The Arctic Tern Project

Volume 2 Issue No. 4 February 27, 2005

Taping Seams

Well, it’s been a very busy two weeks since the last newsletter. Some highs some lows. This newsletter will make you laugh, it’ll make you cry.

Last time I left off having just installed the floor timbers. The glue-up turned out well. Unbelievably, I don’t have a picture of them after installation so you’ll just have to take my word for it. The next thing on the agenda was to get serious about doing some fiberglass work and tape the stitched seams. Each seam is taped with 3 layers of 12 oz. biaxial cloth 6 inches wide laid in a staggered pattern followed by a 12-inch wide layer of 6 oz. woven cloth. The biaxial tape came in a big 6-inch wide roll ready to go. The woven cloth I needed to cut into 12-inch wide strips. I bought some pinking sheers expressly for this purpose.

The long, shallow box you see on the right is called a ‘glassing box and is used to lay-up and saturate the layers of fibreglass with epoxy. Here, I’m using it as a place to measure up and cut the biaxial tape.

After all the tapes are cut they’re laid around the boat near where they’ll be used.

On the right you can faintly see some pencil lines I put in so I can get the tapes centred when the time comes.

The taping process goes like this:

Area to be taped in saturated with unthickened epoxy.
Fillet material is mixed from epoxy, wood flour, and silica to the consistency of stiff peanut butter and applied to the joint.
Biaxial fiberglass tapes are laid up in the glassing box and saturated with epoxy.
Biaxial tapes are installed over the fillet.
Woven tape is applied over the biaxial tape and soaks up any excess epoxy.
Air bubbles are squeegeed out.

So, one sunny morning I donned my safety suit, charcoal filter canister mask and started with the seams in the cockpit area. The safety suit is a hilarious garment. Basically, it’s a semi-disposable overall with hood made of some paper-like fabric. It’s white, and it makes you look like you’re on the front lines of some biohazard clean-up operation. The idea is that it keeps the epoxy of your clothes and body.

I mixed up a big batch of epoxy, got my 3-inch roller and mini-tray handy and stepped into the boat to saturate the seam areas. The first thing that happened was that I split the crotch out of my safety suit. Oh, well. Unlikely I’ll be getting epoxy there. So I started rolling on the epoxy, roller in left hand, and tray in right hand thrust into the air as some artist might wield his palette. I thought, “geez, I’m going through this epoxy fast”. Then I looked at my right hand and realized I’d been drizzling the epoxy out of the tray, up my sleeve and onto my boot. Great. I had to cut the sleeve off my safety suit because it was saturated with epoxy.

Seven hours later I was done with the seams. When I started it was nice and warm but by five o’clock it was getting cold in the shop so I had to hurriedly start the woodstove. Below are the resulting seams the next day. They look pretty good, although initially I thought I could do better. Now I look at them with fond nostalgia. If only the rest of the seams turned out that well (read on!).

Ok, the things I learned on these seams was:

Start early. Make sure you’re ready to go at about 10:30am when the shop is just warming up.
The epoxy fillet will want to sag. Make it as thick as you can.
Pre-load the woodstove so when you run overtime you can warm up the shop with the strike of a single match.
Don’t tip your roller tray.
Buy a larger safety suit.

The things I didn’t learn this time but wish I had:

It’s easy to underestimate the time required because the greatest proportion of your time is spent mixing the damn epoxy!

Avoiding Epoxy Panic

Well, after this moderate success with the cockpit seams I thought I’d be able to do the rest on one go. After all, I was experienced now, right? So having learned from this experience I spent a day cutting tapes, loading the woodstove, and getting everything ready for a 10:30am start. The CD player was loaded with some soothing Mozart. I was prepared! Or was I?

Everything looks neat and tidy at this stage; hopeful, confident, clean and tidy.

I thought it would be smart to work in phases. Saturate all the seam areas, then do all the fillets, then apply all the tapes. BIG MISTAKE! DON’T DO THIS! You will end up committed to doing the whole works even if you run out of time. Only do a couple seams at a time then move on to the next ones. This way you can stop at any time if you get tired, or bored, or hungry, or whatever.

