Refinishing Woodwork & Problems with Wood, Polyester and Glass Construction

This is from the e-mail list, in response to some Bill Green questions.
Bill,

I have a Lindsay (7151) with wood tanks and foredeck. It was pretty beat up when I got it last January. In May, I sanded it to bare wood and refinished it. There has been no maintenance required since, and I don't expect any for years. The boat sees its share of use and abuse, it is sailed at least once a week, often several times a week. We once bumped the boat's rails on a concrete wall and dented them without cracking the finish.

The answer to your question is that the quality of the finish determines the amount of maintenance required. A cheap, non UV protected varnish may need to be stripped and reapplied annually. I applied a layer of West Systems followed by a layer of 4oz fiberglass (it turns invisible), three more layers of West, and then 5 layers of clear Interthane Plus. According to the guys at West, the fiberglass is the secret to low maintenance.

Let me know if you'd like further info on the finishing process.

jef
US7151


You didn't mention if your boat has wood tanks, or just foredeck. I did my entire boat in less than four weeks, working weekends and nights. Three weeks of it was sanding. I had to sand through some old West (it is a very hard surface).

The finish part goes fairly quickly. The West layers were applied 4-6 hours apart and took less than an hour per layer. The Interthane only took 30 minutes to apply and required very light sanding between layers after drying overnight. An option is to skip the West and go straight to Interthane Plus.

jef


Am I correct in assuming that using just the interthane is an option only if the base coat of west epoxy is in good shape?

I'm not sure... My guess is that Interthane is not as hard as the west and doesn't bond as well to the wood. Without the west, the boat would be more likely to get scratched or nicked to bare wood. (Trapeze hooks and both ends of the boom seem to hit the tanks quite often.) The varnish would start to peel around the exposed wood and the maintenance nightmare begins.

The west guys told me the benefits of a layer of glass are that a much thicker finish is obtained with fewer layers (less weight) of epoxy, the glass makes a stronger finish, and the west is less likely to peel if nicked because it is bonded to the glass in addition to the wood. This all seems to be accurate as I've yet to get a scratch through to the wood.

Another issue is that both finishes need to be applied at temperatures over 60 degrees.


Hi everyone,

Since there has been a lot of replys on my answer to bill i thought that I could share some more of my experiences on: -working with epoxy:

  1. choose the right accelerator

    we used the SP 320 system on our boat. When you purchase these systems you can choose between different fast accelerators for the harts. We chose the fastest one which gave us a "pot time" (the time you have to aply the epoxy before it's starting to get hard) of about 15 minutes.

    I wanted the hartz to get stiff as fast as possible so it stays there where I had applied it and wouldn't "run" away.

  2. prepare your work properly, you don't have much time once you have mixed the accelerator and the hartz.
  3. Be sure to have the right mixture ratio, unlike polyester where the accelerator just is a accelerator that accelerates the process and where it isn't so important if you use 2% or 5% of the acc., in epoxy both parts take part in the reaction and will build the final molecular chain. Too much or too little of one part will result in a bad reaction and a less strong coating.
  4. Remember that epoxy has an exothermic reaction. This means once the reaction starts it will generate heat. The smaller the pot the faster the reaction. A big amount of a hartz in a small pot can get so hot that it almost starts to burn, at least it will smoke!!!! and the pot time will just be a few minutes. So use a big enough pot or put your small pot in a bigger one filled with cold water.
  5. don't try to paint the whole boat at once! Take smaller sections like the fore deck or one side tank and complete them. If your hartz gets hard you won't lose so much.
  6. start in one corner and stop at the other, if you have to correct something do it fast. Once the hartz starts to get stiff you can't correct any mistakes anymore.
  7. Make your grounding probably and get rid of all dust on the boat and in the air. I used a humid cloth to remove most of the dust and then a special electrostatic cloth to remove the rest. I didn't use thinner or acetone. thinner is good with normal varnish and I wasn't sure about the acetone and epoxy.
  8. IMPORTANT!!!! When you clean a wooden boat from all varnish be sure that you have enough humidity in the air; if the air is too dry, the boat will start to crack. A too dry enviroment can make big damage just over one night!!
OK it seems I could write a book about this, but I don't have the time. So I stop here. if somebody has questions don't hesitate to ask.

Thomas


Nobody mentions whether their wooden boat is sailed in salt water. I have been told this makes a big difference, and it makes sense that the salt would preserve the wood.

My boat has been mostly sailed in fresh water for 10 years, and I have had annoying rot problems. Last summer it was out of action for a month.

