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PostPosted: March 10th, 2005, 10:22 pm 
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Joined: June 20th, 2001, 7:00 pm
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Location: Wahta Mohawk Territory
Not the whole thing, of course.... :tsk:

Just wanted to know if anyone has tried taking a blow torch to one or more strips to try to create an accent stripe? I figure a few light passes using the same arm technique as one would use when spray painting would get the wood a nice dark colour without damaging the strip. I would do it before machining the cove so as to not burn the delicate wood edge.

Would this affect the glue up in any way? The idea would also be to just do the outside of the strip, not the top or bottom where the glue goes.

Thanks for the insights! :clap:

Cal White


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PostPosted: March 11th, 2005, 1:00 am 
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Location: Squamish, BC
I think that's a great idea.

Are you thinking this on an existing, unfinished canoe? Or are you wanting to do a design on the strips first before you assemble the boat?

If it's the latter, be aware that you will create 'steps' in the outside of the design after you mill your material. That'd still look pretty cool though.


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PostPosted: March 11th, 2005, 8:41 am 
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I've tried darkening wood this way and on somethjing like a table top, haven't been pleased with the results - ended up sanding it off and staining. The problem is that the flame has to be applied at a uniformly constant heating rate over the wood surface - this is hard to do over several feet of wood, and there'll be blotches, and lighter and darker spots. Some areas will darken more quickly that others, even though the amount of flame applied has been uniform. The darkened surface will also sand off and will probably discolor the lighter strips on either side. There's another potential problem that could be caused by the wood charring and weakening to some degree, and not bonding as well with epoxy like the rest of the hull.

Sorry to throw a wet blanket on a hot idea, but I'm almost sure you won't like the results, it's much more of a sure thing to go with another type of wood. Striping tapes are available for accents, and some colors and patterns might be OK - if they don't work, they can be removed and won't affect the surface if paint or varnish is needed later on.

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PostPosted: March 11th, 2005, 10:10 am 
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I would think if you really want the burnt look then it would work better to get a charcoal grill going nice and hot and heat up a peice of metal and use it like a big wood burner.

The closest thing I've come to this was a walking stick I made when I was little. I took a magnifying glass and burn the wood at the grip with texturized the surface as well.

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PostPosted: March 11th, 2005, 10:41 am 
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I see at least two possible problems that could arise, both to do with epoxy/glass, so you should test it out on samples first.
1) burning may raise the grain in the wood. You won't have as smooth a surface for glassing.
2) will epoxy/glass bond as well to wood that has a thin layer of charcoal/carbon?


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PostPosted: March 11th, 2005, 10:50 am 
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Location: Ancaster, Ontario Canda
Quote:
Would this affect the glue up in any way? The idea would also be to just do the outside of the strip, not the top or bottom where the glue goes.

Yes it does. On one of my early striper I did "torched" the surface of cedar strips with the entirely different intent - it was to get rid of any surface imperfections, and tiny specs of dust.
The bond between wood and epoxy was patchy and after two years using it it delaminated to the point that I sanded off all of the fiberglass. (a bad idea! It takes les time to make new one than the sanding it alone).
I guess the cedar wood needs to be somewhat porous and not glass like - since this experiment I just stop fairing with #100 grit sand paper, not any smoother.
just my two cents worth...
:oops: Jan

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PostPosted: March 11th, 2005, 1:41 pm 
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Seems like it would be a lot easier to just use a different colored piece of wood in the first place. I use redwood as accent strips on my boats.

Or if you really want to change an existing wood color, dye it before you glue it up. Though you'll have to be careful glueing and sanding to not disturb the color.

As an example of dyed canoes, check out Martin Step's Green Valley site.

Dan


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PostPosted: March 12th, 2005, 11:55 am 
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I don't see the point either unless you where wanting to burn in a design. I have seen that, and it works fine, doesn't depend on scorching the whole strip, and there is usualy plenty of material to bond to.

If you use an epoxy with good penetrating characteristics, like say MAS, I am sure you could get under the scorching if you where careful about it. The way to work through this is to do a sample strip., Glass down over several strips, some with or whithout the scorching you intend. As long as the scorching didn't char the wood and create a burden of really loose material it would probably work, and physical test would take only a short time to verify the results. If it won't peel back you are golden.

I think you will have to pre-coat these strips, otherwise they will tend to dirty the glass, and adjascent strips when you are putting the glass on.

You would probably have to figure out a way to do your sanding, and then do your scorching/pre-coating, otherwise you will sand the effect off during fairing of the hull, or spread the soot everywhere.

A sooty graphite powder is a standard epoxy additive, if that makes you feel any better about bonding to this.


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PostPosted: March 13th, 2005, 10:15 pm 
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Location: Wahta Mohawk Territory
Thanks for the replies, folks. Lots of things I hadn't thought of in them. :clap:

I suspect it probably won't be worth doing if there is any risk of delamination. This is a new boat (my first!) and I want to be pretty careful. My brother and I are working on it in the shop and we're going very slowly. So far, so good, and i WILL post pix when it's finished.

Thanks again.

Cal White


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