They likewise had a good post on frothing varnish. You might want to print this one out...very long

--------------------------------------------------------------------------

Topic Posted by: Scot Bell Date Posted: Mon May 18 10:20:13 1998

Original Message:

Posted by: Hazen Kent (hak@gate.net ) Date posted: Sun Oct 4 18:21:58 1998 Subject: HELP! FRUSTRATED! Brightwork Question! Message:

Someone, anyone... I need some help here.. What is a possible cure for bubbles after applying the finish coat of varnish. I have switched from foam to bristle brush and still no change. I am wondering if perhaps I should thin the varnish just a touch. I am currently using Interlux Clipper Clear and I live in the south (perhaps humidity is a factor) but my work is being done in a shaded and covered front porch. Anyway, I can't seem to apply without a small froth being created. I am being extremely careful and my strokes are light. The brush seems full enough. Perhaps my coats are too thin. Currently, I am varnishing two valances for the interior of my Tollycraft. Both pieces are about 5 inches wide and 9 feet long. I am covering an area of about 4 to 6 inches each application and then tipping off that application in an attempt to smooth out the bubbles. Hell, I'm stumped!!! Maybe its the varnish. Anyway, a few words of wisdom are welcome. Thanks, Hazen Kent

Reply:

Subject: "Tiny bubbles"......mmmm? Reply Posted by: Bob Cleek (POPEYE_DA_SAILOR@yahoo.com ) Date Posted: Sun Oct 4 21:42:34 1998 Message:

There are a lot of possible causes for the "tiny bubbles" syndrome. Some may insult your intelligence, but I'll mention all I can think of offhand. First, about bubbles themselves. People have written physics doctoral dissertations on the physical properties of bubbles, but varnish bubbles are often sort of like bubble gum bubbles, they arise after the varnish has been put down because either there is air or gasses in the wood which try to escape before the varnish hardens, or there is air in the varnish itself which expands with the ambient temperature increase after application. Now, shaking the varnish will certainly cause bubbles and is a prime culprit for the unitiated. Nimrod would think you ought to shake a can of varnish real well... but no, varnish, like a good martini, is always stirred, not shaken. Shaking just injects a gazillion little bubbles, which when they come out of that cool can into the warm dark wood... not to mention sunlight, expand into bigger tiny bubbles. Another source of bubbles in the can is wiping your brush on the lip of the can and letting the foam drip down into the pot. Of course, chilling varnish before application and applying in the hot sun only exacerbates this problem. Another, more frustrating source of bubbles is the wood itself. Certain woods, luhan mahoganies for instance, as I recall, have a grain structure which can function like a million little soda straws all bundled up. You paint the varnish over the ends of all those straws and as the wood, which you probably took out of the dark cool garage and laid out in the sun on a sawhorse, just starts "blowing bubbles" out the ends of all those "straws" of endgrain. This problem is, of course, more pronounced depending on whether you are varnishing the flat or the endgrain. I have encountered other, truly mystical varnish problems that have seemingly defied diagnosis. One of the wierdest things I ever had happen was a sort of "dimpled" effect in a spot here or there on an otherwise absolutely perfectly finished interior piece. No matter how many times I would try to sand it perfectly smooth with 320 paper even and brush, or even spray a perfect coat down, by the time it laid out, there would be a half dozen little craters where a dimple existed. Finally, I realized that I was using a silicon spray lubricant on another project in the shop and that, despite the distance (I later proved this with an experiment) incredibly minute particles of silicon spray had landed on the finished piece after it dried and between coats. This stuff had apparently modified the surface tension properties of the varnish where it contacted it and created spots where the varnish actually seemed to have been "repelled," causing these little birdseye dimples. A good cleaning of the piece with acetone eliminated the problem immediately. So, make sure your wood is well sealed, preferably with clear penetrating epoxy (check the earlier post here on CPES) so you won't have your wood grain blowing bubbles. DO NOT shake your varnish. (If you have, let it sit for a few days or weeks and things should work out) DO NOT (oh well, try not to) scrape the foam back into the can off of your brush. After years of bristle brushes (grew up in a family of painting contractors) my own preference has changed to foam brushes, which while they don't hold as much paint or varnish as bristle, leave a much smoother surface and are easier to use on flat surfaces at least. ONLY use the "Jen" brand high density foam brushes, though. The cheaper Chinese low density foam ones are useless and a waste of money. The cost of a 39 cent two inch Jen foam brush is less than the thinner it would take to clean a good varnish brush once. Good luck. And remember, the perfect varnish job is a zen exercise...and the element of chance is what makes it so much fun!