So if you say you spend more time sailing than repairing, please would you mention whether you sail in salt or fresh water?

cheers -- Rick


Rick, etal,

I don't know where this info comes from. I have heard it before. However, It is NOT true. I know of no marine grade epoxies or varnishes, including polys. that because of their immersion in salt water, give way any quicker than in fresh. The fact that salt may preserve wood, which doesn't happen by merely dipping it in salt water, is not relevant. If you are spending an inordinant amount of time dealing with rot, dry rot, staining etc, it is because water is getting to it. Dry rot is not dry. But that's another boring night. To simplify, the problem is #1 the initial work was not done properly, which may include and generally does, not getting all of the offending problem the fist time. Or #2; Preventive maintainance is lacking. Preventative being the key word with a woodie. Even for those of us who let a nick dry out and immediatley touch them up with a light sanding and coat of epoxy or varnish, every 2 or 3 years will require a bottom up sanding and refinish job. Inside and out. UV damage to most finishes is also extremely under rated. Pin holes in a finish that are allowed to remain will literally wick moisture into the hull. Another problem is osmosis. Regardless of how exceptional the finishing job, no one has found a way to eliminate osmosis. Owning a woodie is tough. There is no easy way to avoid work if you have one and plan on keeping it. Starting with a ground up refinish job done properly and with a great deal of patience is the best way to keep the boat on the water and out of the garage for the longest periods of time. Any other thoughts on the subject?

Bryan


Rick Leir wrote...

My boat has been mostly sailed in fresh water for 10 years, and I have had annoying rot problems. Last summer it was out of action for a month.

Rick, other all-glass Parkers similar to yours (mid '80s), sailed on salt (though Chesapeake Bay is not as salty as the ocean) water have had similar problems. I believe this is largely due to the construction. I took a close look at Parker 7678, and noted the following:

the CB cap was balsa cored. It was flimsy, and water had gotten into the balsa core around fitting mounting holes (the shroud tension cleat is high load and had turned the round bolt holes into ovals..) and rotted out much of the core, such that part of the cap was coming apart. While probably not the best place to use cored construction, Parker should have used foam not balsa if they felt they had to core it.

The plywood bulkheads were simply painted with polyester resin. Polyester is much more permiable than epoxy; polyester does not seal the wood from water. Putting glass cloth and polyester resin over wood is probably even worse, and may account for the rot where the shroud extensions are turned to go aft (I believe several boats of similar construction have had that problem. I believe that is plywood with glass cloth and polyester over it. I would expect rot in the bulkheads were the fillet (against seat tank) touches the wood. In those cases, water gets in, and does not easily get out.

I think the way you are supposed to do this is completely seal the wood with epoxy, so water never gets in.

George Saunders, current owner of 7678, has almost completed a rebuild which includes a new CB cap and mast step, new thwarts, etc. I'm looking forward to seeing the boat!

To simplify, the problem is #1 the initial work was not done properly, which may include and generally does, not getting all of the offending problem the fist time. Or #2; Preventive maintainance is lacking. Preventative being the key word with a woodie. Even for those of us who let a nick dry out and immediatley touch them up with a light sanding and coat of epoxy or varnish, every 2 or 3 years will require a bottom up sanding and refinish job. Inside and out. UV damage to most finishes is also extremely under rated. Pin holes in a finish that are allowed to remain will literally wick moisture into the hull. Another problem is osmosis. Regardless of how exceptional the finishing job, no one has found a way to eliminate osmosis. Owning a woodie is tough. There is no easy way to avoid work if you have one and plan on keeping it. Starting with a ground up refinish job done properly and with a great deal of patience is the best way to keep the boat on the water and out of the garage for the longest periods of time. Any other thoughts on the subject?

I would be curious to hear from owners of all wooden 505s (lots of older 505s, and the Galletti and Trott boats built during the '80s) regarding keeping wooden hulls in good condition.

After years of admiring the woodwork on the Lindsay and wood-look Waterats, I finally bought one earlier this year. Fortunately Larry Tuttle refinished all the wood (thin oak veneer on the seat tanks, aircraft plywood bulkheads CB case sides, and transom, and mahogany and spruce (I think) thwarts and CB trunk cap). I believe there is more than one coat of WEST epoxy, with a two part polyeurathane (sp?) with a UV barrier on over that.

It is amazing to me how well an older wooden finished boat can be brought back with some work. Seeing the before and after on some recent Lindsay refinish jobs was amazing. These boats do not seem to gain any weight, though with plastic hulls and cored tanks covered in thin veneer, there is not a lot of wood to soak up water.

