Stains | Oil vs Latex | Tips

Stains:
Choices are Semi-transparent vs. Opaque (solid) and Oil vs. Latex

Oil vs Latex:
Latex: Consist of a pigment and binder with water used as carrier

• Easily applied, touched up
• Less odor
• Non-flammable
• Soap and water clean-up
• Quicker drying
• Better gloss and color retention
• Flexible
• Breathable
• Latex solid-color stains are usually more durable than oil-base stains and will last from 1-3 years longer.
• water-based paints expand and contract with the siding. They also allow water vapor generated inside the house to pass through the paint film.

• Better surface penetration (except for damp surfaces)
• Better adhesion
• Wearability
• Better flow and leveling
• Dries to a smoother finish with fewer brush/roller marks
• Oils in alkyd oil-based primers and paints are natural organic materials which serve as mildew food and actually promote mildew growth.
• Oil-base semitransparent stains allow the wood to "breathe," so the finish doesn't blister or peel.
• Oil-based primers can hide heavy water and smoke stains that latex primers can't handle.

Life span of different kinds of finishes: at the USFS Forest Products Laboratory (FPL)

Water repellents	6-12 months
Clear water-repellent preservatives	1-2 years
Pigmented water-repellent preservatives	2-3 years
Varnish	2-3 years
Solid-color stains	3-7 years
Semitransparent stains	3-8 years
Paints	7-10 years

About:
Wood Finishes:
Comments at WoodenBoat.com Forum

David G wrote:
- Most wood finishes are various proportions of 3 components: resin, oil, solvent. A pure oil finish, like tung oil, or linseed oil could be 0% resin, 100% oil, and 0% solvent. A spar varnish has some of each component. The higher the resin content... the faster the film build. The higher the solvent content... the cheaper it is.
- Resins can range from old-school, like copal or amber, to phenolic, alkyd, and polyurethane.
- Oils might be linseed, soy, tung, and safflower.
- Solvents can be anything from water to turpentine, to mineral spirits, to lacquer thinner, to xylene, MEK, etc.

So - in terms of terminology - the Watco and Daly's SeaFin teak oils would be called oil/varnish blends, but not wiping varnishes (as I said earlier - not enough resin content).

So - to the OP - I'd say the same as others have. Decide between 3 strategies.
- First - Leave it bare. It'll weather to a nice dove-gray patina, and be the lowest maintainance approach.
- Second - Use oil. The two most common choices are boiled linseed oil and tung oil. [file:///Users/donmcbride/Sites/donsnotes/home_garden/refinishing-teak.html#caseyIt's easy to apply and easy to touch up. It requires discipline. If you don't refresh the finish religiously - before it appears to need it... you'll have made yourself a mess you'll have to clean up.
- Third - A film finish. Most common is spar varnish. This is what I'd recommend if you decline the bare teak look.

The oil/varnish blends will build a film - just like varnish - they'll just take more coats to do it. If you should go that route - the Daly's product has better quality oils and resins, and a lower proportion of solvents. The Watco Teak Oil I've seen used did not hold up over time.

Boiled Linseed Oil (BLO) vs Pure Tung oil

BLO	Pure Tung oilHas added metal compounds
Dries faster (because of added compounds)	Dries more slowly
Will yellow with age	Doesn't yellow
Can go rancid	Nope
Can mildew	Nope
Nope	Has waterproofing qualities
Nope	Retains some flexibility when hardened
Cheaper	More expensive

Source: Tung oil Debunking the myths

Tips/Notes:

• The problem with light colors in a solid color latex stain is that tannins (present in cedar and redwood especially) will leach through a latex paint unless first primed with a stain blocking primer or an alkyd/oil finish first.
• Semi-transparent stains will fail by erosion. This is a benefit, since you do not have to worry about cracking and peeling (if applied correctly). The negative is that Semi-transparent stains tend to erode rapidly in areas where there is a lot of weathering (like the south and west sections of the house)
• Latex semi-transparent stains are similar in appearance to the oil-based semi-transparent stains. However, the semi-transparent look is achieved by the formation of a thin film and there is little penetration. This film is often not thick enough to provide durability, and it tends to degrade by flaking from the cedar surface.
• Solid stain can peel, but anything solid that looks and acts like paint can peel.
• Kill the mildew/mold with a solution of one part household bleach and three parts water. An alkaline cleaner such as washing soda, or a cleaner containing trisodium phosphate can be added for extra cleaning.
  - Let the solution set for 15 minutes.
  - Scrub the surface with a soft brush.
  - Rinse well.
• Algae can grow on an inert surface because it only needs water and sunlight to grow, while mildew needs organic food such as sugar from wood or oil from paint to develop. Most paint brands focus only on mildew, not algae protection.
• Many manufacturers are switching to latex, because of California restrictions on Volatile Organic Compounds (VOCs) in oil based paints.

