Festool ROS Sander Streaking / Stripping?

[Stewart Lang]

So lately I've been having an issue with my ROS sanders. They want to leave these streaks, as if the pads are off balance. Funny thing is ALL my sanders do this. I've tried my Festool ETS/EC 150/5, my older ETS 150/5 and the 5" 2mm orbit one (Sorry can't remember the name) and they all leave the same thing.

I've mostly been using maple over the past months, and maybe because it's a lighter one I haven't noticed compared to a darker wood (thermo ash), which I just started using. Anyone else experience this?

I'm using my vac at about 30-40% suction and moving at about 1"/sec, maybe slower. I'm not putting any pressure on the sander, other than it's weight itself. I'm sanding left to right, although the streaks still appear if I sand randomly, front-to-back, etc.

(The left side is where I hand-sanded with 220, and it seemed to get rid of them, but I'd like to be able to finish off the ROS)

It's not dust as I tried vacuuming and blowing it off, it's just sanding marks..Photo Oct 14, 4 37 13 PM.jpg

[Erik Loza]

Always thought that was pretty normal? Never "not" had them.

Erik

[Steve Jenkins]

It looks like you are tipping the sander a little bit or putting more pressure toward one side. That’s about all I can think of that would cause that effect with all the sanders

[Larry Frank]

Looks like you are tipping the sander. Maybe the vacuum hose is tipping it. Try without the hose and see what happens.

[peter gagliardi]

Proper sanding involves proper technique. What you are seeing/showing looks like you are sanding across the grain. You are going to have to experiment with your machine to learn how best to get uniform results. I am doubtful there is anything wrong with your multiple machines. My vacs are always on full suction, never an issue from that standpoint.

[Stewart Lang]

Thanks for the responses!

I'm making a point not to tip the sander (that was one of my first guesses). I naturally hold the vac hose up to prevent it from pulling on the sander and I make sure my hand pressure is not too much on one side. I agree with Peter, I dount there is something wrong with all of the sanders. I'm thinking it has to do with the pads, perhaps they are slightly concave towards the center, and the outside edge ends up being more aggressive, leaving uneven wear. Might just be the nature of the machines. Hard to believe I've been sanding with them for years and just now having this realization lol.

[Doug Dawson]

So lately I've been having an issue with my ROS sanders. They want to leave these streaks, as if the pads are off balance. Funny thing is ALL my sanders do this. I've tried my Festool ETS/EC 150/5, my older ETS 150/5 and the 5" 2mm orbit one (Sorry can't remember the name) and they all leave the same thing.

I've mostly been using maple over the past months, and maybe because it's a lighter one I haven't noticed compared to a darker wood (thermo ash), which I just started using. Anyone else experience this?

I'm using my vac at about 30-40% suction and moving at about 1"/sec, maybe slower. I'm not putting any pressure on the sander, other than it's weight itself. I'm sanding left to right, although the streaks still appear if I sand randomly, front-to-back, etc.

(The left side is where I hand-sanded with 220, and it seemed to get rid of them, but I'd like to be able to finish off the ROS)

It's not dust as I tried vacuuming and blowing it off, it's just sanding marks..Photo Oct 14, 4 37 13 PM.jpg

What sandpaper are you using? And with what pad? Festool hard, medium, soft, etc. I use the Festool Ruben sandpaper, typically with a medium pad, along the grain, not substantially skipping grits, not applying undue downward pressure, and I've never seen this. Also, what vac are you using?

[Andrew Hughes]

Awww you wood grinders with your first world problems.

[Rick Potter]

If I am seeing it correctly, it looks like you should overlap more...like 50%, and not go in straight lines.

I was taught to go in small circles as you go across the board, then overlap it a lot for the next pass. Can't say that is best, just how I learned.

[Dylan Wyatt]

I sometimes see these on my first pass over a panel which is almost always against the grain, but on my last pass with each grit of paper I always go with the grain which seems to take the lines away. I don't have a nice sander or vac though to know if that would cause different issues.

[Jim Becker]

'm thinking it has to do with the pads, perhaps they are slightly concave towards the center, and the outside edge ends up being more aggressive, leaving uneven wear. ... Hard to believe I've been sanding with them for years and just now having this realization lol.

SO....when was the last time you replaced the interface pads? They don't last forever and can, in fact, start to cup if they are significantly aged as well as from heat generated by friction over time. I found that to be the case last year when I pulled my Rotex 150 out after a very long period of not needing to use it and realized that the pad was not in very good condition.

[johnny means]

Not enough overlap and sanding across the grain. I struggle with guys doing this everyday. Sanders aren't Swiffers,they need time to actually do their job. It's painfully slow process. The sander doesn't work the same across the entire pad. I say the only part that counts is the outer 1/3 of the trailing side. With a 5" sander my passes would be spaced about 1.5" apart. Sanding with the grain will help mask any streaking.

[Doug Dawson]

SO....when was the last time you replaced the interface pads? They don't last forever and can, in fact, start to cup if they are significantly aged as well as from heat generated by friction over time. I found that to be the case last year when I pulled my Rotex 150 out after a very long period of not needing to use it and realized that the pad was not in very good condition.

If that's the case, this would be a good opportunity to swap out the pads for the newer 42-hole Multi-Jetstream 2 pads, which do a better job of dust collection around the edge of the sanding area. The sandpaper itself is forwards and backwards compatible (and the machine itself is the same.)

I should add, the sandpaper and pad will also run cooler, because of the increased air circulation.

[Stewart Lang]

I'm overlapping about by about 60-80%, so moving over about 1.5" every pass. Obviously it varies with hand movement and all. I just can't imagine going across a tabletop moving at 1"/sec while overlapping by something tiny like 1/4" to get decent results from a ROS sander. Seems like that would take an eternity.

Going with the grain helped, but I still got lines, going parallel with the grain.

My pads are probably getting close to being replaced, (they still grip fine), however my little 5" 2mm orbit Festool sander has a pretty new pad and it still does it.

I did some more research and through a bunch of online digging, it seems thermo ash is known for showing scratches and sanding marks much more distinctly than normal wood. The dust too is also extremely fine, like powder. Even with abranet and and a vac on max the pad still gets dusty. Pretty crazy. At this point I'm going to just assume all sanders do this to some extent, but the dark-colored thermo ash just amplified it to the point of being noticeably visible.

Anyway, I just spent 2 mins hand-sanding it and it ended up removing all the lines very quickly and it looked perfect, so it's all good now.

[Doug Dawson]

I'm overlapping about by about 60-80%, so moving over about 1.5" every pass. Obviously it varies with hand movement and all. I just can't imagine going across a tabletop moving at 1"/sec while overlapping by something tiny like 1/4" to get decent results from a ROS sander. Seems like that would take an eternity.

Going with the grain helped, but I still got lines, going parallel with the grain.

My pads are probably getting close to being replaced, (they still grip fine), however my little 5" 2mm orbit Festool sander has a pretty new pad and it still does it.

I did some more research and through a bunch of online digging, it seems thermo ash is known for showing scratches and sanding marks much more distinctly than normal wood. The dust too is also extremely fine, like powder. Even with abranet and and a vac on max the pad still gets dusty. Pretty crazy..

Another mark against Abranet.