Official Luthiers Forum!

I cannot figure this out. I'm using a Festool sander with Festool paper so IOW quality stuff and this is the finish it's producing. Not happy about it at all. I've triple checked and there is no contamination on the paper. I thought well maybe if there was a loose chip or clogging or something it might cause these marks. Is Festool paper just junk?

Man! That is crazy bad.

It looks like something hard under the paper. Can you post a picture of the sandpaper disk you were using, is there a wear spot in it with something hard under it?

Did the screw that holds the paper backing plate on come loose?

It takes a lot to cut grooves like that.

I looked at my festool sander and the only thing that makes sense other than something hard stuck under the paper is the screw.

From the pattern it looks like something near the center of the disc.

Good thing it wasn't the top of the git, it would have ate spruce right up.

_________________
Brian R, Wood Mechanic
N8ZED

If you’re using a vacuum for dust extraction, make sure it’s not sucking too hard. Sometimes excess suction interferes with the randomness of the ROS. Other than that, it looks like there’s a foreign object as Brian suggests. Or, something’s broken.

I quit using my circular ROS (not Festool) on guitar bodies because I got too many artifacts. I have a quarter sheet orbital sander that I use to sand out the drum sander marks before bending and assembly. After assembly, I hand sand with appropriate grits on sanding blocks and the finer grits on gum erasers as sanding blocks. I didn’t like the machinery undoing my work.

Didn't think about something hard under it so I'll have to check that out. It was a brand new 100 grit disk though.

100 grit is overly aggressive on a DA sander. I usually start sanding at 150 or even 180. And this will remove sanding scratches of my 60 grit Performax drum sander.

My Festool 5" ROS always got me compliments at Tony Fergusons and then Joe Whites, professional finishers who specifically asked me how I prep my guitars since they never had to do any additional prep with my stuff. I used the Festool 5" and a Festool CT 22 dust extractor and it did great.

My most aggressive ROS paper was 120 and never saw anything like that. I'm curious what it could be Festool is well known for how their ROS's actually do move randomly to prevent marks.

I also start at 120 with my Festool 5” and haven’t run into that. I did see a similar pattern with my Mirka 5” sander if I pushed down too hard.

_________________
Steve Smith
"Music is what feelings sound like"

Looks like one of the two "random" mechanisms of RO is failing.
If the belt breaks on my Porter Cable RO, that's what it looks like, but I'm not familiar with the orbital design of the FESTOOL

_________________
Measure Twice,

Karl Borum

Finally - someone defines WEIRD and it fits.

_________________
"Act your age, not your shoe size" - Prince

I have a festool as well and learned a lot about sandpaper

I have found that the festool is by far the best ROS out there but do not assume you never have to replace the base . They wear and collect stuff so clean them , that is what that brush is for.
They don't last forever so when you start having issues it may be time for a new base
also do not use pressure let the sander do the work. The harder you push the more those lines appear
Lastly I have learned a great deal about sandpaper
I use abranet T act and Assilex quality sandpaper for sure.
no longer use micro mesh

speed is also important but no matter what ,you still need to hand sand to remove ROS marks no matter how careful there will
always be some there.

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

I am using a Shop Vac and it doesn't have variable speed suction. I've been eyeballing those Festool vacuums for a long time now but dang they are pricey. Has anyone ever used their disposable bag system? I wonder how well those work. I think I will try replacing the base as John suggested. After looking closely it does have a nick taken out of it and that could be the problem.

I have a similar sander and use a medium interface pad with it.

https://www.festoolusa.com/accessories/ ... erface-pad

Brad


Sent from my iPhone using Tapatalk Pro

_________________
Insta - https://www.instagram.com/cbcguitars/
Facebook - https://www.facebook.com/cbcguitars

The shopvac could be sucking too hard. The Festool vacuum has adjustable suck. I think they accomplish that with a bleed hole somewhere in the system where you vary the amount of the hole covered. You can do the same on your shop vac by drilling holes on one of the hose ends that you cover with a rubber band when you want full suction. I looked at the Festool vacuum but was put off by the 130 cfm volume. The Ridgid that I bought does 220. That’s too much for sanding but it sure is nice cleaning shavings off the floor.

