Primitive Archer
Main Discussion Area => Bows => Topic started by: Lee Lobbestael on January 19, 2017, 09:06:07 pm
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In one of my previous questions on the bamboo backed osage I'm working on. Bryce mentioned sanding through the first skin of layer of bamboo to the one below it. Is this what midst of you do with bamboo? I experimented with a scrap piece and the layer under the top skin/layer is a richer gold color and looks really nice. The surface layer in more cream with a touch of green even
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The less you mess with it the less chance you have of nicking the power fibers.
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Ok so leave it as is?
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I was tempted on mine but in the end I never even sanded the nodes. I don't regret it, the bow looks great, but I still don't know if I could have gotten away with it. If you split a scrap through a node you can see how the grain travels through the node. It looks like you could get quite aggressive but I was chicken.
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Ok so leave it as is?
In order to get a finish to stick well you need to at least take the shine off the natural enamel.
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I like to scrape or sand it off but i stay away from the nodes, and patm is right😒 the waxy rind needs to come off to get a finish on
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Yes remove the outer skin, also known as the rind. I use a scraper then various grits to a smooth finish with steel wool. On this bow you can see where around the knodes still has a little bit of rind still left on and the dye was able to stick to it. It's okay to smooth the knodes out, just don't cut into it, or bear down on there Too much:)
(http://i1346.photobucket.com/albums/p696/Bryce_Ott/6BE85A0F-7C2E-4C46-82E9-9F30A80FC113_zpsjwjm0yur.jpg) (http://s1346.photobucket.com/user/Bryce_Ott/media/6BE85A0F-7C2E-4C46-82E9-9F30A80FC113_zpsjwjm0yur.jpg.html)
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I take off the "bloom" the matt whiteish outer film, I wouldn't even call it a "layer". I take nodes down to a smooth slight bump.
Del
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The outer layer is the rind and no problems at all removing it. However I wouldn't use sandpaper. I use a very sharp thin scraper. Then you can just wipe it off with little chance of touching the important stuff underneath. Sharp tools mean less pressure is needed.
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Ok so how do I determine if I'm through the outer rind? On the test piece I experimented on, there was a very obvious color change after several good scrapes with a scraper. But some of you hesitate to call the outer rind a layer, but in this case it was almost like removing a thin growth ring on osage.is this too deep??
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After the first scrape I got to kind of a porous layer almost like early wood, and then I hit a more dense gloden/cream layer. I assume this is where I should end up
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There ya go!
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If you're seeing power fibers, you're severing them. ;)
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Hmm I guess I don't know what the power fibers look like. Dirty for all the ignorance
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You want to END UP at that more dense, golden layer.... just under the powdery stuff that looks like spring growth. To do that, I use a cabinet scraper, working into the rind and away from what was just exposed. This leaves no tiny nicks behind from the scraper because you're wiping them away as you work.
You can leave a little of of the powdery stuff that can be removed, or mostly removed, with 240 grit. And even after sanding, it's ok to leave some in any valleys/grooves because it's better to leave it there than scrape or sand into the power fibers at ALL while trying to get it all out... it doesn't hurt anything, won't lift, and it kinda looks cool after its finished, especially if some kind of dye is used.
Knodes can have the crusty lip removed and then sanded some, but going too far, like with the rind, raises the chances of lifting a splinter.
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Ok great thanks guys. I meant sorry for the ignorance not dirty ::)
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Hmm I guess I don't know what the power fibers look like. Dirty for all the ignorance
They look like visible strands.
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I asked axactly the same question on here when I did my first boo backing :laugh:
I've done more that two so now I is an expert innit ;)
Del
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Your an expert compared to me Del!
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Lee, take a little test piece and scrape down into it and you'll see what's what.
The bow's back isn't deep, three scrapes or so in the same spot can reveal it.
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The less you mess with it the less chance you have of nicking the power fibers.
This is correct. I don't like the way that thin outer rind looks, and it serves no function by itself. It's just a waxy cuticle, almost like a coating, and has no strength of itself. I remove it because it is harder to stain and taking it off lets me see the bamboo better. (Bamboo does have "grain", and some of the backings I have bought had zig-zags one way and then the other between nodes. That's good to know before you start using a block plane on the sides).
However! Most of the bamboo backing failures I have seen or heard of were from someone flattening the nodes, gouging a corner of a node off to one side, picking up a snag at a node, or similar. If you sand it off, start with, like, really sharp, new 150 grit paper, not 60 or 80 grit. Or, use a sharp scraper and very light pressure. I barely smooth the nodes. Don't take them down at all.