Wooden paddle finish voodoo

bnystrom · August 15, 2009, 11:51pm

The design is the most important thing

– Last Updated: Aug-15-09 8:36 PM EST –

What you use for a finish on a paddle is a distant second at best. More importantly, it largely comes down to personal preference, rather than any important differences. Here's the basic scoop on finishes:

Oil
The main reasons that people choose oil finishes are twofold:
1 - They like the feel. Oil finishes (pure oils, not faux-oil finishing products) cannot be built up to any significant thickness. They produce a soft, matte or satin finish. Consequently, an oiled paddle still feels like wood. Many people, myself included, prefer the feel of an oiled paddle.
2- They like the look. The matte/satin finish is visually appealing because it looks like wood, not like wood that has been coated with something.

Other plusses for oil finishes:
- They are easy to maintain. You simply clean off the paddle, wipe on more oil, then wipe off the excess after 5 minutes or so. OTOH, being relatively soft, they also require more frequent maintenance than other finishes.
- They allow the wood to breathe to an extent, so that any water that gets through the finish can get back out again.

The most common types of oil finishes are:
- Raw linseed oil. This is not generally a good finish for paddles or much of anything else, as it takes weeks or even months to cure. I don't have that much patience nor do I see any advantage to raw linseed oil.
- Boiled linseed oil. This is by far the most common oil product on the market. It's not actually boiled, but it contains heavy metal driers (cobalt) that cause it to cure much more rapidly than its raw cousin. Applying one coat per day is pretty standard. One downside to either linseed oil is that mold and mildew feed on them, which is why they're not a good finish for items that stay wet for long periods of time, like SOF kayak frames. For paddles, this isn't typically a problem.
- Tung oil. Pure tung oil is good wood finish, but you have to read the label. There are a lot of "Tung Oil Finish" products on the market that contain little or no tung oil (they're wiping varnishes - see below). I prefer to use tung oil for paddle finishes, but the functional differences between it and boiled linseed oil are not significant.

Varnish
Most commercial paddles are finished with some form of varnish, either spar varnish or polyurethane (polyurethane is simply varnish made with synthetic oils and resins). It creates a hard film finish that can be very durable. Typically, gloss varnishes are used, which gives the paddle a plastic look and a rather slippery feel. Satin and matte varnishes are available, but with use they get polished in the grip areas and become just as slippery as gloss varnish. You can "renew" the finish with Scotchbrite, steel wool or 600 grit sandpaper, but it just gets polished again with use.

Being a completely waterproof film finish, if it becomes damaged and water wicks into the wood, it becomes trapped and the wood will likely become discolored in that area unless you sand it down, let it dry and refinish it. Rot is possible, but realistically, it's not likely on a paddle.

Epoxy
Epoxy is a hard film finish, but if you wipe it on and off like oil, it can produce a more natural look and feel than gloss varnish. However, epoxy is UV sensitive, so it really should be covered with varnish to protect it, which is what you usually see on commercial paddles. It hardens the surface of the wood substantially and may stiffen the paddle to a noticeable degree. If applied thickly and/or coated with varnish, all the caveats regarding water entrapment apply. As with varnish, it's more involved to maintain it, especially with epoxy/varnish finishes.

There is a class of products called "wiping varnish", which are mainly varnishes with a lot of thinner added (mineral spirits), but sometimes with oils added as well. Most "tung oil finish", "Danish oil" and "Teak oil" finishes fall into this category. Depending on their composition, they will be more like varnish or more like oil. These are generally a very poor value, as you pay a premium price for a product that's mostly cheap thinner.

To further muddy the waters, there is class of oil finishes known as "polymerized oils". Depending on the degree of polymerization, they will behave like oil or varnish. Birchwood Casey Tru-Oil is a good example of a highly polymerized oil that acts like varnish. Polymerized oils are not that common and you're only likely to see them in specialty woodworking stores. Some are marketed as "natural" or "green" finishes, since they don't contain petroleum-based thinners and heavy metal driers, like many other products.

My personal preference in paddle finishes is a 50:50 blend of varnish and pure tung oil. It retains the look, feel and ease of application/maintenance of oil finishes with considerably better durability. I epoxy coat the tips of my paddles for durability and since it's a sacrificial coating, it wears down and requires re-coating before UV damage becomes an issue. I find this to be the best application for these products, at least for my personal use.

