Bubbles in Waterlox Original

[Pat Barry]

Hi everyone, I need help. I have applied Waterlox original, 4 coats now and there are bubbles in the finish. I used a high quality natural bristle brush and I applied the material liberally for each of the coats. So, whats the best bet to fix the mistakes I have made? Should I sand the finish lightly with 320 and then reapply the Waterlox using a wipe on approach? Note - this is a large dining room table top. It looks very pretty if it weren't for the bubbles. Now I'm wishing I had used Minwax poly because I have never had this happen with that finish before.

[Daniel Smith]

I'm curious about what answers you'll receive to this question. I've only used Waterlox twice, so I'm no expert, but I've wet sanded with 400 after wiping on a light coat to smooth the finish.

[Scott Holmes]

A few questions to get more info... What is a quality brush to you? A quality 2" varnish brush will cost about $45. Big box stores don't have top quality varnish brushes; they sell paint brushes. What type of wood is the table? What steps did you take before the Waterlox? Sanding? staining? etc. Did you slightly thin the Waterlox before you applied it? Many varnishes are being shipped a bit thicker to lower the VOC's, thus they need to be thinned. Where the air bubbles caused by the brushing action? Too fast, too much varnish (thickness of film) and/or too varnish can all cause bubbles. Temperature of table and finish when applied? This should be a relatively easy fix.

[Pat Barry]

A few questions to get more info... What is a quality brush to you? A quality 2" varnish brush will cost about $45. Big box stores don't have top quality varnish brushes; they sell paint brushes. What type of wood is the table? What steps did you take before the Waterlox? Sanding? staining? etc. Did you slightly thin the Waterlox before you applied it? Many varnishes are being shipped a bit thicker to lower the VOC's, thus they need to be thinned. Where the air bubbles caused by the brushing action? Too fast, too much varnish (thickness of film) and/or too varnish can all cause bubbles. Temperature of table and finish when applied? This should be a relatively easy fix.

Good questions Scott.
The brush was a Badger 2 inch natural bristle brush (looks like the one in your video). Cost was about $28 at Rockler, purchased about 1 week ago
The table top is cherry veneer over some type of core I am unsure of. The veneer is fairly thick.

I had stripped the original factory finish using laquer thinner and scraping process. Followed this with sanding using ROS at 220 grit. I cleaned up the surface after sanding by brushing off and then wiping with clean damp rag.

I then used Transtint Dark Mission Cherry dye mixed with water to get the color I was looking for. I then rag wiped the dye lightly after it had dried to clean the surface, followed by wipe down with clean rag and mineral spirits. This dried for a couple days.

After that dried I applied the Waterlox liberally with the brush. The first coat dried and 24 hours later reapplied. The first coat looked fine, just a matte finish though as the first coat only seemed to penetrate, not form a finish. I followed this with subsequent coats using a quick surface wipedown with mineral spirts followed by the brush on coat. I tied not to overbrush the surface because I noticed the brushing was generating bubbles. So I tried to just drag the brush tip across the bubbles and remove them while the finish was still very wet.
I repeated this 3 times, one day, 24 hrs between coats.

I think the temp was a bit on the cool side, 50 to 60 degrees.

I have since done some research and found video of a fellow who was saying "you can't overwork" the finish by brushing, so maybe I should just have continued working it??

What I am now pondering is whether to dry sand the surface lightly, or whether it might be better to use a bit of solvent (mineral soirits) and wet sand the surface, then wipe it dow with mineral spirity. Let that dry, then go to a wipe on approach for subsequent layers of finish

[Steve Schoene]

Which Waterlox did you use? There are three versions all called Original. The wipe on version is Sealer/Finish. There is a Gloss, and also a Satin. These two later varieties, especially the gloss, have higher solids content than the Sealer/Finish. If you got bubbles with the Sealer/Finish you have varnish that is defective, perhaps having started to gel. Otherwise I can't imagine the Sealer/Finish holding bubbles even if applied with a chip brush. If it has thickened enough to hold bubbles then you should discard it for fresh material. Gloss could be thick enough that it could require a small amount of thinner so that any bubbles would break before the finish began to cure. (Don't use chip brushes if there aren't bubbles they still shed enough to lead to hair pulling.) Good brushes make a difference when working with full viscosity varnish. By the way, you won't buy a 2" genuine badger brush for under three figures. Most of what is seen at lower prices is dyed white hog bristle.

[Prashun Patel]

I suspect the mineral spirits. That product does not like to go on over remnants of ms.

