Is Purpleheart Wood a choice for woodworking projects?
Let me start by saying, as a woodworker, you just have to be enamored by the beauty of some hardwoods. We all grew up coloring trees with our super fat Crayola Brown Crayon. Who knew that their were colors like Purpleheart, Bloodwood, Canarywood or Tulipwood. Unfortunately, sometimes that beauty comes at a price, and more than just a monetary one.
Purpleheart Wood is a great choice for special projects due to it’s exotic color and sturdiness, but it’s other attributes make it less desirable. Most notably, Purpleheart’s beautiful color is extremely prone to oxidation and UV bleaching. Over time your vibrant purple will turn brown, which is not good for heirloom items. Purpleheart is extremely hard, making it difficult to work with. It has an inner resin or gum that when heated with clog tools. It’s interlocking grain supports “tear-out,” which is a problem that haunts all woodworkers, and it’s toxic.
With these things said, knowing your wood is just like knowing your tools. You can solve many of the difficulties presented by Purpleheart with just a few steps. Read On!
Why is Purpleheart difficult to use?
First I want to start by just listing out the difficulties and then we will work through the solutions to help you make your decisions about your wood choice. I’m listing these in MY order of distress.
- UV fading
- Interlocking Grain
These items just don’t really exist in the average woodworkers wood. To a small extent maybe, but you just don’t see these with something like Hard Maple. Better to know before jumping in for sure!
Oxidation and UV fading.
Wood oxidation and Ultraviolet(UV) fading are separate problems but they interact together. If you have one, you are going to have the other and so forth. Oxidation occurs naturally and everything in on earth is subject to it, some things are just more negatively impacted by it. Browning of fruit, rust and many other types of decomposition are examples of oxidation.
At it’s most basic level oxidation is just the loss of electrons. Very natural, but if you think about that truck in the farmers field rusting away, very damaging.
Ultraviolet fading, is mostly, the same thing. Items are exposed to prolonged amounts of sunlight (or other UV sources) and are electromagnetically radiated over time altering the chemical makeup of the affected item.
Why does Oxidation matter with Purpleheart Wood?
Generally, when you are working with a wood like Purpleheart it is for a more substantial project, an heirloom tool handle or jewelry box. The concept to heirloom, is inherently that you plan to hand it down generation to generation. And while, the wood will absolutely hold up to time, the vibrant color which you chose this wood for, likely will not.
I hope I am not the first to tell you this. Purpleheart wood, so vibrant and beautiful purple, WILL turn a dungy brown. I say will, because time will win. Their are things you can do to slow the oxidation, but they will not stop it.
Essentially, within a generation or two, your stunning work will be far less attractive due to the change in coloration.
Slowing the effects of Oxidation on Wood.
Again, you won’t stop oxidation (well unless you put it in a sealed pressurized environment for, well, forever), but you can slow it. Some of these are probably already common practice for you.
- Finishes: Apply a good well rated finish to the wood. This isn’t feasible with every project, but if it is this will dramatically slow the oxidation process. Finishes like Armor All, Gori 11 Wood Preservative, Osmo WR Base Coat and Cuprinol Wood Preserver are all highly rated, well accepted treatments.
- Storage: Keep your project in a cool dry location. The more heat and humidity, the faster the oxidation.
- Placement: Keep your project out of the sun. Combined with UV damage, oxidation increases rapidly.
- Repair: Anytime you have a damaged or dinged area on the project, try to repair it as soon as possible. The damage, just like an apple, will cause the same outcome. This could mean re-coating with finish or even a spot repair/replacement of the wood.
Ultraviolet damage and Hardwood.
I think at this point in science, the general knowledge of UV light is pretty well known so I won’t go to far with the subject. UV treatment is almost exactly like the steps for oxidation noted above. Keep the project in a cool dark place, ensuring you control the amount of direct sunlight. Adding a layer of UV protectant can be of great advantage in prolonging the items life. I personally like (for many reasons) Walrus Oil Furniture Finish. It’s penetrating Oil-Based finish is a great UV protectant, it is a great overall protectant and it looks great.
Gumming caused by Purpleheart Wood.
Third on my list of reasons Purpleheart wood is not my favorite is gumming. Purpleheart is well known for having a gummy resin that reeks havoc on tools and sandpaper. While this is generally not the worst thing in the world, it does become problematic. You are cutting a VERY hard wood, with gummy cutting edges.
