Gluing the Hull

You’ve already used the resin when you put the panels together. When you glue the hull together, using the syringe and the difficulty of getting the glue into the seams just adds to the challenge. It’s almost a panic when you realize that you’re making a mess and the glue is getting all over the outside of the hull. Don’t panic. The discoloration will disappear almost entirely when you do a full resin coat on the hull. The drips of glue, however, will add significantly to the amount of work you need to do to get the hull ready to glass.

So, three rules. First, don’t let the short pot life make you rush to apply the glue. Second, wipe up the drips as much as possible. Third, put glue on the seams, even when it seems that they are so tight that no glue is getting in. It is. Maybe not great, but some does get in. Some seams will be tight, even if you don’t do much of a chamfer on the edges of the panels.

The bow and stern joints need to be filled with resin that is thick enough not to run. You eventually will sand these joints to round them out, without sanding through the top layer of the okume. As you can see in the above photo, these panels weren’t chamfered very much at their ends, so the joint is relatively wide and requires lots of fill. Consequently, the fill was high enough to cover some of the wires. This looks like a bad thing–when the wires are pulled the fill will break, possibly digging out a hole big enough that the edge can’t be faired in without repairing the hole(s) with more fill. This isn’t a structural problem, it just adds another cure cycle to your schedule. As it turned out, the resin did break, but the seam faired in just fine. Lucked out, for sure.

Tip 7: To avoid a wide, bulging need for fill at the bow and stern, the panels should be aggressively chamfered in this area to make for a more narrow joint.

Tip 8: The bow and stern wires should have their twists over to the side so that when they are removed, the wire can slide through the built-up resin, leaving only a small hole.

Tip 9: If your joints are too tight and you are not confident of the glue, let the hull cure, then turn it over before you remove the wires and fill the inside of the seams. In the case of the Arctic Tern, I chamfered the joints at too shallow an angle, eg, making a knife edge on the panels, which caused two problems–the joints were tight on the outside and open (a wide “V”) on the inside. Filling the joints from the inside solved both of these issues.

It’s time to pull the wires. If you didn’t fill the seams on the inside, you can pull them after 10-12 hours and the resin will still be relatively soft. If you have to wait for the inside to cure, the outside resin will be quite a bit harder and more difficult to scrape, but it can still be done. Now you can get at the seams and scrape away the thickened resin that is invariably gooped up along the seams. This is where the scrapers are invaluable. Be careful if the resin is hard–you can pull off the top veneer layer of the okume. For thick or hard resin, scraping with the blade at a 45 degree angle to the direction of travel will help cut the resin without pulling it off in a lump.

The next big step is to coat the outside with resin. If you have taken care to scrape (and a little sanding) the hull smooth, it will make all subsequent steps easier. So spend a little time getting the hull smooth. You don’t have to remove the glue stains–they will disappear in the resin coat.

Tip 10: Make sure you have a short roller to apply the resin to the hull. Home Depot sells on with a foam roller included. Throw the roller away and cut the 1/8″ thick rollers available from Pygmy to fit (either in half or thirds). The advantage of the cheapie roller from HD is that the roller cage is very loose on the handle and will not lock up on you due to cured resin–you can use it over and over if you clean it a little after each use. You really need to have a roller that is easy to roll–the resin is slippery and most rollers have too much turning friction.