Re: Painting and Fairing Older Hull

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
Foamboat
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Re: Painting and Fairing Older Hull

Postby Foamboat » Mon Aug 29, 2022 6:29 pm

Q1: is the plan for hull refurbishment and paint that I describe below a good plan?

Q2: what color of Interflux PERFECTION is the best choice for a classic NAUSET hull?

Q3: between TotalBoat WetEdge "Whaler Blue" and a two-part-epoxy paint, which should I use?

Q4: what brand and what color of tough two-part-epoxy paint is a match for the blue color used by Boston Whaler

MY PLAN
To rebuild my 1967 NAUSET my plan is to:
  • to sand off the bottom pain;
  • to sand off the crazed gel coat
  • to use TotalBoat filler where needed
  • to sand and fair
  • to apply three coats of TotalBoat epoxy, sanding between coats
  • to apply two coats of Interlux PERFECTION, using either spray or the roll-and-tip hand method.


I have begun sanding off the bottom paint using an angle grinder and 80-grit hook-and-loop sandpaper.

Removal of the bottom paint is going okay.

I wore a respirator, gloves, and goggles.

IMG_3217.jpg
Fig. 1. Bottom paint removal outdoors.
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To work on the boat outside and in the wind is nice. But I keep a vacuum cleaner running as well [to collect the bottom paint dust]. That results in less impact on my open grass runway--and less harm than when a boatyard does it on the edge of an estuary.


ASIDE: I have experience with [fiber]glass work having built a seaplane using carbon fiber, kevlar, and fiberglass. I have a good shop.

jimh
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Re: Painting and Fairing Older Hull

Postby jimh » Tue Aug 30, 2022 8:59 am

Foamboat wrote:Q1: is the plan for hull refurbishment and paint that I describe below a good plan?
You plan sounds very similar to the refurbishment of an older Boston Whaler boat that is demonstrated by TotalBoat in their youTube presentation. Compare at

TotalBoat Boston Whaler Crazing Repair
https://www.youtube.com/watch?v=4tZDBOYqdfA

Foamboat
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Re: Painting and Fairing Older Hull

Postby Foamboat » Tue Aug 30, 2022 11:56 am

I have way too many small cracks on the side panels of the hull to Dremel them all out. That is why I think the solution is to sand most of the finely cracked Gelcoat off and replace it with multiple coats of epoxy primer. I will Dremel out larger cracks but they are mostly in the interior as in the video.

jimh
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Re: Painting and Fairing Older Hull

Postby jimh » Tue Aug 30, 2022 1:09 pm

Thanks for the clarification regarding having too many gel coat cracks to remedy them individually as demonstrated in the TotalBoat youTube presentation.

I think you will have to base the amount of gel coat to be removed on your own observations. I would look carefully at remaining gel coat to be sure it was stable and well bonded to the underlying laminate layers so it won't be likely to try to fracture again.

Have you weighed the bare hull?

Getting the present weight of the hull might be useful. Once you add the additional layers or resins and paints, see how much weight was added could be an interesting datum.

Foamboat
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Re: Painting and Fairing Older Hull

Postby Foamboat » Tue Aug 30, 2022 1:22 pm

I don't have an easy way to weigh the hull but before I bought it I went over it quite carefully with my little tapping hammer and moisture meter. The normal trouble spots all looked good. The floor feels solid everywhere. The brass drain tubes seem ok. It had an Etec 90 on the transom with less than 100 hours. The install looks ok but I will saturate the bolt holes with Smith's penetrating epoxy. I will try to document with pictures how much gelcoat I take off. I plan to use a random orbital sander with 80 grit, not the angle grinder.

That Total Boat two-part epoxy primer seems to remain pretty flexible. I think if I put on three coats and longboard sand in between it should come out ok.

This boat will live on a bunk trailer and will be launched on a pebble/sand beach in front of our house with a 4wd tractor so it will be spared concrete boat ramps and constant submerged life.

