usally hang out over at breaktime,but this question needs alittle more finess than a 24oz hammer! i’ve got a old desk,probably 1925 era,1/4 sawn white oak with lots of “fleck”[i know there is a better term but i’m just a 2×4 type guy,my signature line says it all!!!}.
anyway finish was in bad shape on the top so i scrape the finish off with a razor blade because it seem like the finish was just laying on top and didn’t really penatrate into the wood. picked up a r o sander with 100 grit and started sanding. all of the fleck turn almost black.so i thought maybe it was burning the wood a little so i went to a 40 grit to try and clean up my mess.it helped a little but it’s still brown colored on the flecking of the 1/4 sawn. any ideas what i’ve done wrong and how to fix it? i’ve worked with new 1/4 sawn before and never did it look like this,usally the fleck is a little lighter than the wood.thanks larry
hand me the chainsaw, i need to trim the casing just a hair.
Replies
Whoa with the sand paper, even 100 grit is too heavy to use on furniture, let alone 40 grit--which is heavier than I have used for removing epoxy based bottom paint.
Furniture to be refinished should have the finish stripped, not sanded off. Given the date it is likely that the finish is either shellac or possibly lacquer which was developed in the 20's. It could be an oil based varnish--and the darkened finish you describe could indicate that. See if it softens with denatured alcohol, or with lacquer thinner. In either case, you can remove the old finish by dissolving it with copius amounts of the appropriate thinner, added by steel wool or coarse burlap. If the old finish isn't dissolved by either solvent, then it is a varnish, and can be stripped with a methyl chloride stripper. (USE LOTS OF VENTILATION)
With the finish stripped off, and the residual from the stripper rinsed off, you can do some hand sanding with 220 grit to repair the damage done with coarse sand paper. Then we can figure out how best to refinish the piece.
when i scraped the finish with a razor blade the finish came completely off,i was down to bare wood.i don't think this piece ever was stained .i started with the 100 grit on a random orbit sander,then when the wood turned brown on the fleck i went to the 40 grit. so thats where i'm at now ,bare wood with the fleck a dark brown. thanks larryhand me the chainsaw, i need to trim the casing just a hair.
If the finish were all off, and assuming we are talking about solid wood, not veneer, then I can't think of any reason for sanding to darken the fleck as you describe. So I suspect there really is finish left on the wood, under the layer that powdered off under the razor blade. Perhaps there is a light colored pickeling stain that sands off the flakes first.
If it is some reaction to heat you can easily check that by hand sanding. Use a more moderate sandpaper--150 or finer. But a ROS shouldn't generate that kind of heat.
Can you post a picture or two? That might help pin down what is happening and point to a solution.
Steve, while remote, the oak may have been fumed. In the shop I was involved with, we were asked to re-finish an old oak table so as to match some new items we made. Turned out the item had been fumed and then clear coated with lacquer. Turned out the item was probably made in the 1920's time frame.The point is that we never got all the coloring out even after using A/B bleach. I don't recall the rays turning black though. But, as you probably know, the reason for fuming was to color the rays which don't color with dyes and pigments.Howie.........
That makes sense as far as leaving a dark overall color even though the finish had been removed. But, I don't think is accounts for the fleck becoming darker, but when chemical effects are involved I don't really know.
this is a thought ihad,that maybe it had been fumed ,and this was a remants of that process. i will try to get a pic and post it. thanks larryhand me the chainsaw, i need to trim the casing just a hair.
Are you sure its not veneer? Otherwise the refinishing should be very routine. Oak is one of the easiest woods to refinish...it doesn't blotch and it takes clear topcoats of all kinds very well. I would use a honey shade of analine dye before any other stain or finish. This will establish an aged patina similar to the yellowing on older oak pieces.
To answer your question about ray flakes, they should be lighter that the surrounding wood because there are no visible pores in the flakes. Can't imagine what your problem is without seeing it. If it is solid wood you should be able to sand through to completely raw wood.
If iron comes in contact with oak you will get a black stain. Using steel wool on the wood or washing down with water that contains iron traces can cause this for instance. It seems unlikely that the razor blade would have caused this to happen. Is there something you could have done that would have contaminated the oak with iron?
John W.
I got some cheap silicon carbide paper, the wet-or-dry, black-color stuff, that fell apart in use and stained any wood grayish. I remember it came from China via a company called Redhill...worthless crap. It doesn't sound likely, but it's a thought. 40 grit...good gawd, that's about where i start floor sanding! Your personal quote really says it all, doesn't it?
See if you can get the hand of using a scraper and bring that poor desk back to even. That should clean up the rays (fleck), too.
yea i know 40 sounds a little rough,wasn't my first choice. i planned on 100-150-220,but i had this problem and thought i'd try and remove some wood and see if the fleck would clean up.if it makes you feel a little better i didn't hit the whole desk with it. but you gave me a idea, i have a floor sander,if i'd just get it on top ,i could rally sand it! just kidding. thanks larryhand me the chainsaw, i need to trim the casing just a hair.
Well, the drum sander will take out the little swirl marks...of course, you'll have the horizontal chatter marks then...unless you have a Hummel...?
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