Installing the Minnow’s True 5200 Bottom is progressing nicely. Three-quarters of the bottom planks have been fabricated, which has turned into a near-Herculean task. Why? None of the planks has parallel sides, and the degree to which each plank tapers from chine to keel differs from board to board.
And using the boards from one side as patterns for the other? Well, they are close, but close does not deliver perfect mating with the two boards on either side of the one being fabricated.
John has patiently sanded every plank in using our 36” horizontal, stationary belt sander.
As you see, we lay all the planks out, placing one positioning fastener in each, and then laying out a grid for all the fasteners, and drilling all of the countersink holes, so that the planks end up screwed down where we want them to be.
We test as we go, choosing between #6 and #8 silicon bronze, Frierson wood screws ranging from ¾” to 1-1/2” long.
Why not stainless? Read Danenberg’s article in the Sept-Oct 2014 issue of Classic Boating magazine to find the clearest, science-based, and most objective explanation I have read yet.
Each plank is literally buttered with a 1/8” thick layer of white 3M 5200. Why not mahogany? It costs about 50% more because of the color alone. Since it will end up hidden by five coats of Interlux 2000E Epoxy Barrier Coat Primer, selecting mahogany just wastes money.
As you see, John drives the screws in with an impact gun, and then pounds and pounds the edge of the plank with a large rubber hammer. Doing so drives the 5200 all the way out and beyond the plank’s edge.
What we did not show was the next, not-so-fun step, cleaning the excess 5200 from the plank’s face, edge and surrounding area. Pay special attention to cleaning the trailing edge so that the next plank fits snuggly in place.
Interlux will happily sell you 202 or 216, or some other more exotic solvent. Acetone is our go-to solvent throughout the shop. Unlike the expensive thinners, it flashes off almost immediately, and leaves no residue behind, oily or otherwise.
As John remarks in the clip, “There is nothing clean about installing planks as part of a true 5200 bottom!
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1930 Dodge 16′ Runabout 5200 Bottom Update 1 13 2015
We have been so busy making progress elsewhere that we have been unable to get back to the 1930 Dodge Runabout 5200 bottom project until yesterday.
As of this mid-afternoon yesterday, John, RJ and I have finished re-sawing and milling FAS grade mahogany planks – 6/4×18”x16.5’ – into a collection of 1/4×6-1/2”x48” bottom planking blanks.
John then began fabricating new bottom planks, one-by-one, since ever one is different from all the others. We find John now having fabricated all of the starboard planks, and, as the clip closes, beginning to seal each of them on all four sides with CPES.
We hope to begin screwing them down, heavily bedded in 3M 5200. In his recent article, “What is a True 5200 Bottom?” (Classic Boating, September/October, 2014), Don Danenberg is blunt about how skimping on 5200 simply translates into fool’s errand now, and troubles lurking on the horizon:
In communication with the two 3M scientists who invented and developed the 5200 product, I was told that one of their first, largest customers was Chris-Craft, who used it to replace the two-part Thiokol they were currently using in the plywood Cavalier and Sea-Skiff divisions. It was apparently tried in the main division of planked boats but added far too much in construction costs to be cost-effective. Higher-end boat builders, like Trumpy
Yacht Company, used it as their standard construction procedure after 1966.
The biggest problem I’ve seen here is inadequate amounts being used. Where I recommend 40 to 60 tubes just for the bottom plank installation, these troubled guys reported they had been billed for 24 tubes. This is simply not enough product to fill all voids. Okay, so you saved a few hundred bucks, but compromised the entire operation?” (p. 24.)
Also following Danenberg, five coats of Interlux 2000E Barrier Coat Primer will be applied once the bottom has been installed and the 5200 has cured, a process that takes 7 days.
Quoting Danenberg again from the same article:
“One of the biggest problems I have seen with short-cut 5200 bottoms is either a total lack of, or inadequate amounts of, Interlux 2000E Barrier Coat Primer. This two-part (thus epoxy) paint is a water barrier coats meant to keep the water from soaking into the bottom planks. It does that with minute platelets in the makeup that vastly slow the movement of water. Unlike hard epoxy laminating glues, it is flexible enough to move with the bottom.” (p. 25.)
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Wood Boat Varnish Buffing – RJ’s Clinic
The last coat of varnish has been oh so carefully rolled and tipped. The mahogany gleams, but up close you see a bit of dirt, or maybe even lots of dirt has been trapped on your otherwise gleaming surface.
Using a pneumatic sander set at about half-throttle, RJ begins the buffing and polishing process wet sanding through five increasingly finer grades of wet/dry paper: 1000, 1200 1500, 2000 and 3000. His goal here is sanding every scratch out of the surface without cutting through the built-up layers of varnish.
