Osmo poly x clear matt feels rough

[qwertyu]

Been using Osmo clear matt and just applied second coat to a something yesterday and I always get a rough finish though it looks great.

I sand to 220 (and have tried sanding to 180 too) and it feels REALLY good after sanding. Ive tried blowing off dust with compressed air, vacuuming surface and wiping off with meth spirits and all 3 times it feels rough to the touch after 2 coats of osmo. rough as it feels like there are tiny grains of sand on the surface.

Initially I thought it was because I applied too much and have been applying it super thin (it almost looks like it needs another coat) but still getting a rough finish. I also thought it was because dust was settling on whilst drying so I did it inside last 2 times. Again, always rough.

Ive tried applying it with a brush and roller (though not osmo's Ive used one which was recommended in another thread from bunnings) - still rough.

Ive been knocking it down with 0000 steel wool and it feels great afterwards but I dont want to keep on doing this. It also creates a white dust which can get into grain which is pretty annoying.

Can anyone offer any help?

[FenceFurniture]

My latest test is four thin coats (each one wiped down wet - straight after application - with a very soft cloth to get an even spread). In between each coat I sanded just a few strokes with 800 grit. I also sanded up to 800 grit before any Osmo went on. Nice and smooth! Probably only 2 strokes each way will get the result you want, and then wipe down with a cloth to get the white dust out.

What sander are you using? (brand and size)

The other reason for the 4 coats was to try and get some red wine proofing happening - I will test that after it has cured for two weeks.

The other thing I did with this test was to prep the timber a little more. It is Ironbark which is pretty tight grained, but even so there were some pores that needed filling. I used Intergrain Woodblend filler for that. (spatula on, dry for 30-45 minutes,sand off with 180 and then up to 800). That filler is available in different colours from Bunnings and Mitre 10, and probably other places.

[LGS]

Brett, do yourself a favor and contact Anton Gerner Furniture

. He uses OSMO almost exclusively, (Finishing oils and coloured oils)

Just be polite.

[qwertyu]

Sander is the bosch blue 125mm GEX125 i think the number is. sandpaper is SIA purple

It definitely feels more rough where the grain is quite open.

Im thinking maybe I need to do a better job and removing saw dust. Maybe use a second rag to wipe over to ensure nothing is left. Maybe my Osmo can is contaminated with saw dust (maybe I used a dirty stick to mix...)

People have suggested raising the grain before sanding it - anyone know the technique?

Sand to 180. dampen the area with water. wait for it to dry. sand at 220. meth spirits off saw dust. apply finish?

[FenceFurniture]

People have suggested raising the grain before sanding it - anyone know the technique?

Sand to 180. dampen the area with water. wait for it to dry. sand at 220. meth spirits off saw dust. apply finish?

I get pretty good results with using dilute shellac as a sanding sealer. I had some old shellac and diluted it about 8:1 meths to shellac, as recommended on the shellac bottle. Slop it on fairly liberally, let it dry (not long). Sand it back to the timber (which is not very far - it's a super thin coat of shellac) and then sand up to the level you want. Maybe another sanding seal coat before sanding to high. Water will certainly raise the grain, but can take a fair while longer to dry than meths.

From memory on the Ironbark I sanded to 320, sanding sealer, sanded to 500, filled with Intergrain Woodblend, sanded to 800. I know that the Osmo can says sand to 240 tops, but I'm experimenting with it a little bit to see what I get on this test board. I don't think the Osmo penetrates very far into the timber at all - it tends to sit on top of it.

What is the timber?

[qwertyu]

Timber is the recycled stuff from old houses, so mixed species.

Just spoke to whelan the warehouse who exclusively use osmo, they make heaps of stuff. they just use compress air to clean the surfaces, apply with a roller or a rag (microfibre cloth from bunnings), sand at 800, apply second coat, sand 1200, wipe of powder with very lightly damp rag

[FenceFurniture]

Yes I'm finding that a very similar technique is working quite well.

Actually, just re-reading your first post, you say "Osmo Polyx clear matt". Do you mean the "Raw"? That's what I have been referring to.

[qwertyu]

mine is clear matt - so regular poly x which comes in clear matt, clear satin, clear gloss

but im sure is raw is essentially the same thing

[qwertyu]

FF - so I know you sand really high - when you go that high on finishes are you sanding by hand or ROS? If by hand, do you do with grain or circles?

[FenceFurniture]

ROS, but if it was by hand it would be strictly with the grain.

[Alkahestic]

qwertyu - I'm using Osmo Polyx clear extra thin on spotted gum, applied with lint free cloth. We have the same sander and paper and getting a similar roughness of the surface after the first coat. I believe this roughness is from small amounts of left over sanding dust and dust in the air settling on the surface - the surface that was facing up was definitely rougher than the bottom surface. I used the cloth that I had used for wiping the excess Polyx off to de nib the surfaces. It leaves behind a smooth surface without any work.

The PolyX raw has titanium dioxide - a white pigment in it, so on darker timbers it can leave a whitish residue.

[FenceFurniture]

There might be a couple of things to try there. "After the first coat" suggests that maybe a sanding sealer first would yield a better result. That, followed by grain filling really does make a difference to the smoothness of the timber (species dependent).

The second thing to try is to put the freshly coated surface vertical so that no dust can settle on it. Polyx is a) quite viscous and won't have much self-levelling properties, and b) given that it's been clothed down, it has been spread and thinned, and therefore doesn't need to level out (unlikely that gravity will affect it either).

[hurcorh]

Sand to 180, apply sparingly with roller, 240 sand after at least 24hrs, if needed, rub in second coat removing all excess with lint free cloth, let it cure for 24 hrs (depends on weather) and buff with white pad. Wipe clean. This is typically my process. I'll be finishing about 60 lineal meters of tas myrtle soon, i'll try to post a little bit about doing that. Although, surface finish will of course also be effected by timber species, too. I think Osmo products leave a great finish but for a super high 'polish' as it sounds some are trying to achieve with such high grit sanding, shellac or poly etc may be better suited in my opinion.

[FenceFurniture]

No, not trying to get high gloss, or indeed getting it. Just very smooth. The gloss level is still more or less the same as out of the can.

[LGS]

Can't reproduce the roughness. Maybe it's too dry down here. To me the oil lacks character, but in comparison to Something like HBO, It's cheap (relatively) Diluting it won't give you joy. But it's good enough to look at. If it were (and it is) me, I'll stick to HBO or Sceney's Tung Oil. I like consistency.

Regards,

Rob