Random orbit sander confusion

Hi all, Mary here again with more sanding confusion. Actually I feel like I'm back track now thanks to you guys. It's great that you take the time to help.

(David, I got the cork you spoke of :) I was so overwhelmed that I am glad for the picture since I recognised it as soon as seeing it.)

Before I get to the main question - I can only post on the finishing and restoration forums and wonder if I failed to do something. I got the email when I registered and the activation link worked but I still have awaiting email verification next to name. Advice?


I wanted your thoughts on the Ryobi Random Orbit Sander I was using when I last posted.

I don't know whether the sander, the sandpaper, my lack of dust extraction or a bad technique - or some combination of them all - is causing the problem but it doesn't do much except make wood get thin. It doesn't even get rid of the deeper scratches on Bunnings surfaced four sides wood.

I have four pieces of Tass oak, two of which I cross cut into three pieces (a bit over 200mm each) and two I marked into sections. I used different grits to start 80' 100' and 120 and I tried different speeds and pressure - to the extent of holding the sander's weight off the wood so it was only barely touching to sand. I didn't press down and was careful to hold the sander flat as much as possible.

It did seem to help (hardly touching the wood) but there are still plenty of scratches and a lot of material was removed. Do you think a sander can be this bad? It's a Ryobi s300 something I think. It certainly doesn't seem to do what it says it will. I am wondering if I should return it?

I get that it will leave a pattern- it isn't random movement despite the name, it's a less obvious and more overlapping pattern. But shouldn't the scratches that are initially there be removed if enough material is removed? Perhaps they aren't the same scratches and it was actually making more as I sanded.

I have only one type of sandpaper which was from mitre ten so I don't know what difference that aspect makes.


BTW, I got the old makita 1/4 sheet sander going and it removed the scratches without having to go below 100 grit on the most difficult piece. I have bought the equivalent makita model since then and get far better results. It is easier to use I guess.

Can a cheap sander and bad sandpaper be virtually useless. I got a guarantee with the Ryobi. Plus I just want to know.

Hi Mary;

is it THIS one? The ROS300-S

You are using fairly coarse paper; usually 120 is where I start sanding; and only if I couldn't polish with a plane first. Get some 180, 240, 320 and 400 grit papers and have another crack; for an ultra gloss finish using oils you'll need to progress to 600, 800, 1200 and 1500 grits. Try to stick to brands such as Norton; alternatively the stuff "The Sandpaper Man" sells is very good quality. He's a forum sponsor (his advert is on the R/H sidebar) and his service has been commended many times in these forums. Oh; and good prices too!

You should be holding the sander firmly enough so it doesn't tip over but not so hard that you are really pressing down, basically just the weight of the machine with your hand on top should be sufficient. Don't move the sander around quickly; follow the grain direction at a speed of about 5-10mm per second. If you are getting little swirly circles it's usually because you are pressing too hard, an ROS should give more of a series of wiggly lines that fade as the grits get finer and finer. You are trying to remove the scratches left by the previous grit when you change papers.

The sanding dust left on the surface can contain broken grit which will aggravate scratching; that machine doesn't appear to have any way to fit external dust extraction so you'll need to keep wiping dust off and emptying the collector. Dust extraction and wood dust problems are a whole other subject that I won't go into here but if you are sanding indoors please consider wearing a high quality mask with disposable filter cartridges.

Ryobi are not known for making high performance tools; I personally prefer Ozito when I look specifically for cheap tools as the Ryobi won't perform any better despite the 40% price difference. It's not really surprising that your Makita orbital sander initially gets better results, but once you've mastered the techniques and are using quality abrasives in sequence you will see a difference.

Mary. The orbital sanding should not be your final effort for finishing. Always finish by hand with a block sander and along the grain. I use anything from 180 to 320 grit for a good finish. It all depends on the project.

Regards,

John.

Hi Mary,
I'm just getting back into sanding and experimenting to see the differences as I go. I agree with Chief Tiff that 120 is as low as I need to go with wood (I'm focused on silky oak). Lower than that I find is too drastic. As I am removing old thick varnish and paints I mix between a belt sander and then ROS. The belt sander is for long runs with the grain. It's good for quick removal.

With the ROS I have learnt that removing the bag / filter and using a extraction system makes the least amount of dust and keeps the sand paper surface clean.

I have been experimenting between different brands and while it is an expensive option I bought a new Makita ROS and used with a dust extractor and was very happy with minimal dust compared to no dust extractor. Then I got and opportunity for a Festool ROS (at the right price). I put it with the dust extractor and 99% of the dust was gone. The Festool sand paper remains clean at all times. So yes I can say the cost of the sander and sand paper is high but the quality of the work is best. I also found it takes far less time.

