Hi there,
I am in the process of doing a bar in my home. Got a piece of 8/4 by 12″ by 9′ Vermont Hard Rock Maple. Good grain, looks great. Since surface planing, and edging it, I have spent lots of time (over 6 hours) sanding it. First with a belt sander 80 grit through 150 grit, then a random orbit sander 150 grit through 220. Felt like glass. Trouble is: when I put on a light coat of Zar stain (cherry), I was very surprised to find what appears to be scratch marks from the belt sander. These areas feel just as smooth as the rest of the wood. Question is, what should I do now that the wood is stained? If i just sand the areas with the marks and re-stain, how noticeable will the difference be. Should I have used a lighter “body” stain like minwax? Have had no trouble with the lighter stains in the past, and this is the first time with the heavier “body” Zar stain. Would greatly appreciate some input.
Steve
Replies
Steve, this is what I would do... Slap some 80 on the ROS and get back to sanding. Take the whole thing down evenly then progress back up in grits to 220. Next, wipe it down with a damp rag to raise the grain followed by light hand sanding with 220 to remove the fuzzies. Now re-stain it and you should be O.K.
Steve - in Northern California
Have also had some advise about using scrapers instead of the sander to finish it up. Ever tried them?
Steve
I assume you're talking about card scrapers. If you have experience with them then this would be a good alternative. If not, it will take you considerably longer to learn how to use one properly than it would to use the ROS.Steve - in Northern California
Hi
Got the scraper info from the guys in breaktime. Sounds like it would take a while to learn just how to sharpen the thing, never mind how to use it.
Have you ever tried to use some sort of sealer or pre-treater that prevents too much stain from entering scratches, end-grain etc?
Steve
I would recommend you ask Jeff Jewitt at homestead finishes. He's far more qualified than I will ever be on this subject. http://www.homesteadfinishing.com There is a wealth of good info on his site.Steve - in Northern California
Well guys ,
I think you will all be pleased to know I took some advise from each of you and fixed the board last night. Broke out 2 RO sanders w/ 120 grit, spent two hours shooting the breeze with a buddy over the whine of the motors, and it was back down to bare wood. The stain in the scratches was a good indicator for when to stop sanding a particular area. We then did 1/2 hour with 180, then wiped with mineral spirits. then 1/2 hour with 220, and it felt like glass. Just to be sure, we then used two coats of minwax pre treater for soft wood. this ensures that if any scratches remained, they might not take too much stain, also I wanted to show off the end grain that will be exposed on one side. We then stained two coats, wiped it down, rubbed gently with a lint free rag, and watched the nicest finish I have ever done come to life. Two beers later we finally stopped admiring it, and called it quits for the night.
We will be adding the epoxy finish in a few days. Expect it will look great. Again, thank you all for taking the time to help bail me out.
Regards, Steve
Steve,
The use of smoothing planes, cabinet and card scrapers is really no big deal, pretty basic actually. Not to mention the superior finish one will get....There should be tons of information here on their use. Also, Garrett Hack's The HANDPLANE Book would be highly recommended. FWIW.
Dano"Form and Function are One" - Frank L. Wright
Steve, whatever approach you take to getting the top smooth, check for missed spots by wiping it down with mineral spirits, naphtha or alcohol. This will preview the wood color and missed spots will be easy to see.
Steve, I'm curious as to why you needed to start your sanding with 80 grit. Admittedly, I'm a novice as I've just been using my planer for a few weeks, but when the material comes off of it, were I to use 80 grit sandpaper, I'd be going backwards.
forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
A combination of factors including but not limited to:
Lack of experience with the planer.
Trying to feed a 9' long 12" wide piece of 8/4 in a smooth (non Jerkky) manner without a bench extender or a buddy was a challenge.
Wanted to move a bit faster. Obviously not such a good idea.
Pick one or all of the above.
We live & learn, and when in doubt, we had better find out, so...........I came to the pros. Done one thing right so far. :-) Steve
FG,
You wouldn't be going backwards. As I'm sure you know, all tools that cut with a rotary knife crush more wood than they cut. To get a really well finished piece you have to get rid of all the crushed wood fibers--as well as remove all the scallops left by the rotating knives.
Alan
"As I'm sure you know, all tools that cut with a rotary knife crush more wood than they cut. "
HUH!!!! Where did you come up with that little factoid ?????