I wonder of the Galletti and Trott boats get heavier over time.

Ali


Hi, Rick:

Salt, mostly (SF Bay). But the wood in the Lindsays is sealed and epoxy coated on all surfaces (even inside the tanks. They used fully cured wood throughout, so sealing all the way around didn't represent a problem, and I have made a point of sealing all holes, etc., when I have drilled them to maintain the same level of integrity.

If the wood is sealed, fresh/salt shouldn't matter, but I've seen rot on Parkers and others in the past, expecially in the plywood (per Ali's reply, also). I sailed With Mark Vestrich at West River some years ago and we blew up his Parker rudder. On inspection, we found that it had been made of plywood (not the transverse-laminated strips that Lindsay and Waterat use) and that water had penetrated the plywood and rotted it. I think Parker made centerboards the same way at one time, and you would want to check these and any other plywood structures for rot pretty carefully.

Dave Cahn


Hello All;

I want to add a personal experience to the comments on polyester-over-wood being a BAD thing. My 5o5 is an all polyester boat except for the foreward compartment bulkhead and the spine that extends fore and aft from the c.b. trunk... it is a 1970's Rondar, number 5518. There was, before I had to totally remove it, a plywood bulkhead with a 1" x 2" wooden cap that ran across the cockpit at the aft end of the c.b. trunk. Before I got it, this boat had been left for a long time with water in it, and the water had penetrated the glass tape/polyester resin that attached the plywood to the tanks, the c.b. trunk, and the floor. The Plywood and the ends of the wood cap were totally rotted.

Ali's comment about osmosis is, I believe, right on the mark. Fresh water is worse than salt in this case, since osmosis tries to equalize the concentration of dissolved salts in the solvent (water, in this case) on BOTH sides of a membrane (the "skin" of polyester over the plywood). The polyester resin always has some unreacted salts left in it and the osmosis "forces" water into the resin in an attempt to dilute the salt solution to the same dilution as the salts in the outside solvent (lake or ocean). Fresh water has a lower salt concentration than ocean water, so the concentration difference is higher and the osmotic pressure is higher... Once in there it stays and rots the wood, or (on a hull) causes blisters in the gel-coat...

I had an even bigger problem with gel-coat blisters. After I repaired (sanded out and filled/faired) them, I painted the hull with a urethane based paint (to keep the water infiltration to a minimum).

John Dean
US 5518


The 5o5's built at ML Boatbiulders fall into four types.
1. Parker hulls with ML wood interior.
2. Hexel or Clegecell cored hulls with all wood tanks
3. Same with composite tanks with veneer covering
4. Same with composite deck and interior

The all wood tanks were built with 3 layers of 1/16" veneer. Originally all three layers were sitka spruce, but we swiched to a mahogany top layer to make the tanks more impact resistant. The early tanks were fit (each piece of veneer has to be tapered at the ends to fit tightly against the previous piece) and laminated one layer at a time, using epoxy and microballons for the bond, and staples to hold the veneer to the mold (What a pain!!!). Later on we sealed the tank molds and started laminating the tanks in one shot using a vacum pump for pressure, just stapling the edges to hold the veneer in place. The all wood tanks had 12 ( or 13 ribs, I can't rememeber anymore) made of 1/8" plywood glassed to the inside of the tank with 2" glass tape to stiffen it up. The entire tank was sealed in a thin coat of epoxy, applied with a squeegee. The tanks were then fit in the hull and glassed along the cockpit floor and bulkheads (To the diagonal bulkhead through the holes that were made for compass installation). The all wood tanks are fragile, typically the rib gets delaminated from the tank when the driver or crew land on it too hard. The repair involves trimming the debonded glass and reglassing it to the tank through the compass hole or inspection port hole. Thin, long arms are a plus. The composite core tanks are stronger, but can be punctured with objects like a trapeze hook. Ary holes should be repaired from the inside if possible, and then have a piece of veneer scarfed in to match the wood look.

The finish on all the wood was done in consistent manner. All wood was sealed with epoxy applied with a squeegee. The visible surfaces were then wetsanded with 220 grit paper or drysanded with 180 grit. The bulkheads in the space between the watertight and diagonal bulkheads and the centerboard trunk and cap were finished with two coats of clear Awlgrip using a brush, and sanding between coats. The center spine, thwarts,and cap were sprayed with two coats before installation into the boat. After the boat was assembled, the hull and cockpit floor was masked off, and the deck, tanks, rails, transom and aft side of the diagonal bulkhead were finished with two coats of clear Awlgrip, sprayed. A little touchup was done on the front thwart, to finish the edge of the cap, which was routed to fit the thwarts. Early boats were made with Gougeon epoxy, but we switched to Reichold in about 1978 because the mechanical properties were better, and it did not get that hazy white look when exposed to moisture.

