Ipe (pronounced "ee-pay") is a hardwood grown primarily in Brazil. To say that ipe is a hardwood is a considerable understatement. This type of wood is sometimes referred to as "ironwood" because of its strength and density. If you pick up a piece of ipe, you'll immediately notice just how heavy the wood is.
Ipe is tightly grained, with a color reminiscent of mahogany. Most ipe has very few knots, making it quite straight and stable. This trait, along with its natural resistance to water, makes ipe an ideal choice for decks and outdoor woodworking projects.
What is Ipe?:
Ipe that is typically sold in fine wood suppliers can often be one of about ten different, but very similar species of wood. All come from Brazil, and all have very similar characteristics, but they tend to be lumped together and sold as ipe.
Why should this matter to you? If you're planning a deck or a large project, keep in mind that each of these exact species will likely have slight color variations, and will probably look a little different after finishing. Order all of your ipe from one trusted supplier, and order enough to complete the entire project, and you shouldn't have any visible variations.
Ipe's strength and density makes it a difficult type of wood to cut cleanly. You'll likely find that your blades and bits will dull quite quickly when cutting ipe, so plan accordingly. As you might expect, sanding ipe can be very time consuming. Ipe produces a very fine, yellowish sawdust that is known to be quite irritating to the eyes and respiratory system.
With this in mind, it might be best to work with ipe outdoors as much as possible, ideally on a windy day. Try using carbide saw blades with fewer teeth at a sharp hook angle to keep from making fine sawdust. If you must cut indoors, use proper ventilation.
Fastening with Ipe:
Ipe is not only very dense and strong, but can be a bit brittle. Driving nails into ipe with a pneumatic nailer is only asking for splitting, and driving screws into ipe will break off the heads easily. Using stainless steel screws into pre-drilled holes to fasten ipe boards together works best.
Gluing ipe can be a challenge. Some woodworkers have had success using weather resistant yellow glues, while others have had better luck with epoxy formulas. I'd advise wiping down the wood with acetone or denatured alcohol before gluing, to ensure that the surfaces are completely clean.
Filling Screw Holes:
Ipe doesn't work very well with common wood fillers. Over time, even the best wood fillers seem to dis-lodge from the holes they filled in this wood.
One that seems to work well with ipe is to sink the screws at least 1/8" into the wood, then cut plugs from ipe scrap and plug the screw holes. Another common (but, in my opinion, less desirable) choice is to mix sawdust with waterproof yellow glue to fill the holes.
Ipe, when left untreated and exposed to weather, will develop a grayish tint similar to faded teak. While some may like this look, others may try to preserve the rich color of ipe by applying a protective finish.
The problem with protectants on ipe is that, once again, because of the density of the wood, the finishes don't adhere well. Oil-based protectants sometimes can take weeks to dry, while varnishes will look great initially, but may be troublesome down the line. Polyurethane simply doesn't adhere to ipe, so that's one to avoid.
Some deck builders have reported success using tung oil to help maintain the color of the wood over time. Some protective finishes used on wooden boats that use different formulas consisting of a combination of tung oil, resins and mineral spirits might be a good choice as well.
Since every person's preference will be a little different, experimentation to find a finish that meets your tastes is advisable. Be sure that the ipe has had plenty of time to dry properly and acclimatize before applying the finish.