After carefully wiping the surface dry, first with dry paper towels and then with Acetone, it is time to begin buffing the surface using our Makita buffer set at approximately 2,000 RPM and the Presta Buffing System.
The first two grades of buffing compound, Ultra Cutting Crème and Ultra Cutting Crème Lite, are applied with an 8-inch wool cutting pad. The final step, using a 9,000 grit foam pad, uses Polishing Crème to bring the surface to a brilliant shine.
Getting a fantastic gloss is all about achieving a flat surface, one that is completely devoid of scratches and even tiny hills and valleys. Compare your reflection in a cheap big box store mirror against it in a high-end mirror. The first can be wavy and even distorts the image you see, while the high-end mirror reflects all that stands in front of it perfectly.
Our goal is transforming that varnished surface into one that is as close to that high-end mirror as is humanly possible. Do it well and you see a face smiling back at you as you peer into its surface.
How We Strip Varnish at Snake Mountain Boatworks
There’s nothing fun about stripping varnish from wood chemically, except being finished.
Here I respond to the several messages and calls I have had in recent days asking how we strip varnish at Snake Mountain Boatworks.
Well, here is a short how-we-do-it clip that I hope answers these questions.
The first key is to puddle the stripper on as thickly as possible. Yes, vertical surfaces present particular challenges, but even here, slather it on like it is shaving cream, not a carefully applied coat of varnish.
Patience is the second must. Let the chemical reaction work. Wait half an hour or so, maybe even 45 minutes and sometimes an hour, and then slather it on again, paying special attention to any dry or dull areas. Wait again, much longer than I do in the clip. (Stripping paint typically involves three and even four applications before we begin scraping. I have sometimes applied stripper throughout the day, leaving it to work while attending to other tasks, and then attacking it with my scrapers late in the afternoon.)
After suffering lots of frustration with the cheap Stanley and hardware store brands that are poorly designed and do not stay sharp, we have standardized on Sandvik scrapers and BAHCO blades. Yes, they are much more expensive at the front end, but work unlike any other scraping tool we have tried.
Now you want to take long, purposeful strokes, keeping steady pressure on the surface. Draw the gooey material towards you. As illustrated in the clip, when I am working with released planking, I take advantage of rolling staging so the work is at about waist level. A waster barrel and trash bag are placed beneath the work area so that I can continually slide leavings into it.
More work awaits you once the varnish is released, as the wood is still streaked with residual stain that must be extracted from the wood’s fibers. I apply a thin coat of stripper and immediately begin scrubbing the surface being mindful not to go cross-grain, using one of those stainless steel pot scouring pads you can purchase online or at your local super market or hardware store.
The scrubbing continues until the residual stain is gone, the wood takes on a luster and it is dry, absolutely dry.
Then it’s on to the next plank…
’52 Chris Craft Riviera Varnish Update 12 24 2014
RJ sanded into the night last night, and he and John cleaned every square inch of this 1952 Chris-Craft Riviera’s hull early this morning before they rolled and tipped the next coat of Pettit Hi-Build gloss varnish.
I hope you can see how RJ’s dedication to achieving flat is paying dividends. The sheen is more uniform and becoming brighter as well.
Another coat will be applied Friday, after which it is snow field time again on Monday, albeit with 400 grit dry paper.
We will update you again next week.
’52 C C Riviera Make it Snow and Get Varnish to Die For! 12 23 2014
What do I mean when I say, “Making it snow is the key to delivering varnish that is to die for?”
Here is the answer. Although it may seem counterintuitive, the gloss and ability to reflect light varies directly with the degree to which the surface is flat. The difference between an inexpensive mirror and an expensive one can be seen by your reflection when you look into it. The silver plating on the expensive mirror is absolutely flat, so it accurately reflects light rays hitting it. The cheap mirror’s wavy reflection tells you that its surface is less than absolutely flat.
Here RJ appears to be destroying the glossy surface evident in the last Riviera project clip. It looks like snow, yes? And that is your goal at this stage of the varnishing process.
RJ sanded the surface lightly after three coats of Pettit Hi-Build gloss varnish had been applied. Now, following allowing the fifth coat to cure at 65 degr4ees and 60% humidity for 24 hours, it is time to go for flat. He is able to use the random orbit sander and 220 grit on the flat areas, of which there are precious few on the Riviera’s hull.
The rest, and especially on the corners and edges, and on the rolling gunwales and covering boards, he must sand by hand. using 2-1/2” wide strips of Sikit Gold Roll P220. That sea of discarded strips on the floor around the boat speaks volumes about how quickly the paper fills and thereby becomes useless.