Now I want to talk about a little-discussed condition, or phenomena, called “Epoxy Panic”. This is what happens when you’ve got a bunch of stuff epoxied and it’s hardening up before you have a chance to put the glass tapes on or whatever else you are supposed to be doing. You panic and start slapping down the glass tape, dumping tons of epoxy on it, and hoping it’ll work out. I spent 17 hours that fateful day keeping Epoxy Panic from taking over. That’s right, it took 17 hours to do these seams! From 10:30am to 1:30am the next morning. And you know what took most of the time? Mixing the damn epoxy! The fillets need to be mixed from epoxy, wood flour, and silica to the consistency of stiff peanut butter. This takes a long time and is strenuous as well! Every time I moved on to another seam and the fillet material was a little stiffer than last time I could feel the chilly bile of Epoxy Panic rising in the back of my throat. Mostly, I kept it under control through and that is probably my proudest accomplishment that day. I wasn’t too proud of some of the seams though. The fillet material was kind of lumpy, there were air bubbles in some of the laminates, the work looked sloppy. I still found it impossible to get the fillet material to a consistency where it wouldn’t sag. Not easy!

By 1:30am I was done. After showering and winding down (i.e. drinking two glasses of wine in rapid-fire succession) I was in bed by 3am. I think I stopped once that day at about 4pm for some soup.

The next day I went out to survey the damage. I was little dismayed. This was the first time on the project when I thought I’d done some sloppy work. The first time that I didn’t make it the best I could. Twenty years ago I would have been out there with my grinder first thing in the morning preparing to start over again. I guess age has some compensations. I didn’t even know if grinding back the seams and doing it over again would be as strong. I thought I’d give it a day. Don’t panic, think about it. I sent an email to Sam Devlin (the designer) with pictures of the offending seams and asked his opinion (having never even seen a seam myself I didn’t know if I was just being a perfectionist). Sam didn’t share my dismay and thought the seams were fine. Nothing wrong with them. He also said that if I wasn’t happy with them I could grind them back a bit and re-glass without a loss of strength. Whew! I re-did the top lamination on a couple of the seams where there were some air bubbles. The rest I’ll probably leave (but reserve the right to change my mind at a later date if perfectionism takes control!) They may not be as beautiful as I would like, but they’re strong and they will be mostly hidden when the berth tops go in. Here’s a picture of one of the seams I fixed up.

Now that the seams are done I can start pulling out the stitches that hold the hull panels together. I found a good way to do this. The stitching wires need to be heated up to soften the epoxy around them so they can be pulled out. You can use a propane torch but you risk lighting your boat on fire. I figured I could use a Weller soldering gun with the wire tip removed. This worked like magic! It only takes from 5 to 20 seconds to heat up the wire enough to soften the epoxy. Make sure the wires are making a good connection with the gun (you should hear/feel the gun hum in your hand). After testing the first 20 or so wires for hotness with my thumb (ouch!) I would just wiggle the wire a bit to see if it was loosening up or look for slight wisps of smoke.

Installing the Sheerclamps

Ok, now finally on to the sheerclamps. The units are made up of two laminations of 24-foot lengths of old-growth fir each 1inch by 3inches that get bent around the gunwale. These pictures show the installation of the first lamination. These pieces must be vertical grain because you need to do some edge bending (i.e. bending the hard way). I suspect that with flat grain this would be impossible. I almost ordered flat grain because I thought it would be less likely to split from screws. Thank God I didn’t.

This stuff is surprisingly flexible, however the forward end is impossible to bend to the shape of the bow and so has a curve planed into it.

These pieces need to be clamped about every foot or so, that’s 22 clamps per side. You can buy 44 c-clamps at about 6 bucks a shot or you can make u-clamps. All you need is half a sheet of ¾-inch plywood and half a dozen bundles of shims. These worked brilliantly and end up costing about a dollar each (if you need to buy the plywood).

I dry fit the pieces to make sure everything would fit when the epoxy was flowing. Then I take it all off again. I think I fit the port side about half a dozen times.

The bow needed some temporary doublers to prevent the plywood from kinking at the breasthook. Also, the sheerclamps are allowed to rise up at the bow otherwise the amount of edge-bend required would be excessive.’

The pieces are coated with epoxy, as are the hull panels where they will be installed.

In addition to the u-clamps, each piece is fastened with #10 x 1-1/4” silicon bronze screws on 1-foot centers staggered above and below the centerline. In this way, each piece is either clamped or screwed every six inches.

And there you have it!

Next Time

Install the inner sheerclamp laminations (each finished sheerclamp is to be made up of two 1-inch by 3-inch laminations).