Sanding IPE with Cupped Boards

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So, we just moved into a new house on the East Coast from the Left Coast. My wife came out early and found the house. Before I'd seen the house / deck in person, and before I knew anything about restoring and sealing a deck, I announced that I was going to restore and seal this deck. Now, I'm stuck. The deck is MUCH bigger than I'd anticipated and it's in pretty bad shape.

No one can tell me what the original finish was, but, from the pictures I've seen, there was clearly something on it five years ago when the deck was built.

So, I cleaned with Benjamin Moore Restore, Penafin and an OxyClean blend (each on different sections of the deck) and brightened with Benjamin Moore. I didn't notice much difference between the different cleaners. I've still got a fair amount of green and gray on the deck and some start and stop marks from the pressure washer.

The pressure washer is a little electric unit with a max 1900 psi. I never had the fan close enough to the wood or narrow enough that it didn't cover at least 4", so I wouldn't have thought it would leave marks, but it did. None of the marks are indentations in the wood, just darker spots. In facts, those start and stop marks look clean to me, whereas the rest of the deck does not.

I'm at the point now where I think I need to sand. I noticed that many if not most of the boards are cupped. I thought I'd even those out and make a nice, flat surface that would allow the stain to spread out more evenly. But, running a 6" ROS across the edges of two boards seems to result in over-sanding -- the very edges of the boards start to yellow before the ROS hits the interior of either. From what I've read, this will result in an uneven stain. It also means that I won't be able to use a floor-standing sander to make the project move along more quickly, doesn't it?

So, after all of that, my question is:

Should I forget about trying to even out the cupping? Or, should I take each board down to yellow? Or is there a third option? I can't tell from the sanding pictures on this forum what color I should be going for. Ipe seems to have a number of colors. I start with a silvery-gray board, hand sand down to reddish-brown board and ROS down to almost a bright yellow. I've decided to lightly hand sand a small area of each board with 60 grit to see what color that particular board is in that particular area and then try to stop when I get to that color with the ROS. This is a 1,600 sq/ft deck. There must be an easier faster way.

If I could hire a pro at this point, I'd be glad to do so. But, given that I've started and invested so much time in it already, I feel like I need to finish it and finish it in a way that will make me happy each time I step out onto it.

Thanks for any feedback.

Brad

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Deck before I started.

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Start and stop marks.

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Sanded boards with Festool RO90 for color matching (color shows up differently on different computers, but maybe people can use the Festool blue as a reference color).

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Part sanded, part not sanded.

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Close-up of the cupping. It's easier to see it in person -- it doesn't show up quite as well in the photo. Running the sander over these uneven surfaces seems to be causing some over sanding in the middle of the boards while the middle of the sander isn't in contact with anything.

[RPetry 564]

Start and stop marks.

Brad,

Your ipe' was not cleaned or possibly stripped correctly. That picture in your post tells a tale. A 5 yr. old stain finish on ipe' should be history, so I would guess that a sodium percarbonate based wood cleaner applied, and medium pressure with a washer would do wonders. Follow up with a 6 oz./gal. oxalic brightener and rinse well.

Don't worry about stop/start PW marks if you are going to stain. Try a small amount of stain on a "firred" or "beat up" section of ipe'. If the finish looks bad, get a set of knee pads and sand with a random orbital at 60 grit, but easy, you do not have to get down to bare ipe'. Good luck in doing that and buy stock in the sandpaper company.

Your ipe' should come out looking similar to this before staining.

[bigchaz 157]

I'll second what Rick has said, with a good cleaning you shouldn't need to sand to remove the gray color. If you clean again you can try scrubbing the surface with a stiff bristle brush before using the power washer to rinse.

Cupping is a hard one, Ipe doesn't sand easily so someone else will have to chime in as to whether the cupping can be removed with larger scale sander.

Nice Festool by the way, those things last forever and ever and ever

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Thanks for the responses.

I tried a few different cleaning solutions that were readily available (i.e., things I could find at local stores), including OxyClean, which, as I understand it, is sodium percarbonate. I mixed 1 1/2 cups of OxyClean powder with 2 gallons of water, spread it on with a mop, lightly brushed it in with a broom, let it stand for about 15 minutes, worked it hard with the same stiff-bristled broom and then rinsed it off with a garden hose. I immediately applied Benjamin Moore Brighten (which contains oxalic acid), spread that around with the broom, let it stand 15 minutes, worked at it with the broom and then rinsed it off. That section of the deck isn't clean, either. I tried multiple cleanings and brightenings with the Benjamin Moore products on other sections of the deck with about the same results. I guess it wouldn't hurt to try the OxyClean again on that section. It would beat sanding.

Initially, I was thinking of using Cabot Flame Mahogany. I like the initial look, but I wonder if the build-up over years of application would start to look too dark and a little weird. After reading more in these forums and seeing a nice-looking deck, I'm starting to lean towards Ready Seal in Brown Sugar. It seems to have a rich color with a slight reddish hint to it, seems to go on easy and may last a little longer than the Cabot. Would the RS BS show the start and stop marks?

Thanks again.

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As for the Festool, I have to admit I have a bit of a problem. I'm a Festool addict. I don't have as much time for woodworking as I'd like, but I like building loudspeakers. After having "an incident" with a table saw in the past, when I saw some high-end finish carpenters using some Festools on a job site with an MFT/3, I was sold. There are still ways to hurt yourself with the Festool system, but you kind of have to work at it. Used properly, they're extremely precise and fast to setup. And, I really admire the engineering put into each of these tools. They're definitely not inexpensive, but working with them is so enjoyable it's worth it.

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As I mentioned in the first post, the start and stop marks look clean to me -- there's no gray in those spots and the wood doesn't look damaged. Is it possible that I need to use the pressure washer and a little more pressure than what I have been using? If I'm not scoring the wood and if the start and stop marks where a little more pressure was applied do look clean, that would seem to indicate a little more pressure is required, no? Maybe I try the OxyClean solution, let it stand, scrub it in after 20-30 minutes, then rinse with the power washer. That's the only combination I haven't tried. I'll be careful not to score the wood. The worst thing that can happen is that I have to sand out of a few marks, which is pretty much where I'm at now, anyway...

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Correction on the stain. It's Wood Tux that's available in Brown Sugar. Ready Seal would be Medium Red.

[Doug Black 18]

As I mentioned in the first post, the start and stop marks look clean to me -- there's no gray in those spots and the wood doesn't look damaged. Is it possible that I need to use the pressure washer and a little more pressure than what I have been using? If I'm not scoring the wood and if the start and stop marks where a little more pressure was applied do look clean, that would seem to indicate a little more pressure is required, no? Maybe I try the OxyClean solution, let it stand, scrub it in after 20-30 minutes, then rinse with the power washer. That's the only combination I haven't tried. I'll be careful not to score the wood. The worst thing that can happen is that I have to sand out of a few marks, which is pretty much where I'm at now, anyway...

Yes, you see how it works. For instance, if it would me I could treat it and then hit it with my surface cleaner and be be done in 2 hours max, probably 1. But you could do the same thing thing over a longer time maybe if you had a better pressure washer. Yours is just too puny; but you did far better than a lot of people have done with it. So it you have a 3500 psi 4 gpm pressure washer (which you might be able to rent) you could clean it up with a yellow tip using correct form and distance...which was basically impossible for you with that tiny pressure washer. As far as cupped boards...just spray slow and go back over your back rolling to watch for any pooling. Also the time for tightening decks up is after power washing when they are wet and more pliant.