Almost done...

[pklonowski]

This is the paddle I started working on at the WCHA booth at Canoecopia last March... FINALLY nearing completion. Fiberglass is on both sides of the blade, with a heavy glass-fiber wrap around the end. I didn't want this one to look like it had a rope around it. It's a deep-water paddle anyway, so rocks shouldn't be an issue.

The shaft is maple, the outer parts (grip and blade) are African Mahogany. The mahogany was a garage-sale special.

 

[Douglas Ingram]

Good job, Paul

The maple/mahogany combo should be plenty strong. 2oz. glass would have been plenty for the blade faces. Do you have a picture of the whole paddle?

 

[pklonowski]

Thanks, Doug!

The glass is 2 oz. -- ordered that during the last frenzy of postings in this topic. It's much lighter than the 4 oz. I had been using for the purpose, and makes me think about stripping & re-glassing my other paddles with the 2 oz... a spare time project.

Had 6 or 8 bubbles appear under the glass on the second side, after squeegeeing it, & after taking the pic. This happened on the mahogany only, looks like there was some air trapped in the wood that expanded as the resin heated up. The only one that's very noticeable is inside one of the maple leaves... aws#!t... more work. Any ideas how to prevent this? Besides not using coarse-grained, porous woods? Was thinking maybe put a heavy coat of oil finish on it & letting it get good & dry before glassing, but not sure how well the epoxy would stick to the oil finished surface.

Not sure how good of a pic I can take of the whole paddle all at once -- you wouldn't see any detail. After I finish it up, I can post a pic of the grip, but it's not as pretty as the blade. There's not enough of the mahogany there, to tell that it's not bookmatched.

 

[Douglas Ingram]

The bubbles are caused by either, or both, of two causes:

-First, the wood is off-gassing, air in the wood expands with heat.
-Second, the resin is displacing the air in the wood as it wicks in and saturates.

The resin doesn't heat up enough at this film thickness to be an issue.

A couple of options:

-pre-heat your work environment and the wood to maybe 23C., reduce the temp, then work in cooling temps, down to maybe 20-21C. The exact numbers are less critical, but the drop is. These are suggestions to conserve precious winter time heating $'s. Judicious use of a heat gun can accomplish similar results, but its tricky if you're not careful

-apply a sealer coat of epoxy. Leave it sit for a few minutes, maybe 5-10? and apply some more till the wood no longer gets any "dry" spots. Then apply the glass, carefully as the wood is covered with sticky, gooey resin.

Actually, do both.

Don't bother going back and redoing old paddles. Leave 'em as is and spend your time and effort making new ones. Once you make about 100 you'll start getting the hang of it. By the time you reach 400, you'll be getting pretty consistent results, maybe sooner, if you pay attention to what you're doing!

 

[pklonowski]

So after about 385 more paddles, I should be almost good at this? Sounds like a challenge... Okay, I'm game...

Both suggestions are well-taken; thank you for them. I recall turning the heat up a bit at some point during the weekend (NE wind blowing through the door gaps), if that happened at the right (wrong?!?!?) time, it could cause the bubbles. Especially since the paddle was fairly near the heater. Du-uh.

I thought about an epoxy pre-coat, but figured an oil finish, being less viscous, would penetrate better. I might try both on a scrap & see what they look like.

 

[Douglas Ingram]

Do NOT use oil under epoxy!

Do NOT use oil under epoxy!

Do NOT use oil under epoxy!

 

[pklonowski]

Well, that sounds fairly definitive... I'll guess you've tried this?

Anyway, I sanded the surface last night, dug the top layers off the air bubbles, and filled them with epoxy. Not sure how many I missed, but the worst of them will be invisible. Woodworking is like politics: the art is in the cover-up!

 

[Douglas Ingram]

No need to try it. Any oil finish will hamper the bond of the epoxy.

If you want the saturation, try heating the epoxy prior to coating the wood. It heats pretty quickly, so pay attention. Then apply it. It will spread like water. It may take a few applications to build enough film.

 

[Prairiepaddler]

Nice job, Paul!

I'm about to try glassing a paddle for the first time. I carved it a couple of weeks ago as a demonstration at a science conference. I used western red cedar on the blades, edged with maple. Its the first time I've ever used a wood that soft, so I thought it might be a good time to experiment with glassing and an epoxy edge.

I'll keep the warm-to-cooling in mind and hopefully avoid the bubbles...

 

[pklonowski]

Thanks! Be sure to post pics of yours when you can -- red cedar with maple should be a pretty combination.

I've used cedar & maple in the same blade before, and the only issue I had was in sanding -- the cedar sands much faster. It just took a little extra care to get the surface right, and I used a scraper a lot. The scraper's much quieter than the sander anyway, so it was quite enjoyable!

My daughter (11 yrs) decided she wanted a canoe paddle, so we started picking out parts a couple nights ago. It'll be a cedar shaft (leftover strips from boatbuilding), & a figured cherry blade. She likes otters, so it'll be an ottertail, of course...

