Varnish (Waterlox) brush care between coats

[Alex Yeilding]

What do you varnish brushers do with your bruses between coats? I am used to working with shellac, so have been somewhat blasé about care for my brush between coats--a quick squirt of alcohol takes care of it if it dries out too much. But that approach doesn't work so well with varnish

I'm trying waterlox sealer/finish, and have been leaving finish on the brush and wrappng it tightly in aluminum foil. But enough air is getting in for some evaporation, and I worry that it might start curing in the brush.

Do you fully clean your brushes between coats? Leave soaking (bristles only) in paint thinner/MS/naptha? Half-way clean with thinner, then wrap wet until next coat? What is "best practice"?

[Steve Schoene]

Best practice is clearly to fully clean. The alternative is to solvent clean and then store suspended in solvent. It can be paint thinner for overnight, but for long term storage the maker of the best varnish I know recommends diesel fuel. Then rinse out with thinner before using.

Personally, I try to clean if I will be overnight or longer before the next coat. If it will be 4 or 5 hours I tend to rinse lightly and wrap. I have lost a brush or two when a few hours turned into three days.

[Bob Wingard]

I don't know .. I never use a brush .. I thin it about 50%-60% with VM&P Naptha and apply it with a soft cloth. Been doing it that way for many years. If I'm going to be adding coats, I simply clench the rag in one hand, then remove my latex glove surrounding the rag. Put that glove in the other hand and do the same thing. Rag is safely stored and ready for use later.

[Martin Shupe]

I either wipe Waterlox on with blue shop towels, or use a foam brush and throw it away.

[Al Wasser]

I don't use any finish on wood that requires a brush. I use Scott "RAGS" which are a paper towel. I cut them to the size I need and when done let the rag air dry and toss it. It works with Waterlox. I hate paying good money for a good brush, more money for a solvent, and then have to toss the solvent or let it evaporate and still have brush that is not as good as new

[Howard Acheson]

I'm with Steve. Suspend the brush in mineral spirits with some Saran wrap over the top to slow the evaporation of the mineral spirits.

If I will be using the brush with and hour or so, I will rap it in Saran Wrap. Aluminum foil is generally not air-tight.

[Rich Engelhardt]

Hello,
I brush it out "dry" on newspaper, rinse in solvent, spin it - using a Shur-Line brush and roller spinner, rerinse in another container of clean solvent, respin it, spin it dry then book (wrap) it so the bristles stay straight and free from dust.

The spinner really cuts down both on time and the amount of solvent needed to clean brushes & rollers.

Solvents for solvents for solvent based varnishes are true solvent, not carriers as they are in water based or to a lesser extent shellac based products (alcohol).

Aqueous suspension &/or aqueous emulsion materials - commonly called the common catch term of "waterborne", use water as a carrier (hence the "waterborne" connotation). The carrier in solvent based materials is an oil of some variety, usually alkyd or linseed or tung. Solvents are added to suspend both the pigment and the carrier.

You can see the difference whenever you clean out a paint brush or roller with water. It seems that no matter how much water is used, there's always a trace of color (paint).
On the other hand, with a true solvent such as paint thinner for oil materials, you'll notice that a little goes a long way. It only takes a very small amount of solvent to clean equipment;even when the solvent is extremely contaminated, it still "cuts" the material.

When referring to shellac, alcohol is commonly misused as a "solvent". The true solvent for shellac is ammonia. Alcohol in shellac, and/or water in waterbornes share one characteristic in common. They can both be used to draw out the material to infinity. No matter how much alcohol is added to shellac, or water is added to a waterborne, the final product will always be a contiguous film. Thin to be sure, but a film.
Next time you work in shellac, use ammonia for cleanup and you'll notice that a little goes a long way, and the tools will come out nice and clean and soft. With alcohol, you can rinse and rinse and rinse and rinse, and the tools will still come out somewhat stiff.

For storage, a brush box used to be used. A brush box is a sealed container having a mixture of 2 parts raw linseed oil, 1 part pure gum spirits of turps and 1 part Stoddard solvent (paint thinner &/or K1 kerosene can be substituted for the Stoddard solvent). Brushes were cleaned, then the very tips of the brushes were suspended in the mixture and the box closed. The solvents would evaporate and that solvent charged atmosphere inside the box would both keep any residue soft, and also "wick" it down the bristles.
A homemade smaller substitute can be made from an empty can with a plastic lid.

