Thoughts on Oxalic and Ipe

[plainpainter 217]

Russell among others sells a milder acid that contains citric acids - it's selling points being that it doesn't harshly bleach the wood like oxalic and it improves your spread rate - while I am inclined to agree, I had another thought swimming in my head of mine - the one that Ipe is a hard wood to get anything to stick too. Then in my head I did one of those 'one plus one is two' moments.

If oxalic 'opens' up the wood much more severely than a citric blend - wouldn't it make more sense to use that on a wood like Ipe - to clean out the 'pores' and get a better penetration of your stain, especially woodtux.

And I am not really interested in people talking about the 'integrity' of the wood - and how we are here to preserve it. I am talking about the top few mils. I mean come one - not one of us hesitates to sand down a few mils when confronted by a nasty restoration job. Can't we just all agree the top few mils is fair game when it comes to getting stain to adhere? I mean in an inch you got 1,000 mils to play with before you run out. Floor sanders wack out your hardwood floors after the 3rd sanding. What's the big deal about getting that top few mils cleaned out for better penetration of stain. A penetration that once in place will stop or put a great damper on wood decay and allow longevity of your wood.

[Beth n Rod 1,279]

You don't want to remove the extractives any more than you have to. I don't think it will lengthen the life of any product significantly to do so. If you put so much acid on an ipe deck that you run a red river off of it, you just went way too far in my opinion. Less is better for the wood, not more.

Beth

[plainpainter 217]

But Beth - the problems with adherence with stains and woods like Ipe - is the denseness of the extractives in the wood. If you free up some space to allow stain to penetrate - then you increased the stains effectiveness in it's ability to stick. I ain't talking running a red river from a deck - but perhaps well timed dwelling of oxalic acid - where as woods like cedar or fir, oxalic may be too harsh - but for ipe it would be more appropriate. Heck someone should do this as an experiment - half an ipe deck neutralised with a citric acid and the other half with oxalic - and see if there is an improvement in durability.

[RPetry 564]

Daniel,

Your idea seems plausible enough. I'm not sure of any facts but 2 comments.

Is oxalic truly any different than straight citric acid when dealing with wood and its ability to absorb a stain? I've always used pure citric acid due to poisonous characteristics of oxalic and the "green" marketing feature of citric. Never had a problem with any wood soaking up Ready Seal.

Second, you can nearly hit ipe' with a friggin' flamethrower followed by a sledgehammer to do any damage to the wood. Might discolor it a bit, but the wood has the fire rating of concrete.

[PressurePros 248]

Dan, I suggest this to my RAD customers and utilize this technique in the field.

[Beth n Rod 1,279]

I would rather suggest to an owner to let ipe age 6 months to a year before doing anything. This accomplishes the same thing as you are trying to do with the acid. It has worked for us on woods such as ipe and teak.

Beth

[plainpainter 217]

Ken - I thought your Rad product was a citric blend, please explain what you mean.

Rick - I am only bringing this up, because some people are selling citric neutralizing because you get better spread rates - this I assume because they are implying you aren't removing as much extractives and leaving less room for stain. But I can't really comment from experience - as I am limited to only working with pressure treated decks with stains and on occasion fir decks with either solid latex stain or porch and floor enamels.

Beth - I am bringing this up, because supposedly from what I hear you can only expect 1 year durability even from Woodtux. If oxalic can free up some more room and possibly get 2 years on Ipe - this is something to be explored. Don't you think? Have you done decks side by side with different acids and seen the outcomes so drastic as to only choose citric or citric blend over oxalic? I mean why would I spend lots of money for citric based acids if I can get oxalic cheap. Or if I can get better durability by 'burning' the ipe a little more - and heck what Rick says has lots of truth anyways - in that you couldn't hurt Ipe that much even if you tried, so what's the harm by using a stonger acid that is far cheaper, may give better results on harder woods? I can tend to agree that maybe it poses more of a work hazard to the person applying it - that may be a real concern and reason why to go citric instead.