There is no such thing as water base. Water is a solvent for water-borne coatings. Water-borne finishes can contain oils, alkyd resins, epoxy resins, polyurethane resins, etc. These are the various kinds of binders. They all have different properties. To apply water base to them as a means of explaining their values is not only misleading it is stupid.

Water reducible coatings that use latex resin as the vehicle (pigment carrier) may wet-crock (soften when wet) and rub off when you walk on them when wet.

Stains:

Semi Transparent vs. Opaque (solid-color):
Exterior stains for clapboard and cedar-shake siding come in solid and semitransparent formulations. Opaque (solid-color) finishes look almost paintlike, covering the wood completely so the grain doesn't show. Semitransparent stains add color to the wood but let the grain show. Either type soaks into the wood, leaving a flat dull, finish.
Opaque finishes tend to last longer.

They also come in Oil and Latex.

At Finishes for Exterior Wood Surfaces: Options For The Painting Contractor on Historic HomeWorks.com web site they say:

Semi-transparent stains are probably the most popular and widely used of all the natural finishes. These products are available in a wide variety of colors but, like the other natural finishes, they are penetrating and, thus, do not fail by blistering, flaking, or peeling in the way that film-forming coatings may fail.

Solid body, solid color, or solid hide stains are much more similar in nature to paint systems than they are to semi-transparent stains. These products, whether water-based acrylics or oiled-based solvent-borne systems, form a coating on the wood surface, hiding most of the wood and usually dramatically altering the color of the natural grain and character of the wood. When applied over extractive rich woods such as redwood and cedar, acrylic solid color stains should be applied over a top quality oil- or alkyd-based primer specifically formulated for extractive rich woods. As with the other finishes previously discussed, where the manufacturers' formulations allow, a minimum of two coats should be applied for the best performance. Solid body stains may need re-application every five to seven years. Coatings such as these are not recommended for decks and walking surfaces.

Varnishes and other clear film-forming finishes are generally not recommended for use on exterior wood due to their rapid failure from UV light.

Comparison of different clear finishes:
wax, shellac, Nitrocellulose lacquer, Conversion Varnish, Alkyd varnish, Polyurethane varnish, Linseed oil, Tung oil, Water-based polyurethane, oil-varnish mixes.
See: Timber Finishes - Interior | WoodSolutions.com.au

Latex over Oil and vice-versa:
You cannot apply latex paint over an oil base because it will not adhere properly and will peel or scratch off easily. In general, you should always put an oil-based paint over an oil base, and water-based paint over a water base. Although you can paint oil over latex, over time it will crack. The only exception to these rules is alkyd primer. Most alkyd primers are formulated to go under both oil and water bases.
In Latex Paints Over Oil-Based at Paint Quality Institute they say:
The rule of thumb is that, given proper surface preparation, for exterior use you can apply quality latex paints over oil-based, but not the reverse. However, if you have many layers of oil based paint, stick to using oil on oil.
Another article stated:
Up until recent years, painting latex over oil was taboo since it had no adhesion properties designed to make it stick to oil surfaces, which meant that you could literally take it off using a fingernail or even just attempting to wash the wall.

If you can paint latex over oil based primer, why can't you paint latex over oil based paint?
The reason why latex can be painted over oil primers is because oil primers are formulated differently than oil finish products. Oil primers actually have a lot of flexibility, allowing them to move, much like latex. Oil paints are much too hard when they dry, not allowing for much flexibility at all.

We would not recommend using a latex primer to be coated with an oil finish in most exterior cases due to the difference in flexibility, but an oil/alkyd primer under latex finish paint is a good method.

For interior surfaces once they are properly prepared and primed it is not an issue to apply oil over latex or latex over oil. Modern primers will accept either over either. The relatively new High Performance interior acrylic paints claim to be the self-priming super stars of interior trim paint.

Application:
Brush application is usually superior to roller, spray, or painting-pad application, especially for the first coat. Professional painters can usually spray paint and obtain good performance.
The main reason professional painters spray paint on these days is to save costs on both labor and materials. It would probably be too expensive for you to pay professionals to hand roll or brush an entire exterior today.
However, a spray is a surface application only and does not fill cracks, or seal most rough-sawn wood or stucco properly. That is why you should always backroll and brush after most spray applications, to enhance the look and achieve a longer lasting paint job. A painter who does not take this extra step may charge a little less, but you are right that in most cases, a spray-only paint job simply will not hold up as long or well.

Spray-only applications are appropriate on smooth surfaces where rollers or brushes will leave undesirable finishes. These would include smooth lap siding, garage doors, exterior metal doors and some gutters. In these cases, it's recommended to spray on a good quality enamel exterior finish with a fine orifice tipped sprayer to achieve professional factory-finished results.