 

[Dan Lindberg]

Listen to Doug,

oil or oil finish of any kind shouldn't be anywhere near epoxy resin, not even in the same room where you would apply resin.
BTW, same with any silicone product, shouldn't be anywhere near where epoxy resin is used.

Dan

 

[pklonowski]

"not even in the same room where you would apply resin"


Well, that presents a bit of a problem. I don't have a separate finishing room, let alone a separate 'glassing room. Everything, including rough milling, assembly, sanding, 'glassing, and final topcoat finishing gets done in the same garage. No way the rest of the family is going to put up with sanding dust or fumes in the rest of the house. Tried the basement once, but the whole house reeked of varnish.

Typically, when I'm done sanding, the garage gets vacuumed out reasonably well, allowed to settle a couple days, vacuum & settle again, before I start resin or finish work. This seems to reduce the dust specks in the coats; might this also reduce the ill effects of oil vs resin? What else can/should I do?

Good thing I'm just a hobbyist, and only do this between the day job & running the kids around! That'd be a lot of downtime for a real shop...

The other thing I'll note is that I just finished doing annual maintenance on my local forest preserve district's Voyageur paddles. These have had oil finishes on them since they were new (at least 7 years ago, no telling how many more). They get used several times a week during the spring-summer-fall programs season, so it's not like they're collecting dust. Three of the five paddles developed cracks in the shafts, and I've epoxied them back together (made a whole new top end for one), put fiberglass casts around the breaks, and I've been sanding & oiling the eposed wood annually. The 'glass is holding up well, and it's been 4-5 years since it was put on. Perhaps fully cured oil has lost whatever solvents impact the epoxy, and fully cured epoxy resists the oil solvents? Any thoughts?

 

[Dan Lindberg]

Paul,

I don't know about resin and dryed oil, just that it doesn't take much to effect an epoxy job.

I used to do the sanding and epoxying in the same area, and even the varnish, but no oil or silicone in the area. I have had "fisheyes" for some unknown reason, the best guess I and the supplier had was that I wiped the surface with contamined ("new') solvent.

I am being "forced" to move my shop/canoe work area out to the garage from the basement, so I'm not sure how that will work out. (My wife like your's, didn't like the dust and smell during varnish time. The worst BTW is oiling with turp, very strong smell, this has to be done outside.)

When I varnish, I do setup a plastic "room" to minimize dust in the finish.

Dan

 

[Douglas Ingram]

I have to do all of my work in one room, wish that I had more!

If you're careful not to cross contaminate, you should be OK to use oil based products in the same room.

The people who use those old paddles are probably not concerned about extra fine finishes. The oil finish is probably old enough to not be critical, and the surface prep is probably pretty aggressive, and the job that the glass and epoxy has to do is not very critical. So, it works well enough for the situation.

Dust is an issue, but if you work your timing out, its manageable. Base coats are less sensitive than finish coats. You'll be sanding your work anyway, right?

As for wood combinations, I'm partial to:

-white cedar with maple, especially curly maple.
-tan and chocolate WRC with cherry or walnut.

I like a cedar shaft core with hardwood faces, not a solid hardwood shaft. Taper the core to a feather edge at the grip end, and build it up with the hardwood. This way you get a nice hardwood grip without the big core at the end. Done well, its practically invisible. Well, not quite, but it doesn't stick out like a sore thumb.

 

[pklonowski]

I've thought about laminating the shafts, but it just seems like an awful lot more work. No question on weight savings, just the practical consideration of how long it takes me to get anything done. THis last paddle took 8 months... Heck, I've been planning to overhaul the wall around our fireplace for 9 years now...

But once I built the canoe (strip & 'glass), anything with flat surfaces & right angles is just not exciting enough.

Now if I can just get started on the next boat...

 

[Prairiepaddler]

Hmm, I agree with the laminated shaft. I find it fairly easy to make, and it really does shave off a lot of ounces. I think mine only adds a day or so to the milling and glue-up.

 

[pklonowski]

No, the Forest Preserve District isn't concerned about an extra fine finish on their Voyageur paddles, but they are concerned with splinters, cracks, and damage beyond usability. The paddles cost $150 apiece (don't know where they got them, but probably through Ralph Frese), and the staff likes having them in working order. The cracked & broken shafts come from pry strokes, the beaten up tips come from grinding into the sand/rock lakebed, and the gouges in the grips are from ... from what? Transporting them in the back of the van? Anybody's guess is as good as mine. I suggested they make fleece paddle bags for them...

The glass work does perform a pretty critical function, though -- it keeps the shafts intact. Remember, these are casts -- think of like a cast on a broken arm -- and while the pieces of shaft are epoxied to each other inside the cast, the monster pry strokes required for maneuvering their 34foot boats put a lot of stress on them! So every year, I sand, repair, & oil them, and the 'glass work is holding up well, despite pry strokes & oil underneath. I'm pretty happy with how they're holding up...

I'm always careful with surface prep -- I know too well what happens when you aren't!