[Beth n Rod 1,279]

We have been caring for ipe for years. You won't get two years on it. You simply can't change the physical characteristics of the wood enough to do so (in my silly little ipe loving girly girl opinion). Good luck with your tests.

One thing I have heard people talk about but have not done myself, is to seal the wood, then lightly sand it to etch the surface, then seal it again to give better adhesion. This is akin to what is done with furniture finishing. It makes some sense given the density of the wood, but again, have not tried it.

Beth

[PressurePros 248]

Dan, take a wild guess what is in the blend? ;-) (I don't want to discuss that here though)

[RPetry 564]

Daniel,

because some people are selling citric neutralizing because you get better spread rates

Had to read this twice to understand what I think you are stating. Are you saying that manu's or others are claiming that citric acid does not "open" the wood as much as oxalic, so you will get more sq. ft. coverage per gallon of stain?

Thought I had been around a while but this is the first time I've heard that. Anyone have any testing data or hard evidence on this?

[plainpainter 217]

Rick - that's exactly what I am saying. Understand - I have no real world experience on this - I don't know first hand. But re-read the posts - Russell has stated this in writing at least half a dozen times in the last few weeks, along with Beth and Rod intimating this as well. Again I have no proof of this - just repeating what I have read on these boards. Oxalic in the system is no good to our kidneys - but that isn't the selling point for citric acid neutralizing on these boards.

[RPetry 564]

Daniel,

I must have selective memory lapses, tossing aside stuff I read that I consider, to be nice, "questionable". If ESI or other distributors or manufacturers can produce some studies or factual evidence of such claims I would be very interested.

I think I know only three primary differences between citric and oxalic acids on exterior wood. Citric is benign while oxalic has health issues. Citric is mostly ineffective on removing "nail bleed" while oxalic will temporarily remove a lot. Citric is ~ twice the cost of oxalic.

Both acids are cheap. Citric use may be less hazardous to the immediate environment.

If there are other factors when using on exterior wood, I'm all ears.

[Proclean 14]

OK. I'll help out.

Tell me EXACTLY what you want done. New Ipe or old (restore). Explain what procedure to do with exact mix ratio's.

I'll post before & after pics and we'll follow the demo.

[plainpainter 217]

Well for starters - I think this mostly has to do with new Ipe decks - mostly because I think Ipe is relatively new on the market place - so most of it is new. Perhaps older decks with lots of wear won't have these problems. And then what products are you familiar with using, Paul? Perhaps use Russel's citric product at recommended dilution and Bob's oxalic product as well - and perhaps both products again at half dose. So four sections for testing?

[RPetry 564]

Daniel asked:

Heck someone should do this as an experiment - half an ipe deck neutralised with a citric acid and the other half with oxalic - and see if there is an improvement in durability.

I'll give it a go. I have a small ipe' deck that I stripped about this time last year and have let it just weather back to a silver patina. As the weather here in NJ is not looking good through the weekend for customer work, was going to percarb and neutralize it today or tomorrow. The ipe' is 4 years old.

I've got ~ 50 lbs. of pure citric acid in stock but no oxalic. I'll see if I can buy some locally today. My citric is always mixed at 6 oz. / gal. I'll mix the oxalic in the same proportion.

Stain ( with the weather, it may be a while before application ) will be Ready Seal, probably medium red.

[plainpainter 217]

That sounds great Rick - take lots of before and after photos - and also see if the wood looks lighter after being neutralised with the oxalic vs. citric. I am really interested how things will turn out. I wish I had an ipe deck to care for.

[RPetry 564]

Daniel says:

I wish I had an ipe deck to care for.

You know not what you wish for. Ipe' is a pain to take care of every year!

Called my local Ace Hardware this AM. They have "Wood Bleach" which I assume is oxalic. Of course I'll check it out before purchase and use. I'll post some before pictures on my web server in a little while and post here with links.

