Refastening the 1960 Cruisers Seafarer bottom has launched in earnest.
Here I share the how and why of filling fastener holes with hardwood (maple) toothpicks and glue. Doing so gives us fresh wood into which we will drill pilot holes and new countersinks. Not doing so risks having screws spin out, or worse, never bite into the wood.
Tomorrow I will use a Japanese cabinet maker’s saw and trim off the protruding material flush to the surface.
We will also replace the original #8 x 3/4” silicon bronze screws with #8 x 1”. Given that the sheathing is half-inch thick, the longer screw will be driven about 5/8” into the ribs thereby assuring stronger fastening.
I have had several requests for a video showing our crew installing the bottom planks into a bed of 3M5200.
Here it is. Using the 1959 17’ Chris-Craft Sportsman as our “lab rat,” John and RJ share some of the tricks we have learned that help us ensure a complete seal between the planking and the plywood outer skin, and, what in some ways is critical, that the 3M5200 ends up where we want it without suffering hours of misery cleaning the 5200 off places it does not belong – in countersinks, oozing between the planks, and – horror of horrors, dripping down the topsides.
First and foremost, as Danenberg urges to all who will listen, scrimping on the 5200 translates into a shortcut 5200 bottom that will not last. Lay it on … thickly. We lay down at least 1/8” to 3/16” of the goo. Yes, that translates into a huge number of very expensive tubes of 5200, probably at least 60 for the layer between the inner plywood skin and the bottom planks in this case of this 17’ hull. And, yes, you will end up removing lots and lots of the stuff where it squeezes out through the seams. But, as is so trite, but also so true, price and cost diverge quickly here. A proper 5200 bottom means investing in mountains of 5200. Do it right, however, and you have a bottom that will last many decades. Take the shortcut route and, well, you might well experience the pain and suffering of removing a failed cheap alternative.
And, not Life Caulk, which is fantastic when used for its intended applications, cannot be substituted to save money. It’s cheaper now for sure, but oh so much more expensive in the long run.
We use blue painter’s tape to keep the 5200 away from adjoining planks and also the surface of the plank being installed. You will see how in the clip.
We learned the hard way what a disaster we and you will have on your hands if the 5200 pushes up through empty pre-drilled fastener holes. The silicon bronze fasteners, the drill bit, the disposable gloves, and the plank’s surface end up hopelessly befouled by 5200. Yes, it can be cleaned using Interlux Brushing Liquid 333, but why put this horror show on you when a technique John and RJ developed absolutely ensures no fountains of 5200 rising through fastener holes?
As with so many super creative and completely intuitive solutions, this one is trivially simple. Sink a fastener in each hole, but stop just short of driving it home. The fastener head will have seated in its countersink just enough to act as a seal. No 5200 can squeeze by.
Once all of the fasteners have been sunk in this manner, a crew member begins at each end of the plank, driving them home. As is illustrated in the video, yes, there is squeeze out, and lots of it, but the escaping 5200 lands on the blue tape, not the wood, or the screws or the gloves, well, not so much on the gloves.
Once every screw has been driven home, the squeeze-out is scooped off the tape using a combination of a plastic scraper and a simple wood paint stirring stick. Having removed all of it, we simply pull the tape, leaving an almost clean surface.
Using Interlux Brushing Liquid 333, we then scrub everything absolutely clean. However, the 333 actually retards 5200 curing, so the final step involves wiping everything down with Acetone.
“Always start with the least abrasive grit that will work, as you don’t want to remove any more of the finish than necessary…” (The Brass Bell, “Buffing Varnish,” p. 42. https://www.dropbox.com/s/z6hzszvd760…)
Industry Standard: 3M Finesse-it II (www.3m.com) will remove up to 1500 grit scratches, but our goal is to remove scratches down to 3000 grit. (Here is where we stopped buffing Voodoo Child, my 1953 22’ Shepherd Model 110-S.)
1. Using a 1,500 RPM pneumatic palm sander, we sand the surface using 600 grit dry paper until it looks like a field of unbroken snow.
2. Wet sand using rubber hand sanding blocks through a progression of papers – 900 1200 1500 2000 2500.
3. Wet sand using the palm sander and a continuation of ever-finer grits – 3000 5000
4. Using a variable speed electric Makita buffer and a foam waffle pad, we first buff with Mequiar’s (www.meguiars.com) Mirror Glaze, first with M105 Ultra Cut Compound, and then with Ultra Polishing Polish 205.
