Choosing a Finish
Your finish choices will fall into one of the two following types:
A penetrating oil with or without wax
This type of finish is used primarily in commercial settings, as it requires a regular maintenance program. As most of our woods are exceedingly hard they do not need a protective film finish, which under commercial use eventually scratches and then requires re-sanding and refinishing to renew. For commercial applications, especially on dark woods where scratches show up lighter and in great contrast, a penetrating oil allows any wear spots to be simply re-oiled and buffed as part of the regular maintenance program already in place in commercial locations. This finish imparts a deep, rich, if somewhat flat, look to the wood. To build up additional sheen, wax is sometimes used which in turn requires periodic buffing to maintain.
A surface film finish
This is a finish coating that sits on top of the wood forming a protective film. A surface film finish is the treatment of choice for residential use, as it requires little maintenance in low traffic conditions. Film finishes are available in a variety of sheens from matte to satin to gloss.
There are three types of film finishes:
- Water Based Urethanes – These are the latest finishes out, are quick drying and are being formulated with increasing durability. They tend to inhibit the color change certain woods undergo over time so they are a good choice should you wish to inhibit this change. Water based finishes tend to leave the woods lighter in color and looking somewhat washed out. For those who prefer the richer look an oil based finish provides, a penetrating oil/stain may be applied first and then the floor can be top coated with water based urethane. Please refer to your finish manufacturer for their specific recommendations. Here are several we recommend.
- Bona Kemi offers a system that allows for their oil based sealer to be used first and then top coated with water based finishes.
Bona Kemi can be reached at 800-872-5515 – www.bonakemi.com
- Berger Seidel offers a system especially formulated for exotic woods.
Berger Seidel can be reached at 800-979-9272
- Basic Coatings offers several water based systems.
They can be reached at 800-441-1934 – www.basiccoatings.com
- Oil Based Urethanes – These are the old standby type of floor finishes now being phased out due to environmental concerns. However, they have proven durability and impart a rich look to imported woods.
- Acid Cure and Moisture Cure Urethanes – These are two part formulations which include the “Swedish” type finishes and moisture cure urethanes, and are among the most durable of all the finishes. They are, however, quite odiferous when applying.
Once again, after having made your finish choice, please test your finish choice on actual samples of the wood to insure compatibility prior to use on the floor itself.
Finish Compatibility Issues with Exotic Woods:
In general, water based finishes adhere well to all our woods while oil based finishes may experience drying and/or color change problems when used on some of our woods. To date, we have experienced some finish compatibility problems when using certain oil based finishes on the following woods:
- Ebonies (all types)
- Rosewoods (all types except Caribbean and Patagonian Rosewood)
- Walnut, Brazilian and Patagonian
- Walnut, African (mansonia)
The above list is provided as a service by Wood Flooring International. It was derived from feedback from several of our customers who, when using certain finishes, experienced compatibility problems in the past. However, Wood Flooring International shall not be held liable for any finish complications on any of our woods, as it is the installer’s responsibility to adequately test the compatibility of the proposed finish they will be using on actual samples of the flooring prior to installation. There are simply too many different finishes (and changes being made to existing finishes), on the market today for Wood Flooring International to keep current with them all.
Exotic Wood Finishing Tips:
All the woods listed above have experienced some drying issues when finished with certain oil based finishes – use extreme caution and thoroughly test the intended finish on ANY unfinished product first! We list a few of our most popular species below and recount installer feedback on finish issues. But this information shall be considered incomplete as it is merely compiled from feedback received. Furthermore it is impossible for Wood Flooring International to know how every finish interacts with our wood. It is the installer's responsibility to always test first!
- Brazilian & Patagonian Walnut – has caused more finish problems than all the other species combined. This species has a number of alkalines in its chemical makeup which interfere with drying, adhesion and staining. While some oil finishes will dry on this wood, most will not. Also, some neutral oil finishes have reacted with these alkalines and turned red when used with this wood. Water based finishes are the safest bet.
- Australian Cypress – there are some finish adhesion issues on the knots. Please check the finish you are using first on some hand samples and, once dry, try scratching the finish off the knots. If the finish fails try another finish. Wood Flooring International has researched several finishes and offers specific recommendations in our Special Australian Cypress Instructions.
- Brazilian Cherry – to date, all finishes seem to work on Brazilian Cherry.
Of special note: occasionally, certain trees have a high content of a white silica/sap, which is almost imperceptible to the eye in the freshly milled flooring, before finishing. This silica/sap shows up as faint spots – almost as if drops of skim milk had dried on the wood, once the wood is finished and then, as Brazilian Cherry darkens over time, these white spots (which do not darken) become more prominent against the now darker wood. Also, when finished with some oil based finishes, the finish may not harden fully above these spots, while with water based finishes it does fully cure. There have been many instances when using Brazilian Cherry where several, (to dozens), of boards in a floor may contain these spots, which we stress are in wood itself and not in the finish, even though it may look that way at first. The only way to avoid them is to visually spot them before installing and not use boards with them. Once installed and then found objectionable, the individual pieces would have to be be replaced. Many installers/ finishers, the first time they run into this issue, think that by resanding the floor and recoating, that these spots will disappear but this is not the case as the “white spots” are through the entire thickness of the wood and cannot be sanded out. As this is a natural feature of the wood and is not visible when the wood is freshly milled, it is not considered a defect in solid unfinished wood. In prefinished products, it is possible to spot at least the stronger in color white spots once the finish is applied and these are graded out at the mill. However, the installer should still look for those spots not graded out and not install pieces with these spots.
- Santos Mahogany – to date, all finishes seem to work on Santos. However, we have had some recent reports that Santos adversely affects the way the flattening agents in some oil based Satin finishes settle – leaving a blotchy finish. Also, in the summer, when you open the packs of flooring, many times there will be spots of oil which have bled out of the flooring when it got heated. This oil, to date as far as we know, has not adversely affected any oil or water based finishes.
- Southern Chestnut – to date all finishes seem to work on Southern Chestnut. Peculiar to this species, some trees have large silica spots which show up as circles or half circles of slightly lighter colored material. We attempt to cut most of these out of color clear grade but allow them in the lower grades. When finished, the lighter contrast remains. It is a feature of this wood and if objectionable, care should be taken when installing this wood to select out any pieces exhibiting these spots and cut them out prior to installing as they will not “sand” out.