Staining on Red Oak

I built a wagon using all Red Oak I finished my project with Boiled Linseed oil but when I put wagon outside, after first rain I got a lot of black staining. (zoom into tree to see)
I'm being told that the reason for this is the acid in the red oak reacts to water and BLO does NOT seal the wood, thus the staining.

Can I mix BLO with spar varnish (oil Based) and finish with that? I'm hoping the varnish would create a seal to stop the staining.
Reason I would like to still use BLO if possible is because of the way it brings out the colour in the wood.
Any suggestions, advise would be greatly appreciated.

JohnnyAttachment 494118

Can't help with the staining issue but the wagon looks fantastic:2tsup:

G'day Johnny

Use the BLO first to bring out the depth of colour in the wood. Allow it to fully dry under cover and then coat it with your spar varnish or polyurethane. As for the stain. The only stained bit I can see from the photo is on the singletree (cross bar) and on the falling tongue (draw bar). Probably the best you can do is to re-sand those areas to get rid of the staining but that might not work as the stain may be deep into the timber.

Think you'll find that the wood you have used will be tannin rich and could stain up from lots of things especially metal when it gets wet. You may be able to remove some of the staining with oxalic but you would need to remove the oil before using the acid.

Putting more oil on it won't help it will only make the stain more noticeable.

Personally I'd be inclined to just call it the first bit of patina/character/history.

I used to watch Wagon Train and all the cowboy movies and can't recall ever seeing a nice fresh new wagon only ones with lots and lots of patina / character.

By the way, for what it's worth..... Mixing BLO and spar varnish it basically the original formula for Danish Oil.

Hope this is of some help.

Cheers - Neil :U

Thanks for the help guys.
From what I'm hearing all around is the staining is caused by the acid in the wood. I have completely stripped the finish off using Activox and then sanding.
Spoke to a gentleman that has experience in this and he tells me to mix 1/3 BLO, 1/3 Spar Varnish (Marine), 1/3 Paint thinner. He says this will seal off the pores in the wood and keep it from staining.
I trust that will work. Will also apply another coat or 2 of Spar varnish after first coating of mixture.
I guess we learn by doing! Told my wife I will caulk this up as "Education Tax"
Johnny

What hardware did you use? Steel bolts, screws etc? - most likely a Yes

Does the staining appear around the hardware? or below it? - from the photo - Yes.

Are you near the sea? - Alberta = No.

As Neil mentioned above Red Oak is tannin rich, and the amount of reaction to steel will depend upon the pH of the rainfall in your area. Pure water has a pH of 7 (neutral) however due to atmospheric contaminants rainfall / rainwater can become acidic or salty. the contaminants may come from hundreds of kilometres away.

Search "wood ebonizing solution" - that will give you info on the "staining" process.

Unfortunately there is not much you can do now to limit the "ebonizing process." There are ways to impregnate the raw wood with epoxy resin which may limit the staining, the key word being may.

I would be more inclined to use a satin or mat finish polyurethane as this will give you a much longer term surface protection than spar varnish.

Do a search for spar varnish v polyurethane. I agree with Mobyturns about the metalwork and staining.

Quote:

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Originally Posted by Johnny W

From what I'm hearing all around is the staining is caused by the acid in the wood.

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It is tannic acid (commonly called tannin) in red oak the same stuff that's in tea. All oaks are tanin rich and that's what cause greying, and a number of other colours ranging from green and red through to black when the tanin reacts with all sorts of other things, metal, chemicals, water, wine and more. The blue/grey/black staining from metal is more common in oak that is not kiln dried as it is the moisture in the wood that allows the tannin to leach out and run.

There is a good article here -> All About Tannin in Wood | Wood Blog | English Woodlands Timber definitely well worth a look. There is also a lot of information in my book about using chemicals and mordants to dye tannin rich wood in my book "A Polishers Handbook".

Sorry about the blatant plug for the book, but just couldn't help myself. :B

Hope this is of more interest and a little more help.

Cheers - Neil :U

Did my first apprenticeship as a coach builder. Used a lot of oak. All timber to metal joints were daubed. In fact, all unglued timber joints were daubed also to help prevent rot. Iron and steel are very prone to staining timber, particularly high tannin species like oak. Stain penetration through end grain travels the furthest into the timber.
For unpainted vehicles we used a black, thick, non drying paint daub between iron and wood. Any other colour tended to stick out like the proverbial.
Nice job on the wagon . Now all you need is a couple of sturdy hoofers to pull it.