[RPetry 564]

Daniel or others interested,

Linked are four "before cleaning" pics of my townhouse ipe' deck, being used for oxalic / citric test.

http://windsorwoodcare.com/images/bboard_photos/dscf0009.jpg

http://windsorwoodcare.com/images/bboard_photos/dscf0010.jpg

Two overall views. Top rail, fascia, stair 2x4's are ipe'. Balustrade, stair stringers, lattice, posts, and rr ties are 18 yr. old PT.

http://windsorwoodcare.com/images/bboard_photos/dscf0011.jpg

Close up of 5/4 x 6 ipe' deck boards. Not obvious but old Cabot Austrailian Timber oil still present on edges after a pretty hot strip last year.

http://windsorwoodcare.com/images/bboard_photos/dscf0013.jpg

Side view of ipe' decking with old Aussie oil still discoloring the ipe' beneath an overhang. It is my belief that the tung oil in the product makes it difficult to remove. Am not going to bother with another strip, one NaOH hit is enough. RS will hide any discoloring left after cleaning/brightening I hope!

Once cleaned and brightened with both acids and dried, I'll link up additional pics.

[James 624]

Using two different acids on the same deck will produce a color variation .I find letting the wood sit produces the best results for more depth of product.

[RPetry 564]

Jim,

I'm not following you. Just cleaned the ipe' floor with percarb and was planning on using 6 oz. of citric/gal. on one half and 6 oz. of oxalic/gal. on the other half to neutralize/brighten.

This is a test for Daniel's ideas. Should we be doing something different?

[plainpainter 217]

Jim - correct me if I am wrong - but if Rick said previously that the Readyseal will hide any differences left by some residual ATO - isn't the product more than capable of covering up any differences between two sides neutralized with different acids?

[plainpainter 217]

Not to mention, Jim, if you think it's better to let a deck 'sit'. Aren't you implying you are sealing over greyed wood? What do you do to remove grey wood fibers and neutralise the wood?

[Beth n Rod 1,279]

I find letting the wood sit produces the best results for more depth of product.

I agree!

Beth

[plainpainter 217]

Beth - I am confused - since you agreed with Jim - you understood what he meant, what did he mean by - its better to let the wood sit?

[Beth n Rod 1,279]

Same thing I was referring to earlier on I suspect....when you have a new ipe deck, it is better to let it sit and age, let it naturally grey and get that silver patina prior to cleaning and sealing it for the first time. You get better product penetration due to the wood being drier. We tend to let ipe age 6 months to a year (we suggest it - not all homeowners listen to the advice however) before the initial cleaning and sealing. We would suggest this on teak furniture as well. However we do not suggest this for PT, cedar or redwood.

Beth

[plainpainter 217]

Ok - I understand now - I do the same thing with pressure treated - but that's for first time deck jobs. Once a deck has gone through several 'conditionings' - it is no longer a new deck, but a deck being perpetually restored and maintained. I am more interested in a deck that has already gone through several cycles - not to mention, once you remove the greyed out wood fibers from either percarbs, bleach, etc. You are now down to a 'newer' level of the wood. Kind of like if you sanded a hardwood floor of it's topmost layer of wood - you are back to a fresher piece of wood. So at that point - what can be done to improve stain durability?

Sure I can agree that oxalic may 'burn' more of the sugars out of the wood.

But that may be what is needed for better life of deck stains. What's the difference if you let ipe say age naturally? Aren't you allowing nature to 'naturally' weather out the sugars and tannins from the top few mils of the wood anyways? But now this 'naturally' aged wood has 'opened' up. But this wood that is now 'opened' up is now oxidized and greyed out wood fibers incapable of holding a deck stain. So now you have to remove that layer of 'dead' greyed wood - and you are back to a layer of fresher wood stocked with natural tannins and sugars. So you are back to square one.

Why not 'bleach' out the sugars a little from the top few mils with additional strength acid - and then apply a stain. Because at least now - the wood has 'opened' up it's pores - and the wood is still intact, undamaged by a year of weather and UV degradation - ready to accept more stain and form a stronger mechanical bond that is anchored deeper into the wood.

Anyways - theories aside - science is crap unless someone goes to the 'lab' and tests the theory out. So I am looking forward to Rick's outcomes.