It is absolutely necessary to clean and sharpen your saw, plane, or other blades during the cutting process. Not a big deal if you are making something small, but a large box would be difficult. The same concept doubles for drill bits. It is a constant woe once the wood has warmed up.
For those who are return readers, you know that I run Hill Country CNC & Woodworking! And I bring up that plug because with CNC work, gumming can be downright disastrous. Cutting a wood like Purpleheart with a normal downcut bit will cause tremendous heat which in turn will gum the resin. With a dull (or gummed) CNC bit your chance of breaking that bit goes up exponentially.
How to clean Gumming from Resin.
The best way to clean the gumming resin is to soak (as possible , ie. most handsaws can’t be soaked) your tool with a anti-resin chemical. I personally use Simple Green for all my resin/sap issues on ALL my tools. Works great on chainsaws too! Because of the heat, I end up soaking my CNC bits rather often. I just have a small container with Simple Green in it, I place the bit in there over night and clean it in the morning. Works great.
The Rockler Pitch and Resin Remover is highly recommended, but I can not swear to it. I like Simple Green because it works, it’s cheap, and their are no crazy chemicals. I can get it on my skin with no worries.
Last comment on this topic, after cleaning your tool with a anti-resin chemical, you need to treat it with an anti-rust agent. I prefer Camellia Oil and/or Boeshield T-9 Rust and Corrosion Protection/Waterproof Lubrication (sold at Rockler). Both are important, remember it’s not one or the other. Some tools will like one, other tools will like the other.
How to deal with Purpleheart's hardness.
My standard answer for dealing with really hard wood is to use quality tools that are sharp. It’s about that simple. I went to a master woodworking class with one of our present day true woodworking masters and you would just not believe how often he sharpens his planes and chisels. For that matter the saws too!
For the powertools, it’s just having sharp blades and trying to run them at the right speed (chip rate)and temperature. Replacing blades on your chop or table saw before or during a hard wood project is advisable. Think about it, Purpleheart is at a Janka scale of 1860. That’s pretty dang hard for almost every woodworker, not many go above that.
The well known interlocking grain pattern of Purpleheart Wood presents two problems, of which we can fix one. The first issue is that of “tear-out,” a common problem facing woodworkers, generally while working with the end grain. A quick synopsis of tear-out is that you splinter the edge of the wood instead of cutting the grain cleanly. This happens alot with planing the end grain.
Two common fixes are:
- Use sharp tools. Seriously. This will fix most of your issues with tear-out.
- Attach a sacrificial board to the piece you are cutting on the lead out side. The board should be level to, or maybe a 64th lower than the board you are working on, and it should be a softer wood than the piece you are trying to protect.
The second issue with the interlocking grain is that it is generally boring visually. Add on to that the color change over time, what was a stunning piece of craftsmanship, is now just blah. All you can do here is protect your color!
Toxicity of Purpleheart Wood.
Purpleheart Wood is toxic. But mostly to bugs. It has a chemical in it called dalbergione, which is a neoflavonoid. The neoflavonoid is toxic to bugs and animals but not so much you and me. With that said, I still take my precautions with all wood.
- Again, sharp tools reduce dust.
- Use dust extraction! I run the Jet 708659K DC-1100VX-CK Dust Collector, 1.5HP 1PH 115/230V, 2-Micron Canister Kit.
- Use a overall air filtration system, like the Jet 708620B AFS-1000B, 1000 CFM Air Filtration System.
- Wear a Respirator!
- And las but not least Eye Protection.
Revisiting the Good, the Bad and the Ugly.
Despite its persnicketiness (that’s an actual word) writing this blog has really made me think about my experiences with Purpleheart Wood, and maybe I just made myself want to do more with it! Truth of the matter is that most of us don’t get into fine woodworking because it is easy. It’s a challenge, and that’s a good thing!
Maybe the Bad and the Ugly can be trumped by the Good. After all, it IS a beautiful beautiful wood.
BTW, a small personal note, I got into Purpleheart Wood because I was awarded the Purple Heart Award. You really can’t receive the award without being profoundly affected by the circumstances that got you there, and in that, I grew an attachment to the kindred named wood.
Hope you enjoyed this and please make sure to check out the rest of my website and blog!
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