Reply:

Subject: Bubbles Reply Posted by: Bill Eppick (weppick@olympus.net ) Organization: SKYE Boat Works Date Posted: Sun Oct 4 22:53:22 1998 Message:

Hazen, You do have a tough one! Bob's comments are good, try them. For sure, don't drag your brush over the edge of the can. Really fastidious varnish people don't ever let any excess from the brush get back into the varnish pot you are using just for the reason of bubbles. However, one point I might dispute with Bob is on the heat issue. I used to use Calahan's Chilled Varnish (no longer available). The idea was to chill the varnish before application so that the surface didn't seal over before the bubbles were able to break the surface. Going on that assumption it might be that you could experiment with a little thinner that will lengthen the set time. Interlux has one, but I don't use the particular varnish you are using. Check the can. If no luck call Interlux. They used to have a 800 number just for problems like yours. -Bill

Reply:

Subject: varnish bubbles Reply Posted by: gary Lowell (glowell@mailexcite.com ) Organization: Lowell Boats Date Posted: Mon Oct 5 7:33:47 1998 Message:

I have been varnishing for many years and occasionally I still get bubbles. Being in the south, I usually thin my varnish a little, that helps. Sometimes I can slap on a build up coat and it goes on better than the top coats that I fuss over. Your first few coats, some bubbles might be expected, but after about 4 coats you should be able to get a clean coat. Keep trying. Good luck and fair seas

Reply:

Subject: Brightwork Reply Posted by: Don Ziolkowski (Zmonster1@aol.com ) Date Posted: Mon Oct 5 10:12:56 1998 Message:

OK, so the first thing you do is you get a copy of Rebecca Whitman's book _Brightwork. The Art of Finishing Wood._ Get two copies, one to keep in the workshop where you will refer to it often, and it will get all marked up and annotated and dog eared with sticky notes on every other page. The other one to keep on your coffee table so you can look at all the pretty pictures. That accomplished, move on. I've never used the varnish you are using, so I don't know its solids content. It makes a difference. I have used Epiphanes (preferred, and high solids), and Schooner (a good second choice, slightly cheaper than Epiphanes). Wood breathing makes a difference. So does the number of coats. Thin the first coat. A Lot. A high solids finish like Epiphanes recommends 50%. This will help seal the wood, without being so thick that bubbles can form. (I've never used penetrating epoxy, so I can't speak for how the two would interreact). Thin the next coat a little less. By the fourth coat, you don't have a good shine (too thin), but you have sealed the wood. Now all the other stuff really applies. Don't shake (and I think Mr. Bond would argue the martini issue). Don't put the varnish back in the can, strain it into a paper bowl. Greenpeace and the Sierra Club will hate you for wasting a natural resource, but we need to make a choice between being environmentally correct, and having beautiful brightwork. Foam is less painful than natural bristles, but both work. Make appropriate sacrifices to the Varnish God, the Lack of Dust God, and Our Lady of Blessed Viscosity. I used to warm my varnish before applying it by putting the can in a pot of hot water. As I said, Epifanes is very thick, and this helped it pour. That doesn't mean the varnish should be hot. Just warm. Consult the latest copy of the Nautical Almanac, and when Jupiter and Mars are in alignment, apply at least ten coats. And if the last coat or two isn't perfect? Well... Make a choice. Sand it down and do it over, or, realize that it's never going to be perfect, and live with it until it's time to do it over next year.

Reply:

Subject: perfect varnish Reply Posted by: Roy Fulmer (quarlo@olympus.net ) Date Posted: Mon Oct 5 13:48:04 1998 Message:

I know I'm gonna get flamed for this, but here goes...There is no perfect varnish job, though some I've seen are close. Too late for CPES, a shame as it makes varnishing much easier, but I use Man'o'War spar varnish, thinned about 5% to 8% with the proper thinner, (see can) and 3% to 5% Penetrol. I seldom get bubbles, and the Penetrol seems to level the varnish so it coats evenly, and any bubbles have time to pop and the aforementioned levelling takes care of any irregularities. It also flows very well, and it's easy to keep the wet edge. Man'o'War is fairly cheap, but has held up on my masts and spars for 3 years so far, but that's with 2 undercoats of CPES.Ain't woodies fun?