Finishing Ipe Locker Room Benches

Ways to deal with Ipe wood's oily nature and its tendency to fade to gray. June 8, 2008

Has anyone finished ipe? We are working on a project where the architect wants to use it for locker room benches.

Forum Responses
(Finishing Forum)
From contributor A:
The typical finish for ipe is a product called Penofin. It's a great penetrating oil finish with substantial UV protection. I would not recommend it for this application since you are inside and I think it might get on clothing easily. You can use more or less any film finish - it will stick to ipe with proper prep work.

From contributor C:
Only if your client is adamant on keeping the natural color of the wood intact is it necessary to coat the wood at all. Ipe is capable of withstanding harsh exterior weather without any coatings. The drawback of course is the natural graying of the wood surface. If he is adamant, I would use a lignin stabilizer, coupled with a polymerized oil finish containing a top line UV protectant. This will ensure the natural color will stay stable for the longest possible time. If the client insists on a film forming finish, I would choose a two-component urethane and thin by at least 50% to give the least amount of build, or a shellac with UV. Fresh shellac - not premixed off the shelf! Here again only thin coats, so it is easy to maintain.

From contributor T:
Since I assume the locker room is inside, UV shouldn't be a problem, you can use any waterbased wood finish. The oils, excluding decking sealers, will not dry on ipe. Another option that's easy to do and touch up later is Rubio Monocoat.

From contributor C:
All polymerized drying oils will dry hard on ipe or teak or Brazilian rosewood, or others, if it's first treated with a solution of 5% phosphoric acid followed by wiping with methanol, and then 95% ethyl alcohol.

From contributor A:
In my experience ipe is like teak. Wash the surface with acetone or denatured alcohol, and then put on a thinned sealer coat of whatever finish you prefer. Haven't used phosphoric acid for anything besides taking rust off of steel... but I'm not a chemist.

From contributor C:
Though a wipe of acetone or alcohol will remove the topmost portion of the oily/waxy surface, it does not do anywhere near as thorough of a job as what I posted. In the early part of the 1900's, piano and furniture manufacturers stopped using rosewood especially, not because of scarcity, but because of finish failure due to the live sap/albuminous matter in the wood. Around the 1920's, chemists found that if they treated the oily woods such as Brazilian rosewood, teak, ipe, and others with a weak solution of phosphoric acid, it would coagulate this matter immediately on the uppermost surface of the wood. The methanol, wood alcohol would immediately reduce it to an insoluble state, not being able to interfere with coatings applied over it. The idea here is to destroy the activity of the sap/oil/wax/etc. on the same principal as sap is destroyed by ethyl alcohol shellac before being painted. The ethanol being the solute, the lac being the barrier coat. The technique I use just gets the surface materials better prepared to accept any finish than alcohol or acetone alone will.

From contributor N:
Unless this is a dainty ladies locker room with only incandescent table lamps, you probably have overhead fluorescent lamps which still emit UV, not as much as direct sunlight due to the coating on the tube, but still damaging over time.

From contributor C:
You're right - most lights used in normal conditions have some amount of UV, and will affect the ipe over time, slowly but surely. It does not hurt to use chemistry that will slow this fading or darkening down if the original color is to be kept as long as possible. Though I must admit that resanding through the affected top layer in the future will put it back in original color condition if necessary. The HALS will just keep you from having to do it as often.

From contributor J:
You should definitely finish it, even though it isn't necessary. The wood can get splintery over time, and there will certainly be some bare skin against it. Plus, it has some toxic properties that will cause rashes on some people when exposed to the dust. A lot of lumberyards sell the stuff pre-finished or at least with some coating on it. If you buy that, all you've got to do is seal the ends.

From contributor X:
Sand it down p120. Wipe with acetone or lacquer thinner. Apply 3-4 coats of premium waterborne urethane. This is the fastest and easiest way to finish any of these oily woods.

From contributor E:
Just another caution with ipe. We have had more reaction by workers with the sanding powder than any other wood.

From contributor M:
Our ML rep recommended the catalyzed polyurethane that they sell. Was wicked expensive, I think like twice the price of Krystal, but worked out well and haven't got a callback yet. Knock on simulated wood grain panel.

From contributor C:
Contributor J is correct. I try to stay away from it and spalted maple as well as some others, but those two can be very troublesome as far as wood allergies and reactions to toxins in the wood makeup.

From contributor R:
I installed an ipe hardwood floor in my home. After reading multitudes of posts on professional hardwood flooring forums, I decided on Zinsser Seal Coat as a bonding agent, followed by 2 coats of Duraseal polyurethane. After 4 years and dog traffic, it looks and wears awesome.