Wednesday, March 30, 2011

Tuesday, March 29, 2011

Tech Tip Tuesday

Don't be afraid of the Goo...

I've said it before and I'll say it again - students seem to be intimidated by working with epoxy. It's not as scary as it may seem. I think the biggest concern that most people have is that it is going to set up before they're ready for it to, or that it will not set up at all.

First, let me say that while I've posted an image of West System's 105 epoxy resin, there are many good epoxy manufacturers. West System is one, System III, Raka, MAS and others all make good epoxy. Choose one that is appropriate for your use. If you're building a canoe that you want to have a clear finish on that shows off the beauty of the woo, the clarity of the epoxy is an important choice. If you'll coat with a colored paint, this isn't such an important feature of the epoxy. Recently, my students have been working with West's 105/207 resin-hardener combination with good results.

Before you ever start working with the epoxy you should prepare. Read the manufacturer's instructions carefully. Get proper protective equipment including gloves, barrier cream, goggles, and organic vapor/particulate masks and/or great ventilation. You want to avoid exposure to the resin so that you will reduce your potential for sensitization to the epoxy. Get good materials to clean up after your epoxy - white vinegar is good for cleaning up uncured epoxy and acetone (some vendors recommend their proprietary solvents...) is good for cleaning up cured epoxy. Avoid using acetone or other solvents on your skin as they can drive the epoxy through your skin and into your system. Disposable wipes and paper towels should be handy as should drop cloths to protect surfaces that you don't want to have spoiled with epoxy. Set up a workstation with the supplies you will want - epoxy and pumps or other metering equipment, mixing cups and sticks, fillers, reinforcements, tape, scissors, razor blades, rollers, squeegees, brushes (foam or chip bristle - but if you use bristle, trim them short to make them stiff and apply epoxy to the base of the bristles near the ferrule to retain the bristles) a waste basket and spare gloves - in short anything you think you might want. Wear clothes you don't value much, or buy Tyvek (tm) coveralls - you will likely get epoxy on yourself.

If at all possible, work with items which are ultimately disposable if they will come in contact with epoxy.

Are you ready?

Nope. Not quite.

If at all possible, you probably want to work with a friend and plan your work. One person should be applying the epoxy, the other should be supplying them with mixed resin and materials as required. It really reduces the panic potential. Have a plan worked out for who will do what ahead of time - and whatever you do, don't let the person mixing the epoxy get interrupted and mess up the mix ratio. If you want pre-cut pieces of glass-cloth reinforcement, or bias cut strips, prepare them now.

You should both be prepared with an almost Zen-like calmness. There is no reason to rush and panic - you should be working within the temperatures that the manufacturer recommends for the resin system you've chosen. There are some things that will let you have more working time - don't leave mixed resin in a mass in a cup - put it in container that will spread it out a bit or apply it to the boat to slow the process down a bit. Keep in mind that typically for every 10°F rise in temperature, curing time will be cut in half and for every 10°F drop in temperature, the curing time doubles.

Are we ready yet?

Nope. Not yet.

We need to make sure that our work environment is correct. I know that there is no ideal workspace, but you need to do the best you can. It should have good lighting, be dust/dirt/fur/bug free, have good ventilation, out of direct sunlight, no animals, children or other distractions, be 70-75°F (for most resins, but again - read the manufacturer's instructions) with the ability to control temperature.



You've got to make a decision about how much time you and your assistant will have to work with the epoxy at a session. If you've got limited time, you'll need to let the epoxy set between coats (which requires a proscribed time/temperature combination for the specific epoxy system), and prepare the surface per the manufacturer's recommendations prior to applying subsequent coats. Typically this includes washing off amine blush with some form of liquid cleaner (usually soap and water and/or ammonia and water) and then lightly abrade the surface to provide a mechanical bond - 3M's Scotch-Brite (tm) is a good way to clean and abrade at the same time. We usually use denatured alcohol to wipe the hull down after that to assure that there isn't any residue left.

Ideally, I would have all boats we work on hot-coated. Because of the limited amount of time in my classes, we don't usually "hot coat" as there isn't enough time. I've discussed this before. This is because the hot-coating process provides for both a chemical and mechanical bond between the layers of epoxy. The downside? It takes a whole day (usually about 14 hours or more) to do this for the outside of the canoe.

We also usually put a sealer coat of epoxy on the hull before applying cloth - this helps minimize bubbles and "starved cloth" which is weak, structurally and not cosmetically pretty. When applying epoxy to bare wood, the ideal situation is to warm the work space up to heat up the wooden hull - to say 80°F or more. Then turn the heat off and allow the hull to cool as you apply epoxy - this avoids off-gassing of the hull which makes bubbles and improves epoxy saturation of the wood. If you try to epoxy in the sun, the sun will heat the wood, driving off gasses and giving you MILLIONS of bubbles. Not good.