I guess the bottom line is that different finishes are appropriate for different uses and paddlers. If someone tells you that a particular product or procedure is "the only way to finish a paddle", turn around and walk away.

Glenn_MacGrady · August 16, 2009, 2:59am

More answers

– Last Updated: Aug-16-09 7:10 AM EST –

"OK, I'm not convinced I need epoxy on non-FG'd wood"

You don't "need" to do it unless you have a specific reason, like hardening the surface.

"but I'm sort of convinced that there should be a UV protectant over an epoxy finish. I understand both poly and spar varnish have UV protection."

Except in areas where the epoxy is sacrificial, it should be coated with a UV protectant. AFAIK, all spar varnishes are designed for exterior use, so they have UV inhibitors in them (spar varnish is NOT a generic term for natural varnishes, it's a specific type of marine varnish). That is not true for all polyurethane varnishes, as you can get interior poly's that don't have UV inhibitors. What you need to look for is the word "exterior", as that will indicate UV additives are present.

"What is the aesthetic, functional, tactile or other difference between spar and poly for a paddle?"

The difference isn't much and it generally comes down to poly's being more durable.

"Will any of the oils provide the necessary UV protection if put over epoxy?"

I forgot to mention in my previous post that putting oil over anything else is pointless, as it cannot be built up to any significant degree. For best results, oil must be applied over bare wood.

"I know you can pretty easily sand off varnish. Can you sand off an oiled finish? (I realize Marc said it doesn't matter much.)"

If you want to remove all of either type of finish, you have to sand deep enough to remove the pores that the finish has wicked into. If you're just refinishing a paddle, that's not necessary. Oil finishes can be sanded, but they're soft and tend to clog the paper.

"Does anyone else vote for beeswax? Onno, how does this compare or differ from an oil or varnish finish?"

I've heard of a lot of people that blend bee's wax with oils and some finishing products contain it as a component. I don't know that I would want to use only bee's wax as a finish, as it wouldn't be very protective.

"I have heard that Greenland paddle aficionados have some strong opinions on this subject. I don't know what they are, however. Whale or seal oil, perhaps."

While those products may be used in Greenland, they're illegal here, so it's irrelevant. Most of the GP users I know, myself included, tend to lean toward oil finishes or blends that produce the same type of surface, though many prefer no finish at all. If you use woods like cedar, you don't actually need a finish, but finishing the paddle helps to keep the grip surface smooth and prevents it from gaining a lot of water weight in use.

FadedRed · August 16, 2009, 11:14am

Glen
The finish You put on a paddle can also be determined somewhat by whether or not it’s a laminated paddle where the lamination joints are already epoxy and you wish to keep the wood from swelling around the glued surface.

If The paddle is made from one piece of wood, then this possiable wetting of the wood is a non-issue.

Where laminatated paddles are concerned,(especially if any carbon fiber has been used in the layers to change the flex charicterists) I prefer to seal the paddle and tie the glue joints with an exterior finish of epoxy.

If the paddle is laminated from scraps and longevity is of no concern…then the finish could be anything You chose.

I spray epoxy finished paddles with (deadly) two part eurathane as a UV protector and I like the amount of grip/feel it has rather than the feel of the epoxy.

Best Wishes

Roy

MOrnstein · August 16, 2009, 11:19am

The only reason
I mentioned fiberglassing the blade is that spar varnish is the “standard” method of UV protection for epoxy/fiberglass construction, be it large yachts or stripper canoes. As such, the issue of compatibility has long been established.

Oil finished, as have been discussed here provide minimal UV protection. Even if the product contains a UV inhibitor the film thickness is too thin to be of much value.

Spar varnishes tend to be softer/more flexible than other varnishes and are thus preferred for exterior applications where there may be more expansion or contraction of the wood with temperature and moisture changes. That flexibility also makes them more suitable for applications where the wood may be routinely flexed as well as making it less prone to chipping than harder varnishes.

As for sanding off oil finishes. Since most of the oil finished mentioned in this forum are of the penetrating type, sanding off such a finish necessarily means removing a substantial amount of wood as well. You’d not want to do that too many times on a paddle. When I’ve refinished wood that had previously been oiled, I’ve lightly sanded the surface in order to “clean it up”, but not so deeply that all of the old finish was removed.

