Transom finishing

[davidpm]

I got a little carried away on a spindrift 10N and laminated 1/8" magahony on the transom which I intend to finish with varnish and regret shortly after.

So the question is what is the best way to do the joint between the transom and the rest of the boat? I plan on using that water based stuff Ray likes as I'm doing this in my basement and my wife is a canary when it comes to fumes.

I could just go for a knife edge or wrap the paint on top of my beautiful varnish an inch all around.

What to do?

[PAR]

I'm doing the same thing on a CS-17 with 1/6th inch mahogany veneer. Typically the planking is visible on the transom edge. I elected to use a 1/2" thick "look" to the planking. The edges of the transom were built up with thickened epoxy, against a dam made of a strip of wood, covered in plastic packaging tape. This is painted the hull colors and leaves a 1/2" reveal around the sides and bottom of the transom. The mahogany is "let" into the recess between the sides and bottom, in a bed of thickened epoxy. They'll be sanded flush with the fake plank ends and then the shooting match hit with Bristol finish.

Do yourself a favor and use the best clear finish you can afford, it'll save you effort come refinishing time. I'm not sure where you are, but here in Florida, the cheap stuff doesn't even last a year, before it's starting to change color, lose gloss and flake. The good stuff (I use Bristol) can last three years if well cared for, before repairs need to be made.

[davidpm]

I didn't think of the dam and 1/2" idea. So now I've got to figure the best way to finish? Probably should have thought it through a little more.

[PAR]

Bristol is a catalyzed polyurethane (which is what a LPU is) Ray, not a traditional varnish. The System Three clear is a WR-LPU (water soluble) and I use their paints sometimes, though Sterling's standard LPU has better gloss and color retention (slightly) then the WR-LPU's, but you pay for it. It appears the WR-LPU's also are slightly less hard then the regular LPU's, but the clean up, drying time and ease of use makes the WR-LPU's hard to resist.

David, I prepped for the fake transom planks, then 'glassed the boat, prepped for paint and then primed. Then I cut the veneers to fit the transom area, but will wait until the boat has it's paint on and well cured, before I glue the veneers in place.

[Charlie Jones]

Bristol is good stuff ( so far for us anyway) Laura redid the mast on Tehani just over a year ago and it's flawless still, and that in our Texas summer time sun. She's gradually switching over as things need refinishing.

The thing she liked most was getting 5 coats on the first day, then doing the finish coats the next, and only sanding once or twice. ;D

[Dale Niemann]

PAR,

Could you give us some photos of your CS 17 transom.  I am having trouble visualizing what you are describing.

Thanks,

Dale

[Tom Lathrop]

Charlie,

We see these photos of Laura spraying, Laura sanding, Laura doing this and Laura doing that.  What kind of division of labor have you got going down there?  Maybe it is that Laura does not know how to operate a camera and show photos of you working. ;D

Has Laura been made aware of her rights ??? ???

[PAR]

My digital camera was bought when they first came out and has something like a 1/100 of a pixel, producing barely in focus images. I do have it on regular film, but not processed yet.

The way I did it was to take a few pieces of scrap, the same thickness (actually slightly thicker) as the veneers I planed to use. I stapled this to the transom, 1/2" inboard of the edge on the bottom and sides. The wooden strips where covered with packaging tape before hand, as was the transom under the strips. I didn't want the putty to stick to anything except where I wanted it. I then filled the area with putty, sanded it flush with the tops of the wooden strips and removed the strips. This left a 3/16 thick (there about) reveal, 1/2" wide around the perimeter of the transom. This reveal simulates where the planking would be on a carvel built boat and is purely an aesthetic consideration. The reveal is painted with the rest of the hull. Inside the space created by the 1/2" reveal, I lay the mahogany veneers, sanding flush with the reveal. Fitting the veneers is much like any veneer work and requires precise fitting and cutting, but it's not so tough with very sharp tools and the willingness to take your time.

[attachment=1][attachment=2]

These are the strips, before getting back filled with putty. If it looks different it's because the transom is curved, not flat.

[Charlie Jones]

Tom- I do the gritty stuff like grinding fiberglass, etc. and most of the actual construction and fiberglass work. She does most of the finish work and is capable of doing most anything in the wood shop, so either of us might build wood parts.

She worked along side me for 7 years in the furniture shop, can run anything in there from sander to lathe to shaper. She isn't fond of the 3 HP router ;D

I or we have gotten this-"Hey Charlie- you did a GREAT job on that", when she worked as hard as I did on it. So I decided some while ago to be SURE she got the recognition and credit she deserves. So anytime I get a chance, I snap pics of her working on the boat.

She's a helluva good woodworker, and an excellent finish person. Plus seamstress- she does sail, Bimini and other canvas work also.

SO when people comment on our boat, I want them to KNOW that the boat belongs to BOTH of us, and is maintained by both of us.

AND- she's taken Tehani out on an 11 days single hand cruise-  She's an excellent sailor.

