Saturday 29 October 2022

Upper Hull | Final Gloss & Wet Sanding

A lot of work has taken place since the previous post but there has been almost no visible change in the appearance of PocketShip so there was nothing to post about.

Glossing of the upper hull was completed, with the addition of five more coats to make a total of ten.

Here is the hull after the tenth coat was applied.

It looks pretty nice but the finish is marred by brush strokes, even after very careful rolling on and tipping out of the paint.

So, as discovered when painting the underside of the hull, a massive task now awaited me - wet sanding the entire upper hull to a very fine finish.

I knew this was going to be tedious in the extreme, so I girded up my loins and got on with it.

The worst job would be flatting off the entire upper hull to a P800 surface, ready for finishing with finer grits.

It's best to buy the P800 grit in 5m rolls - we get through an awful lot of it. Here it is.

I investigated wet sanding techniques on the internet and found that I had been doing it all wrong. Not for the first time ...

When wet sanding you are supposed to sand unidirectionally, in the direction of the brush marks.

Not with a circular motion as I had been doing. That's for dry sanding.

So now you tell me...

You are also required to use a sanding block. Here is the one which I close.

It is a big and heavy rubber block slotted at each end and fitted with sharp pins to hold the grit firmly in place. It's also very slightly flexible so it doesn't dig in and leave tram lines.

And here is the wet sanding tool kit. Buckets of water for the sanding block and sponges, and a water spray bottle. Plus the sanding block, and a sponge for wiping down the sanded surface.

As previously mentioned, a really good light source is essential for achieving a good, flat and even surface.

Here I am using a 45W work light to illuminate the upper hull sides when trying the sanding block and revised techniques for the first time.

It all worked very well. I found that using a small hair dryer to dry off the sponged down surface was an excellent way of immediately seeing how good the surface was and how many brush marks were still visible. Here it is.

So far so good!

Having learned the correct technique for wet sanding I settled into the mind numbingly tedious business of wet sanding the entire upper hull.

Many hours and days followed when I did nothing else, until the day came when the P800 sanding was finally complete.

This is the upper hull seen from the side.

And here it is from the front.

Here is a view of the cockpit.

And here is the forward deck.

It's probably impossible to tell from the photos but the resulting surface is very smooth, and the fillets have all blended in beautifully.

Now for the next and final phase of wet sanding and buffing all the way through to a P9000 grit.

It will of course be just as tedious as this last phase but shouldn't take as long because now I am effectively polishing rather than flattening out.

We will go through P1200, P1500, P2000 and P2500 wet sanded grits. And the final finish will be achieved with P5000 and P9000 buffing compound.

We're getting there!