Trouble with end grain sanding sealer

[Robb Nielsen]

I can’t seem to find a way to get the outside of the bowl to be smooth with the sanding sealer so I can apply a friction polish. I’ve not used sanding sealer much before except for some bottle stoppers I’ve been doing.

I put some on and let is soak in, spin it and applied pressure to seal it. Did that a couple times. Then decided I’d sand it and used a power sander with 1000 grit. Then more sealer and still get this happening. Also, starting to get kind of tacky / gummy because I’ve pribebly out too many coats (3-4?) on. How do you guys deal with the end grain like this?

Thank you in advance!

 

[Paul M. Kaplowitz]

The only time I use sanding sealer is on spalted wood if I need to firm up soft spots. To do that bowl I would sand to 400 grit and then use Black Bison paste wax applied with a very fine steel wool(0000) made by Liberon. 3 coats.

 

[Robb Nielsen]

Ok Paul Thank you. I’ll re-sand and get the sealer off and see if I can find that paste wax. Applying wax with steel wool - interesting. Never heard of that. Will give it a try. Thanks!

 

[Richard Coers]

Is the wood slightly damp? Lacquer sanding sealer and moisture don't play well together. Is you shop cold? Lacquer dries slower when cold. How long do you wait between coats? Lacquer dries quickly, but it does need some time if you don't thin it. You've put friction polish on top of lacquer sanding sealer before? Sanding sealer has stearates in it for easy sanding. It's not meant to be a finish

 

[Robb Nielsen]

My shop was very cold today. Maybe 43?

And yes, I put friction polish over sanding sealer. I thought the sanding sealer was to seal the wood so it would’t absorb the friction polish.

 

[Bill Boehme]

The picture looks like torn end grain perhaps from using a dull tool or punky wood or maybe too much sanding pressure. Try sharpening and then honing .your bowl gouge and taking very light shear cuts to clean up the surface.

Power sanding with 1000 grit isn't a good idea. It will mostly generate heat and gum things up. End grain on open pore wood will absorb a lot of finish and might require several coats. I think that shellac might work better than lacquer. You should hand sand with the lathe off and use either 320 or 400 grit. I don't use friction polish so I can't help with that question.

 

[hockenbery]

While it is hard to be sure looking at the photo, I agree with @Bill Boehme that it looks like torn endgrain.
If it is walnut, walnut does have visible pores but they don’t usually look that large.
This is endgrain on a bowl with oil finish. The wood is Pacific Northwest walnut.
It is close view and you can see a few pores. In use or in display you don’t see them.

I sand walnut to 320. Then begin applying in finish like Waterlox. The first dry coat is sanded with 400.
Subsequent dry coats are sanded with 0000 scotch brite.
It seldom makes sense to sand any north American hardwood beyond 320. The wood fibers limit the effect beyond 220 grit in most cases.
Sanding finishes at higher grits does make sense.

If it were my bowl I would sand again 120, 180, 220, 320. Then apply a coat of finish

 

[Richard Coers]

My shop was very cold today. Maybe 43?

And yes, I put friction polish over sanding sealer. I thought the sanding sealer was to seal the wood so it would’t absorb the friction polish.

In my opinion, sanding sealer is like a primer. It stands up wood fibers and adds a layer of material that is easy to sand, and you are right, seal the surface. I don't know anyone that advocates 3-4 coats of sanding sealer, especially in a 43 degree shop. To me, the white indicates a reaction between the lacquer and the alcohol that is the solvent for friction polish. The sanding sealer may have felt dry, but it was not cured. That and the grain appears torn like others have said. That odd angled arc near the rim would seem to indicate torn grain there for sure.

 

[robo hippy]

Well, not positive here, but friction polish requires a bit of heat to go on and 'flow'. So, if you sand after with 1000 grit, you will generate more heat, which would make things gum up. For me, I sand up to 400, then apply walnut oil (Doctor's Woodshop) with the synthetic grey steel wool pads from Norton. Walnut is open grain so the pore holes will show. If you are applying a wet finish with the grey pads, a bit of a slurry forms and will at least kind of fill in the pores. I prefer a shear scrape as my final pass before sanding, and I prefer a burnished burr on a scraper for that cut (I do have a video on just that subject...). As for sanding, supposedly some where around 600 grit, the scratches are invisible to the human eye. So, sanding to 400 is close, and the grey pads are in that range. I don't use real steel wool any more because it always leaves little nibs all over the wood. Not much of a visible problem on dark wood like walnut, but on some thing like maple, highly visible, and just humid air will cause metal stains in the wood.

robo hippy

 

[Dennis J Gooding]

There seems to be quite a bit of misunderstanding of what Sanding Sealer is and what it is intended to do. To paraphrase Finishing Gurus Bob Flexner and Michael Dresdner, sanding sealer is a lacquer to which has been added a mineral soap, typically zinc sterate, to facilitate sanding after it is dried. It is not intended as a final finish, but is intended to fill the pores of the wood and act as a barrier to further penetration by subsequent coats of the final finish. Typically, most of it is sanded away before the finish coats are applied. Because of the added sterate, the sealer is fairly soft and presents very low friction (hence heat generation)during the sanding process. This is in contrast to lacquer and some other finishes that can be very difficult sand. Normally, given a cleanly cut surface, one coat of sanding sealer will do the job. If there are defects such as tear-out, more coats may help, but the dried sealer is slightly cloudy and multiple coats left unsanded will obscure the wood grain.

 

[john lucas]

Dennis pretty much nailed. That and power.sanding with 1000 grit which would generate a lot of heat and cause the sealer to pull up even though the Stearate is there to try and prevent this. It also.looks.to me like you have readout that would need to be filled to get a really even clear.finish.

 

[Don Wattenhofer]

DIDO the comments about tearout you need to get a better surface before you start with any finish. I have had good luck with nothing more than about 4 to 5 heavy coats of lacquer (not rattle cans) with sanding between coats. The sanding on the first coat is just enough to get rid of the majority of the shiny spots without going through the finish. The sanding of the following coats should progress until no shiny spots are present. To prevent the appearance of rings around the piece hand sanding parallel to the axis works well. After the final coat is sanded to 400 grit I use the grey synthetic wool and then rub with pumice, then rotten stone and finish with a quality wax. My profile picture has the finish I just described and no end grain marks show, however I did miss a small check in the walnut edge of the lid that illustrates the need for a blemish free surface before putting the finish on. The polishing has been discussed in other threads so you might want to look at those also.

 

[Matthew Ferriter]

I like it - has a nice rustic look. Looks better than a couple I've turned out recently. Maybe I should take a class or sharpen my tools.

 

[Matthew Ferriter]

I like it - has a nice rustic look. Looks better than a couple I've turned out recently. Maybe I should take a class or sharpen my tools.

Are you more concerned with the end grain or the pores?

 

[Don Jarvie]

Once I hit 320 I wipe the piece with Naphta to see what it looks like. Once it dry (it dries very quickly) you can get a good look at the piece especially the scratches. End grain takes some work to get it smooth.