14 REFIT STAGE 4 – Fairing and Priming

Tris...Int14Leave a Comment

Last of the Sand and Sprays

Spray guns, paint and sand paper….

So after months of part time sanding and then fairing it felt really good to be in a position to actually start putting paint on the boat. While starting to add filler and getting the hull faired was the point that we turned the corner and started moving closer to being finished where as previously it felt we were getting further away from it, the first spray was the big mile stone as it was the first time we could see the boat becoming a functioning animal again.

It terms of fairing compound we considered two options;

  • AWL Grip 545 Epoxy Primer
  • Durepox 2K Epoxy Urethane Primer

Durapox is probably in more common usage, it is slightly cheaper, but we knew we wanted to use a AWL Grip only top colour and while Durapox can be used for this, it is usually better to stick with the same manufacturer. In addition Nick felt that 545 was an easier compound to sand and remained easier to sand for longer.

As the boat was still in Ireland when we sprayed her, Ali’s brother, a carpenter, agreed to do the spraying for us. An excellent wood worker he also does his own varnish and epoxy spraying, so it wasn’t a huge jump to do the primer spraying for a boat. The gun required for primer is not particularly specialised so we were able acquire one for about £25 from Amazon.

First step was to mask off anywhere we didn’t want primed. So the racks, space frame, new control decks and rudder gantry. Doing this was time consuming primarily due to the awkwardness of the shapes. But a roll of light plastic sheeting and lots of Blue masking tape and not a small amount of cursing saw it completed.

A Tip; Blue Masking tape doesn’t leave adhesive behind when it is pealed off, the Diall tape sold in B&Q seems to work perfectly adequately, although the genuine 3M tape tends to be better.

After ‘keying’ the boat with 120 Grit Sandpaper, we were ready to spray. As Peter had never sprayed marine primer before, we decided to do the deck first so he could get his eye in and understand how the paint sprayed. Think he might have a knack for it…

We had agreed with Nick Harvey (Our technical advisor) that the best approach was three sprays for the hull, and two sprays for the deck, with sanding between each spray.

The first spray; it is actually two coats; with a light ‘Tac’ coat with settles on the keyed surface and provides the chemical bound for the first ‘full’ coat. The Tac coat shouldn’t be allowed to fully cure before putting the full coat on the hull. We mixed the 545 with a small amount of reducing agent to thin the paint slightly.

545 cures quite quickly, which meant we could do a second coat quickly after the first full coat. Then we left the whole lot to cure over night. The end result can be seen below.

We then turned the boat and repeated the same process on the hull. A light Tac coat followed by two full coats. The hull went as well as the deck had done, and as we did the sprays in the morning we were able to leave the primer to cure until the afternoon and then do the first of the sanding.

As before, the sanding was done with the flexible board, using the same sanding technique and a small sanding block for the detail areas. We used warm water in a bucket with Washing up liquid added. The warm water was primarily for comfort, the washing up liquid helps the paper move over the hull, and also helps to stop the paper from clogging up.

By sanding we ensure that the we not only get a really smooth and fair finish, but also minimise the amount of additional weight we add to the hull. For each spray we ultimately only added one layer of 545.

  • First sand- 200 Grit Wet and Dry until the red filler was just visible through the 545
  • Second Sand – 400 Grit Wet and Dry until the filler is only very faintly visible
  • Third Sand – 600 Grit Wet and Dry, this is the finish coat and if done correctly the finish should have a faint shine to it.
  • The second and third sprays follow the same process as the first, a Tac Coat and two full coats of paint.

By mixing up a small amount of 545 and using a small artists brush, many thanks to Ali for sacrificing one of her brushes, we were able to target the worst areas before we did the wet and dry sand each time. It was a laborious and time consuming piece of work, but ultimately worth it.

Having completed the hull we turned it and did a 400 Grit sand on the deck, did a second spray and 600 Grit sand.

End result was pretty amazing. If we hadn’t already bought Top Coat we might just stopped there..

At this point we had dealt with the vast majority of the pin holes, going from arguably millions down to a few dozen which we hoped, would be dealt with by the Top Coat sprays.

In the mean time the boat had to travel back to the UK for the final Top Coat spray and fitting out.

Image gallery:

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.