Cut a slit like this >-----< in the lid lager enough to accommodate the ferrel of the brush. After cleaning the brush with the first rinse, if you plan on using it in the next day or two or three, spin the brush dry and insert it into the lid, then put the lid on the can. Pour just enough solvent in the can so that the very tips of the bristles just touch the surface. Don't immerse them too far. When ready to use it the next time, spin the brush to remove any residue, then place it in a very small amount of varnish and brush it out dry on a sheet of newspaper.
Wrapping them for overnight, no matter how airtight it may seem, usually results in little hard "crystals" of semi dried varnish.
(Usually one of those little hard crystals ends up smack dab in the center of the work too! *sigh* I swear those little things have brains.)
Seriously, what is often mistaken for dust in a finish is actually a small piece of dried varnish that comes out of a brush that's been wrapped & stored overnight.

If you do decide to wrap the brush, or there isn't a handy container to use, then slather it up pretty well with varnish, wrap it and stick it in the refrigerator. The extra material will help insulate the core of the brush and also reduce the tendency for the material to dry. The cold will also retard drying. Personally, I don't care for using that method. The cold makes the varnish flow like chewing gum until the brush warms up to room temperature. I've know a lot of people over the years that swore by it though. YMMV.

Anyhow - sorry for the "too much information".
These days, I use the method I mentioned at the beginning for two basic reasons. #1 - I'm not always sure I can get back to something the next day. Overnight turns into a few days or a week most of the time.
#2- I usually don't buy cheap brushes. It's tough to look at a $40.00 brush that's more suited for use as a hammer than a brush. Worse yet, it's hard to resist using a brush for varnish that should be used for cleaning chores or paint. I've given into that temptation before and ended up with a ruined clear coat,,,and a lot of sanding.

[Alex Yeilding]

Thanks for the suggestions. I've decided to clean completely between coats. And maybe waiting for the brush to dry thouroughly will help me to have the patience that seems to be more necessary with varnish than with shellac!

Steve: Your post begs the question,what is "the best varnish you know", whose maker recommends diesel fuel for brush storage?

Bob: I really like the glove storage system. Will have to try that when padding shellac. When you use thinned varnish for wiping, I take it that, like padding shellac, you are putting down super-thin layers, which tend to dry very quickly. Do you just wait until tack-free before addng another layer? How many layers do you do that way before waiting a while for whatever you have built to cure?

Rich: Your method ends with solvent cleaning. Do you follow up with detergent and water if the brushes are going into longer retirement before the next project?

I'm not sure I understand the chemistry behnid the distinction you are making between solvent and carrier. Correct that. Should read "I'm sure I don't understand..." I thought shellac in alcohol was a solution, not a suspension (and that's as far as my 10th-grade chemistry gets me ). Assuming dewaxed shellac, of course. But I have noticed the phenomenon you mentioned; even after several rinsings in alcohol, followed by detergent and water, the bristles still dry a little stiff from shellac. Maybe household ammonia will emulsify the shellac better with water for washing out?

And while we are on the subject of solutions versus supensions, I take it that the oils and resins of varnish are in solution, so that stirring is necessary only when there are flatteners in suspension? This seems to be implied by the waterlox packaging--the sealer/finish and high gloss are sold in rectangular cans with pour spouts like solvents are sold in, while the satin in sold in a stir-stick friendly "paint can".

[Steve Schoene]

The best varnish is Epifanes Gloss. But, by best I mean for its intended use as a marine spar varnish. It's not a good choice for furniture. Epifanes is an old line Dutch company specializing in yacht finishes. (There are two other marine spar varnishes that are in the league--Interlux Schooner, and Pettit Captain's. There are no other "spar varnishes" that should be considered for brightwork.)

[Alex Yeilding]

The best varnish is Epifanes Gloss. But, by best I mean for its intended use as a marine spar varnish. It's not a good choice for furniture. Epifanes is an old line Dutch company specializing in yacht finishes. (There are two other marine spar varnishes that are in the league--Interlux Schooner, and Pettit Captain's. There are no other "spar varnishes" that should be considered for brightwork.)

Thanks. Would one of these be a good choice for wooden deck furniture? And a terminology question: I have seen previously, in marine references, the term "brightwork" used as you have. What is meant by that term in this context? It brings to my mind things like polished brass fittings. Is that correct, and would you varnish them? (My ignorance is showing )

[Steve Schoene]

Brightwork is wood, often teak, that is varnished. Brass is just brass. I once had a quartermaster working for me that made a point of checking to see if any fittings were brass that had been painted--much to the disgust of the seamen who had the task of chipping off the paint and then maintaining the shine on a daily basis.