After we've got the hull saturated and have prepared the surface, we drape the hull with fiberglass cloth. Fiberglass cloth has a coating - sometimes Volan (tm) which is a water-based coating that help the cloth saturate with either epoxy or polyester resin. You don't want to handle the cloth with bare hands and get oils from your body on the cloth which may prevent good saturation. Wear your nitrile gloves. Also, keep the cloth clean and dry to avoid loss of the coating and loss of transparency. To cut the cloth, it is a good idea to pull a single thread from the cloth's edge where you want to cut to give you a mark to cut along. This isn't as hard as it sounds, but requires a bit of practice to avoid breaking the 'glass yarn in the middle. Roll or "flake" the leftover cloth and store it so that it stays clean and dry and doesn't crease.

Smooth the cloth over the hull and work out any irregularities by carefully "massaging" the cloth with gloved hands. Avoid snagging the cloth on sharp edges.

Now we're ready to apply resin.

We measure out the proper ratio of resin/hardener and mix for at least 1/2 a minute being sure to get into all of the corners of the container to properly mix the epoxy. While we do this, we avoid mixing in excess air - you're not trying to whip the epoxy. Only mix an amount you are comfortable working with - if you mix too much, you're likely to waste it. You can always mix more, you can't mix less.

Apply the resin to the hull starting from the middle of the hull and working outwards methodically, avoiding wrinkles. The goal is to get all the cloth wet out so it is transparent. Pay attention for dry spots and bubbles. The most difficult thing to do is to apply epoxy to vertical surfaces with a squeegee - I usually hold the edge of the squeegee near the sheer against the hull and pour a little resin on the hull just above the squeegee and pull upwards towards the keel. Don't panic at this point - I tell students that it usually takes about 3 or 4 canoes before you really get comfortable with the process. I'm joking here, but not much.

If the epoxy you're working with starts to heat up or gel - stop using it and put it aside. You'll only make a mess if you try to use it.

When the hull is wet out, we go back, starting at the center of the hull and use the squeegee to remove excess epoxy by working from the keel towards the sheer with light pressure. This is because the cloth tends to "float" on the resin adding weight, but not strength. You should be able to see the texture of the cloth when this is done properly, but without white areas that indicate resin "starved" cloth. We wipe the excess epoxy off the squeegee using a paper cut with a vertical slit in it about 2" down from the rim. When the hull gets to the "green" stage - just starting to cure - it can be trimmed at the sheer and stems and reinforcements added at the stems and wet out. This is much easier than when the cloth is fully cured and hard.

Subsequent coats of epoxy can be applied with your choice of brush, roller or squeegee until the cloth is "buried" - avoid sanding the cloth which weakens the actual composite and ruins the transparency.

Not that hard, really, it just takes some patience, knowledge and practice.

While you're working, avoid contact and work as neatly and cleanly as possible. If you spill, stop and clean up - you'll only be spreading uncured resin everywhere. When done, clean up and throw away the items you can. One caveat here - avoid throwing away large amounts of mixed resin as curing epoxy is an exothermic reaction (it generates heat!) and can cause some real problems when it gets hot enough to smoke, melt cups and could potentially cause a fire. Dispose of carefully!

Monday, March 28, 2011

Maine Boatbuiders Show 2011 : Part 1

Another year has passed and spring is around the corner again so it must be time to head to Portland for the Maine Boatbuilders Show again. Every year I encourage my students to go to the show as an opportunity to see the variety of boats that are there and the different ways that the builders approach trim and details. After spending the better part of the year building their own as-yet-unfinished boats, it is a wonderful bit of enthusiasm and encouragement to look at the beautiful boats that have been brought to the show. It is also a great opportunity to get those items from show vendors or next door at Hamilton Marine that will go into making their canoes the works of art that people will say "ooh" and "ahhh" over at the school's exhibition in June. While there are very few canoes or small boats at the show, it also seems to be a mind-expanding trip for the students in seeing the possibilities.

I usually try to do a quick trip through the first floor of the show to get an idea of the whole show in order to get an idea of the boats and booths that I want to spend more of my limited time at the show seeing. I suppose that I should mention that my students and I meet at the school at 6:00 AM to put the canoes back in the barn before getting in the car for the drive to Maine to go to the show stopping along the way for breakfast, the show, Hamilton Marine, and a late lunch before heading back home. It's quite the kamikaze run...

At any rate, I found it slightly difficult to do my usual zip through the show as I found both friends and vendors that I wound up stopping to talk to along the way. Don't get me wrong - I was very glad to see them, it just took me a bit longer than usual.

