt in this setting:

“Stainless steel was invented in 1913. The 300 series (302-316) includes 18-20% chromium and 8-12% nickel. (316 has 2-3% molybdenum, which makes it slightly less susceptible to crevice corrosion.) In the presence of oxygen, the chromium and nickel form a surface coating that protects 70% of the material is mild steel. If you bury them in the hull, covered with putty and paint, they are cut off from oxygen and will soon corrode like mild steel. Only silicon bronze is long lasting here. The only apparent reason some use stainless steel is that, coming from Taiwan, they are cheap!

“It doesn’t matter if they are advertised as ‘marine grade.” That only applies in the presence of oxygen. Please see this website (sic) link: http://www.stevedmarineconsulting.com…

This clip illustrates exactly what Danenberg asserts. These fasteners have been in the chine planks for fewer than eight years, and have already failed completely.

Please insist on silicon bronze below – or near – the waterline. In fact, Snake Mountain Boatworks will not fasten anything but hardware with stainless. Yes, the silicon bronze, Frearson head fastener is much more expensive.

Here once again is a prima facie example of how eventual cost being seldom equals the initial price. Chines should not fail in fewer than eight years, and replacing them is far, far more expensive than the original cost differential between stainless and silicon bronze would have been had this owner insisted that only the latter be used to fasten her new chines.

Clinching (sometimes spelled “clenching”) is when you drive a nail that passes through both thicknesses of wood you are fastening. The tip of this nail sticks out about 1/4” and is bent over and driven into the wood.

That is all and good, but how about the poor person trying to repair or preserve a wood boat like the 1942 Century Imperial Sportsman that has been clenched?

If you can get to the edge of a board so fastened, and there is room for the tool, the nails can simply be cut off using a tool like a Fein MultiMaster.. It is quick, clean and relatively easy to execute. It also leaves the tip of the nail imbedded into whatever framing the nail was clenched to. Woe be unto the unsuspecting person who reaches in there with a fine handsaw or worse, has released the frame member that is too thick for some reason and runs it through his/her planer! Those blades are anything but free!
Seeing me with the Fein tool in hand, RJ suggested pulling them with a simple hand tool, a staple or upholstery tack puller.

Voila’! Yes, a bit of patience and care is involved, but the tool can be gently inserted beneath the nail’s head, which is then carefully rocked upward to reveal its shaft.

In the clip I used right-angle needle nose pliers to finish carefully levering the nail free. Yes, it works, but it is also clumsy and can exert too much force all at once. (Or the operator can do so!)

Shifting to a six inch, very fine flat bar is the answer. Levering it slowly caused the nail to rotate as it was releasing, thereby leaving only a very small hole behind, one that is easily repaired with toothpicks and Gorilla Glue and faired.

I do not recommend this method on planking that is finished bright as it does tend to tear the edges of the holes left behind on the outer surface’s. Here I would go back to the Fein tool method so I could either clench anew or use silicon bronze wood screws during reassembly.

Do not try to pull the nails out by hand! I did so and yelped. That copper head’s edges are super sharp. Putting your heart into your work is one thing. Bleeding on it is quite another!