While such varnish is the only way to maintain a true clear finish on exterior furniture is not a simple thing. It calls for over six coats of full strength varnish initially--sanding lightly between coats, and then there is near annual maintenance, sanding and adding an additional coat. (Perhaps less frequently if the furniture is in shade for a substantial part of the day, more often if the deck is very much south of the Mason Dixon line.) Every so often, the finish starts to deteriorate from the inside and the varnish lifts so that it must all be stripped off and the process starts again.

My choice for outdoor furniture is to choose the right wood--teak, mahogany, or white oak (plus several of the exotics) and to let it weather naturally. Scrub it down occasionally and you're all set.

[Bob Wingard]

Bob: I really like the glove storage system. Will have to try that when padding shellac. When you use thinned varnish for wiping, I take it that, like padding shellac, you are putting down super-thin layers, which tend to dry very quickly. Do you just wait until tack-free before addng another layer? How many layers do you do that way before waiting a while for whatever you have built to cure?


Actually, I pretty much flood the surface with the thinned finish .. give it a few seconds to enter and fill the pores, then wipe off the excess, which goes on the next area to be finished. The coats are much thinner, obviously than brushing an unthinned finish. They do dry quickly, and after a slight wipe with a Scotch-Brite pad or something similar, you're ready to go with the next coat. I can usually get at least three coats on in a day, and the application goes so quickly, it's a breeze. I normally do about six coats using this method, give or take a few, depending on the look I'm after. A few years back, I built two solid cherry bookcases as gifts to some very special people. One, I finished with WaterLox using this method, and rubbed it out after curing for a few weeks. The other, I sprayed with M.L. Campbell lacquer, also rubbing out to a satin finish. It would be very difficult to tell whwich is which at first glance. This is the only method I've found that makes polyurethane-type finished acceptable to me.

[Rich Engelhardt]

Hello Alex,
Detergent and water rinse are optional and up to the individual.
I generally don't with pure bristle brushes, but do with nylon or polyester.

re: Solution.
Let's see if I can do this without botching it too badly.
Shellac - Flake shellac is dissolved in alcohol to make a liquid. The alcohol forms a viscous fluid for application. One applied, the alcohol evaporates and the shellac reverts back to a solid.(cures)
The fine distinction here is that the alcohol in this case is used as a carrier.
True - it dissolves the flakes, but only temporarily. It can also redissolve the cured shellac.
Ammonia will render the substance, but only in an uncured state. Once cured, the shellac will no longer react with the ammonia in the same way.
There's also a finite limit as to the amount of ammonia that can be added to the shellac slurry.

Not to side step the issue - but - sometimes you'll see two different materials listed on a product's label for reducing the material and for cleanup. One it that products "carrier" - the one for reduction - and the other is that product's "solvent".

Using the Waterlox Sealer finish as an example:
73% is Stoddard solvent.
2 % is Trimethylbenzene
The Stoddard solvent would be the carrier in this case. Using Stoddard solvent (or mineral spirits) for cleanup would require a fair amount of it to really clean the tools. (fair amount being a very relative term)
OTOH - a "working kissing cousin" of TMB (which is this case is the "solvent") is lacquer thinner. VMP Naphtha will clean better than mineral spirits, toluol or xylol a little better than naphtha, and lacquer thinner best of all - but - there's a small chance the lacquer thinner will "gel" the Waterlox. With that in mind I'd use xylene (xylol) if I had it on hand, or naptha instead.

I'm trying to keep this somewhat low-tech - and in keeping with the original context of the post - that being "What should I clean up with so I don't ruin an expensive brush".

BTW - My friend Steve there is spot on about diesel fuel if you have it on hand for storage. K1 will work also as well as JP jet fuel if you can lay your hands on it. All of them are slow drying and have a fairly high flash point & a lot of "oil".

He's also jogged my memory about "brightwork". My favorite uncle is an "old salt" - a WWII Navy man. He had a Chris Craft back in the 50's that I spent a precious few number of hours fishing with him in. That's probably where I got my love of spar varnish from.
LOL! We probalby could have spent a lot more time on the water if he had a fiberglass boat - seems like he was constantly redoing the "brightwork".
3 guess who's job it was to help? (P.S. I loved every second of it)