[Pat Barry]

The brush I bought was this one http://www.rockler.com/natural-badge...ristle-brushes
The finish I am using is the Original Sealer / Finish, not the Gloss.
So, the damage is done, is there a fix?

[Prashun Patel]

Can you post a picture?

[Pat Barry]

Can you post a picture?

Having difficulty getting a picture. My good camera is MIA. My cell phone camera is low quality and I can't get it to focus up close. The macro pictures get washed out by the lights and the reflective surface.

Familiar with Don Ho? - He had tiny bubbles in the wine. - Mine are similar in size to the tiny bubbles in a sparkling wine and lots of them. The surface is heavily affected, not just one or two bubbles. I mean I got a bubble farm on my hands here.

Looking closer at Waterlox product information I see this note "Do not apply a new coat of finish over one that has not completely dried". It could be that 24 hours was not enough time to completely dry the underlying coats. Lets assume this was the case, would bubbling be the result? Is this fixable?

Barring any ideas I intend to lightly knock the surface down with 320, dry, wipe it down with Mineral Spirits and if it looks promising, try to wipe on a thin coat.

[Prashun Patel]

That is incompatibility, not brush technique. I still bet its the ms. If you can, sand it smooth with 320 or 220' then after you wipe with ms, let it dry for a couple hours before putting on the next coat. Wipe that coat on, just to remove the brush as a variable, and to waste less product if it still doesnt work.

[Pat Barry]

That is incompatibility, not brush technique. I still bet its the ms. If you can, sand it smooth with 320 or 220' then after you wipe with ms, let it dry for a couple hours before putting on the next coat. Wipe that coat on, just to remove the brush as a variable, and to waste less product if it still doesnt work.

That's exactly what I am thinking Prashun. I had watched one of Scott's video's before I started and used his techniques and felt my brushing technique itself was OK. I should have stopped and not put subsequent layers on but I was in a hurry to finish (pardon the pun). I'm hoping some solvency characteristics of the material will help when I wipe on the next layer after sanding and prep.

[Howard Acheson]

>>>> It could be that 24 hours was not enough time to completely dry the underlying coats. Lets assume this was the case, would bubbling be the result? Is this fixable

I think that is one of your issues. Waterlox is a slow drying finish and applying a new coat over a non-dried coat will lead to problem.

Second you mention you applied heavy coats. That's not good with Waterlox. The thick coats take much longer to dry and, in some cases, will not dry at all. Apply thin coats.

Finally, are you thinning the Waterlox?

[Pat Barry]

Howie,

No I did not thin it. I guess I misinterpreted the directions from Waterlox to apply at 500 sf / gal. Thats 125 ft / qt and thats about 1/4 quart per my table top so thats what I was trying to accomplish. I do think that was a lot though but thats what the directions said.

Here is from the Waterlox Woodworking FInishing Guide "COVERAGE/THINNING One gallon covers 500 square feet per coat. One quart covers 125 square feet per coat. The number of coats depends on the porosity of the wood being finished"
http://www.waterlox.com/assets/pdfs/...uide-FINAL.pdf

For what its worth the 320 grit sanding is doing a good job of leveling it out, so far. Taking it pretty slow because I don't want to sand thru the finish and screw up the dye.

[Scott Holmes]

I doubt the MS is the problem. Make sure you "condition" your brush before you use it... (see Video top sticky note of Forum.) Waterlox sealer/finish is already thinned to wipe-on consistency. No need to thin any more. 3 Coats of Sealer finish is only about one coat of regular Waterlox brushed on... Wipe-on thin varnish will still be very, very, thin even if brushed on. Pooling the varnish is way too much... brush on a thin coat and let it dry; over brushing a quicker drying wipe-on can lead to issues, although Waterlox is very forgiving. You need 5 or 6 more coats to start to see what the Waterlox can really do. Comparing Waterlox wipe -on to full bodied poly is not an apples to apples. Waterlox is much harder and more durable than any of the big box store polys.

[Pat Barry]

Time for a quick update. Dry sanding this stuff with 320 grit wet or dry sandpaper to remove the bubbles works, but it is really slow - there must be a better way. The material doesn't sand well - maybe that's a function of curing. It tends to roll up and create little nubs that have to be continually wiped away. I did manage to get thru the entire table top but want to do a better job of it to get more uniformity. I experimented with wet sanding using a splash of mineral spirits and the same 320 grit. I also tried a 3M finishing pad and I liked that better. Anyone here have any experience / comments / watch-outs with regard to wet sanding?