Thoughts on sanding drywall with a Festool sander.

[Brice Burrell]

Thoughts on sanding drywall with a Festool sander.

I used my DTS400 to sand drywall compound in a 15' X 15' room (with a lot of windows) last week and here some of observations. But before I get too far into this I should first mention that drywall compound dust is very fine so it can be harmful to tools used extensively in this application. I wouldn't recommend sanding drywall compound regularly with sanders and vacuums not made specifically for this task.  However, occasional sanding with Festool sanders and vacs should hold up just fine.

I used 120 grit Brilliant 2, I would have preferred 150 grit but I didn't have any with me at the time. I had the suction turned down fairly low for sanding the walls, a bit under 1/4 power, so the sander would glide nicely across the surface. The sander moved freely but the dust collection wasn't bad but not great either. I'd guess maybe 70% of the dust was collected. While this was a big improvement over hand sanding with no dust collection it wasn't good enough to sand without being concerned about the dust migrating throughout the work space and beyond.

For the ceiling I turned the section up to about 1/3, the increased suction helped hold the sander up to the ceiling to some small degree. Dust collection improved to about 75-80%.  Managing hose was certainly more difficult sanding the ceiling but doable. I pretty much needed to hold the hose with one hand and the sanding with the other to keep the dangling hose from pulling the sanding off the ceiling. This limited my reach somewhat since I couldn't extend far hanging on the ladder and managing the hose. The upshot was I didn't end up with a face covered in dust.

The sander makes quick work of drywall compound so you really need to keep the sander moving briskly to avoid sanding through to the tape or over sanding the paper. In fact, I'd be so busy keeping the sander moving I couldn't focus my attention on the quality of the job. I had to stop sanding to carefully check out areas to make sure they were sanded adequately. Managing a ladder, light, sander, hose, vacuum and power cords isn't always easy with two guys working in a small room.

The challenges I run into were holding the sander flat (more so on the ceiling than the walls), managing the vac/hose and aggressiveness of the sander. The advantages were, dust collection and sanding easily in corners/edges. For this particular job there was no significant advantage to using a power sander over hand sanding. No real time or effort saved, the improvement dust collection wasn't important and the quality of the job wasn't any better. I would bother with using a power sander again unless I was sanding a small area where dust collection was important.

Since most guys are used to using a pole sander the quality of the job is probably the same. On my job the room had a lot of natural light coming through the windows so the drywall needed to finished and sanded well to not see imperfections so this job wasn't ideal for a power sander. I might have been better with a hand sander carefully sanding with a light in my free hand to spot any imperfections. For the average job a Festool sander could save some time and effort over hand sanding once you develop your technique for the speed of the sander and managing the hose. My advice for those wanting to try your Festool sander, 150 grit paper, play with the suction on the vac to find a good balance between dust collection and sander movement.

In the end I was a bit disappointed given the rave reviews of others on this forum. I by no means started this discussion to talk anyone out of trying this. I welcome comments and suggestions.  

 

[peter halle]

Brice,

I have used my rotex for sanding drywall patched and repairs.  I too found that the dust collection was not as I would have expected, until I found out that it is significantly better working in one direction versus the other.  I think it was better moving left to right or clockwise or down versus up.  In the other direction the dust was pretty much not collected.

Did you notice similar symptoms?

Peter

 

[Holzhacker]

