Sanding problem

[Salty]

This looks like it came from my ROS. I use a PC 333 sander. I had not noticed this before on this project. I thought maybe it was the new norton sanding discs that I just started using. But, I saw the same thing on a piece that was sanded with the old discs. I was using an 80 grit to do the initial sanding and then to a 320 for finish.
Maybe I should use one or two grits in between.
Or, should I get a new pad? The edges are a bit worn and it does not seem to be a very soft pad.

Salty

[SARGE..g-47]

First.. you can't use 80 grit then jump to 320 and expect the variance to remove the scratches from that course a grit. In your case I would use the 80.. 120.. 180.. 220.. then the 320. But.. these old eyes see some heavy swirls in that stock that look deep. You have to keep your sander moving and never let it sit in one spot. You can't tip it or the edge will dig in. And IMO.. most over-sand which I used to be guilty of... a double pass the width of ROS and then over-lap to the next raw area for a double pass until complete and move up in grit. Not saying you have done either.. just making sure.

If the above doesn't cure what you have... you may have an un-even pad or damage on the edges as you mentioned. But.. a quick visual check of the pad should be a tell if that is true.

Good luck...

[crybdr]

80 to 320 is a pretty big jump. It would be difficult to remove the 80 grit swirls with 320. Use a 150 or 220 pad in between and you should see improvement.

Unless the surface needs some major leveling/smoothing to begin with - 80 seems a little aggressive? You may want to start with 150 next time?

Also, the swirls look very localized and deep - like a single piece of something sharp (dirt, debris, stray piece of grit) got in between your work and the sanding pad. Try to brush off the work thoroughly and check the pad for embedded objects before sanding. Hope that helps.....

[cabinetman]

80 to 320 is a pretty big jump. It would be difficult to remove the 80 grit swirls with 320. Use a 150 or 220 pad in between and you should see improvement.

Unless the surface needs some major leveling/smoothing to begin with - 80 seems a little aggressive? You may want to start with 150 next time?

Also, the swirls look very localized and deep - like a single piece of something sharp (dirt, debris, stray piece of grit) got in between your work and the sanding pad. Try to brush off the work thoroughly and check the pad for embedded objects before sanding. Hope that helps.....

+1. 80x is rough. starting with 120x or even 100x should be abrasive enough. I also think from looking at the picture that some grit particle, or a piece of something got on the sandpaper. Also check under the sandpaper.
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[JR]

I sometimes get marks like those if I'm not careful when putting the sander on the work piece. My sander has to be at full stop when I set it down. I can't lift it to inspect then set it right back down.

HTH,
JR

[Uncle Cracker]

Also check the backing pad on the ROS. It may be that a metal filing or something like that has embedded itself in the pad, and is poking through the paper and into your work.

[steve-norrell]

I have had the same thing happen to me more than once. Its especially annoying because I usually don't notice the "little curlies" until after I have applied a coat of shellac or other finish.

I would second the other comments that a jump from #80 to #320 is way too big and you should take smaller steps, as suggested by Sarge.

Here are two other tips that I picked up from this forum and articles in woodworking mags.

1. Clean the sanding pad frequently -- I just run the vac hose over it every once in a while to remove sanding dust and any pieces of grit that may have loosened from the sanding pad.

2. Move the ROS across the surface very slowly -- about one inch per minute. This may seem incredibly slow, but, at least for me, it really seems to help. Also, it does produce better sanding results in a shorter time and the overall time spent sanding seems to be reduced.

Finally, when I raised this same question previously on this forum, at least two of the responders recommended using a Milwaukee 6021-21 ROS. Well, never being one to pass up an opportunity to "upgrade" my tool collection, I picked one up at the local Borg. A smart move on my part! It has "soft start" technology and very smooth action. But, even if you don't want to purchase another ROS, the two recommendations noted above should prevent most, but probably not all, of those curlies from forming.

Good luck and regards, Steve.

[SARGE..g-47]

I have had the same thing happen to me more than once. Its especially annoying because I usually don't notice the "little curlies" until after I have applied a coat of shellac or other finish.

I would second the other comments that a jump from #80 to #320 is way too big and you should take smaller steps, as suggested by Sarge.

Here are two other tips that I picked up from this forum and articles in woodworking mags.

