What's going on with this finish

[Prashun Patel]

I'm just repeating what I've read elsewhere:

Both Behlens and Waterlox are phenolic resins.
They are both more amber and more moisture resistant than their alkyd or polyurethane counterparts.

As far as ease of application, I don't think there's appreciable difference between the classes of varnish. For me the biggest factor has been how and how much it's been thinned.

[Andrew Pitonyak]

According to the Waterlox people, you can use the VOC compliant stuff on top of the original formulation after the Waterlox has cured for six months.

[Alan Lightstone]

According to the Waterlox people, you can use the VOC compliant stuff on top of the original formulation after the Waterlox has cured for six months.

LOL. I'll get right on that..... In six months.

Actually, if you live in California and have an old piece that you need to refinish, there might be a niche for that.

Me? Not so much.

[Jon Middleton]

If you read Flexner's chapter on rubbing out, a couple of things come to mind. First, your final coat will rarely be smooth enough, so you'll need to rub it out. Also, if your final coat is thin, you may wear through it in places, which gives rise to ghosting. This means your final coat should be thick enough to avoid that. If it is, it will also fill in the scratches left by 320 or even 220 grit paper. Your next to last coat only need be level and smooth, not polished. Lastly, varnishes cure slowly. If you rub it out too soon, your perfect finish will dry down and the pores will show. I'll be waiting a month, but even that may not be long enough. We'll see.

[Alan Lightstone]

I typically wait a month or more with Waterlox before placing anything on the surface, allowing it extended cure time. I haven't rubbed out a surface with it before. There is a good chance I will do it with the drafting table I am finishing now.

I've never sanded the next-to-last coat of Waterlox with anything less than 600 grit. FWIW, just what I've done personally. I would think 600 grit scratches should fill easily with even a wiped on coat of wiping varnish.

I have copious amounts of automobile finishing supplies / tools. I keep being tempted to polish one of the table tops I make with compound or even finer auto polishing compounds (Menzerna 106FF/106FA comes to mind to try on a piece sometime.)

BTW, what is "ghosting"?

[Kent A Bathurst]

I dunno the specific Menzerna compounds, but that technique is used by a lot of people. I use 3M Perfect-It.

[Howard Acheson]

>>>> BTW, what is "ghosting"?

I believe he is referring to the line that develops when you sand through a lay of varnish. With oil based finishes each coat remains as a distinct film layer. When you sand through a layer and into the prior layer, a jagged outline of the sand through develops.

[Scott Holmes]

>>>> BTW, what is "ghosting"?

I think the term most commonly used is witness lines.

[Alan Lightstone]

Is there any way to get rid of witness lines? Can they simply be sanded, or does that exacerbate the problem by causing new ones.

What do you do if a previous coat of varnish leaves an area that is thicker than surrounding areas (drips, etc...)?

[Scott Holmes]

Removing witness lines by sanding would be extremely unlikely. You would need to remove all the the top layer and not go through the next layer too deeply.

Best approach is to sand it flat (unless it's a curved surface) and recoat. Witness lines will not show.

[Jon Middleton]

That's pretty much it. It can show up as a halo. Your final coat should be thick enough to prevent your cutting through it. I read about ghosting, then experienced it when I did a built up finish with Minwax Tung Oil Finish. I don't recommend using it for a pore filling finish, it's too soft.

[Scott Holmes]

Jon,

MinWax Tung oil finish is an oil/varnish blend. You should not try to build a film finish with an oil/varnsih blend, they are way too soft. Oil/varnish blends are "in-the-wood" finishes. Ghosts & halos would be referring to something other than witness lines.

Witness lines are shiny lines that show up when a varnish layer is sanded through and the layer below has not yet been sanded and the transition shows up as a wavey / shiny line.

[Jon Middleton]

Actually, Scott, I did build up a finish using the Minwax Tung Oil Finish. Both on a 20 gauge Beretta Silver Pigeon V and a 12 gauge SP II. Filled the pores, rubbed it out starting with 1000 grit and mineral oil, then 2000 grit, finishing up with Rottenstone with mineral oil. The O/V blends behave differently depending on the ratio of oil to varnish. I can tell you that the Minwax is quite soft when built up. And I did get ghosting when rubbing it out, as the coats were quite thin. As a result, I'm now using Behlen Rockhard on the SP V. I'll eave the 12 gauge as is for now.

Here is the 12 gauge buttstock. You can see the pores are filled. It's a nice finish if it wasn't so soft:

[Scott Holmes]

I suspect the beautiful, filled finish we see in this picture is your grain filler more than it's your Minwax Tung oil Finish.

The grain filler is the hardness most of the minwax was removed... as you agreed it's soft.

You said "The O/V blends behave differently depending on the ratio of oil to varnish." I completely agree; FYI Minwax Tung oil Finish is 65% mineral spirits, so the amount of oil/varnish in the can is <35% not much chance to build a film. Of course they don't tell you how much varnish, nor how much oil; I know there is no tung oil in the mix it's linseed oil.

[Jon Middleton]

Scott, I didn't fill the grain. The pigment you see is the factory stain, which didn't fill the pores. The grain was filled with umpteen coats of the Minwax stuff. I actually stripped the 20 gauge, and repeated the same process. No grain filler, just the Tung Oil Finish. This photo doesn't show it well, but I achieved the same finish as on the 12 gauge:





Also, the Minwax is 65% MS, which is, as you say, irrelevant to the question of the O/V ratio. That 35% could be 50/50, or 90/10, or anything.