Your goal, one that must be achieved without cutting through the varnish to wood, is a uniformly dull snow field, as RJ explains in detail here.
Coat number six will be rolled and tipped tomorrow morning, and we will share the results with the community in a follow-on video.
’52 Penn Yan Captivator Bottom Plank Removal 12 16 2014
Thanks to the several of you who asked to see how we excise a bottom plank once all of the nails have been removed.
Here is a clip showing John and me, but mainly John using one of our Fein Multi-Masters and a smooth semi-circular blade to literally vibrate through the wood filler that the previous worker, now dubbed Bondo Man, insisted on paying into every seam.
This stuff is now akin to concrete. Our challenge is to cut through it without damaging the edges of the neighboring planks.
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’57 Penn Yan Captivator Bottom Transom Deconstruction Update 12 16 2014
Well, our hopes for repairing rather than replacing bottom planking was dashed as soon as we did a bit more exploration. Test extraction of several fasteners produced once-copper, now rusted ring-shank nails. And applying pressure externally while John observed from beneath the boat unearthed another problem. Much of the planking is no longer well-fastened to the ribs and/or framing.
Bottom line, we have begun releasing the most severely split planks, and will replace them. And we must refasten the bottom planking to the frame.
At the same time John began exploring the bottom transom board in hopes of determining where the Dutchmen patches must go. Well, there will be no Dutchmen patches as the wood filler also held moisture, and 90% of that transom plank is gone. Gone as well are large sections of a thin sheet of marine plywood that spanned the transom inboard of this plank.
It is not pretty, but hammer and chisel are the go-to tolls and technique for this job. John will continue excavating until he has removed this entire plank. The final result, fabricating and installing an entirely new plank will produce the correct result, but doing so is hugely time-consuming.
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1957 Penn Yan Captivator Bottom Stripped 12 15 2014
DeWe flipped the Captivator, fully intending to extract all of the residual black walnut stain from the topsides using Circa 1850 paint and varnish remover. But I decided to test removing the bottom paint, first with a heat gun and scraper, and when that failed, grabbed our infrared Silent Stripper.
The entire bottom had been glazed with the same wood filler we have already encountered elsewhere. In some places the “glaze” was as much as 3/16” deep. The heat gun softened the paint, but scraping it off the filler proved impossible.
Even though its operating range is 300-500 degree Fahrenheit, the filler began vaporizing and smoking, and quickly even a full-face respirator failed to protect me against the noxious odors and gases, so away it went.
While I do not enjoy using a chemical removed in the presence of what I am virtually certain is lead paint, a test with the Circa 1850 not only bubbled the paint, it also softened the filler to the point that, with lots of effort, I was able to scrape 95%+ of it down to bare wood.
My attention turned to stripping the bottom below the waterline, so the topsides are still waiting to be de-stained.
Sanding the entire bottom with 100 grit followed the stripping, and then I began inspecting the bottom for issues and defects, of which you will see were many indeed.
At this juncture our hope, not our expectation, is that we can repair the damage and issues you will see in this clip. Time will tell whether repair morphs into required replacement as we begin working on the red cedar bottom planking.
57 Penn Yan Captivator Stripping Milestone 12 10 2014
DescriptionIt was a long, long day. With heat gun in hand, RJ completed stripping the coamings and the dash, but the starboard topsides were all mine.
Several of you questioned why I am not using a chemical stripper like Circa 1850 on the painted splash rails and eventually the bottom. We cannot be sure that we are not dealing with lead paint. Since lead will not vaporize below 1,000 F, so we set our guns at 900 F, which keeps the lead encapsulated with the scrapings, which remain dry and safe to handle.
RJ carefully released the stem-to-stern long spray rails, despite the forest of sheetrock screws from the outside-in, and an even denser forest of stainless square drive screws driven from inside and through the topsides every 8-010 inches. Happily with a bit of repair using Total Boat Thixio thickened epoxy, the starboard spray rail can be saved.
And the best news of all is that there is no rot in the topside planks behind the spray rails. We did unearth some rot in the three aft-most starboard ribs. The ribs will be sistered using steam-bent white oak.
The aft section of the port rail must be fabricated anew. We will match the factory scarf joint found on the starboard side, thereby producing a result that, other than the new white oak, matches the original design.
I misspoke in the video when I said she is ready to move into the main shop and flip. Before that can happen we must extract all of the residual black walnut stain out of the mahogany topsides, decks, coamings, etc. using Circa 1850 Heavy Body remover, scrapers, brass brushes and repurposed stainless kitchen scouring pads.