Nail Stains in Redwood Siding

[mkochsch 14]

I'm in the middle of cleaning and prepping a 3200 sq ft. home which is clad in 8" Redwood channel siding. The home was built around 1966 and is located in Winnipeg, Canada where the temperature ranges from -40 to +40C. The original build used a 2" finishing type of nail to hold the siding on. The siding may have been unfinished for a few years before the owners decided slap a coat of solid stain on it, (probably to cover the nail bleeds). Many of the nails have popped or the board pulls through. The nails don't appear to have rusted so I'm thinking they are probably SS or Galvanized. Is there anyway to tell the composition of the nail? Grinder wheel perhaps. What's the best way to get rid of the bleed marks? We really like the look of the original Redwood and are considering going with a semi-transparent finish. I've been looking at Cabot and Flood for products on the recommendation of a neighbour who's a pro' in the business. Thanks for any advice and help.

Michael

[seymore 90]

Oxalic acid or citric acid is your best bet to removing nail stains on redwood or any wood

[mkochsch 14]

So would a standard Oxalic based deck cleaner work or should I mix a concentrated batch (I'm also a bee keeper and have Oxalic crystals on hand). Do I apply and then wait until the stain goes away and then remove the acid with water? Thx.

Michael

[MMI Enterprises 289]

Thought the citric wasn't tried and true on this compared to oxalic..

Michael, it's up in the air sorta on whether you need to rinse the oxalic off but the consensus is that if your top coating it with a film former type coating then you should rinse after you've achieved the look your after.

[mkochsch 14]

I'm beginning to think the nail stains are there for good and I'm going to have to live with them. Using a darker semi might reduce the visual impact or using a solid to cover them completely. A very sad thing to do to redwood. Also I think because of the choice of nail the builders used the staining will just keep coming back. Short of pulling all the nail out and starting again I think my options are becoming limited. Hmm.

~m

[MMI Enterprises 289]

I'm beginning to think the nail stains are there for good and I'm going to have to live with them. Using a darker semi might reduce the visual impact or using a solid to cover them completely. A very sad thing to do to redwood. Also I think because of the choice of nail the builders used the staining will just keep coming back. Short of pulling all the nail out and starting again I think my options are becoming limited. Hmm.

~m

Is that to say you tried the oxalic and it did not work?

[mkochsch 14]

The stains are bad. I'm beginning to wonder if these were common bright finishing nails or just poor quality galvanized nails that gave out too soon. The oxalic brighten the wood up a bit but not much change in the stains.

Another question. I had some areas where pressure washing wasn't able to remove the solid colour stain. On those parts I used a Sodium Hydroxide cleaner (Thompson's) and after the initial stain was washed off there continued to be a "darker" substance washing out. Are these just tannins coming out of the Redwood? I washed until I thought I'd gotten most of the stripper off. I'm letting the wall sit overnight and then I'll hit it was the Oxalic to brighten it tomorrow.

Also, if I don't have an Osborn Brush (part no. 32132 ?) where do I find "defurring" pads? Can I just use a pole sander and 80 grit sheets to knock down the fuzzies?

Thx. This site is great!

~m

[MMI Enterprises 289]

Your using retail cleaners available at box stores with oxalic in them aren't you??

Normal industrially avaliable oxalic mix ratio for neutralizing is about 6 oz. to the gal. if I not mistaken. In your case if you want them nail bleeds gone I would say make it double that and test an area or keep strengthening it all the way up until the water will hold no more. Do it in a spray bottle first to figure the ratio you need then translate it to your pump sprayer or whatever your using to apply. Do these things with utmost safety and wear protection..Oxalic is not a consumer product and can hurt you or others around you!

When the areas with darker stuff bleeding out is dry do a splash test to see if it absorbs like the other areas. Could be left over who knows what or could be tannins. This wood is old 'heartwood' and so should have plenty of resins left in it that the stripper you used is attacking and leaching out. When you neutralized the alkaline of the stripper you ended that deal so as long as the color evens after a good dry out I would say leave it alone. You might need to use a redwood only type stain if you wish the wood to not darken on you.

Maybe some seasoned pro will jump in here and advise on how you might procede....

"I've been looking at Cabot and Flood for products on the recommendation of a neighbour who's a pro' in the business. "

What this guy say?

[Beth n Rod 1,279]

Post pics please. They help. They really help.

Beth

[mkochsch 14]

I may have been too hasty in saying the Oxalic wasn't working. This morning when I went out to shoot these pictures my test patch seemed to have cleared much more. So maybe I just need to soak a little more.

What should I do about the nails. Pulling and replacing would be ideal but not practical. How effective will a semi-transparent be again further bleeding?

Thx everybody.

~m

The first picture is a general exterior of the home.

The second picture shows a typical nail bleed. Some are worse than this example.

The Third photo shows the effect of using the Oxalic Acid based stripper. (REZ deck cleaner.)

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[mkochsch 14]

A couple more exteriors of the house and a close up of wood that has fur on it from pressure washing. What I found interesting was that wood that was stripped using sodium hydroxide and lightly rinsed also had fur but it was much finer and softer than the fur left behind from straight stripping with the pressure washer. I'm planning on judiciously sanding some of the highly visible area at the front of house during prep. So far it's taken me about a week to get half way around the house. My local Osborn Brush dealer says it'll take three week to get that brush if I really want it. Are there other brands of this cup brush that could work? I'm thinking just a pole sander and 80 grit as I already mentioned. thx.

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[mkochsch 14]

...and a couple of shots showing the colour and condition of the wood last week prior to stripping.

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[MMI Enterprises 289]

Michael,

The hydroxide and too high pressure is not going to do you any favors on them higher areas especially.. If this was a deck job I believe plenty would not have problem with removing the furing as it is readily accesable. If you can at all get by with lesser strength to remove the old stain then that would be a good thing. The last few pics show up to me as a possable job for a sodium percarbonate mix as it don't look like it's much of a solid. It'll do less damage if you can get by with it...first pic looks a bit more solid type stain at a distance but so...... I would test out the percarb (wood bleach). There is a mix recipe I have up in the 'apple sauce' thread where I substituted percarb for bleach. It really sticks and foams well on wood. I mean trst it out if you like in a small quantity first to see it it'll work. That amount of defuring on verticle walls looks like a PITA. If I had to defure that much verticle I would hook like a 10-13" 3m HiPro scrub pad meant for floor care onto a hand polisher of whatever type I could to get mechanics working for me. A green or brown pad will work too. Ozborn a bit small.

[mkochsch 14]

Could someone give me the names of some brands which make a Sodium Percarbonate stripper. So far I've only see sod. hydroxide strippers and sodium hypochlorate and Oxalic "brighteners" at the BORG.

thx.

~m

[bjp_ne_elec 14]

mkochsch - have you moved out on this project? I'd be very interested in how you proceeded, and then would love to see some pics. I just looked at a house that was sided with redwood, and some of the wood has those "grooves" and fuzz - and I've never dealt with on that was in this bad a shape. It looks to me that there's a whole lot of sanding - so I'm interested if you had to do the same, or your worked it in another way.

Thanks