The Wagner Power Roller speeds up painting, but it is a bear to clean. If you only have a moderate sized area to paint it may not be worth it.

Natural bristle brushes should be used for oil-based paints and stains, and not for water-based or latex products because they get limp.

the topcoat should go on within two weeks of the primer. If you wait too long, the mechanical bond between the two won't be as strong because the surface texture of the primer breaks down. And if two topcoats are used (recommended for new construction), the second should go on within two weeks of the first.

Stains:
Semi-transparent, oil-based penetrating stains may be applied by brush, spray, pad, or roller. Brushing will usually give the best penetration and performance. Spray or roller application followed by back-brushing is also an acceptable method of application. Stain that has been applied by spray without back-brushing is particularly prone to show blotchy patterns as it weathers.

Latex semi-transparent stains do not penetrate the wood surface, but they are easy to apply and less likely to form lap marks. These stains are film-forming and are not as durable as oil-based stains.

Unlike paint, a solid-color stain may leave lap marks.
Lap marks can be prevented by staining continuous lengths. This method prevents the front edge of the stained area from drying before a logical stopping place is reached.

Exterior-Painting-Techniques at servicemagic.com
Exterior Painting at Philpott Evitt Building Centre in BC

Products:
Consumer Reports (June 2006) likes Olympic Premium 596 (latex) S, Behr Plus 10 (alkyd, water cleanup), Cabot O.V.T 0600 (latex), Cabot O.V.T 6500 (alkyd) & Olympic Wood Protector Deck, Fence & Siding 793 (latex). They are all solid stains; The top semi-transparent was ranked number 8.
Contractors at Tahoe like:
Preserva Wood
Duckback
These are oil-base transparent preservatives with some pigments for color. Preserva Wood has a chemical to stop salts from leaching out of the wood. They penetrate better than semi-transparent stains, but they may not hide variations in weathered wood as well as semi-transparent or semi-solid stains.
Some painters put one of these on as a primer, followed by a solid or semi-solid latex on top.

Article at SFGate

Deck Finishes

Stained wood surfaces may need to be retreated every 2-3 years or earlier depending on weather exposure.

Aliphatic elastomeric urethane waterproofing systems are UV resistant, VOC compliant and provide a flexible, seamless, watertight, non-porous film over most treated surfaces.

Deck Resurface Products: Deck resurface products are basically similar to an extremely thick paint. They are designed to mask the wood and fill large cracks or voids.
See Deck Paints and Resurfacers in products

Application:
Intermix all the gallons to in five-gallon bucket to iensure color consistency.
Stir, stir, stir.

At Finishing Wood Decks from Historic HomeWorks.com they say:
The solvent-borne semi-transparent stains penetrate into the wood without forming a continuous layer, and consequently, will not blister or peel even if excessive moisture enters the wood. The pigment protects the wood surface from sunlight, thus increasing service life. The binder in the solvent-borne oil-based, semi-transparent stain absorbs into the wood surface, just as it does with the water-repellent preservative (WRP), and there is no film formation.

Peeling:
Peeling with oil deck stains is rare; unless, the wrong stain is used (solid color house stain versus deck stain) or too many coats are applied (we only recommend one coat). Peeling with the acrylic solid color deck stain can happen from a couple things:
We do not recommend rolling the solid color deck stain because it leaves pinholes in the film which can allow moisture to get through the coating and cause peeling.

Comments on "Your Life Forum" at bostom.com says:
Use semitransparent deck stain. The solid stain is useless, will not last very long and is born to peel. The semitransparent stain is oil based. One coat is needed every 3 to 5 years.

At weatherall.com they say:
Peeling is generally a sign of a lot of coalesced film on the surface and not enough penetration. This could be due to surface contamination, high moisture content in the wood, a previous stain not allowing the stain to penetrate, or a wet on dry application instead of wet on wet.

Links:
Deck Paints and Resurfacers
Preparation and Priming
Refinishing Teak
Why is my paint peeling at This Old House
Advantages Of Oil VS. Latex at PaintingYourHouse.info
Painting and Painting exterior wood - oil vs latex at Al's Home Improvement center.
Paint, Stain, Varnish, or Preservative? at the USFS Forest Products Laboratory (FPL)
Finishes at CarolinaColortones.
Finishing Western Red Cedar Siding
Before you Stain your Wood Siding at True Value Projects
20 most frequently asked questions at Morwear.com
Painting cedar siding and cedar siding maintenance and care at cedar-siding.org
13 Painting Secrets the Pros Won’t Tell You
All About Exterior Paint and Stain at paint-and-supplies.hardwarestore.com
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