And cute ;D

Edited to add-

when we met, she was an industrial photographer for Lufkin Industries, photographing everything from the foundry floor operations, to aerial shoots of truck body's on the highway, to oil field pumping jacks. So she for sure knows cameras.

[Ken_Potts]

Charlie, I may have already asked this before but does Laura have a sister who's single?

[Charlie Jones]

She has a sister, but they are SO different ;D

Besides, the sister has two kids

[Greg Luckett]

Charlie,

Did you forget to mention that Laura is a darn FINE!! artist too?  Someday I hope to afford both a trip to visit you and have money to buy one of her originals.

Greg.

[Charlie Jones]

Yeah, but I had mentioned that before. She is an OUTSTANDING artist, in several mediums.

Most of them are stored on the laptop, which is packed away, but here's just three quick pics, one you should be familiar with ;D

[Dale Niemann]

Thanks PAR for your explanation.  I think I understand it now. 

What did you use for what you call "putty"?

This seems like a lot of work and precise fitting.  I do not think I am capable of this.

Tom,

How did you do your transom?

Thanks,

Dale

[PAR]

Dale I made a change to that transom yesterday. I thought about that putty (thickened epoxy) getting banged into a dock or other boat and without transom corner protectors, the putty wouldn't survive long. So, I ground the putty flush with the transom, ripped some white oak to just shy of the thickness of the veneers I'll use and made them a 1/2" wide. These were glued to the edges of the transom (I just removed the clamps) and given a very light rounding on the outer edge. These can take some beating without putty cracking and falling out. I'll epoxy them down and fair them in tonight, then they'll be ready for paint.

I like this solution much better because you don't have to be a wizard with a putty knife and the edges are machined, not cast to shape, plus the edge is a lot harder too.

The precise fitting part comes when I do the veneers, but all veneer work requires this type of fitting.

[Dale Niemann]

Thanks PAR that makes more sense to me.

Dale

[SUKIE]

Hello PAR,

Your solution looks like a good one, but I have a couple questions. I've been told by a boat builder that epoxy doesn't adhere well to oak, although I've used oak myself myself once and so far it's OK. Have you used it anywhere that it's survived the test of time?

Also, I like the idea of dressing up the transom and have been thinking of doing mine (CS 17) with cedar strips, possibly edges with oak as you suggested. Any thoughts on that?

Sukie

[PAR]

Yes, I've used oak of two types for many years, if prepped right, the wood fails, before the glue line. I've laminated ribs as replacements for steam bent, made scarfed in repairs, deck beams, trim, etc. If I have the luxury, I'll use resorcinol, but this requires a perfectly fitting joint, lots of clamping pressure, a well stained glue line (too much for bright finishes) and a good watch on conditions. Often, especially in repairs, you just don't have all of these requirements satisfied, so epoxy is the choice.

I prefer live oak where strength is most important. It's interlocking grain resists checks, splits and not as much movement as other "whites". If your laminations are thin, below 15% moisture content, well sanded and very clean, a quick scrubbing with some solvent will remove the tannins and a good bond can be had. If you're laminations are thicker then say 7/16" then you can run into trouble trying to epoxy oak. Also if it's not clean, dry and well "toothed" you can have issues.

Oak, like all hardwoods move a lot more then softwoods with moisture content. This sets up internal strains inside each piece. If the piece is thick enough, sufficient internal strains, plus the weakened bond to remaining tannins, will cause the joint to fail. This is only true of epoxy as an adhesive in pieces that will wet/dry cycle. It's this wet/dry cycling that causes the internal stresses to set, then relax, then set up, repeatly. It will eventually cause the glue line to fail, if the piece is big enough (thick) to generate sufficient internal loading. By keeping the laminates thin, these stresses are kept under control with the multiple glue lines and the bonds.

If using oak like - this prep the pieces, then scrub (not just wipe) each bond surface with denatured alcohol or other suitable tannin solvent. Do this just before applying epoxy (let it flash off naturally) and the oak will bond just fine. I usually don't use pieces thicker then 3/8". The strips on the transom were about 1/8" thick. These transom pieces will become (tonight actually) part of the boat, being faired in and painted over with the rest of the hull.

I recently replaced and repaired a handful of ribs in a 50's vintage power cruiser. The original white oak ribs had some tension cracks and a few broken ones. I made a jig for bending the replacements and repair pieces. Then I steamed 5/16" by 1" wide live oak stock for about 20 miniutes. They were placed in the jig, three deep, per station and let dry for a few days. They were labeled, removed and prepped for epoxy, buttered up, placed back in the jig and wedged in place. When they came out of the jig again they were roughly an inch square. They were fed through a table saw to square up the sides and sanded smooth. These ribs and rib repairs (some were scarfed into existing ribs) will out last the current owner of the boat and I'll be long dead when they fail. With paint on them, you can't tell they're laminated ribs, though these happened to get a few coats of 3 pound shellac. I don't plan on dieing soon eather.