Interesting timing on this post since I am looking at getting a DS400 to work with my ETS125. I use my ETS125 exclusively for drywall/plaster sanding. Not sure if it has actually seen wood. I do a fair amount of 'technical retrofits', don't do big rock jobs anymore. Cans, registers, switch boxes, backing for heavy art or TV's blah blah. I used to use my PC 1/4 sheet sander, have 3 of them. They were the best when they first came out years ago. Now I just use the scrap paper to sand the corners the ets doesn't get. Unfortunately that generates more dust than all of the ets sanding.
Anyway, I usually have to do some sanding of rock or plaster in occupied spaces, Comm and Res where dust isn't welcome.
I've been using 150 brilliant on the ets125. Results are good but I'm not thrilled with the life of the paper. Thinking of switching to something else but don't know what.
The ets125 works really well for sanding rock/plaster. There is a steep learning curve though. I agree with Brice that the Festool sanders require a lot lighter touch. If you are used to a pole or 1/4 sander, it is easy to eat a wall quick with a Festool sander. I used to get a lot of swirl marks and gouges at first. As Brice mentioned you have to keep the sander moving.
I have the ets hooked to my CT22 now. Previously I used it with my Fein TII. For walls I have the vac set at just under 50%. For ceilings, just over 50%. Dust collection is very good at those settings for me. Wall work is easy. Ceiling is difficult due to the pull of the hose and cord. At first I just draped the hose/cord over my shoulder that helped a lot. Then I tied one end of an old scarf around my shoulder (under arm pit and over shoulder). The other end I tied to the hose/cord. It took a few tries to get the amount of slack right but once I did it really helped keep the sander on the ceiling.
I agree that there probably isn't much if any time savings in using a festool sander/vac for sanding out a room compared to regular methods. The savings comes in clean-up time, client happiness and not breathing that crap.
Don't know that I would want to use a DS400 for large surfaces though, seems a bit small. I would recommend the 125 over the 150, even though I haven't used a 150. I've found that around windows, trims and fixtures the 125 just fits, whereas the 150 definitely would not.
Just read Peters' post and have to completely agree. Direction of movement definitely affects DC.

 

[AlexThePalex]

Brice, I did the same job about 3 weeks ago with my RTS400, using Brilliant2 120, and it worked like a charm. I was worried about the effect of the dust on the machine but it turned out perfectly ok. When I cleaned it afterwards, I couldn't find any dust on or in it, except on the pad.

I kept the suction almost at 100% and it was funny to feel how the RTS was sucked to the wall, needing almost no force to hold it up.

When I needed to sand the ceiling, at first I had the same problem as you with holding the hose up, but I taped a pole to my ladder and taped the hose to that pole.  

 

[Brice Burrell]

Brice,

I have used my rotex for sanding drywall patched and repairs.  I too found that the dust collection was not as I would have expected, until I found out that it is significantly better working in one direction versus the other.  I think it was better moving left to right or clockwise or down versus up.  In the other direction the dust was pretty much not collected.

Did you notice similar symptoms?

Peter

Peter and Markus, I didn't notice much difference in DC with direction but I wasn't looking for it either. You guys have used random orbit sander and I bet direction makes a bigger difference with them compared to the orbitals like the DTS, RTS sanders.

Markus, I had a small problem with the Brilliant 2 paper. Since its so thin in folds fairly easily, I carelessly sanded over an outlet box that folded over the tip of the paper causing some ugly gouges in the few seconds before I could stop sanding. I'll try Rubin next time, if there is a next time.

I'm sort of surprised by people using random orbit sanders, I'd think they would be far too aggressive.

Brice, I did the same job about 3 weeks ago with my RTS400, using Brilliant2 120, and it worked like a charm. I was worried about the effect of the dust on the machine but it turned out perfectly ok. When I cleaned it afterwards, I couldn't find any dust on or in it, except on the pad.

I kept the suction almost at 100% and it was funny to feel how the RTS was sucked to the wall, needing almost no force to hold it up.

When I needed to sand the ceiling, at first I had the same problem as you with holding the hose up, but I taped a pole to my ladder and taped the hose to that pole. 

Near full suction, interesting. Our drywall compound is very light weight so its very soft and the extra suction would really bit the sander into the compound, probably too much.

 

[AlexThePalex]

Near full suction, interesting. Our drywall compound is very light weight so its very soft and the extra suction would really bit the sander into the compound, probably too much.

I got no clue how hard or soft your drywall is, but with our walls over here, I think I could easily use the Rotex in aggressive mode if I wanted, without doing too much damage (if using above 120 grit). Haven't tried it tough. When the job came up, I'd thought I'd use the cheap beat-up RTS of which I'm the 4th owner instead of the expensive Rotex I got as new.

But with the RTS400 and the vac nearly on full, no way that it would bite into the wall, the plaster is too hard for that. I was still just sanding the surface, no eating anything. I just turned the vac down a tiny little bit because on 100% it was a bit uncomfortable to move the RTS around, but now it went ok.

 

[mastercabman]

I have sanded drywall with my Rotex and CT22 at full speed with very little dust in the air.I have done about 5-6 jobs,not too big,just half of a room, soffit,knee wall ,or patch up.