Marc Ornstein

Dogpaddle Canoe Works

Custom Paddles and Cedar Strip Canoes

kanoniem · August 16, 2009, 1:48pm

raw linseed oil
The advantage of raw linseed oil over boiled linseed oil, is that raw linseed oil impregnates the wood much better. When the wood is fully saturated with raw linseed oil, one can finish with boiled linseed oil and/or tung oil, which will dry in a couple of days.

Once wood has been treated with raw linseed oil, treating it with epoxy makes no sense anymore, I think. Spar varnish will be no problem though.

bnystrom · August 16, 2009, 4:07pm

Penetration mythology

– Last Updated: Aug-16-09 1:06 PM EST –

There are a lot of myths regarding the penetration of oil and other finishes into wood. The truth is that the only substantial penetration you'll get is on end grain, where it can wick in along the cell structure. On flat grain, you get a few thousandths of an inch of penetration at best in most woods. On coarse-grained woods like oak, you'll get more penetration where there are exposed pores, but you still get very little elsewhere.

For the skeptics out there who may think I'm blowing smoke, here's a really simple test:

- Take a sharp plane and set it to make a .002"-.003" shaving.

- Take an oil-finished paddle or test piece and count how many plane strokes it takes to get down to bare wood. In my experience, two or three is about it on face grain.

While it's true that raw linseed oil stays liquid longer and will at least theoretically penetrate farther into the wood, whether you end up with .004" of penetration or .008" of penetration doesn't make a whole lot of difference, certainly not enough to justify putting up with a finish that takes forever to cure. Applying a faster curing finish over it will increase the curing time of the raw linseed oil dramatically, as it will cut it off from the oxygen it needs to cure. "Saturation" will never occur unless you soak the wood in oil for weeks to months and even then it may not fully penetrate an object as long as a paddle.

I haven't found that thinning oils increases penetration appreciably, either. The thinners evaporate too quickly to do much good. They also result in a more porous finish, since the evaporating thinner leaves open pores in the oil or varnish film.

There is one more thing that's important to understand about oils and varnishes; they don't "dry" like lacquer or shellac (where the solvent simply evaporates), they "cure" by combining with oxygen in the air. The resulting finish is chemically different than the original oil or varnish and applying more over it will not dissolve the underlying finish and bond to it. There is a finite window where the best bond between coats can be achieved. If you apply the next coat too soon, you cut off the oxygen supply to the underlying coat and it takes MUCH longer for it to cure. This is what happens when a varnish job is rushed and slathered on too quickly/heavily and it stays soft for weeks or months. OTOH, if you don't apply the next coat soon enough, you won't get any chemical bonding, so you need to sand the surface to enhance the mechanical bond between coats. Oils are somewhat more forgiving, since they don't build up much film thickness, but if you slop on oil and don't wipe it off, you end up with a gooey mess that again takes forever to cure.

For anyone interested in more information on various finishing products, how they work and where they are best applied, I highly recommend Bob Flexner's book "Understanding Wood Finishing". It spells it all out and dispels many common myths.

FrankNC · August 16, 2009, 5:02pm

Seems like you all forgot about PAINT
Paint is the number one wood protective coating these days. It lasts much longer than varnish and is easy to maintain.

Of course then other won’t be able to tell you are using a real wood paddle from a distance and that might hurt your feelings, but it will not hurt the paddle at all.

Glenn_MacGrady · August 16, 2009, 5:07pm

Oil isn’t always oil

– Last Updated: Aug-16-09 1:09 PM EST –

I did some googling.

This article says that many popular oils, such as Watco and other "Danish" oils, are really just blends of varnish and an oil.

http://www.popularwoodworking.com/features/finish2.html

Another article specifically says Watco is linseed and varnish.

The linked article and others I have seen, along with one paddle maker, say pure tung is very difficult to use. It must be sanded vigorously after every application and many, many coats must be used.

Most of the articles say oil has no UV protecting qualities. Some say it should be applied over bare wood with nothing underneath it.

If any of these are correct, it would seem that if you are going to apply oil, you shouldn't apply an epoxy sealer first. The epoxy will interfere with the saturation and polymerization of the oil, and the epoxy won't be protected from UV by the oil.

