Wordless Wednesday

Okay, okay... I can't resist. "You can never be too rich, too good-looking or have too many clamps."

Tech Tip Tuesday

This week's Tech Tip Tuesday is devoted to an often misunderstood and often abused subject - solvents.

Solvents can be very helpful in removing cured epoxy resin and for preparing surfaces for a new layer of epoxy. They should, however, be used carefully. I say misunderstood and abused as people often do not read and understand the MSDS documents for the solvents that they are using, and use solvents when something else would suffice.

Before you start, read the manufacturer's instructions for the epoxy/coating that you'll be using. Find out what solvents the manufacturer recommends and read the MSDS documents for both the solvent and the epoxy/coating that you'll be dealing with.

When working with solvents, you should be using the proper protective materials. This includes gloves, eye protection, a respirator with the appropriate cartridges (usually "organic vapor" cartridges), a powered respirator which brings in fresh air from a slightly distant source. The manufacturer will more than likely list what is appropriate. Be aware that the protection offered by these cartridge respirators is limited and they may become "saturated" with the vapors.
These solvents can damage your internal organs, particularly your brain and liver. You should be working in a well-ventilated area without a source of ignition. (sparks, heaters, open flame, etc.) Your protective equipment must be made from the materials that are indicated in the MSDS as some materials may be dissolved by the solvent that you are using. Remember that what may be the "right " protective material for one solvent may be the "wrong" on for a different solvent."

Never use solvents to clean up bare skin that has epoxy on it. This is a very bad practice as it can actually act as a delivery system to help the chemicals in the epoxy pass through your skin. For un-cured epoxy, vinegar is very useful in preventing the epoxy from curing. Once the cure has been inhibited with the vinegar, you can clean up using soap and water. Some people find waterless hand cleaners to be very good for this purpose.

Use the least volatile solvent that you can. While we could use acetone, instead we use denatured alcohol to prepare surfaces for subsequent coats of epoxy because of where and how we work. If we were working in different circumstances, a soap and water wash or a rinse with ammonia would do the same job to help remove any amine blush that might prevent layers of epoxy from bonding to one-another.



People often underestimate the flammability of solvents until they have a flash fire. Solvents may have vapors that "pool" and create the conditions for spark to ignite the vapors leading back to the can or cloths used with the solvent. We recently had an incident at work where we received some shipping containers that had an open can of Xylol that had spilled. As the vendor who shipped these contianers sheepishly pointed out, it was good that nobody at our facility was a smoker!

Last but not least, be very careful about how you dispose of the materials that are saturated with solvents. Depending on what you're doing, if you have cloths with solvent and products that contain linseed oil, when the solvent evaporates, you can wind up with a situation where the remaining linseed oil can spontaneously combust! This is an altogether too common occurrence.

Please, read and understand how to handle the solvents that you'll be using for your own safety as well as that of those around you.

More Ultralight.

We've started a new session of classes in my cedar-strip canoe building class. I have two new students joining the class this year along with previous students returning to complete boats that are in-progress. One thing I am pleased about is that my two new students are experienced woodworkers. One is a retired contractor and the other still works in the trade running his own business.

These two students are building the Wee Lassie II design to Mac McCarthy's plans. After our successful use of box-beam construction last year for the Prospector Ranger we opted to use this strongback style for the Wee Lassies as well. We've also removed material from the station molds to remove weight there as well.

One thing to remember is that a strongback and station molds need to be robust. Most builders do not move the forms once built so that the shape of the canoe doesn't change as it is being built. For our class, we need to move the boats on a weekly basis so the forms need to be both light and rigid. The box beam does this for us.

The box beam consists of a 1/2" thick plywood deck 1/4" thick Luan ply sides and 2x6" blocking. It is remarkably stiff once assembled and has the advantage of being stable with temperature and moisture changes.

We rip the 1/2" plywood deck to be 7-1/2" wide and the 2x6 blocking to match. Because the ply is only 8' long, we glue and screw the blocks to the underside of the ply with a block beneath the center joint.


The Luan is ripped to be the width of the 2x6 (actually 5-1/2") and the thickness of the ply (*close* to 1/2", but not exact), so it is nearly 6" wide. Again, because the sheet goods aren't long enough for a continuous piece the sides have a patch that is 5" wide and 2' long that gets glued to the side panels at the joint. We stagger the joints so that they are not in the same place, weakening the structure.


Once the sides have cured, the whole structure is glued and screwed (or in this case stapled - one of the students had a pneumatic stapler which made life very easy) to assemble the beam. When the cut edges are lined up, the structure is straight and flat. The large surface area that is glued up when the sides are assembled makes the structure very rigid.