Yes there is a degree of compression when wood is machined (with any tool either orthogonally or peripherally). It is due to the visco-elastic nature of wood. Springback after cutting is almost instaneous and why there is a clearance angle >0 degrees for tooling. The most obvious indicator of the phenomenon of springback is to measure final kerf width and compare it to actual tooth width (most easily done with formed rather than set teeth). Kerf width is always less than tooth width.
There is a worst case scenario that creates a defect known as raised grain. Raised grain results from either dull knives (very dull knives) or knives that are overly jointed such that there is an insufficient clearance angle. Raised grain generally occurs in softer woods with variable intra ring density and with higher moisture contents. Basically the dull knives hammer the wood, press the more dense areas into the softer ones before "cutting" occurs. After machining, the less dense regions springback and you have "raised" grain.
If you keep your tooling sharp, more cutting than compression will occur.
I would additionally like to comment that I consider scratching to be a machining defect. Some woods are more susceptible to scratch, as a defect, than others; hard maple is probably the most troublesome (due to its relatively high density, the fact that it is diffuse porous and because of its light color). Other problematic woods include cherry, madrone and hickory. Generally the coarser the wood and the softer it is, the less trouble you have with scratch. Ash is an exception due to the fact that the dense latewood (summerwood) is both prominent and without much texture, and will show scratch.
It might be helpful to change your thinking about sanding. Instead of trying to get a surface as smooth as glass, consider sanding as a method of removing defect. I hate sanding (albeit necessary) and as such I try to minimize the amount I have to do.
Ideally, a perfectly acceptable surface can be obtained with rotary tooling (eg planing or shaping) if there are sufficient knife marks per inch (KM/I). A circular cutter head produces a circular cut -- a side view reveals two ridges separated by a rounded valley. The more KM/I, the lesser is the distance between ridges and also the less is the distance between high and low spots. Thus the wood surface is more planar.
Dimension lumber, where surface quality is of less importance, may have as few as 3 or 4 KM/I. Furniture factories, and moulding and millwork operations require a better surface and will have KM/I values > 16. When you start getting to values of 40 or more KM/I, the resulting surface is extremely smooth; and as such may require only minimal sanding. KM/I is directly correlated with feed speed and the number of knives in the cutter head -- obviously the slower the feed rate and the more knives, the more KM/I you will get.
With regard to sanding, I consider it manditory to finish sand by hand. Any orbital sander will leave a scratch and the circular pattern left by orbital sanders can really make for some ugly work/finishes especially when pigmented colorants are used. The pigment will hang up in these circular scratchs and is very visible.
Sanding is in that nether region between woodworking and wood finishing. Sanding to satisfy a woodworker may never satisfy a wood finisher. Sanding is also a learned practice -- you need to make a proper evaluation of the surface quality and from there, determine what is necessary. If you simply follow some rules, you will likely be making work for yourself and increasing the likelihood of making a mistake. If the surface is sufficient good, using coarse gritted paper or belts is foolish.
The other key determination you need to make regarding sanding is when enough is enough. For some woods (if you are sanding rather than scraping), it may be totally unnecessary to go beyond 150 grit paper on bare wood (especially if you will be subsequently sanding a finishing sealer). Walnut is a good example of a wood that sanding to 220 or 320 grit, in my opinion and based on the lacquer finishing I do, is a waste of time and energy.
Steve,
I ran into the same problem with some Ash. I flipped the board over to do a test spot using a scraper..which took out the marks but when the stain was reapplied did not look so good...lighter tone. My alternatives at that point were to scrape the whole piece, stain and see what happens or bleach, scrape and stain. I left the scratches in and chalked it up to experience. In my next piece I scraped and hit with water three times lightly sanding with 400 between water hits. Hope this helps...
Somewhere along the line you missed some deep scratches, probably from the 80 grit belt. I generally don't go below 120 - 150 with a belt sander. I know it's back-tracking, but once the planer marks and blow-out are gone I'll start at 100 with the RO. Using a 400w halogen worklight at a low angle and a good vac on the RO will reveal any deep scratches. I stay with the 100 until I have a nice, even RO scratch pattern. From there it's easy to run through the grits because it's just a matter of refining the RO scratch pattern with the flaws completely removed.