I will allow John and RJ to fill in the rest of the story in this flip
This morning’s 1942 Century Imperial Sportsman preservation project update is a plea, “Please, please do not pay 3M5200 into below-waterline seams.”
It is an adhesive, not caulk, pure and simple.
I have lost count of the number of otherwise wonderful woodies who arrive at the shop presenting curtains of old 3M5200 – stalactites – hanging from the bottom plank seams.
Once cured, 3M5200 will not compress when wetted planks try to expand. The result? Here is stark evidence of what happens next. The planks buckle and split, as several of them have in the ’42 Imperial Sportsman.
I have begun cleaning the seams using a curved pick and a reefing hook, supported by utterances that are for other than polite company.
As John noticed when he examined my growing pile of released 5200, “Most of this stuff never even adhered to the edges of the planks! Look at all the dirt and debris. So, not only did putting it in there buckle planks, it did not even work as an impediment to moisture infiltration!”
Right and right.
OK, what will we use in its place? I am opening seams that are up to 3/16” wide, which is at the outer limit of what it can bridge effectively, but we will use Interlux Seam Sealer for below-waterline applications. It cures, holds paint, and makes a watertight seal, but, even when cured, it never becomes hard. It compresses as the planks expand and expands if/when the planks shrink.
After applying the CPES and one coat of Interlux 2000E barrier coat primer, we will work up to three coats into the seams until they are almost fair with the planks. The wider seams may require more.
Some folks use Life Caulk for this purpose, a product I have used for bedding sailboat deck hardware, but never below the waterline, so I really do not have a view on its efficacy or appropriateness for this purpose.)
Then we will apply four more coats of the 2000E before we apply one coat of Pettit Tie Coat Primer and at least three of the deep, dark green topcoat our owner has approved. (Since she will be a trailer boat, We will likely reach for a paint like Interlux Brightside or Premium Yacht Enamel, unless we can find a gloss hard bottom paint.)
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.
By this time next week we should be fabricating and installing the inner layer of 1/8” Aquatek marine plywood to the bottom.
John will first fabricate an entire set of paper pattern sheets for each of the two surfaces and transfer them to the plywood. Once each component is cut and installed to test for fit, it will be removed and all sides will be sealed with Clear Penetrating Epoxy Sealer, followed by two coats of Sandusky Chris-Craft Red Mahogany bilge paint.
Then all three of us will work together applying mahogany 3M5200 to all ribs and other landings, followed by sinking thousands of silicon bronze screws.
The fun begins once the plywood is screwed down – cleaning the squeeze out, and there should be copious amounts of squeeze out, or you have not applied sufficient 3M5200.
The mahogany planks are next, and, while we will do our best to save the original planking, it is in pretty poor shape, which will force us to fabricate new planking using the originals as patterns.
But such considerations push us way ahead of where we are now, which is all about passing the bottom framing complete milestone!
Given the evidence that it has shrunk – a very wide seam between it and the next transom plank above, I fully expected to release the bottom transom plank.
However, the prospect of first stripping bottom paint lying on my back and then releasing all the fasteners driven through the tails of the bottom planks and into the bottom transom plank was foreboding at best.
Then, when I was having difficulty with the last few fasteners, I called in, RJ, who has what he terms his “special touch” releasing buried wood screws. As the last one backed out, RJ exclaimed, “I think your plank is free already!” And it was and is. We now know that Chris-Craft moved the final course of fasteners forward from the tails, just enough that they are driven into the transom frame’s bottom bow.
The attempt to waterproof the seam along the bottom edge of the bottom plank was attempted using the oil-permeated canvas we have all seen when releasing bottom planking. Suffice it to say that, like the stuff under bottom planking, this course of canvas had long since lost whatever waterproofing qualities it had in 1959.
When the time comes we will install the bottom plank bedded in copious amounts of mahogany 3M5200.
A combination of finding green, and therefore moisture adulterated, fasteners behind the test bungs I popped, and a ubiquitous design issue that translates into a chronic, although slow leak, we also released the next transom plank. The issue occurs at both ends of that plank, from its bottom edge up about 2 inches. Chris-Craft originally sealed the seam between this plank and the transom frame member it lands on using the same sealer-impregnated canvas technique.
However, each of the first 3 1954-1959 17’ Sportsman models we have preserved to date tended to seep water through that joint until we bedded them in 3M5200.
Proving that even old boat guys can learn, we routinely release this plank, remove what is left of the canvas and install it anew bedded in mahogany 3M5200.
With Christmas weekend peaking over the horizon, cleaning out the bilge and then pressure washing it will not begin until next Monday.
