Special Sanding: Make Sanding Heart Pine Easier

Heart pine requires special techniques to perfect. I was first taught to sand heart pine by Daniel Boone of Daniel Boone WFT Inc. He told me, "If you try to sand heart pine the same way you would oak or maple, you will immediately run into problems from the resin." According to the book "Longleaf Pine" (USDA, 1946), even long after virgin-growth heart pine was cut, the heartwood still contains 7 to 21 percent oleoresin. The resin makes heart pine hard, a rich red color and more difficult to sand.

Getting started

Daniel started with 36- or 40-grit, or sometimes 24-grit paper. Today, new equipment and papers offer many options. Depending on the quality of the milling, installation and equipment, you might start with 50-grit, or even 60, and be fine. When sanding heart pine you want to minimize the scratch pattern and generate as little heat as possible to use less paper. 

Regardless of your starting grit, try a 15- to 30-degree diagonal. This allows for more aggressive sanding. If your paper loads up quickly, that is not unusual, just change paper as often as needed. 

When sanding any pine floor, be sure to clean big machine and edger wheels frequently, as they may load up with resin just like your abrasive does, causing uneven sanding.Edges

Gary Smith of Custom Hardwood in St. Augustine, Fla., recommends scraping edges when sanding heart pine. He says, "Sand and screen the field of the floor completely, then use a 2-inch scraper to feather into the field. Your sandpaper can load up in 2 feet when edging heart pine, so you save money and time if you scrape edges. It is more physical."

If using an edger, start with the same grit used on the field for the first cut and feather into the field. If using a multi-disc machine, try thinner papers. The thicker-backed papers tend to bend on heart pine, creating swirl marks. 

Final sanding

Sand with consecutive grits until done, and make sure you feather into the edges. Remember, the paper will likely load up, so be sure to change when needed. Don't skip grits, and clean between each sanding. 

The hard work begins

Now that you've completed the "easy" work, it's time to dig into the final steps. It is imperative to hand-scrape anything and everything needed to make the floor flat. This includes door jambs, toe kicks, wall lines and corners. Hand-sand scraped areas with the grain using the same grit as the final sand, carefully smoothing and blending the edges from the field to the walls. Grab that vac and thoroughly clean the floors. 

Screening

Now you're ready for the final step before the finish: screening. Use a screen with the next higher grit. Yes, the screens will load up too. This can, in some cases, cause swirls on the floor. I cannot stress how imperative it is to keep the floor and screens clean during this process to avoid these potentially unsightly swirls. Screen again with a grit higher. This will help improve the smoothness of the wood. 

Yet another variation

Pat Bailey of Artisan Hardwood Floors in Austin, Texas, hand-scraped the entire floor and used only a buffer and 220-grit screens to smooth scraping marks when he recently put a heart pine floor in the Texas Governor's Mansion. He says, "Hand-distressing heartpine is not easy! We had eight guys distress over 5,000 feet of heart pine. Not using modern sanding equipment gave us an opportunity to create a completely unique floor using techniques that founded our industry.

"When sanding heart pine, most of our problems are small scratches from the screening process. Our solution has been a multi-paper Satellite head and using 150-grit sanding tape before the final coat. We often water-pop to help with fine scratches."

Crossing the finish line

Once you are ready for finishing, be sure you have consulted the finish manufacturer. They will be able to tell you the best way to go about applying their product to heart pine. Always be safe and use proper protection equipment when working with finishes. 

These techniques should help ensure your heart pine flooring will maintain its magnificence and allure for generations to come. Sanding heart pine is more time-intensive than many other species, however, the end result is well worth the extra work. Remember, you are not just sanding wood, you are preserving a story!