Foamboat
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Re: Painting and Fairing Older Hull

Postby Foamboat » Tue Aug 30, 2022 6:16 pm

Most of the bottom paint is off.

invertedHullBeingSanded.jpg
Fig. 2. A second view of the bottom of a hull with the bottom paint partially removed. Compare to Figure 1, above.
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Q5: which resin is harder to sand: MARINTEEX or WEST System Epoxy thickened with milled fibers?

Foamboat
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Re: Painting and Fairing Older Hull

Postby Foamboat » Sun Sep 04, 2022 7:59 am

I sanded down the gel coat down about halfway until the crazing cracks were mostly gone.

gelcoatCloseup.jpg
Fig. 3. Before and after sanding of cracked gel coat surface.
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A 5-inch random orbital sander and 80 grit seemed to work best.

I hope that a new top coat of flexible epoxy primer will keep the cracks from reappearing over the years.

jimh
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Re: Painting and Fairing Older Hull

Postby jimh » Sun Sep 04, 2022 8:50 am

The pattern in the gel coat as seen in Figure 3 (above) looks remarkably similar to the intentionally molded-in faux leather pattern seen on larger Boston Whaler boats on flat console surfaces.

jimh
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Re: Painting and Fairing Older Hull

Postby jimh » Sun Sep 04, 2022 8:54 am

Foamboat wrote:Q5: which resin is harder to sand: MARINTEEX or WEST System Epoxy thickened with milled fibers?
I cannot offer an opinion on those two specific epoxy resin and filler mixtures.

But be careful when sanding: generally any cured epoxy resin will be more resistant to removal by abrasion than the 40- to 50-year-old gel coat resin on an older Boston Whaler boat. For that reason, when trying to fair any repairs made with epoxy into a gel coat surface, the sanding will remove the old gel coat resin much faster than it will remove new epoxy resin.

Foamboat
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Re: Painting and Fairing Older Hull

Postby Foamboat » Sun Sep 04, 2022 8:38 pm

I am worried about that as well. I think I will just put thickened epoxy where holes need to be filled but leave them below the gelcoat layer and put fairing compound on all the surfaces that need it.

Foamboat
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Re: Painting and Fairing Older Hull

Postby Foamboat » Fri Sep 30, 2022 4:54 pm

Below is the hull as it now sits after the following process of preparation and painting:
  • strip off the bottom paint using an angle grinder and 60 grit
  • sand down the gel coat until spider cracks were almost gone
  • fix 186 holes or places where the gelcoat was broken down to the fiberglass
  • apply thee coats of Total Boat fairing compound and sanded with 80 grit
  • roll-on three coats of Total Boat two-part epoxy primer; the first coat was gray; the next coats were white so I could see what I was taking off while sanding with 80 grit; final sanding with 120 grit.
  • apply four coats of Interlux Perfection two-part [later clarified to be an polyurethane] gloss paint using quality foam roller and hand sanded with 220 grit pads between coats; thinned the paint 9:1 with the recommended thinner; air temperature was about 70-degrees-F.

NOTES:
  1. I found if I used 60-percent of the hardener recommended the two-part [polyurethane] paint seemed to flatten out better.
  2. Always wear a respirator when painting and sanding with these toxic paints.

IMG_3255.jpg
Fig. 4. Repainted hull.
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IMG_3253.jpg
Fig. 5. Closer view of repainted hull.
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jimh
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Re: Painting and Fairing Older Hull

Postby jimh » Sat Oct 01, 2022 8:15 am

Foamboat wrote:I found if I used 60-percent of the hardener recommended the two-part epoxy paint seemed to flatten out better.


Q6: Did the manufacturer of the two-part epoxy paint specifically recommend or endorse the use of non-recommended portions of the epoxy resin and hardener materials as you have done?

