Purpleheart Recommendations

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C

chaplain1101

Member
Joined
Oct 31, 2019
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3
Location
Two Harbors, MN
Good morning to all. I have been pen-turning for about 3 years and only recently became interested in Purpleheart. I turn several pens
but have yet to discover a consistent process, including final finishing techniques, to bring out the full potential of the wood. Any suggestions
would be greatly appreciated. FYI - I have tried heat application, but with less than desirable results.
 
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Hello Chris welcome to the site. Glad you found us. I will give you my opinions on the beautiful wood purpleheart. Others will jump in and also help. First and foremeost you are working with an exotic wood that will darken with age and very tough to keep color as intended. Just the nature of the wood. But there are a few things you can do to help prolong the beauty. Purpleheart is not all the same. It comes from various trees and from various countries so the color richness can vary as well as the ability to maintain color. Which trees are better I am not sure so will leave that to others but will say this wood from Brazil is a better quality. The more dense the wood is the better it will hold its color.

To work the wood, you notice when first cut it will be a grey to a muddy brown color but when exposed to air and sunlight it will start to turn purple as the tanins in it start to change. There is a fine point of when it will stop changing color and when it will start to reverse back to brownish. Usually a few days left exposed will give you a good idea what intensity your wood will look like. This is a wood where patience is needed for mother nature to do its job. You need to allow the wood to have air circulate around it by flipping each day As I said some purpleheart is more intense than others. But I found a best way to preserve the color is to after you let it set and get the color that is desired, to apply a coat of shellac sanding sealer such as Zinsser nowax sealer. It dries quick so after it dries I would use about 3 coats to soak in the wood. Now sand after dry and apply a good lacquer. I like to use Watco or sometimes Deft for my work. People have used poly such as Spar varnish which is a marine varnish and the best for UV protection. that is designed for outdoors because it as UV prohibitors in it and UV is what will age wood and cause it to darken over time. It does work also but waterbased is best because it dries clear and that is why I like lacquer. In the long run purpleheart is a wood that does darken and there are many others out there as well. Good luck. Hope this helps
 
Hello and greetings from Nebraska. I have had my best luck with Purpleheart (as far as color is concerned) by turning the parts down, sanding them, and then setting them aside for a week or so before applying a finish.

The closest procedure I have read about in Woodworker's Journal (and other sources) to expedite this was to wipe it with acetone and put it in sunlight following sanding. Then every hour or so, re-wipe it with acetone and rotate it so the back side gets exposure. And finally, let the wood dry out completely for a day or so before applying a finish.

Many have or will suggest using a UV protective finish such as spar urethane to slow down the inevitable color change towards brown. Even with a non UV protective finish, make sure to seal all of the exposed surfaces to reduce color changes due to exposure.

My understanding is that the color in Purpleheart as well as in many other colored wood species is due to conjugated dienes, organic compounds that reflect light in the low and high ends of the visible spectrum. Some of these compounds are highly soluble in water while others are soluble in organic solvents.

Water happens to be a polar protic liquid and although Acetone is unique because it is an organic solvent that is also highly polar therefore it is effective at dissolving both water and solvent soluble materials. Dissolving these compounds helps them work their way to the surface of the wood bringing all of their bright colors along with them. The UV exposure then does it's part by starting an oxidation reaction that first brings out the color and then over a longer period causes the chemical reaction leading to brown. Of course nobody really wants brown Purpleheart so the key is to wait until just the right time and then stop (or slow as much as possible) the oxidation and UV exposure process by applying a finish.

I hope you find a regimen that works for you. Purpleheart really is gorgeous when it is at it's peak purpleness! - Dave
 
I purchased a toaster oven at a second-hand store and then made a quick jig consisting of a block of wood with a long finish nail in it.

I hang the turned and sanded pen blank on the nail and then "cook" the blank. It's amazing to watch the blank go from muddy brown to a purple grape color.

I will watch it closely and rotate the blank every 2 minutes or so. This will help get a consistent purple color all around the blank.

After that I go through the typical CA finish steps.

Here's an example

DSCF7788.JPG
 
BCnabe said:
I purchased a toaster oven at a second-hand store and then made a quick jig consisting of a block of wood with a long finish nail in it.

I hang the turned and sanded pen blank on the nail and then "cook" the blank. It's amazing to watch the blank go from muddy brown to a purple grape color.

I will watch it closely and rotate the blank every 2 minutes or so. This will help get a consistent purple color all around the blank.

After that I go through the typical CA finish steps.

Here's an example

View attachment 351486
Click to expand...
Very pretty. Would you mind sharing the temperature you cook it at and for how long?
 
jcm71 said:
Very pretty. Would you mind sharing the temperature you cook it at and for how long?
Click to expand...
Usually around 350-400 degrees on the toaster oven dial, but I'm not sure how accurate that is. The time will vary depending on the wood but around 8-10 minutes.

You'll want to experiment and watch it closely. I've had a few go too long and they got too dark.

It seems like they continue to darken a little after taking it out of the oven so you might want to pull it out when it's a little lighter than what you prefer. I think the CA tends to darken and deepen the purple as well.
 
I use a heat gun once I've turned it down and sanded it to 600. Once I get the deep purple color I'm looking for, time for a CA finish. It does darken the wood as CBnabe points out.

Sunlight will do the trick, also as others have mentioned, but my cheap Harbor Freight heat gun is much faster.

Good luck!
 
jttheclockman said:
You do know CA is not a protect UV inhibitor so it will turn brown with time. Just saying.
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Indeed. I've got a couple of peices laying around that are pretty old and still have some purple left in them.

What do you recommend for a finish to retain the purple, poly? I see you mention it in your post above.
 
BCnabe said:
Might be, but haven't had it happen yet in the 30-40 pieces I've done over the last 8-10 years.

You're mileage may vary.
Click to expand...
Again as I said all purpleheart is not the same. Intensity in color is due to the place of origin. Same goes for all woods. I have seen black walnut that is a slight tan and some that is pure chocolate brown and the color is outstanding. Not sure if you have in your possession all pieces you turned that were purpleheart but if you do and they never changed then they probably are not seeing the light of day. Cherry wood turns dark over time it is mother nature. I love exotic woods. They are some great colored woods. Good luck.
 
I'll take my heat gun and warm it up really good. That will cause the purple to be more pronounced. But be careful... you can also make it too dark. Experiment before turning.
 
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