Upper Hull | Wet Sanding

It has been exactly one calendar month since I started wet sanding the entire upper hull, as instructed by the Epifanes mono-urethane gloss technical data.

In total the task consumed about 50 hours of wet sanding with P400 wet'n'dry grit. That would only be about 12 days of work at my preferred rate of 4 hours per day. Say two weeks.

But it actually took four weeks because I found myself doing just about anything rather than face the mind-numbing tedium of preparing for the final coat.

So quite a lot of chores got done; domestic, financial, automotive. Even they were more fun than sanding.

But I got there in the end.

The first task was to tape the rails to protect them from water and mess. I used the 3M gold professional tape because it is waterproof.

Here the starboard rub rail, toe rail and the companionway hood grab rail are all taped up.

I sanded the footwell and cockpit first, then the forward deck well. After that came the companionway hood and cabin roof, and finally the topside panels.

Here I am working on the top of the hood.

I did not sand any edges or fillets because I was sure I would sand through to the bare substrate if I did.

So when all the sanding was complete I burnished all the edges and fillets with a medium grit nylon abrasive pad.

At last the day came (today!) when I could stand back and admire the fully prepared upper hull.

This is a view of the cockpit from astern.

And here is the forward deck well and cabin top.

The plastic sheeting taped to the rub rails and transom skirt to protect the lower hull from damage now also served to protect it from the mess created by wet sanding.  

The surface is now beautifully flat, smooth and matt. All ready for what I fervently hope will be the fifth and final coat of gloss.

We will see... 

Upper Hull | Preparation for the Fifth Coat of Gloss

I stated in a previous post that I would be wet sanding the fourth coat of gloss in readiness for the fifth, which I hoped would be the final coat.

I chickened out temporarily, thinking that dry sanding would be so much quicker and easier.

So I got the sander set up ready. Like this.

But something was nagging away in the back of my mind, so I reviewed the Epifanes recommendations. Again.

That didn't help a lot. The product guide tells us to wet sand for the final coat, but the You Tube tutorial by Dan Lee Boatbuilding tells us to dry sand between all coats with no more than a P220 grit.

Who was right? I decided to consult the technical data sheet for the mono-urethane gloss.

That states categorically that we should be wet sanding with a P400 grit between each coat. It even adds, ominously: "Preferably by hand".

I have ignored the data sheet before, with terrible consequences. Which is why I am repainting this boat!

There was nothing to be done about the first four build coats. They had all been dry sanded with a P280 grit.

But I would have to make sure the final coat had a flawless substrate. By wet sanding.

I started work on the port cockpit deck. Like this.

It immediately became obvious that this was going to take a long time to complete. Possibly weeks...

So this is an interim post. At time of writing I have wet sanded the port cockpit deck, rear cabin wall. seatback and the transom.

It may be some time before I post again to say that the task is complete.

Time for a beer, I think.

Dorade Boxes | First Coat of Primer

I decided to start on the Dorade box interiors, again while waiting for the gloss to harden.

I thought a foam pad would do the job, applied from inside through the ventilator hole.

How wrong I was! It was not at all effective. Look at this mess.

I will need to find a better way of doing this. Luckily it isn't urgent or on the critical path!

Seatback Lockers | First Coat of Gloss

While waiting for the fourth coat of gloss to harden for sanding, I applied gloss paint to the seatback locker interiors.

This will have to be done in two stages - the areas that are not visible, and those that are on show.

Clearly the invisible areas do not need to have a top quality finish, which is just as well because it would be nigh on impossible. A foam pad will suffice to do this.

The areas on show are the floor, back wall and forward bulkhead.

I decided to paint the latter first, using the techniques learned from applying primer. Use a roller to apply the paint, and the 1" brush for tipping out.

Here they are.

That worked well. This is the view inside the starboard locker.

Not bad at all. Four more coats will do the job.

Upper Hull | Fourth Coat of Gloss

I left the newly applied white gloss to harden for a few days before sanding in preparation for the fourth coat.

This was predictably tedious but I took solace from knowing that I would probably only have to do it one more time, if all went well.

Here I am sanding the cockpit deck and footwell with a P280 grit. The blue tape is preventing the sander hose and cable from damaging the now pristine seatback tops.