I am asking because an epoxy resin and hardener reaction MUST be done with the the exact specific volumes of each reagent. Epoxy resin mixed with only 60-percent of the volume of hardener recommended will result with 40-percent of the resin remaining uncured. This results in a much weaker cured material. There is generally never any reason to alter the proportions of resin and hardener in using epoxy. Unless the two-part paint manufacturer endorses and recommends using a different volumetric ratio of the reagents, I would think experimenting with those ratios would be likely to leave parts of one reagent out of the reaction, resulting in a contamination of the final resin cure.

Foamboat
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Re: Painting and Fairing Older Hull

Postby Foamboat » Sat Oct 01, 2022 9:10 am

It is now over a week since the final coat. I left it alone to cure slowly. It seems very hard and tough. I think it just cured more slowly. We will see.

jimh
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Re: Painting and Fairing Older Hull

Postby jimh » Sat Oct 01, 2022 9:37 am

Foamboat wrote:It is now over a week since the final coat. I left it alone to cure slowly. It seems very hard and tough. I think it just cured more slowly.
I interpret you answer as "NO." That is, the manufacturer did not instruct you to intentionally alter the proportions of the epoxy resin and hardener with the goal of making a smoother surface finish. If that is wrong, please correct me.

Everything that I have read about using epoxy recommends that the volume ratio of the resin to the hardener is very important and must be carefully measured to produce a proper outcome.

Epoxy resin is not in the process of curing in the can like polyester resins. A volume of epoxy resin will remain a liquid for many decades without any sign of curing into a hard and strong substance. Epoxy resin cures by a chemical reaction with its other component, called the hardener. Like any chemical reaction, the reagents combine with each other in a set proportion. That is why directions for use of epoxy always specify a certain volume ratio of the two liquids, and that they must be very thoroughly mixed together before applying them.

Maybe the so-called two-part paints are not the same as epoxy adhesive resins. I would only change the mix ratio of an epoxy material upon advice and blessing of the manufacture of the epoxy.

Tom Hemphill
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Re: Painting and Fairing Older Hull

Postby Tom Hemphill » Sat Oct 01, 2022 10:26 am

Was it the primer or top coat where the mixing ratio was altered?

Incidentally, Interlux Perfection is two-part polyurethane paint.

Foamboat
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Re: Painting and Fairing Older Hull

Postby Foamboat » Sat Oct 01, 2022 12:04 pm

Tom Hemphill is correct: Interlux Perfection is a two-part polyurethane paint.

Adjusting the amount of hardener appeared to allow Interlux Perfection = to flow out and smooth more than the first coat, which was not as smooth.

[Changing the ratio or paint to harderner] seemed to just affect the amount of time for the paint to cure or harden.

Will [Interlux Perfection tow-part polyurethane paint applied with an incorrect ratio of paint to harder\ last as long [as paint applied with the recommended ratio of paint to hardener]?
Who knows the answer to that question?

I will keep [readers of this thread] informed [about the durability of Interlux Perfection two-part polyurethane paint that was applied with a reduction in the ratio of hardener].

However, [the final finish of the Interlux Perfection two-part polyurethane paint on the restored hull of the 16-footer] turned out very nice compared to what I started with.

jimh
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Re: Painting and Fairing Older Hull

Postby jimh » Sat Oct 01, 2022 12:26 pm

Thanks for the correction on the type of paint. Many resins are already heading for a cured state and a catalyst or “hardener” additive just hugely accelerates the chemical reaction.

However, I am still curious if the paint manufacturer suggested or recommended altering the mix ratio.

And, yes, the new finish on the hull looks very nice. You have done a very good job, particularly considering what you started with. I am impressed with the amount of work done and the very nice outcome.

Foamboat
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Re: Painting and Fairing Older Hull

Postby Foamboat » Sat Oct 01, 2022 3:14 pm

I did not ask Interlux about reducing the amount of hardener.

I just reduced the amount in small steps from 2-to-1 (33%) to almost 4-to-1 (25%) by the fourth coat. The fourth coat flowed out really nicely. A week later feels the paint surface seems very hard and quite smooth. [The surface of the Interlux Perfection paint] feels much harder than gel coat.

