Issues with Waterlox

[Tim M Tuttle]

Morning all,

I am using Waterlox on some walnut shelves and need a little guidance as I have never used Waterlox before and my overall finishing experience is in low supply.

I've wiped on two coats thus far and am getting some, for lack of a better or appropriate term, shiny spots. The picture below is after the second coat. I put it on last night around 6 so it's been drying for about 18 hours.

tJ28yqE.jpg

Normal? Abnormal? All help is appreciated.

Thanks

[glenn bradley]

The figured area is irregularly porous and will soak up finish irregularly. It is hard to tell from the pic but, it looks like I would have done some more surface prep prior to application. Once the surface is sealed by initial coats, it will start to build. If the surface is pretty irregular relative to the finish's film tension characteristics it can take a lot of coats. If you are after a more natural appearance, a sealer of very thin shellac can be your friend prior to applying your finish. I will let others chime in as you are past the initial application and we hve some bright folks here.

[Doug Hepler]

Tim,

Glen is on target This looks pretty normal to me for 2 coats on walnut. I don't know what appearance you are seeking. Let each coat dry until it sands well and keep going until you get what you want. Sanding with fine, e.g. 320, grit will dull the shiny spots so that the finish looks a bit more uniform. If you want to fill the pores it may take LOTS of coats.

Doug

[Tim M Tuttle]

Thanks for the tips, fellas. Finishing is not my strong suit!

[Robert Cherry]

I use Waterlox quite a bit, that is normal for the first few coats from my experience. As the finish builds it will even out. I usually allow 24 hours between coats to be sure it is fully dry.

[Patrick Chase]

As others have said, normal.

Waterlox has relatively low solids content, and wiping produces thin coats. While each coat will appear to fill the pores when it goes on, the low solids content means that the resulting film shrinks to a small fraction of its wet thickness when the solvents evaporate. When that happens the thicker spots (i.e. the filled-in pores) will recede relative to the rest of the surface.

If you've already put on 2 coats then you should be able to at least partially level the finish with 320# paper on a flat block. Doing that will be faster than continuing to wipe on coats until everything levels on its own.

[Tim M Tuttle]

As others have said, normal.

Waterlox has relatively low solids content, and wiping produces thin coats. While each coat will appear to fill the pores when it goes on, the low solids content means that the resulting film shrinks to a small fraction of its wet thickness when the solvents evaporate. When that happens the thicker spots (i.e. the filled-in pores) will recede relative to the rest of the surface.

If you've already put on 2 coats then you should be able to at least partially level the finish with 320# paper on a flat block. Doing that will be faster than continuing to wipe on coats until everything levels on its own.

Put on the third coat a few hours ago and it's looking better now than it did last night. I am guessing one more coat. Been hitting it with 400 between coats.

[Robert LaPlaca]

Waterlox OSF has been my go to finish, as been previously posted it’s a low solid finish, so the patchyness is normal. I typically use a couple of coats of 1 lb dewaxed shellac under OSF, mostly as a barrier coat between the other parts finishing schedule, the shellac also helps the OSF to build quicker. The only coat of OSF that gets any sanding is the last coat, which gets scuff sanded with 1200, OSF doesn’t require sanding between coats for adhesion purposes like other finishes and the stuffing of the last coat is just for denibbing purposes.

[Ron Citerone]

I usually brush 3 coats and let it dry well before wiping last 2 coats. I usually don't sand until after 3rd coat. I put the first coat on pretty heavy and when it soaks into porous areas I take my brush and work it from the wetter areas into the porous areas several times on the first coat. Waterlox takes some patience, but IMHO it really brings out the beauty of the wood as good if not better than most others.

[Bill McNiel]

I usually brush 3 coats and let it dry well before wiping last 2 coats. I usually don't sand until after 3rd coat. I put the first coat on pretty heavy and when it soaks into porous areas I take my brush and work it from the wetter areas into the porous areas several times on the first coat. Waterlox takes some patience, but IMHO it really brings out the beauty of the wood as good if not better than most others.

I use WaterLox OSF a lot and apply it in a similar manor. IMHO - starting with wiping on coats is a waste of time and energy. Two to three "heavy" coats as described by Ron applied with a quality foam brush and tipped off, . Then start the wiped on coats. I sand after the last brushed coat and before the final one or two final coats assuming nothing ugly has attached/embedded itself. Then wait forever (30 days +/-) to do the final rubout using either MicroMesh or often just a brown paper bag depending on the desired finish sheen.

[Patrick Chase]

Put on the third coat a few hours ago and it's looking better now than it did last night. I am guessing one more coat. Been hitting it with 400 between coats.

When you say "hitting it with 400 between coats" are you actually leveling the finish with a flat block, or are you just scuff-sanding to eliminate dust etc?

The reason I ask is because while you might scuff sand between every pair of coats (I prefer not to) you would ideally only level the finish once. You usually do it when you think that the lowest point of the finish surface is higher than the highest point of the wood, such that you can sand everything flat without cutting through.

Of course if you guess wrong then you have to apply more coats and do it again :-).

Out of curiosity, does anybody happen to know if Waterlox has a max dry film thickness?

[Tim M Tuttle]

When you say "hitting it with 400 between coats" are you actually leveling the finish with a flat block, or are you just scuff-sanding to eliminate dust etc?

The reason I ask is because while you might scuff sand between every pair of coats (I prefer not to) you would ideally only level the finish once. You usually do it when you think that the lowest point of the finish surface is higher than the highest point of the wood, such that you can sand everything flat without cutting through.

Of course if you guess wrong then you have to apply more coats and do it again :-).

Out of curiosity, does anybody happen to know if Waterlox has a max dry film thickness?

Just scuff sanding however after reading all of this I am going to stop that and just try to get the finish even before doing a final sanding.

[John C Cox]

You must scuff it between coats or you risk the next layer peeling off... Fine scotch brite is commonly used but you can also scuff with 400 or 600.. If you use sand paper - use a very very light touch because you don't want to sand through.

The shiny spots were from not wiping off all the varnish when wiping it. Drag marks or dull spots are from your wiping-off paper or cloth having varnish residue on it - flip to a clean side or get a new piece.

Here's a good tutorial. It's on a guitar and he is using tru oil but the process is the same for furniture and basically any wiping varnish....

[Patrick Chase]

You must scuff it between coats or you risk the next layer peeling of

No, that's simply not true. Their documentation very clearly and prominently says that you don't need to, and that's been my (limited) experience.

For most reactive varnishes you need to sand if the lower layer has had time to fully cure such that it won't cross-link with the next one. Most manufacturers allow ~24 hrs between coats without sanding. Waterlox goes further and claims that you never need to re-sand.

[John C Cox]

No, that's simply not true. Their documentation very clearly and prominently says that you don't need to, and that's been my (limited) experience.

For most reactive varnishes you need to sand if the lower layer has had time to fully cure such that it won't cross-link with the next one. Most manufacturers allow ~24 hrs between coats without sanding. Waterlox goes further and claims that you never need to re-sand.

Waterlox is a phenolic based polymerized tung oil short oil varnish. Unless they are doing something massively magical - it's going to behave more or less like every other phenolic resin base polymerized tung oil short oil varnishes.. They don't burn in at all like a solvent based finish...

After having phenolic based tung oi varnishes delaminate during levelling - I am not going to go without scuffing between coats... I suppose you can do what you want...