What the heck happens to epoxy anyway if it isn't UV protected? Something horrific?

I'm more interested in protecting the wood than the epoxy. Does wood itself need UV protection?

My investigations this summer have not changed my longstanding subjective preference for the feel of oiled grips over varnished grips. But now I wonder certain things. Should I oil the whole shaft? If I do, shouldn't I forbid an epoxy "sealant" underneath it? But, confusingly, if the oils I'm using are really half varnish anyway, maybe I'm back to voodoo and have always been fooling myself about "oil".

Oh, on top of all this, other articles say that "oil" or "varnish" are preferred or not for finishing depending on what kind of wood is being used. Cherry is different from oak. Something to do with pore sizes.

http://74.125.93.132/search?q=cache%3AUkxpObvIAPUJ%3Awww.woodcentral.com%2Fbparticles%2Foil_finishes.pdf+watco+oil&hl=en&gl=us

I guess I forgot my botany. I thought wood was a closed cell structure.

bnystrom · August 16, 2009, 5:47pm

There’s nothing wrong with paint…
…but very few people use it on paddles, either commercial or home-made. I didn’t forget about it, it’s just not particularly relevant to the discussion at hand.

Glenn_MacGrady · August 16, 2009, 6:07pm

Effects of finish on wood color
I forgot to bring up this issue in my previous posts, but it may be of more or less significance to discriminating paddlers.

I have read that, among varnishes, spar will discolor (yellowy) more than polyurethane. I have also read that different oils will have different color effects over the short and especially long term – though I haven’t seen anything go into exact specifics.

I personally would prefer the finish to have minimal effects on color IF I have spent a lot of time and/or money selecting or specifying my woods for color aesthetics – such as my ebony, bloodwood, curly maple and kauri dream paddle.

bnystrom · August 16, 2009, 6:22pm

Even more answers
"This article says that many popular oils, such as Watco and other “Danish” oils, are really just blends of varnish and an oil.

http://www.popularwoodworking.com/features/finish2.html

Another article specifically says Watco is linseed and varnish."

As I mentioned previously, most “oil finish” products are blends. They typically mostly thinner, blended with varnish and in some cases linseed or tung oil. The only way to know that you’re actually applying an oil finish is to use pure oils.

"The linked article and others I have seen, along with one paddle maker, say pure tung is very difficult to use. It must be sanded vigorously after every application and many, many coats must be used.

That’s complete BS. Tung oil is incredibly easy to use as a finish, as is boiled linseed oil. You wipe it on, let it penetrate, then wipe it off. Each succeeding coat helps fill the pores in the wood, but it won’t build to any appreciable thickness. Perhaps that’s the issue with the author of the article, he’s trying to create a varnish like finish with tung oil, which is a complete waste of time and a poor application for it. As with any finishing product, you have to understand it and use it where it’s appropriate. Lack of understanding is where most finishing myths come from.

BTW, for finishing paddles, I’ve found that there’s no point in applying more than 4 or 5 coats of oil or oil/varnish blend and as few as 3 will do the trick.

“Most of the articles say oil has no UV protecting qualities. Some say it should be applied over bare wood with nothing underneath it.”

Correct on both counts.

“If any of these are correct, it would seem that if you are going to apply oil, you shouldn’t apply an epoxy sealer first. The epoxy will interfere with the saturation and polymerization of the oil, and the epoxy won’t be protected from UV by the oil.”

Correct again, except that the epoxy shouldn’t affect the polymerization of the oil, since all that’s required for that is oxygen.

“What the heck happens to epoxy anyway if it isn’t UV protected? Something horrific?”

It breaks downs and gets chalky, losing all of its strength in the process. If it’s used as a wipe on/wipe off coating on wood (applied like oil), it is somewhat protected by the wood itself. If it’s applied as a film coating (applied like varnish), it’s unprotected and subject to degradation. Depending on how much you use your paddle and how you store it, the damage could take anywhere from months to years to become bad enough to raise concerns.

“I’m more interested in protecting the wood than the epoxy. Does wood itself need UV protection?”

In general, no, as wood is not damaged by UV. Some - perhaps most - woods change color due to UV exposure. Pine turns orange, purple heart turns brown, etc. If the color change is undesirable, a UV protectant will slow the change, but I don’t know if it’s possible to completely eliminate it.