To refinish the wood you need to sand all dings, and seal them with epoxy resin. It is ok to fill with the clear epoxy to fill in minor gouges. Bigger gouges can be filled with veneer by scarfing in a new piece. The supplier we had for the mahogay veneer was ML Condon in New York, but I don't even know if they are in business or sell the veneer any more. You should test for leaks at this point, before finishing. Leaks often develop around the pvc tubes which the forestay and shrouds go through. A good method for leak testing is to pressurize the tanks and watertight compartment and apply soapy water to any suspicious places. Leaks will cause bubbles to form. Once all the wood is sealed, sand everything to make it smooth. You do not need to sand all the way down to the epoxy. If you are taking the finish off down to bare wood you need to be careful about sanding through the thin layer of veneer on the plywood. It is only 1/32" thick and it is easy to sand through, especially on the foredeck at the watertight bulkhead. You do not need to remove the epoxy to get a nice finish. The boat I sail in is the very first Lindsay (6821), and we have never stripped the epoxy finish off. Once everything is sealed and smooth, brush on one or two coats of clear awlgrip, sanding between coats. Spraying awlgrip is very difficult, I don't recommend you try even if you are used to spraypainting. The awlgrip has a 20 minute set time, and there is very little margin between orangepeel caused by too little material to runs caused by too much. If there are areas that are damaged by fittings, etc. fill the area with a mixture of resin and chopped fiber or glass bubbles, or scarf in new wood. Epoxy with microballons is too weak.

To keep the wood in top condition, make sure that you seal dings with epoxy or 2 part polyeurethane (awlgrip). If you use gougeon resin, you must sand and paint over with poly to keep it from turning white from moisture.

Jan Aase (aase@crd.ge.com)


Lauren Abramson, who along with Tom O'Toole very recently purchased Lindsay 6987 (built 1979) asked about refinishing wooden boats. This prompted some additional discussion on the subject.
Lauren:

I have done four refinishing jobs on Lindsey 50's. I don't think you will find any disagreement over what to do for the base coat:

  1. Remove all the old finish.
  2. If you have splitting veneer, cover those areas with a 4oz cloth. This will keep it from splitting again.
  3. Apply two coats of epoxy, I use West 207 hardner (uv, uv, uv) You can do both coats at once or sand between them. Just be carefull not to "pull" the resin. If you pull it, it will turn white. The object is the saturate the veneer and end with a smooth flat surface. My last sanding is a 320 grit wet sand. This ensures I have a smooth and clean (very important) surface.

Now its time for a top coat. This is where the agreement breaks down, and unfortunately this is the most important step. Most people will agree that you should use a UV protected urethane. There are several brands and I have used three: Pettit(sp), USPaint (Awgrip), System3 waterbased urethane, and West 1000. Heres my expierence with these products:

  1. Pettit and Awgrip These are similar products. Both were relatively easy to get a good brushed finish. Both lasted about 3 seasons. The boat was keep outside under covers or in a garage.
  2. System3 This stuff was great because you did not need a respirator and you can clean up with water! Unfortunately, you can't brush it (I tried). I don't know how long this stuff lasts. I put it on the tanks of the boat I sold after keeping it the garage. So far, its seen one season and its stored outside under covers.
  3. West 1000 I've refinished my current boat with this stuff back in '91. Most people that see the boat thinks its a new finish. I think that maybe I will have to refinish in the next few years. This boat has been garage kept for all but one season.

I have notice a big difference in the hardness of the Pettit/USpaint as compared to the West 1000. The Pettit/USPaint finishes dry to a very hard and brittle finish. (The stuff that dries in the bottom of the bucket is like glass.) The West 1000 stuff dries hard but is not brittle (The left over stuff is pliable). I think this is very important on wood surfaces. What generally happens is that you get dings in your finish that water gets into. Next you have the finish delaminating. The wood is softer than the finish. The West stuff doesn't ding. It dimples but doesn't crack; i.e. there is a better match between the wood and its finish.

Needless to say I am impressed with the West product.

I hope this helps

Kenny Elliott
US7092
kbesls@widomaker.com