The bright work light placed at right angles to the brush strokes clearly shows when the surface is flat and smooth.

When all surfaces were sanded I used a medium grit nylon pad to abrade the fillets and edges.

Everything was washed with water to remove paint dust, and wiped down with thinners immediately before painting.

The cockpit was now ready for more gloss, looking like this.

With previous coats I had some difficulty obtaining good coverage on edges and joins, so for the next coat I  decided to roll over onto the adjoining face.

This is the port view of the footwell, seatback top and transom. Masking tape shows where to apply paint to cover edges.

I thinned the paint with 5% Epifanes Easy Flow, to improve flow and reduce brush marks.

I first painted the cockpit and forward deck well, using the 100mm ANZA brush for tipping out. See previous posts for more details.

It is certainly a fast way of tipping out fresh paint, but I found the brush's bristles clung together in spikes and created very noticeable brush strokes. Tram lines, in fact!

So the following day when I painted the topsides I used a soft 1" brush for tipping out. Here it is, with the roller.

It is a top quality synthetic brush. Very soft and supple.

I washed it in thinners when it stiffened with drying paint and started to drag.

It worked well and I was very pleased with the result.

This is the cockpit after gloss.

Here is a close up of the port quarter, showing how well this coat has covered and flowed on flat and curved surfaces.

As I always do now, I removed all masking tape while the gloss was still wet. I no longer keep it in place until painting is complete, because that leaves a pronounced step to the edge and often causes and hides flaws.

Here are the cockpit and transom skirt, all tape pulled.

I was really pleased with how things turned out. This is the port topsides. Nice and shiny.

I did not lose the wet edge once, and the brush marks are slight when using the 1" brush.

So I think I may have finally cracked the secret of how to get a good finish with a roller and brush.

In theory the fifth coat will be the last, so I will be extra vigilant and keep my fingers crossed!

The Epifanes product guide tells us to wet sand for the final coat with a P400 grit.

That won't be much fun, but I suppose it will have to be done... I will let the gloss get nice and hard before starting.

Onwards and upwards!

Seatback Lockers | Sanding Interiors

The seatback lockers had previously received four coats of primer, and while I was waiting for the third coat of gloss to harden I decided to start work on the locker interiors.

They too would be repainted with gloss, meaning that the primer would need to be sanded.

The finish did not matter where it could not be seen, as long as a protective coat was in place.

However, the finish did matter where the interior was visible. Meaning the forward bulkhead face, the back wall, and the floor.

Here I am trying various techniques.

The only tool which really worked was a small 'rubber' made of rolled up cardboard and tape, and some P180 grit.

This is it.

I made a selection of these rubbers when shaping the epoxy resin fillets, and they worked well.

This small one was ideal for reaching into the lockers and carefully sanding to a smooth finish where it mattered.

It took a surprising amount of time to achieve a good result, but we got there.

This is the port locker, ready for gloss paint.

The next task is sanding the upper hull ready for the fourth coat of gloss.

Progress indeed...

Upper Hull | Third Coat of Gloss

I left the second coat to harden for a few days before sanding it smooth. This time I used a P280 grit, having found the P320 was making hard work of it.

This is the forward deck well.

And this is the cockpit.

The paint was nice and hard and sanded well - no bare patches this time!

I was now using abrasive nylon finishing pads to sand the fillets and rounded edges. This is them.

The red medium grade is ideal for abrading the gloss - not too aggressive and not too fine.

Then the third coat went on. This time I reduced the amount of thinners to 5% to see if it made much difference to the flow out. It didn't seem to.

This is the port quarter after gloss.

This is the starboard cabin top.

That's not too bad!

I'm still having the occasional problem with losing the wet edge, and I have not covered the rounded edges too well in places, but I'm pretty sure that's because I didn't use enough paint and 'starved' the surface.

The finish gets better as the task progresses and the roller sleeve gets fully loaded up with paint. I think with more care and better lighting I could get it right.

I will now leave everything to harden off before more sanding. I'm going to switch to Epifanes Easy Flow to thin the paint to see if that improves flow and finish.

We are getting there!