“My investigations this summer have not changed my longstanding subjective preference for the feel of oiled grips over varnished grips. But now I wonder certain things. Should I oil the whole shaft? If I do, shouldn’t I forbid an epoxy “sealant” underneath it? But, confusingly, if the oils I’m using are really half varnish anyway, maybe I’m back to voodoo and have always been fooling myself about “oil”.”

That’s one of the biggest problems with wood finishing, the huge amount of misinformation foisted on the public by finish manufacturers. Calling a wiping varnish an “Oil Finish” is confusing to the consumer and just plain wrong.

To answer your question, if you like the look and feel of oil finishes, either use pure oil or make your own oil/varnish blend. Unless you have a specific need for epoxy, there’s no point in using it. As I mentioned, I epoxy coat the tips of my paddles for durability and use an oil varnish blend on the rest of the paddle. It gives me the look and feel I like with better durability that just oiling the entire paddle. You may prefer a different approach. Now that you understand what these products are and how they work, you can figure out what’s the optimum finish for your needs.

“Oh, on top of all this, other articles say that “oil” or “varnish” are preferred or not for finishing depending on what kind of wood is being used. Cherry is different from oak. Something to do with pore sizes.”

Again, it depends on the application. What you use on furniture or cabinets may not the the ideal finish for a paddle. It also depends on what one is trying to achieve with the finish. Blanket statements like that simply cannot be correct for every application. You need to know the goals of the author and the materials being used.

“http://74.125.93.132/search?q=cache%3AUkxpObvIAPUJ%3Awww.woodcentral.com%2Fbparticles%2Foil_finishes.pdf+watco+oil&hl=en&gl=us”

In this case, the author apparently doesn’t know what he’s using. Because Watco contains varnish, it can be built up slowly by using many thin coats. He also doesn’t seem to realize that the sanding he’s doing is filling in the pores and knocking down the high spots, which is what ultimately produces a fine finish. I routinely apply the last two coats of finish on my paddles using 400 and 600 grit sandpaper. Even on cedar, the results are impressive.

“I guess I forgot my botany. I thought wood was a closed cell structure.”

Yes and no. There are closed cells, but there are also tubular structures. This varies greatly between various species of wood. Sawing/planing/scraping/sanding opens some cells and tubes, which will then absorb a finish. Sanding plows furrows in the wood, which will also hold finishes. It’s a whole 'nuther world at that level.

Glenn_MacGrady · August 16, 2009, 6:42pm

bnystrom
Thank you for your in depth contributions. Do you mind saying something about your background in this area.

You say that one should use “pure” oils in order to know what you are actually using. That sounds reasonable. But the only oils I’ve heard about so far are tung and linseed (not counting beeswax). You’ve said you use tung.

Not to be argumentative, but one of the authors whose comment about tung you called BS is the same author you recommended earlier, Bob Flexner. He says in the article I linked:

“But tung oil is too difficult for most people to use by itself as a finish. You apply tung oil just like linseed oil or oil/varnish blend, but you have to sand tung oil after every coat, not just after the first, and it takes five to seven coats, allowing two to three days drying time between each, to achieve a smooth, attractive sheen.”

This kind of statement deters a novice like me from even trying tung. Would you mind elaborating on why you are saying tung doesn’t have to be vigorously sanded and dried multiple times. Is it because you are cutting the tung with varnish in the first place?

angstrom · August 16, 2009, 7:55pm

Epoxy with/without varnish
http://www.oneoceankayaks.com/Epoxyhtm/epox12m.htm

Glenn_MacGrady · August 16, 2009, 8:46pm

Terrific. Empirical evidence. Thanks.
I have been bothered throughout my summer paddle journey, including this thread, by the lack of empirical evidence to back up claims. Everything seemed to be subjective, anecdotal and/or mechanical confirmation bias. (By mechanical confirmation bias, I mean someone who has shot a number of free throws with two hands, and hence recommends two-handed free throw shooting. She may never have tried one-handed or under-handed free throw shooting.)

If I’m reading the test results correctly, the whitening-cracking-crumbling can only be reduced by applying and leaving on very thick filler coats of epoxy – which of course would add unwanted weight in something like a paddle. It also seems as if varnish does help reduce the degradation, but doesn’t stop it.