John O'Connell - JKO Handcrafted Woodworking
Life is tough. It's tougher if you're stupid - John Wayne
I think it was going from 80 to 150 and skipping the 100 and 120 grits in between. Just like the ROS he needed to make the big scratches into small scratches but only made small scratches between the big scratches and never got down far enough to make the big ones into small ones. Does that make sense or am I loosing it again.Steve - in Northern California
Well guys and gal,
I think you will all be pleased to know I took some advise from each of you and fixed the board last night. Broke out 2 RO sanders w/ 120 grit, spent two hours shooting the breeze with a buddy over the whine of the motors, and it was back down to bare wood. The stain in the scratches was a good indicator for when to stop sanding a particular area. We then did 1/2 hour with 180, then wiped with mineral spirits. then 1/2 hour with 220, and it felt like glass. Just to be sure, we then used two coats of minwax pre treater for soft wood. this ensures that if any scratches remained, they might not take too much stain, also I wanted to show off the end grain that will be exposed on one side. We then stained two coats, wiped it down, rubbed gently with a lint free rag, and watched the nicest finish I have ever done come to life. Two beers later we finally stopped admiring it, and called it quits for the night.
We will be adding the epoxy finish in a few days. Expect it will look great. Again, thank you all for taking the time to help bail me out.
Regards, Steve
Edited 7/24/2002 9:24:08 AM ET by Steve
Congrats Steve, sounds like you made the best of this unpleasant situation. Got that belt sander safely corraled somewhere?? LOL! On your next project, remember you can provide your own sanding indicators by placing some light pencil marks across the surface of the workpiece.
Gonna post some pics? Would love to see 'em.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Thanks, I will probably post some pics when all is done. Will be doing the finishing this weekend, and probably install early next week. Check back on me in a week or two.
Actually I did 120 with the RO in between. But like I said to "elcoholic", belt sanders are good for something I'm sure, I just don't know what.
Steve
It will be a cold day in hell before I let a belt sander get near a piece of wood that is going to be finished any more than PT deck framing. RO sanders take longer but leave you with a much better finish.
Steve
Edited 7/24/2002 9:24:57 AM ET by Steve
I understand completely, although I've not been happy with the inevitable dips that occur when you start chasing tearout or leveling an edge joint with a 5" RO. I use a 4 x 24 belt sander as a 'surfacing' tool, not a 'finishing' tool. The key difference is that I use a sanding frame and fine grits to remove any wood, which keeps things nice and flat. Then finish it with the RO.John O'Connell - JKO Handcrafted Woodworking
Life is tough. It's tougher if you're stupid - John Wayne
Nothing wrong with a belt sander. It was one of the first power tools I learned to use in a shop. Before ROS, wide belt sanders and the common availability of planers it was the primary tool for flattening a glued up panel and for most of the required sanding. The last time I did it, it probably took me 15-20 minutes to flatten and smooth to 150 grit a 30x48" panel one side.
Like anything, it's in getting the proper instruction and then some practice and experience.
Howie,
I agree. I use a belt sander, ROS, hand planes and a scraper plane, depending on what needs to be done, and they can all work effectively. I suspect that Steve Schefer hit his problem earlier, and that's knowing when to change grits. It really doesn't matter if you skip grits, except you'll need to work (much) longer at each one to remove all scratches from the previous one. Here you often need to wet the wood (e.g. naptha) and have a raking light.
Occasionally, you may miss some until after you've advanced several grits, then have to go back a bit, so keep looking.
Like any other tool, a belt sander can be very effective once you get familiar with it, or a lot of grief while learning. Just made two end table tops that needed to be flattened. Too big for my planer, so a straight edge, chalk, and 60 grit belt cross grain quickly flattened them. Clean up with grain, and advance to 80, 120, 150, 220, checking for scratches as I go. The end result was much faster and actually better than any ROS, and the steps made for quick sanding at each grit.
As somebody recently said, "Like anything, it's in getting the proper instruction and then some practice and experience." And, part of that means that you should learn how to use it _before_ trying it on your actual project wood.
Regarding a previous comment on scrapers, I'd suggest a scraper plane. It's much easier to learn and use than a hand scraper. I'll often use one on virtually any wood to remove machining marks, then very lightly scuff sand and I'm done.
Gerry
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