1. Clean the sanding pad frequently -- I just run the vac hose over it every once in a while to remove sanding dust and any pieces of grit that may have loosened from the sanding pad.

2. Move the ROS across the surface very slowly -- about one inch per minute. This may seem incredibly slow, but, at least for me, it really seems to help. Also, it does produce better sanding results in a shorter time and the overall time spent sanding seems to be reduced.
Finally, when I raised this same question previously on this forum, at least two of the responders recommended using a Milwaukee 6021-21 ROS. Well, never being one to pass up an opportunity to "upgrade" my tool collection, I picked one up at the local Borg. A smart move on my part! It has "soft start" technology and very smooth action. But, even if you don't want to purchase another ROS, the two recommendations noted above should prevent most, but probably not all, of those curlies from forming.

Good luck and regards, Steve.

That's interesting Steve.. the one inch per minute deal. I find that keeping it moving is my best approach. I run it to one end.. run it back then progress to the next swath to do the same. I used to sand.. and sand.. and sand but I discovered it was a waste of time for me and I often ended up with a burnished surface when I didn't want one.

My stock comes off a planer or hand plane depending and I start with 120.
I could probably get away with 150 but the 120 is quicker to remove a machine mark if any. On soft-wood I progress to 150 then 180 and stop.. On soft-wood I progress to 150.. then 220 and stop.

The only time I will take it higher is when I use shellac and I want a buffed out french polish finish. When I do that I will move the sand slower in the higher grits which will burnish a surface (close the pores from heat) but never on the standard A & C styles I build. I also sand up to 2000 with Abra-lon in that case but I rarely build anything anymore with a high gloss finish rubbed out to satin by hand.

Again.. interesting!

[cabinetman]

Learning to scrape can save time and produce much better results than sanding. Instead of roughing the surface (abrading) to smoother degrees, scraping cuts wood fibers leaving a very smooth surface.

There are several sizes and shapes for scrapers, and dressing them isn't that difficult. Even a sharp bench chisel used bevel up drawn backward can be used as a scraper.
.

[Salty]

Thank you one and all.
I have learned a great deal about the best ways to use my sander....and ways that I should not have.
I'm guilty of so many of the mentioned mistakes I don't know where to start. Definately, I either need a new sander or a new pad. I have used this one for everything from drywall to pine wood so it has earned it's keep.
These swirls have apparently been because I was careless when starting and stopping the sander and sometimes leaving it on the wood when I turn it off to slow it down. Bad idea that!
I have used 80 grit many times because I often have a glue joint to sand out and that takes it down quickly. I'll endeavor to be more patient and take more time. Actually, I may sand out the table top that these are in just to do a better job. So many of those flaws show up real good after you stain.

Thanks again.

Salty

[SARGE..g-47]

Salty.. what CB mentioned about a scraper is a very valuable time saver for taking ridges on glue lines out. I have been using a hand scraper since 1973 but... for glue lines I use an old plane iron held almost vertical. Face the bevel away from you and pull. A normal hand scraper will work but a plane iron around 2"- 2 3/8" wide is much quicker than a standard hand scraper as it's thicker and won't flex. Pay attention to the direction of the grain just as you have to using a hand plane and you will see that is will make short order of glue and ridge lines.

And sanding with 80 grit is just a lot of saw-dust flying. That may not be a concern to you now if you are young but.. wait about 25 years and you see that the fine saw-dust catches up with your lungs. So.. less fine saw-dust in your lungs and less of it hiding in your shop as you can't vacuum every crack and crevice daily.

Good luck...

[Salty]

Thanks Sarge, for the advise and the concern.
I think I pretty well have the dust controled. Not perfect but better then it used to be. The ROS is connected to the vac and that goes through the separator and then the paper filter and then through the main vac filter. I generally don't sneeze in there anymore like I used to.
I took some time to sand out the entire top using 150 grit going over it about 10 times. I also did not put any pressure on the sander and just let it glide across. I also turned it on before touching the board and removed it before turning it off. I ran over it about 5 times with the 320 and held the sander up slightly so it would barely press on the board. After another round of stain it looks near perfect to me.
Probably not the best job of matching grain direction, but for ash wood it doesn't look too bad. This stuff is something of a pain in the ash to work with!
Thanks again for all the help and I will take my time in the future.

Salty

[dbhost]

WOW, what a jump!