Makes me think about whether I want any epoxy or composite cloths on an expensive wooden paddle. Sort of a trade off between ultimately fixing some damaged wood or ultimately fixing some damaged epoxy and cloth. On the other hand, I have 25+ year old wood paddle blades with FG wraps that look perfectly fine. They’ve been lightly sanded and varnished just two or three times.

FadedRed · August 16, 2009, 10:52pm

like
these?

http://www.woodsongcanoes.com/paddles.htm

Best Wishes

Roy

I use the finish Phil uses. He;s the one that told me.

bnystrom · August 17, 2009, 12:20am

Yet more
"Thank you for your in depth contributions. Do you mind saying something about your background in this area."

It’s pretty simple really, I’ve read a lot about finishes and I’ve experimented with them on paddles and SOF frames.

“You say that one should use “pure” oils in order to know what you are actually using. That sounds reasonable. But the only oils I’ve heard about so far are tung and linseed (not counting beeswax). You’ve said you use tung.”

You can buy pure linseed oil - either raw or boiled - just about anywhere. I don’t recall ever seeing any products advertised as linseed oil that weren’t actually that. Tung oil is another matter, as there are myriad “Tung Oil Finish” products on the market that are wiping varnishes or blends. You can get pure tung oil, but generally you have to get it through a woodworking supplier, as the stuff you find on the shelves at home centers and hardware stores is suspect unless it actually says “100% tung oil” on the container.

“Not to be argumentative, but one of the authors whose comment about tung you called BS is the same author you recommended earlier, Bob Flexner. He says in the article I linked:

“But tung oil is too difficult for most people to use by itself as a finish. You apply tung oil just like linseed oil or oil/varnish blend, but you have to sand tung oil after every coat, not just after the first, and it takes five to seven coats, allowing two to three days drying time between each, to achieve a smooth, attractive sheen.”

This kind of statement deters a novice like me from even trying tung. Would you mind elaborating on why you are saying tung doesn’t have to be vigorously sanded and dried multiple times. Is it because you are cutting the tung with varnish in the first place?”

That’s interesting, but without context, I can only assume he’s talking about using it as a furniture finish, which is his primary business. Personally, I wouldn’t use straight tung or linseed oil as a furniture finish, as it’s not durable enough and I wouldn’t want to be renewing it constantly.

As a paddle finish, none of what he said is true unless you’re determined to have a flawless, furniture-grade finish on your paddle. I used straight tung oil on a number or paddles (and straight boiled linseed oil, too) before I experimented with blends and ultimately switched to them. It was a wipe-on, wipe off process, just as with linseed oil; there were no special techniques or other gyrations involved. It couldn’t have been easier.

I understand your confusion, as the subject of wood finishing is full of myth, folklore and just plain nonsense that’s been passed down for ages. Bob’s book helps shed some light on the subject, but as you can see, there’s still a lot of variability in finishing and it is entirely dependent on the nature of the object you’re finishing and how it will be used.

bnystrom · August 17, 2009, 1:03am

Vaclav has done some great work…
…in the area of fabrics and epoxies, among other things. Keep in mind that these are the results of an extreme test. Unless you leave your paddles out exposed to the weather year-round, you won’t see the kind of degradation that he did for quite a while.

Whether to use epoxy and fiberglass should be a decision based on whether you need the reinforcement or not; it’s really not about finishing. Epoxy and glass are structural components, not just cosmetic coatings like finishing products. If you don’t need their structural properties, there is absolutely no point in using them.

Glenn_MacGrady · August 17, 2009, 2:04am

Billionaires and paddles
Exactly.

I called Phil and he said he was making a canoe for a billionaire in Connecticut. I told him that wasn’t me, but I did have $87.95 to splurge on a paddle.

Turns out he’s from Connecticut, too, and we had a great chat talking about paddling in the uber-magnificent Sparkelberry Swamp and rolling canoes with S-blades. He sent me his DVD, which is breathtaking.

What’s a mere $3,500 for an ancient wood paddle when you are buying a $130,000 ebony canoe to hang in the boathouse of your $30,000,000 yacht?

YakOfSteel · August 17, 2009, 4:03pm

Cheap.
He should have charged him much more . . . .

YoS