Happy sanding.

Chief Tiff -yes that's the one. Perhaps it is a combination. The sandpaper quality made a huge difference with hand sanding. The dust or sandpaper particles may be producing more scratches. I didn't explain well. I had become confused with sanding but thanks to help from the forum and improved health (reduced brain fog and more time to sand) I am doing o.k. I wasn't trying to get the wood to a point where it was ready for finish or looking really good. I didn't get that far. I find that there are some scratches that are particularly important to remove initially. You get to where those worst scratches are gone and then you keep going. But if you don't get those nasty ones out initially they are never going to come out. There seemed no point in going further when no matter what I tried those were still there or more being created.

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The multiple bits of wood, approaches and grits was an attempt to learn to use the random orbital sander. I was trying to minimise the variables. If I got a bad result it may have nothing to do with the way I was sanding. Perhaps it was the sandpaper grit or the wood. Maybe I could sand the same way and get a good result with a different grit. Maybe I could do exactly the same and get a different result with different wood. ***************************************************************************************** I actually started out just trying to work out the right technique. I was using 120 grit and trying to work out what I was doing wrong. When I didn't get anywhere I added the different wood in case the wood was particularly difficult to sand. Then I started trying more variations including coarser grits

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I have the same or similar sander Ryobi ROS300W and have had no issues with it. No radial scratches or anything. I usually sand from 120, then 240, then 400 and follow that with a hand sand of 400 with a block focusing on feature areas.
I bought a bunch of sanding discs via ebay but will try the "The Sandpaper Man" next time.

Now that I have become more serious about working with wood if I was to buy again I would look at the AEG or Makita. But I wouldn't expect a huge performance upgrade I think they would do much the same but be faster and probably feel nicer to use. Would love to try a Festool but I think I would have trouble justifying the price unless I started selling my work.

Hi have you tried to use either hot water under cotton wool or metho to initially reduce the scratches.?

Very interested in this comment. How does it work?

I'm currently slowly stripping a table over a hundred years old and only want the varnish (or whatever the nasty stuff is) to come off and not damage the wood. The knocks in the wood I discover are just the patina of recorded stories for me :)

Dints or knocks in wood can be removed or seriously reduced by steaming.

You take a piece of cotton rag that is damp and fold it several times. Place the rag over the dint and (when SHMBO is not watching) use her iron to heat the rag. The resultant steam expands the compressed wood fibres and the dint disappears.

If it doesn't go away the first time repeat till you are happy with the result.

Thank you Bohdan, I so forgot about this. I will be experimenting again :)

Thanks twist,

I was thinking today that I should get someone who has experience with ROS to give it a go.

- -
I suspect as people have mentioned that the sandpaper is part of the problem. I will try with better paper. I have also been using it without the dust collector. I kinda broke it. So add that in. I have not used it long either so I guess it all adds up.

Thank you.

There are a few threads in this one I think. Thread 1. ROS and sandpaper

Mary, in my opinion the quality and design of the ROS are very important indeed. Different ROS have different 'random' circles built in (though some such as the Bosch Blue 150mm (can't remember model number) I use can switch between them. A larger random 'circle' gives a more aggressive cut. If coupled with a coarse paper that leaves grit on the surface then problems can ensue. With Festool ROS one can buy a fine sander or a coarse sander depending on what you want. Festool are expensive, but produce great quality machines with excellent dust extraction, especially when coupled with one of their dust extractors. I use a Festool dust extractor with my Bosch.

Dust extraction is essential for a quality finish.

The 'new kid on the block' in sanders are the Mirko with their mesh type sanding materials. I haven't used one but they seem to get great reviews - also worth looking into I suggest.

The quality of the paper is very important. Yes, the Sandpaper Man. Yes, look at Mirko. Festool also produce top quality. I have also bought good quality from a supplier on eBay but would not recommend that source necessarily.

Thread 2. removing bruises and small marks: I would not recommend using the house's clothes iron. You can get a cheap steam iron from KMart or similar for about $12 - they work well and there is no unpleasantness when a big burn appears on a favourite piece of clothing. The one I have has a shot of steam, a water spray feature and works well. Sometimes I use some wet cotton fabric under it, sometime I just dip my finger in cold water, apply to ding/scratch and then direct steam.

Thread 3 - a new one. Mary, have you considered other than sanding? Using a card scraper can be fun, and can produce much better results because the scraper cuts the wood fibres on the surface cleanly rather than knocking all the fibres over. All C19th furniture was finished with a plane or scraper.