Water or Mineral Spirits - Removing Poly Dust from sanding between coats

[Adrian Anguiano]

I'm going to get to propose this one in reverse with more details later.

When Applying General Finishes Arm-a-Seal I let it fully cure, then sanded. It left a nice coat of white dust.

At this point using a cloth, vacuum, etc wouldn't remove all the dust.

If I wanted to dampen a lint free rag to clean off the remaining dust, should I use Water or Mineral Spirits to dampen the rag? Or does it matter which one I use?

[Sam Puhalovich]

Adrian, I use a shop vac ... with the hose plugged into the 'exhaust' port ... and wipe with a dry lint-free rag as I am blowing away.
Blowing-it-off is much more efficient than trying to suck-it-up ... I spray a lot and do this out-side.
I use a small brush to get into the closed corners if they don't look completely clean.

[James Dudley]

are you going to re-coat afterwards? or is this just a final cleaning?

I'm not familiar with that finish specifically, so check with the manufacturer to make sure you don't use something that'll harm the finish.

But MS, denatured alcohol, and water are all usable for the task. So is naptha. The goal is to use something that'll help you pick up the particles without leaving a film on the finish.

[Kent A Bathurst]

I wouldn't use MS - had an issue some time back that I attrribute to [but cannot guarantee] MS residue between coats. Perhaps did not wait long enough.

Regardless of that, the DNA flashes off much faster than MS or water.

[Prashun Patel]

I'd use mineral spirits. I have no issue with Arm-R-Seal or other polys and MS compatibility. If this were Waterlox, I'd have different advice, but with Arm-R-Seal, you can use a lightly MS moistened rag to pull up residual dust out of the pores. The issue is even the ms won't pull everything out. In fact, it may leave some residual dust swirls on the surface. So, after that dries, use a dry shop towel and just wipe and wipe until it comes away without any white residue.

Last, any residual sanding dust in the pores will become clear under the next coat of Arm-R-Seal; so you don't need to worry if there's a tad bit left. Truth be told, when I'm in a rush (read, most of the time) I just wipe the dust off as best I can with MS, and then wipe a fresh coat of Arm R Seal on top before waiting for it to dry. It's very compatible (unlike Waterlox).

At least, that's my experience.

[John TenEyck]

DNA is not a good thing to use as it could damage the finish. Probably won't, but there's no reason to use it anyway. In fact, I don't use any liquid; I use a microfiber cloth after I vacuum. It gets every little bit of sanding dust except perhaps those in the corners where the cloth won't go. For those, I use the vacuum with a small crevice tool and a dry paint brush to sweep them out. Don't blow the dust off your work either, unless you do it outside, because all those newly airborne dust particles will settle in your next coat of finish unless you wait a long time for them to settle.

But let's go back to what your finishing process. You shouldn't have to sand Arm-R-Seal very much between coats. A light scuff sanding with 320 or 400 grit is all it should take to knock off the nibs. The idea is to apply it uniformly so that you don't have to sand it level. There are two schools of thought on how to apply it uniformly. One approach is to apply it very thinly, almost like wax that you polish off. It takes a lot of coats to build up a film with this approach. The other approach is to wipe it on or brush it on pretty wet, so that it will flow out and self level. Both ways work. What doesn't work is to apply it somewhere in between; too much to polish off and too little to flow out. What you end up with then is streaks and even ridges, and that's when you get into sanding as remedial action.

Or are you talking about rubbing out the fully cured final finish as another poster interpreted?

John

[Adrian Anguiano]

all.jpg110544.jpgCapture.JPG

Here's some pictures showing the issue. It only shows when the light reflects off the surface a certain way as you can tell from the 3 pictures. In one pic its hugely noticeable, in the others you cant really tell.

I used WATER rag to wipe it off and was thinking it might have done it, but, now that i think about it, there was some brown on the rag, so I guess there were some spots that werent fully sealed and I probably dragged the stain over the top of the poly and it smeared and streaked. Maybe thats right?

[Adrian Anguiano]

20141223_112741.jpg
Here is the rag for reference

[Prashun Patel]

Good pictures. You can see that your sanding is actually picking up some of the color. After sanding, it's ok for the finish to appear flat and muted. As long as your finger comes up dry, when you apply more finish, it will make the dust inside the pores clear. It will also fill in microscopic scratches from your sanding and appear shiny again.

After an aggressive sanding, it can take a couple wipe on coats before the sheen establishes again.

[John TenEyck]

all.jpg110544.jpgCapture.JPG

Here's some pictures showing the issue. It only shows when the light reflects off the surface a certain way as you can tell from the 3 pictures. In one pic its hugely noticeable, in the others you cant really tell.

I used WATER rag to wipe it off and was thinking it might have done it, but, now that i think about it, there was some brown on the rag, so I guess there were some spots that werent fully sealed and I probably dragged the stain over the top of the poly and it smeared and streaked. Maybe thats right?

Maybe, but maybe you used too coarse of a sandpaper and dulled the finish. What grit did you use and how was it supported? I really don't see dust. What I see is either streaking from what was on the rag or the sandpaper dulled the finish. I would wipe it really well with MS. If it's still dull after the MS has dried then it wasn't what was on the rag and you probably dulled the finish with the sanding process. If so, the solution is to apply another thin coat of Arm-R-Seal. When that has cured for about a week, just rub it with a flat piece of brown paper grocery bag. That will round over any dust nibs so that it feels smooth w/o changing the sheen.

John

[scott vroom]

I use Arm-R-Seal infrequently but when I do I use a 4" bristle paint brush to dust it off between coats...residual dust always disappears with subsequent coat. Looking at your pics I'm guessing that maybe your subsequent coat was too light....you need to put enough on the rag to saturate the pores and use some force to work it in.

[Adrian Anguiano]

John I used 320 grit Brilliant Festool paper with my ets 150 on low speed.

So I applied another coat around Noon, 7 hours later and here is the results. The previous coat (2nd coat) look went away, and now this coat (3rd) looks different. Now it has streaks from when I applied the finish with my rag.. Hmmm.. I'm a little suprised to see the previous marks gone, and suprised to see these streaks. We shall see what it looks like in the morning.

Ill do one more coat with the rag tomorrow (which is what they suggest on the can) and if it still leaves marks maybe I can try to spray it with my hvlp for a final 5th coat.

Any other thoughts? And thoughts on the new streaks?

I will say though that these streaks are less noticable than the previous ones. OR maybe they are just less annoying, or a little of both

20141223_175433.jpg

[Prashun Patel]

After an aggressive sanding, it can take a couple coats before the sheen becomes even.

[Adrian Anguiano]

Hmm.. well, I did another coat, and almost the exact same streaks, not better not worse. Now I'm starting to wonder if my can of finish is old or expired. I've never experienced this arm-a-seal being so picky. Ill put some pics up tonight.

Anyone have thoughts on the streaking?

[Adrian Anguiano]

20141225_202825.jpg

Well the picture makes it look worse this go around.