I will keep posting on here next summer when the boat will be loaded on and off the trailer for every use. We will see how [the finish using Interlux Perfection paint] holds up.

Thanks for the compliment on the job. I am working faster than I would like because I want to finish the interior paint before November 2022. I am always fighting my perfectionist side. I keep telling myself this is not another airplane project; this is a boat you are going to pull bluefish into and let the grandkids use.

jimh
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Re: Painting and Fairing Older Hull

Postby jimh » Mon Oct 03, 2022 6:13 pm

On reactions in which a catalyst is added to increase the speed of the chemical reaction, the curing time is going to be in some proportion to the amount of catalyst, or, at least, that it the general rule of chemical reactions.

In your specific case, your report of a firm and hard cure of the polyurethane paint suggest the chemical reaction has properly cured.

The beauty of gel coat resin with regard to abrasions is the thickness of the resin layer. With gel coat resin, there usually is enough thickness that a minor surface defect can be removed with careful abrasion of the surface. A typical gel coat resin thickness might be 0.020-inch (twenty-thousandths).

A painted surface thickness is not generally that thick. Surface defects in the paint are probably not able to be removed by careful application of a mild abrasive.

Of course, in the instance of an older hull with a gel coat surface, complete re-coating of the gel coat surface with a new layer of gel coat is very impractical. Painting is often the only solution that can be realized.

With some care in loading on the trailer and launching from the trailer, most abrasions in the paint will be confined to surfaces that won't generally be visible. Just be very careful when approaching a dock--as I can attest from personal experience.

Foamboat
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Re: Painting and Fairing Older Hull

Postby Foamboat » Wed Oct 05, 2022 10:30 am

The [1967 NAUSET 16 that is being refurbished and discussed in this thread] is now right-side-up on the trailer.

The interior does not have many stress cracks and the molded-in non-skid looks really good. I didn't want to sand on the non-skid so I used a stainless steel wire wheel to clean out the pattern. On the non-skid I plan to [apply] one thin coat of Total Boat two-part primer and follow that will one coat of Total Boat Wet Edge in Whaler Blue.

twoPaintCans.jpg
Fig. 6. Two cans of paint with labels and very unusual retainers holding the lids in place.
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boatCockpitWithToolInForeground.jpg
Fig. 7. The boat cockpit with tools and extension cords visible. This view shows the rigging tunnel exit normally hidden below the console.
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The rest of the interior has been sanded with 80 grit to remove gel coat with oxidation, and to prepare the surface for good adhesion to the primer paint.

140 HOLES
I will inject Smith's clear penetrating epoxy into each of the 140 holes that have been drilled. Then I will fill the holes with West System epoxy mixed with milled fibers using a big syringe. Then I will grind off the get coat around each hole with my mini belt sander and apply two layers of glass. This should end up below the existing gel coat level. Then I will fair everything out using Total Boat fairing compound.

Next I plan to apply two coats of two-part primer. I like to use gray for the first coat and white for the second which makes [it seeing how much surface has been removed easier when] sanding. Then I will apply two coats of Wet Edge, while sanding in between with a 220 grit pad.

I hope to get all this done before November 2022, when I will be out of commission myself due to a surgical procedure.

jimh
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Re: Painting and Fairing Older Hull

Postby jimh » Wed Oct 05, 2022 10:56 am

Thanks for laying out the next steps. I hope they go as well as the refurbishment of the hull bottom and sides.

Peter3
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Re: Painting and Fairing Older Hull

Postby Peter3 » Fri Oct 07, 2022 6:50 pm

Q7: when the hull was flipped over, was it done with manpower or was a machine used?