The goal here is removing fairing-compound-filled countersinks and releasing the over 1,000 fasteners driven through the bottom planking and chines without damaging the edges of the countersink hole.
We begin with a portable drill and drill bit. (We use a pilot bit because it can withstand lateral pressure without breaking.)
Why drill all these holes? The Rotabroach cutter includes a positioning, spring-loaded pin. Yes, it can position the cutter in the countersink center, but it quickly gets loaded up with residue and fails to pop out once a countersink is opened. Then it walks across the plank until you grab a vice grip, remove the cutter and clean it.
Drilling the pilot hole gives the pin someplace to go without being pressed into the cutter head.
Next clean the hole using a scratch awl, and then the Frearson head slots using a pick, and blow the hole clean with an air chuck. (A shop vacuum will work here if the crevice tool is used, but the blast of compressed air cleans much, much more thoroughly.
Grab the impact gun to which you have fitted a #2 Frearson (Reed & Prince) driver and carefully back the screw out. (The impact gun’s trigger must be feathered so that it turns as slowly as possible for the initial rotations. A portable screw gun can be used, but it is much slower.)
The mini hook comes into play for those fasteners that simply spin in the hole. Carefully work the hook under the screw head and apply a bit of upward pressure by levering against the edge of the countersink. (Yes, “unpleasant” utterances are part of this process.)
Once you have all the fasteners – which you absolutely will not reuse – safely in the recycling bucket, and have teased all the planks off the inner planking, you are ready for the next steps. In the case of the ’59 Chris-Craft Sportsman, since the plywood inner skin presents as almost new, the next step is scraping all the canvas off, cleaning the surface and proceeding to toothpicking every fastener hole in the entire bottom.
Once you have inserted 4 to 5 toothpicks dipped in Gorilla Glue, or about 5,000 in total, into all the fastener holes, and the glue has set, reach for your Fein Multimaster and “shave” the plywood. What a mess!
Time for CPES, 3M5200 and installing bottom planking!
Ninnyfish is slowly coming together, but only after she rose up and demanded more attention than we had included in our expected scope of work.
Once released for cleaning, sealing and priming, we discovered that the keelson and keel were badly hogged in a matching pattern. And there is a full ¼” deep layer of rot on the keel’s inner face. Neither could be saved, and both have now been fabricated from FAS grade white oak. Both have been sealed with three coats of CPES and primed with multiple coats of Interlux 2000-E. As you see in this clip, the new keel has been installed and is as straight as an arrow. Yahoo! (not @yahoo… )
Happily, a close inspection of the hull confirmed that every clinch nail remains solidly in place and tight, but wood shrinks just enough over the years that most of the heads were proud of the surface. Fairing every strake from stem to stern using 3M Premium Marine Filler, which is approved for both above- and below-waterline applications provides the solution.
But first RJ sanded the entire strake surface with 80 and then 120 grit longboard paper. (We use the longboard here to protect against producing the moonscape look we have encountered in way too many hull surfaces.) Three full coats of CPES followed the sanding.
John then taped all of the strake-to-strake seams to keep the Filler out of these difficult-to-sand areas. Applying two coats of the Filler followed. He has completed applying the Filler on port and is now sanding the surface, again with 80- and then 120-grit paper. The sanding is accomplished with a dual-action random orbit sander, which John moves quickly over the surface.
Once the sanding is complete, he will seal every strake-to-strake seam with white 3M 5200. Starboard awaits…..
Ninnyfish, a 1949 13.5-foot Lyman Leader, came to us for a complete preservation. In the process of stripping many, many pounds of paint, we discovered extensive rot in her transom, transom gussets and interior transom framing.
Replacing all of it was our only choice.
A major source of the problem is that Ninnyfish was painted with other than proper bottom paint from the waterline down. That paint has failed severely over the years, and the worst of it was the transom’s bottom plank and the seam between the two transom planks.
Someone had attempted to address the issues by excavating that seam and filling it with some sort of 5200-esque goop. While the intensions were good, the result was a huge water trap that spanned the entire seam.
Happily the aft ends of the strakes are fine. No rot has been exposed there, or anywhere else on the entire hull, save for the one small outer gunwale failure on port where a bolt passed through the gunwale and secured the forward leg of the transom gusset on that side.
We will finish the interior surface of the transom planks and all of the transom framing ahead of putting everything back together. (While the exterior surfaces will be stained with the Sandusky Paint Company’s Lyman Mahogany filler stain, we will add some walnut to these interior surfaces so they more closely match the stain we found there.