I don't even own 80 grit pads for my ROS. Start at 100, go to 180, 220, THEN 320. 80 grit is what I use the the quarter sheet sander for fast stock removal.

It does however look like some damage I did early on in the game by being overly anxious to remove finishes with the sander, and letting the edge dig in. That is going to be TOUGH to get out and make it look right...

#1. Keep the sander flat on the surface.
#2. The sander has a motor for a reason. Let it do the work, you are just there to guide it and keep it from walking off the workpiece.
#3. Keep the sander moving, don't just sit in one spot, you'll dig a divot that way...
#4. Work in a sequential fashion, like going up and down corn rows, except overlapping each pass slightly so to not create a ridge.
#5. Like was mentioned already, work from a course grit, but finer than 80, say starting with 100, or even 120, and work your way up. 80 grit is pretty rough, and will leave a LOT of deep scratches that you need to work out.

Best of luck!

Uh, never mind, you got it squared away...

[steve-norrell]

That's interesting Steve.. the one inch per minute deal. I find that keeping it moving is my best approach. I run it to one end.. run it back then progress to the next swath to do the same.

Sarge..g-47, you are right. I should have said one inch per second. However, that still is pretty slow compared to what I had been doing. I apologize for the confusion -- chalk it up to a 'senior moment'. Anyway, here is the link from Woodworker's Journal:

http://www.woodworkersjournal.com/Ma...hart_5463.aspx

And the item itself:

"Most people, though, sand with a machine, typically a random orbit or vibrating sander. These sand in a tiny round pattern, so the direction you move the sander is irrelevant. What does matter is the speed you move the tool. Sanders are usually designed to be moved only about one inch per second, which is quite slow. Almost everyone moves their sander much faster than that. Moving the sander too fast can result in pigtails; small spirals that show up during staining.

Try this: Run your finger along a twelve inch ruler, making sure you take twelve seconds to get from one end to the other. You may be surprised, but that is how slowly you should be moving the sander.

Each step in the sanding process has a specific goal. If you don't know the goal, you won't know when to stop sanding and you will either sand too much or too little. The goal of the first sanding is to remove machine or tool marks, and in some cases to flatten boards. I find 80 grit aluminum oxide paper is best for that step. It cuts fast but does not leave egregious scratches."

Again, sorry for the confusion. Regards, Steve

[SARGE..g-47]

Sarge..g-47, you are right. I should have said one inch per second. However, that still is pretty slow compared to what I had been doing. I apologize for the confusion -- chalk it up to a 'senior moment'. Anyway, here is the link from Woodworker's Journal:

http://www.woodworkersjournal.com/Ma...hart_5463.aspx

And the item itself:

"Most people, though, sand with a machine, typically a random orbit or vibrating sander. These sand in a tiny round pattern, so the direction you move the sander is irrelevant. What does matter is the speed you move the tool. Sanders are usually designed to be moved only about one inch per second, which is quite slow. Almost everyone moves their sander much faster than that. Moving the sander too fast can result in pigtails; small spirals that show up during staining.

Try this: Run your finger along a twelve inch ruler, making sure you take twelve seconds to get from one end to the other. You may be surprised, but that is how slowly you should be moving the sander.

Each step in the sanding process has a specific goal. If you don't know the goal, you won't know when to stop sanding and you will either sand too much or too little. The goal of the first sanding is to remove machine or tool marks, and in some cases to flatten boards. I find 80 grit aluminum oxide paper is best for that step. It cuts fast but does not leave egregious scratches."

Again, sorry for the confusion. Regards, Steve

No need for apology Steve.. you just got in a hurry which I stay in the majority of the time. All you have to do is look at my spelling I don't really have time to go back and check and you see that clearly. I have also made statements where I substituted the wrong measurement... etc.. Without proof reading the mistake will stick out like a sore thumb until someone corrects it or I notice after I hit post and go back and edit.

BTW... I have two of the Milwaukee 5" ROS's you mentioned. Best ROS I have found out there with soft start.. end result and dust. I have an old PC and a Bosch that sit collecting dust on the main-frame as a result. I use them in utility situations outside at this point. The "M" is a well balanced.. efficient machine. Someone told me the newer 5" Ridgid is similar in build... I can't really comment as I haven't compared or used it.

Regards...