I am finishing some 1X6 clear heart Redwood siding. I am sanding with a RO sander up to 180 then a final pass by hand with 220. I remove all dust then apply two coats of Penofin Marine Oil. Some of the boards are coming out with a striping pattern as shown on the picture. Any ideas what is causing this or how to minimize this? Thanks for any help.
Dan
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Sorry Forgot the picture.
Dan
Since you have sanded it very well it would be my guess that it is the difference in the grain. The lighter area is harder wood that the darker.
It looks like planer marks--like the surface paner at the mill left high and low spots that your sanding wasn't able to smooth out--if you run your hand over them, do you feel ripples? If so, planing or running them through a drum sander may help. If not, maybe something like a wood conditioner would get the oil to be absorbed more evenly. (Have only heard of using conditioner with stain though--maybe if you dyed the wood it would even out the color before putting the oil on--maybe a neutral or golden colored dye?) (I'm just giving you wild arsed guesses here!)
(What happens if you stop sanding after 120 grit? Maybe the 220 is burnishing (like mill glaze--or it may even be mill glaze) some of the surface so it won't absorb oil as well. 120 grit may open the pores up and allow the oil ito penetrate better.)
I was going to mention that those are not planner marks and is in fact figured wood but after looking at it for a second time I'm not so sure?
Doug
I'm no woodmaster, but if I'm not mistaken, similar results occur with cherry. It's called, "blotching." Thousands of articles and books have been written about dealing with such.
I've followed the advice of using a Danish oil on cherry, followed by shellac, followed by a water based Ultima Spray lacquer.
But the OP is outside. I'm thinking the expected results are not consistent with the wood being used in this application.
My bet is figure. Looks like it has some quilting going on, he sanded to 220 and applied oil, that has to be it.
Any wood that got compression (near the roots esp) will get that "chatoyance" when fine sanded and oiled, I see it in almost all of the firewood I get, it comes from the butt cuts from a veneer log buyer. All that weight squashes the grain into ripples.
Walnut ,cherry, oaks, maple are the species they deal with mostly, and my guy buys the butts and splits it up for sale..damm shame to burn some of it..as a matter of fact, all through the winter the wife and I set aside spectacular hunks , and when it gets to the end of the season, and I don't want to haul another load of wood home, it finally gets burnt (G).
BTW Chatoyance in Fr. for Cat's Eye, which have that shimmer effect.Spheramid Enterprises Architectural Woodworks
"If you want something you've never had, do something you've never done"
I'm with you, Duane. It looks like figure to me, not planer marks. Never thought about the French roots of the word "chatoyance." Thanks for that.Bill
Like I told Pif, thats high dollar stuff in Lutherie. And even Redwood can make a guitar top. I have used wide Red Cedar shingles planed down to .100 for old timey wood top banjo's.
I am wanting to remember that it was Takemine ( owned by Kaman) that made a Model with a Redwood sound board..the Santa Fe I think..back in the mid-90's.
Mostly one wants straight grain aircraft quality spruce ( grain deviation of no more than 1/8" in X amount of feet, x# of rings per inch , etc.) and even that can exhibit wild yet subtle chatoyance..i'm looking over my shoulder at one of my acoustics with a Sitka Spruce top, and it shimmers in the right angle of reflection...even a lowly SPF 2x4 from the yard can be cleaned up and show off the same properties, under oil and in the right light.
As a cautionary note, I'll add that that type of figgure also denotes a weakness in the lumber, those ripples are confused grain and will shear along the short lines having been interuppted by the saw across it's once longer section.Spheramid Enterprises Architectural Woodworks
"If you want something you've never had, do something you've never done"
I agree with you that what he is seeing in his finish is the figuring in the wood.but to take a side road here and chase a rabbit for a minute - My understanding was that this is not from only dead weight of the tree above, but when it waves back and forth in the wind, the side under compression each wave is getting rippled in like that.I have seen it in large maples I've harvested where it grows leaning all one direction. The side of the trunk where the load is leaning on it will have the compression and a lot of those ripples, but the other side where the wood cells are growing in constant tension has a straight grain.
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Yup, it is that too.
Man we paid dearly for figgured tone woods..it is graded by "WOW" factor..LOL you could buy AAA, AA, A..etc.
We got a lot of Quilted Maple from the PNW area, Big Leaf maple IIRC, seems to do well there.
Now what I wantto know is: who the heck sands siding down to 220? And WHY? (G)Spheramid Enterprises Architectural Woodworks
"If you want something you've never had, do something you've never done"
Wow! I missed that it was for siding! WTF?
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Piffin
My understanding was that this is not from only dead weight of the tree above, but when it waves back and forth in the wind, the side under compression each wave is getting rippled in like that.
As a big fan of figured woods, especially maple and cherry I've wondered about it for years now. Your explanation has been repeated over and over but there is always another expert that comes along and dispels it.
You'll get a lot more figure in maple out in the eastern states, specifically parts of Penn. Conn. NY, RI some of Ohio. But you get this far east(Ia) and figure in maple is very uncommon. You don't have any stronger winds there then we do here.
I remember having discussions with the late Jon Arno over at knots regarding this very topic and he said that there really wasn't a good explanation for figure in wood. Birdseye maple will be very prominent in one maple tree and another one standing right next to it, same age........will be the clearest maple that you'll ever lay your eyes on. How is it possible that two seemingly identical trees in identical situations produce such varying degrees of wood.
The wind issue should do the same to both trees if it had the effect that you propose, yet it doesn't! There has never been any rhyme or reason to why some trees figure and others don't. Some of the experts still have no opinion as to why it occurs.
Nature still has some unknown variables!
Doug
Doug
Edited 11/23/2007 7:12 pm ET by DougU
Well, I was only saying this is what my understanding was about it to add to the discussion. Certainly won't argue strongly on it.We lost a lot with Arno
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I'd say planer marks as others have suggested. I've seen the same thing before.
If you have a metal ruler or a wide drywall knife, try placing across some marks with a bright light behind and see if you see 'valleys'.
BTW, figuring in wood is a good thing, not a flaw, in most cases. You pay extra for it in cabinet and furniture wood.
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