Put your setup back together and try sanding scrap wood with and without the vacuum and see if there’s a difference.

Clever. So like 1/4in holes maybe?

You can buy one of these at Home Depot:

https://www.homedepot.com/p/RIDGID-2-1- ... /204220709

I have one, and it works fine for adjusting the suck.

Gosh, I hope no one quotes these posts out of context . . .

Might look into that. I am using a smaller hose though but they might have one for that size too.

I'm using mine pointed in reverse, in order to have the connections match up. For my Festool CT-SYS (one of the rare Festool dust extractors without adjustable suction), I have it between the unit and the hose, and it fits perfectly (but arse backwards).

No that's not how Festool's dust extractors work. They are variable speed not using a bleed hole. So when I turn mine down the vac motors slows down to where I have it set. They also use a smaller hose with less capacity as well when using the ROS.

Great system mine's been a complete joy. I even redid my deck with mine.

As for the bags they work fine but the real beauty of the Festool system is HEPA filtration and the health benefits of near total dust collection at the source of the work/sanding when using a matching Festool dust extractor.

There is a post on the OLF somewhere from 2005 when I placed black construction paper on horizontal surfaces in my shop and then sanded an entire body and neck prior to finishing. I then wiped down the box and neck and took pics of the black construction paper.

No visible dust on any of my shop horizontal surfaces.

So with a Festool ROS and dust extractor you can control vac speed/CFM without a bleed hole(s) and the speed of the ROS. If I plug into the AC outlet on the Festool dust extractor both the ROS and the dust extractor are turned on and off with the ROS. When I turn the ROS off the dust extractor automatically runs 5 additional seconds to clear the dust hose.

My Festool dust extractor is in my home shop and 20 years old next year and looks and runs like new, zero issues. In the same time I have been through 4 shop Vac vacs at our commercial Lutherie shop making the Festool system not only perform better it was more economical too.

Same deal with my Festool drill that I do use at our commercial shop to wind strings on every guitar that I have ever worked on which is over 15,000 now. It's been flawless and in the same time Dave has had four drills of the usual suspect brands. This makes my Festool drill more economical too.

Great stuff and as someone who appreciates good tools I'm more than satisfied with my Festool purchases AND they have not only provided me with a joy to use tooling with superb results that again people noticed and commented on they have been more economical to own too.

I would imagine that a couple of 1/2” holes would be more effective than 1/4” holes. Hesh, thank you for the explanation of the Festool operation. I like that. As I remember, the Festool is also a bit quieter. That would be nice. I have the biggest Ridgid vacuum with a HEPA filter. I like it a lot. It has a lifetime warranty.

It's true that sometimes expensive quality made things are actually cheaper. I still have a shop vac that I bought in the 90's that works, but is loud as hell, the one I have now is only 3 years old and the motor sounds like it's about to die.

I use a Clear Vue Mini dust funnel thing in front of the Shop vac and it does a killer job. Can you plug the Festool collector right into a drum sander or a band saw?

You're welcome Bob and yes it's very quiet and I use the variable speed a lot because often the low, super quiet speed is good enough for what I do these days.

When I bought it it was expensive but I had hoped that if I bought good stuff it would last me well into retirement and that has been the case with Festool.

Yep JF we use shop vac products in the commercial shop and they seem disposable now and we only get three years or so and then the bearings go and they squeal when they run.

YES before I bought a 1,100 CFM dust collector and we plumbed in into the tool room I thickness sanded with my Performax 10 - 20 with only the Festool CT22 which is rated at 122 CFM IIRC. It worked fine and I built maybe 20 guitars doing it this way. When I got the 1,100 CFM beast it was clear that more dust extraction also cooled the drum and made the paper last longer. But the Festool did do the job. Be aware too that the 10 - 20 only hits about 2/3rds of the width of say a top at once so it's not a big amount of dust generated either.

I wanted to add that what goes into the thing, CT 22 stays in it too. The machine stays very clean on the outside and mine looks like new still and it's nearly 20 years old. Mine is HEPA rated.