 

[Michael Kellough]

Brice, try 220 grit and near full suction, unless your vac bag is fresh.
It will soon get clogged enough that you'll be ready to crank it up.

 

[Dan Clark]

I've tried dustless drywall sanding with my Rotex and RTS400, and with several dustless hand and pole sanders.  IMO, it's too much hassle.  The FASTEST and easiest way to sand drywall is with a Radius 360: http://www.amazon.com/Radius-360%C2%BA-360-Drywall-Sander/dp/B0002ILWFW.  Then get a small sanding block and sand the corners.    When all is done, I suck up the dust with my CT22.  Then I throw away the bag and clean the filters. 

It is not dustless and you have to wear a mask, but it's much better than any other method I've tried (and I've tried a bunch).

Regards,

Dan.

 

[Jim Becker]

Honestly, before you even consider sanding drywall mud, consider applying it to minimize sanding. Watch the pros...I did that when I subcontracted out that particular job for my kitchen renovation back in 2003 and learned a whole lot in the space of a couple days including using the knife to knock down high spots between coats. Each time I've had to use mud since, my sanding has been minimal and fast just by hand. The pros who did our addition also used hand-sanding where it was required. It can be so easy to break the surface of the drywall with over sanding which might be of higher concern if an electrical appliance was used. (Not to mention the potential damage to the tool from the abrasive dust)

 

[Holzhacker]

A $170 sander better be able to eat all the dust I want it to and better not cry about it. Otherwise it isn't worth my time to smash it with a sledgehammer. I have 3 PC 1/4 sanders that still eat rock dust anytime I want them to after 10 years. If a tool that fails were Ok, I'd buy them at big orange, not Festool.

"When all is done, I suck up the dust with my CT22.  Then I throw away the bag and clean the filters. 
It is not dustless and you have to wear a mask, but it's much better than any other method I've tried (and I've tried a bunch)."

And you are satisfied with that? If I were satisfied with that method I wouldn't own Festool. CT22 and ETS125 = not having to wear a mask and not having dust all over. I like my method much better.

 

[WarnerConstCo.]

I use my PC 7800 most of the time. 

I have ground down textures so I could patch back with my rotex.

I have done the occasional hallway, bath, small closet with my rotex.  I use 220 and have no problems.  I do use the green or black lid mud for everything.  It is much harder than the lightweight topping compound.

 

[Nigel]

Brice,I,ve done this with Rotex 150 and brilliant2 120 grit.Full suction with very little dust.I even tried rotary mode  briefly to see what happened.Well, it just became a bit uncontrollable but didn't destroy the wall.I think there must be fair difference in compound hardness between European and USA.I wouldn,t consider hand sanding .I used to use 1/3 sheet RO but found the Rotex to be far better.I certainly hope the Rotex can handle a bit of plaster dust!I have an old Festool catalogue showing sanders being used for this purpose so if it's good enough for Festool.

 

[Dan Clark]

Honestly, before you even consider sanding drywall mud, consider applying it to minimize sanding. Watch the pros...I did that when I subcontracted out that particular job for my kitchen renovation back in 2003 and learned a whole lot in the space of a couple days including using the knife to knock down high spots between coats. Each time I've had to use mud since, my sanding has been minimal and fast just by hand. The pros who did our addition also used hand-sanding where it was required. It can be so easy to break the surface of the drywall with over sanding which might be of higher concern if an electrical appliance was used. (Not to mention the potential damage to the tool from the abrasive dust)

I'm in Jim's camp - if you're doing it right, you should need minimal sanding.   Use a 6" knife to knock down high spots between coats.  Sand ONLY the mud and not the rock (that can damage the paper surface).   Minimal, light sanding takes care of most issues.

I prefer to use 90 or 45 minute hot mud for everything except the final finishing coat.  I use standard drying mud (not lightweight) for the skim coating phase.   This method produces much faster results.   The downside is that you need to work fast and use good knife technique.  

Like the rest of the Festool tools, the vacs and sanders are precision instruments.   I don't believe in using them for drywall work.   The fine drywall dust clogs the pores in the bag and causes the vac's motor to work harder.   The dust gets in the sanders moving parts and can cause premature failure.  