Here are a few of the sights that caught my eye on the way in - first, some traditional split ash-creels and a lovely caned seat at the Shaw and Tenney Booth. Oh yeah, they also make some of the loveliest traditional paddles and oars you'll find.

Hanging on the wall outside what must be an office space at Portland Yacht services is this single scull which has been there for many years. I'm always curious what the story is behind this particular boat. One year I'll work up the interest to find one of Phin's employees to ask what the story is.

While not being much of a power-boat fan, I could see one of these runabouts at a dock in my future. Love the pinstripe decks and the detail that went into her. I try to make my students appreciate all of the disciplines that go into making these craft.

More to come...

Thursday, March 24, 2011

Over the Bar : Harold H. "Dynamite" Payson

Sadly, the boat-building world has lost another one of it's foundations. Harold H. Payson passed away on the 23rd of March. Payson, known to most if not all as "Dynamite" Payson was a boatbuilder who encouraged many handy-persons to go out and build their own boat using Dynamite's "instant" boatbuilding method of building boats. Dynamite also had a fantastic relationship with Phil Bolger and had Phil develop plywood boat designs he sold that would work well with his "instant" method and Yankee sense of thrift. With Phil's passing in 2009 and now Dynamite's passing, a wonderful team has left us.

Update : Some thoughts from Carl Cramer and Dynamite's obituary from the Bangor Daily News

Wednesday, March 23, 2011

Thursday, March 17, 2011

Happy St. Patrick's Day!

Be sure you are prepared...

and enjoy!

Wednesday, March 16, 2011

Wordless Wednesday

Must be a boat-builder cooking...

Monday, March 14, 2011

Mumble... Grumble... Grump...

Being a boatbuilder who lives where I live can be very frustrating.

Very frustrating.

Most of the lumber that I want to work with is available, but not readily. You've got to look around. I've got a few projects that I've been thinking of and they require specific types of stock. They include the following:

Atlantic White Cedar

Atlantic White Cedar

Western Red Cedar

Atlantic White Cedar, a relatively local wood, requires a drive to the lumberyards nearer to the coast than I am located. For Northern White Cedar, again, a relatively local wood, I have to head further North. Western Red Cedar, which actually grows nowhere near here, is available at almost every local lumberyard.

Go figure... The irony here is that I'm really looking for the local woods in decent quality with some, but relatively few knots. It will take me a bit of work to get as I'll have to track down a sawyer who deals in it.

Then again, there is some plywood I'm looking to find as well. It's marine plywood. Marine plywood is pretty specific stuff. It is stamped (as in the image below) BS 1088 which refers to a very specific British Standard specification. The reason for the specification is to get a product with a uniform thickness, no flaws or voids, resistance (obviously) to moisture and attack by fungus, hot, cold and uniform dimensions and plies.

BS1088 plywood is tested and certified by Lloyd's Register Group. (note the stamp below)

There are a variety of manufacturers. Just because they meet British Specification 1088 doesn't mean they have to be manufactured in Britian, Shelman S.A. which makes Shelmarine is in Greece and Joubert Group is located in France with manufacturing operations in France and Gabon.

To get this marine plywood, I'd have to drive at least two hours each way to a supplier, and get it back in one piece without losing it off the roof-rack or borrow a truck to stick it in the back. Time is money and so is gas and tolls. So, I've tried my local lumberyards. Local lumberyards don't carry the stuff and I'd have to special order it. One yard wanted more than three times the going rate for a sheet of plywood to get it here - $165/sheet for 4mm Okoume (Actual per sheet cost? $49!) Another yard couldn't even get the stuff from their suppliers. I could get it shipped by Boulter Plywood of Somerville, MA. However, shipping would be $40 for packaging and another $90 for the shipping fee via common carrier - if it is delivered to a commercial address.


This stuff can be hard to find. Still, the end results are worth the time and effort to get the stock.

Friday, March 11, 2011

Consider a donation...

A horrible natural disaster has happened again, this time in Japan. Please consider a donation to the American Red Cross to support disaster relief efforts.

Wednesday, March 9, 2011

Sunday, March 6, 2011

That time of year again...

Warmer days are coming and there is a definite change in the air. You can smell the earthiness of the ground escaping it's coating of snow. That must mean that it's time for the Maine Boatbuilders Show again!

On March 18th, 19th and 20th at the Portland Yacht Services building on Fore Street in Portland, Maine, Phin Sprague and his crew will be hosting boat builders and suppliers in what is often called the first rite of spring in the Maine boating season. If you have any interest in boats large or small, you owe it to yourself to go!