Foamboat
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Re: Painting and Fairing Older Hull

Postby Foamboat » Sat Oct 08, 2022 4:57 pm

Peter3 wrote:Q7: when the hull was flipped over, was it done with manpower or was a machine used?
I am lucky I have access to a forklift that can lift 40-feet and up to 8,000-lbs. I used that with straps to the lifting eyes to move the hull. The hull can be unloaded from the trailer onto grass, and then four strong guys can flip over the hull. I didn't have any help so had to use a machine.

RECENT WORK
  • finished sanding the interior with 80 grit
  • used a wire wheel brush on the nonskid
  • squirted Clear Penetration Epoxy Sealer in all the holes drilled in the hull
  • put West System epoxy thickened to toothpaste consistency in each hole with a syringe
I used green masking tape cover the horizontal holes to hold the resin place until it hardens. The resin does not seem to stick to the tape. Among the railing mounts, the bimini mounts, the trolling motor mounts, the battery box mounts, the console, and the seat mounts there were 145 holes in the hull.

NEXT TWO STEPS
  • more sanding
  • apply epoxy primer paint

IMG_3274.jpg
Fig. 8 A very wide view of the boat hull during renovation and the interior of the building where the work is being done. In the foreground are three holes that apparently have been repaired as described above.
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Foamboat
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Re: Painting and Fairing Older Hull

Postby Foamboat » Wed Oct 12, 2022 4:59 pm

Today's Work

dremelTool_.jpg
Fig. 9. A DREMEL TOOL with a very small tool bit was used to widen and deepen a few cracks in the gel coat.
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fairingCompound_.jpg
Fig. 10. A fairing compound was applied over the holes that had been filled with resin.
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Foamboat
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Re: Painting and Fairing Older Hull

Postby Foamboat » Sun Oct 16, 2022 1:43 pm

Interior primed with Total Boat 2 part epoxy primer. Some gray some white because that is the paint I had on hand. Got one and a half coats on until I ran out of paint. One more coat (when paint gets here) then two coats of Whaler Blue then the painting is done.
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Foamboat
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Re: Painting and Fairing Older Hull

Postby Foamboat » Fri Oct 21, 2022 4:06 pm

Well, my whaler is back to its correct interior color! There is something about the old blue whalers. To me when they are painted any other color it's not the same. This is coat #1 of 3 thinish coats or Total Boat Wet Edge thinned with 10% thinner. The Wet Edge paint does not seem to destroy foam rollers as the two-part primer did. Thinned 10% one quart covered the entire interior including the floor. On the non-skid floor, I did just one coat of two-part top-side primer and one coat of the Wet Edge blue because I do not want to fill in the nonskid texture. I found painting the non-skid part a 1/8" nap fuzzy roller worked best.
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Foamboat
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Re: Painting and Fairing Older Hull

Postby Foamboat » Sun Oct 23, 2022 3:29 pm

In an effort to share knowledge, I want to tell you about a screw-up. After the first coat of Total Boat Wet Edge Whaler Blue, I sanded lightly with an 80-grit pad and then vacuumed up the dust. I then proceeded to start wiping down with acetone on a rag. The paint immediately bubbled up like I had used a paint stripper. (See photo of the bow). Luckily I only did a little. Next, I tried wiping it down using Total Boat Special Thinner 100. The same thing happened just not as aggressively (see picture of stern). This may have occurred because the paint was pretty young about 20 hours since painting. I resanded down those areas and just used a brush and strong vacuum to get up the dust. I think painted coat #2 with no problems. This morning I gave a light hand sanding with a sanding pad and put on coat #3. I was debating doing only 2 coats but expect dropped anchors, tackle boxes, etc. The non-skid floor has only one coat of 2-part primer and one coat of wet edge so the non-skid does not get filled up with paint.

The painting on this project is now done. Next is the installation of the console, seats, engine, controls, etc. There will be a delay on this while I get my hip replaced.
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Foamboat
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Re: Painting and Fairing Older Hull

Postby Foamboat » Sun Oct 23, 2022 3:31 pm

The finished interior. I am quite happy with it.
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