What's going on with this finish

[Alan Lightstone]

Take heart Alan, you will soon be the Sawmill Creek Waterlox expert .

LOL. Would have been happy just being a gifted amateur.

The more I think about it, the more I think that I did not mix the new and old formulations. But it is very possible that I jumped the gun after wet-sanding with MS and put the next coat on too soon.

How long do you have to wait after wet-sanding with mineral spirits before putting on another coat?

[Sam Murdoch]

Sorry can't say for sure - just needs to be dry - too many variables for a definite answer. Vacuum and use a tack cloth?

[Chad Bender]

I've seen this before, and agree it is extremely annoying. My experience is that the response from Waterlox is correct - the undercoat was not sufficiently dry. I don't know why this is, or how to suggest checking if the surface is dry enough for another coating. However, my experience is that waiting another day solves the problem (I immediately try to wipe off the newly applied coat with clean rags).

If the beaded up surface is already tacky, you'll be able to sand it back and re-coat. Just be sure to use a block or something to keep the paper flat, and don't sand through any dye coat!

I should add that all of my experience is with the old, toxic formulation.

I'd also recommend against introducing a tack cloth onto the surface. To remove dust, very lightly moisten a lint-free shop towel with mineral spirits and wipe. Let the surface dry for 10-15 min before putting on the waterlox coat.

[Howard Acheson]

Here is a article you may want to read. There are lots of reports of problems with the new Waterlox Original low VOC formulation. I would not mix the new with the old on the same surface.

http://www.popularwoodworking.com/wo...liant-finishes

[Sam Murdoch]

Well alright then enough speculating . I am doing an experiment.

I have 2 boards each with a previously done Waterlox finish.

1) I have just wiped down one (a cherry board) with mineral spirits and with the mineral spirits being very obviously NOT COMPLETELY DRY I have wiped on a new coat of Waterlox Original Sealer.

2) On the second board (this one is alder) I have wiped on a new coat of Waterlox on a clean mineral spirits free surface.

These are both now in a warm dry environment. Before I go to bed tonight - about 5.5 hours from now - I will wipe on a second coat on the Alder sample. This should be 20 hours sooner than the directions recommend and according to Waterlox Central the finish will look like that in Alan's photo. Will see my results in the morning. May not be able to report until tomorrow at this time but I will report. Until then...

[Alan Lightstone]

Wow, Sam. Thanks.

I was planning on doing something similar tonight, but looks like I may never get home from work.

I'm anxiously waiting the results of your experiment.

[Alan Lightstone]

Here is a article you may want to read. There are lots of reports of problems with the new Waterlox Original low VOC formulation. I would not mix the new with the old on the same surface.

http://www.popularwoodworking.com/wo...liant-finishes

Howard, that's a great description of the problem I am having. I wish I could switch mid-piece to the old formulation, but that sounds like it will create a different set of problems. Fortunately, after this portion of the desk is finished, I can switch to the old stuff as those parts haven't had finish applied to them yet.

[Sam Murdoch]

Just about ready for the 2nd coat on the Alder. I do have 3 open "holes" in the finish that was wet with mineral spirits but nothing like in Alan's photo. Will know more in the AM about wet on wet application. Meanwhile this from the Woodcraft page where I bought my "original formula" sealer.

Screen shot 2012-02-06 at 10.16.10 PM.jpg

[Prashun Patel]

Sanding might not be necessary if the surface is still tacky - which is a real possibility when two layers are incompatible.

A couple years ago, I thinned oil-based polyurethane with Dipropylene Glycol Methyl Ether. This is a solvent that has been used in the fragrance industry and in the ink/paint industry in the past. When I applied it over top of the previous coat (which was brushed on undiluted) it laid on fine, but within a minute, it started beading up and looked exactly like your surface. I was able to wipe it all off quickly.

Waterlox is a confusing product to purchase. Here are the full names of the two sealer finishes:

Original Sealer Finish (Original Formula) TB 5284
Original Sealer Finish (VOC compliant formula) TB 6038

So, you may THINK yr ordering the original formula, when you place an order for "Original Sealer Finish".

I called Woodcraft for my last order of the stuff. They do carry both, but the assistant I spoke with was unaware of the difference or which sku was which. Order it by the part# (TBxxxx). You can also tell the diff btn the two by the price. The VOC is north of $30 for a qt; the 'original' Original is south of $30.

[Alan Lightstone]

Surface wasn't tacky, so I embarked on sanding this morning. So far, so good. I tried 600 grit first, but clearly wasn't agressive enough. Dropped to 320 followed by 600 and did much better. All wet-sanding with mineral spirits as a lubricant.

I'm going to allow it to dry for 8 hours just to be sure, then try one undiluted coat brushed on. If that looks okay, I'll switch back to wiping varnish, though I still am concerned that the mineral spirits aren't compatible with the VOC compliant Waterlox.

I need to find a test piece to try that out on.

[Todd Burch]

Question here for the Waterlox users.

Mineral spirits is more oily than Naptha. Why wouldn't you use Naptha? Does Waterlox specify to use mineral spirits?

Chad - this was funny:

I should add that all of my experience is with the old, toxic formulation.

... and not the new, toxic formulation?

[Prashun Patel]

Mineral spirits is technically just a heavier fraction of petroleum hydrocarbons than naphtha. MS will evaporate slightly slower than naphtha, but not enough to make a huge difference in the drying ability of an oil based varnish. In theory it might lead to a shorter open time b4 the varnish starts to tack, but in practice I have not noticed much difference. I've used both and they've not performed differently.

In terms of compatibility, they are also practically interchangeable with respect to oil-based varnishes - including Waterlox.

[Chad Bender]

Question here for the Waterlox users.

Mineral spirits is more oily than Naptha. Why wouldn't you use Naptha? Does Waterlox specify to use mineral spirits?

Chad - this was funny:


... and not the new, toxic formulation?

Valid point. I wouldn't recommend eating either of them.

I'm still able to get the old formulation, so will continue to use it. I'm a hobbiest, working alone, and wear a mask with cartridge filter, so don't really see any downsides to non-VOC compliant finishes (although my Woodcraft stocks both versions of Waterlox). They are cheaper and time-tested.

[Howard Acheson]

Couple of things that have come to mind.

Did you use one of the new "green" paint thinners?

Was the mineral spirits allowed to fully evaporate or were than wiped dry?

Did you use a stearated sandpaper? The stearate (soaps) can cause finishing problem but generally they are associated with waterborne finishes. But who knows now days with the new formulations of may finishes.

The picture is showing a rather classic reaction to surface contamination.

[Alan Lightstone]

Couple of things that have come to mind.

Did you use one of the new "green" paint thinners?

Was the mineral spirits allowed to fully evaporate or were than wiped dry?

Did you use a stearated sandpaper? The stearate (soaps) can cause finishing problem but generally they are associated with waterborne finishes. But who knows now days with the new formulations of may finishes.

The picture is showing a rather classic reaction to surface contamination.

I see no indication on the container that the mineral spirits was a new "green" paint thinner.

The mineral spirits was wiped dry after the wet sanding stage, then allowed to dry for a few hours.

I've been wondering about the stearated sandpaper myself. I don't see any indications on the container that it was stearated. It's 3M Cat #9086 Waterproof Silicon Carbide Sandpaper (Varnish and Paint, Wet or Dry Finishing).

What's interesting about the sandpaper is the Sommerville Lumber price tag on it. That means I bought it when I lived in Boston, so it's at a minimum purchased before 1989. Any issues with 23+ year old sandpaper? Did they even make stearated sandpaper 23+ years ago. Do I get pack-rat points for using/storing it for that long?