Wet sanding question - re extraction

[FenceFurniture]

I've not done any wet sanding before, and it would seem logical that dust extraction is disconnected to save the oil being sucked up through the sander and subsequent hose.

However, there is still the sander's fan at work.

The discs that I have are some samples of discs that have been designed specifically for wet sanding. The odd thing is that they are still perforated. Maybe this is so that they can still be used as normal abrasives, or maybe it was an oversight in their development, who knows, but it seems a little odd.

For this particular job the smaller diameter 90mm sander would be the most appropriate, and it has an interchangable polishing head which is not perforated, so to me it makes sense to use this head, and that solves the problem for this job.

But what about larger jobs using a 150mm sander that doesn't have a head without DE holes? Surely even a small amount of oil lining the internals of the sander is going to lead to a gunk problem? Should I use abrasives that are not perforated in this case?

Thanks
Brett

[rsser]

Good question Brett.

Have seen in passing wetsanding with an ROS at wood shows and the slurry looked pretty heavy.

[Enfield Guy]

You can get an interface pad to put on the machine. About 10mm thick with hook on one side and loop on the other. It too has the holes for dust extraction but the pad can be offset to cover the holes, the sanding disk can also be offset which minimises the risk of contamination.

Cheers

[FenceFurniture]

Thanks EG, and good thinking. I've got an interface pad. The extra softness of the pad shouldn't matter a jot.

[Arron]

If you obscure the holes, won't the sander overheat. I had an Ros that burnt out and that seemed to be the reason - maybe.
Arron

[FenceFurniture]

Good point Arron. The interface pad that EG mentions is air permeable (sponge). However, when I was using the polishing head (no holes)on the 90mm sander yesterday (Rotex 90) I did note that it got pretty warm.

[A Duke]

Hi,
I do my wet sanding with the original style Triton ROS that goes on a 100mm grinder. No holes, no dust control no guards or any thing, but gee can it sand.
Regards

[Drillit]

Hello Fencefurniture,
I cant see why you cant take off the cloth backed catcher and replace it with a plastic bag taped to the outlet.
To me that would solve the problem. Personally I have found that hand sanding using water with 400-600-800
gives a real good final base for a tip top finish. If I am using say 3 coats, I dry sand the first with ROS, wet sand the second,
and then use clean water on a damp cloth to ensure all is well before final coat. I usually let the piece dry o/n after wiping over with
clean damp cloth and before the final coat. Some wax after the final coat has taken. Let's know how you go, because I am intrigued
to see how the ROS goes with the wet sander. I have seen it demonstrated (heavy slurry)
but I think that it also would spread a mess. Hope that helps a little. Drillit.

[FenceFurniture]

Hugh & Drillit, thanks for your input - will let you know.

[themage21]

Reviving an old thread, but I used it for advice, so figured it was only fair to share back...

I used an interface pad (i.e. foam pad with hook and loop on both sides) turned to block all but the central hole in my ROS (which is an outgoing hole anyway) and there was still plenty of slurry to give an excellent finish with a burnishing oil.

[FenceFurniture]

Reviving an old thread, but I used it for advice, so figured it was only fair to share back...

I used an interface pad (i.e. foam pad with hook and loop on both sides) turned to block all but the central hole in my ROS (which is an outgoing hole anyway) and there was still plenty of slurry to give an excellent finish with a burnishing oil.

How did the sander go for heating up, and how long were you sanding for?

[themage21]

Ran the sander for around an hour and a half, no discernible heating above the usual. Given that the interface pad is pretty thick, there's plenty of room for return air to get back. Also, I don't think my sander pulls it's cooling air from the sanding disc, so that'd probably help.

[Skew ChiDAMN!!]

I didn't spot this thread the first time around...

But when I bought my ROS I was given a bucket-load of sanding disks to suit by a fellow forumite. (Thanks again, Waldo!)

A percentage of these were perforated 'stick on' disks instead of velcro, at 120, 240 & 320 grit. Now, as I used to do a lot of wet sanding I found these very, very handy.

I place a velcro disk of the appropriate grit on the sander, then slap one of these 'sticky backed' ones (same grit, of course!) on top so it blocks the holes. Can't say I've ever noticed the ROS overheating, but when wet-sanding I lower the speed considerably anyway. 'Sides, like themage's ROS, mine has a separate cooling intake.

[ubeaut]

I also missed this first time around.

Pretty sure you can buy non perforated Wet n Dry abrasive discs to suit most ROS's in grades up to 2000 grit and above. Try a paint shop that supplies the automotive trade.

Even try Festool. I actually have a number if finer grade non perf discs from them which I use.

Heating of the head or machine shouldn't be a problem as they are air cooled but not by the dust extraction unit or the dust wouldn't make it to the bag or the extractor.

I could be wrong but don't think so. I use non perf discs on Festool ROS all the time for sanding with both oil and water. Never had a problem.

Hope this is of some help.

Cheers - Neil