With my large drywall sander (the radius 360) a couple swipes across a taped seam is all it takes to smooth down the surface.  For skim coats, the large surface of the sander glides over the mud and flattens it nicely.   Most of the work is in the corners and other tough spots where you need something more precise like a sanding sponge.   Sometimes the side of an angled sanding sponge is even too large.

Each to his own, but a powered sander is the wrong tool for the vast majority of drywall work.  IMO, of course.

Dan.

p.s. I'm reminded of the question that I see repeated MANY times in wood working forums, "What's the best way to break down sheet goods on my table saw?"  Unless you have a large slider, my response is always, "Wrong question!"     The right question is, "What's the best way to break down sheet goods?"   And the right answer for most people is "a rail-guided circular saw!"   The issue here is the same - for the vast majority of people, using a powered sander to deal with drywall mud issues is the wrong approach and way too much work.

 

[WarnerConstCo.]

I hate hand sanding.  I don't have to sand too much off, learnt that lesson years ago.

When working in an occupied home I always use some sort of sander with a vac.

Wether it be my PC or my rotex.

In all seriousness, these are just tools man, tools that are meant to be used for working.  If I buy a new tool and am too afraid to use it for a certain task for fear of hurting the tool, I would be better off shoping at Harbor Freight and just disposing of tools after each use.

Do you guys polish your tools after one cut or a little bit of sanding.

Get out there and get them dirty, push them, try and over work them (probably wont happen).

Tools are not like trophies, they dont just get set on a shelf for people to look at.

 

[chrisrosenb]

I use my tools, but I also take care of them.
I also do not like sanding drywall.

 

[GreenGA]

We have used both 400's, and, on occasion a 150/3, sanding the walls and ceilings in a number of rooms.  Not a peep out of anything. 

Before using the 400, we used a ROS from DeWalt in a 4x6 closet and there was dust everywhere!  We then switched to using the 400 and doing two hallways, a 13x13 dining room, a 17x20 family room and another small closet.  Using the 400 & CT22 we had less dust in all these rooms combined than the one closet using the other ROS.

After each day's use we would thouroughly clean and wipe down the sanders.

 

[honeydoman]

i do several patch jobs every month and one of my selling points is dustless sanding.  people love that. plus I hate sanding drywall.  and the 125 works great for this especially above your head on a ceiling.  even if I blew up the vac and sander in 1 year I would buy another one due to the wont do it without it factor.

I go into the house, patch with 20 minute, blow dry with heat gun, another coat, blow dry, maybe one more thin skin blow dry, sand, paint get check leave..    less than 2 hours for most smaller patches. 3' x 3'  or less. which I get quite a few of husband put foot through attic , or plumber cut small hole, or electricians cut a hole etc.    most guys make this small job a 2 part.  mud then come back the next day.  why?  i can get in and out.  and $150 to 200 bucks. done deal.

one of the main reasons I do more patching is because of the festool dust ct22, because before that I hated overhead patch.  plus the sander really makes it look great.

so even if one year later i had to get a whole new set up... for 500 bucks or so.... 40 bucks a month it is well worth it.  Howver, festool will last a heck of lot longer than that.

 

[dmckoy]

Using the Longlife filter elements in the CTs, pn 454869, rather than the HEPA filter elements, might help capturing a higher percentage of the drywall dust.  They only capture particles to 1 micron, have a different type of filter medium fold, and there is less filter surface area.

 

[ForumMFG]

I recently put up drywall in my garage which is now my shop and got to the point where I needed to sand the mud.  I refereed to this thread for some advice and to follow up on my concerns using my festool sanders and CT because of the dust.  I sanded a 20' x 20' room with my ETS125 and DTS400 and I had what I consider amazing results based on what everyone else had to say.  I used Brilliant 120 grit on my ETS125 and had my CT suction power turned up to 3/4".  Now, some people said not to turn it up that high but I played around with it and found that I got 95% of the dust collected throughout the whole process and with minimal problems having the sander sucked down to the wall because of suction force..  I was really amazed because of what everone else had to say and how their suction was about 70%-85%  The only time the dust wasn't collected was when the sander wasn't completely flat on the wall.  So, next time someone goes to sand mud, try what I did and see if you get the same results.  The sandpaper was the only thing I wasn't impressed with.  I was changing the paper after each 8' wide section.  I thought I could get a little more out of it.