We then mark the centerline and lay out the location of station molds. The station molds get screwed (but NOT glued) to the 1/2" plywood deck.


You will note the unsupported ends which have a taper cut on them. The taper is to clear the hull that we'll be building on the forms. We're also avoiding fiberglassing the hull to the strongback with this clearance cut. It is likely that we will support this with a small piece of 2x4 screwed into the end blocking and to the deck so it isn't flapping in the breeze. You will also note that the stem molds are not in place yet - we use them as forms to laminate the stems before they are installed on the strongback.

We have decided that there are a few flaws here, however. The old method, which used dimensional lumber, gave us a "ledge" which we could clamp to when screwing down the station molds. I'm concerned that we could crush the 1/4" sides if we clamped to them, so I need to either design in a ledge, or have a removable block to fit under the deck to clamp to when screwing down the molds. The other concern is how to support this at a reasonable work height. Small sawhorses seem to be the best solution for this at the moment. The Luan is also a bit splintery, but not bad - a little sanding at the top edge seems to solve that problem.

Travel? Wow.

I think my head has almost stopped spinning.

Can't say I can remember a few weeks when I've been so busy. I've also been a bit sick, which hasn't helped things. I spent three days last week traveling for business. Before I get into the details about what we've been doing in class, I thought I'd give you a little bit about what I've been up to.

We flew down to El Paso, Texas on business via Dallas-Fort Worth airport. With the advent of baggage fees and the reduction of amenities on domestic flights, I have to say that dining in airports has gotten more expensive than I ever dreamed of and carry-on baggage and the jostling for overhead space has become a fine art. I also can't say that I can ever remember more crowded flights (all four legs with full planes) or being treated like more like cattle than on this trip.

*MOO!*

I had the misfortune on two of the longest legs of my journey to have the center seat on a 737 and find myself sitting next to little old ladies with very sharp elbows. On the short legs from Dallas to El Paso, I was fortunate enough to have the aisle seat.

Our journey's destination was Las Cruces, NM and when we touched down in El Paso, we were treated to a truly spectacular sunset that made me wish I'd brought my camera along for the trip. (Sorry! No pictures!) We drove our rental Hummer H3 (not our first choice) from El Paso up to Las Cruces for the night. Along the way we were treated to the view of an illuminated star - 468 feet tall! - on the mountainside near El Paso's community college. After checking into our hotel in Las Cruces, we enjoyed a nice, but late, meal at a place called La Posta that was located in La Mesilla, NM - a cute little town on the outskirts of Las Cruces with traditional adobe houses and a relatively long history including being a stop on the Butterfield Stage Coach trail and the location of courthouse and the trial of Billy the Kid.

The next day when we awoke, the sun was rising behind the mountains and the clouds above were lit up with orange, pink and red hues that you seem to only see in the desert Southwest. Very rugged, but very beautiful. We spent most of the day shut away in a conference room and a shop doing out jobs, but enjoyed a lunch outside with a wonderful view of the mountains again. After our meeting, we drove back down to El Paso, just missing a severe thunderstorm that we later learned had dumped 2" hail on the area.


After checking in to our hotel, we drove over to the Stateline BBQ - it's right on the Texas/New Mexico border. It is an area with a large number of casinos and race tracks to tempt Texans to cross into New Mexico and spend their money. It's an interestingly decorated BBQ and steak restaurant which had some melt-in-your-mouth baby back ribs and perfectly cooked steaks. What's particularly interesting is that there is a hallway by the bar that runs between the restaurant (in Texas where there are some strict liquor laws) and a liquor store. (in New Mexico with more lax liquor laws) The idea here is that when alcoholic beverages can't be sold in Texas, you walk over the border to New Mexico for a drink and bring it back to your table in Texas.

When we left the restaurant it was a moonlit night with broken cloud, but we could see the lightning playing over the top of the mountains and off to the east - the result of the severe storms. The fellow that I was traveling with was fascinated by the fact that we were so very close to the Mexican border - a fact advertised by a flagpole several hundred feet high with a massive Mexican flag flying. He wanted to drive a along the border on our trip back to the hotel which we did, but I was pleased he didn't want to go over the border into Juarez - one of the most dangerous towns in all of Mexico due to the drug trade.

It is a stunningly beautiful and rugged place. I don't mind visiting, but I can't say I'd like to live there. Not enough places to paddle!

Wordless Wednesday

NOW I KNOW!!

Where all the socks go...

It wasn't what I thought...

Rollin Thurlow - A "Neighbors" Essay.

Photographer Doug Bruns of Portland, Maine posted a great interview with Rollin Thurlow of Northwoods Canoe.

Enjoy.