Chlorine Bleach vs Oxygen Bleach vs Oxalic Acid

[Guest HuskerFan]

I'd like to hear what the Pros think about this subject with the added info I've provided below. I know there has been alot of controversary on the subject of using bleaches, but while I was researching a cheaper method to cleaning my wood I ran across this interesting info. It talks about the different types of Bleaches and may answer some questions this forum has had. I've provided the link where you can view the full article. I also provided a link which compares various Oxygen Bleach products. Interesting stuff.

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Chlorine-Based Bleaches

Common types of chlorine bleach used in deck cleaning products are sodium hypochlorite, calcium hypochlorite and dichloroisocyanurate. The first two are typically used in laundry detergents while the last is a swimming pool additive. These chemicals are effective against mildew but do little to remove dirt or other surface deposits (which is why bleach alone does not get clothes clean). When used on wood decks, chlorine-based bleached products can do more harm than good. They can result in the wood's having a whitish unnatural tone due to the bleaching of natural components or a fuzzing of the wood's surface due to the loosening of small fibers during the cleaning process. Moreover, if not rinsed properly, the chlorine salt residues can result in premature graying of wood from the action of sunlight.

As noted previously, household bleach and other products containing chlorine-based bleaches should not be mixed with

products containing ammonia.

Oxygen-Type Bleaches

Products in this category are usually based on disodium peroxydicarbonate, commonly known as sodium percarbonate, an ingredient present in some color safe fabric bleaches. Sodium percarbonate is a powder. When added to water it forms hydrogen peroxide--a common oxygen bleach--and sodium carbonate (soda ash). Hydrogen peroxide is commonly used as a disinfectant and a stripper of hair coloring. On wood it is effective in removing mildew stains and weathered gray residue from UV (sunlight) degradation. The sodium carbonate acts as a built-in detergent, removing dirt and other deposits. Thus, sodium percarbonate-based cleaners are effective in removing dirt, mildew and weathered gray residues. Once treated, the wood returns to its natural original appearance.

Oxalic-Based Products

Certain wood species such as cedar and redwood contain natural resins known as tannins. These are water soluble materials which are reddish brown in color. Water can extract the resins from within the wood and deposit them on the surface, leaving brown or black discolorations. Tannins can also react with iron present in fasteners or nails resulting in blue-black stains. Neither chlorine bleaches nor oxygen bleaches are effective against tannin stains or iron stains. Oxalic acid, on the other hand, solubilizes tannins and iron stains and renders them colorless. Thus, it is the material of choice for use on redwood or cedar. However, oxalic acid is not as effective against mildew. For this reason some homeowners and contractors will treat redwood and cedar with a sodium percarbonate or chlorine-based cleaner and follow it up with an oxalic acid-based product if tannin staining is apparent. Concentrating oxalic acid is toxic and should be handled and used with car.

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here's the link to the full web page:

http://www.historichomeworks.com/hhw/library/coatings/cleanersandrestorers.html

For those of you who do approve the use of such products, here is a link I found regarding the various Oxygen Bleach cleaners on the market. It's quite informative:

http://www.laundry-alternative.com/Oxygen_bleach_research.html

[Paul Kassander 26]

Excellent article.

[john@AEC 37]

Thanks for the info.

The science behind it is very interesting, and I'll have to do some local product/supplier research and testing. While I love the way that Sodium Hypochlorite works, I hate smelling of it and the other issues.

[Guest Danebob]

Good to see that. I was doing a little research on those bleaches as well. very informitive article.

[loamland 14]

I was also interested in the oxygen based products. I have tried them and they do work. Most work best when mixed using warm water and once mixed they have a limited life of about 6 hours. I have used them on asphalt roofs and also on vinyl siding. On really dirty surfaces they foam up like household hydrogen peroxide does. My results have been good. It's alot slower process on asphalt roofs but on siding it really works quick. The great thing is the products break down to hydrogen gas, oxygen and water. No chemical runoff at all. Great enviromental product.

[David O'Connell Jr. 14]

How long does the roof take? and are you scrubbing the roof to clean it?

[loamland 14]

The roofs we have used it own, we did not scrub. We sprayed the roofs off after about a 40 minute dwell time using about 200psi. These were not extremely bad roofs, but they did have a good bit of algae on them. Not sure how well it will work on a more severe problem but will be finding out soon. We were using a pure sodium percarbonate formula. Our mix was 3/4 cup/ gallon of water. Gave good results on the roofs we tried it on.

[David O'Connell Jr. 14]

40 minutes dwell, and how large was the house?

How long did the rinse take?

[Beth n Rod 1,279]

Each of them is known as a wood bleach but there is also Sodium Hydroxide and Hydrogen Peroxide that in addition to the others are classified as wood bleaches by the USDA Forestry Labs.

To elaborate more: Any chemical alone or in compound form that becomes a strong oxidizer is considered a bleaching agent.

Regardless, each has a function in the art of wood restoration and each requires experience in order to obtain the optimum results.

As far as one 'vs' the other, I feel this should not be the emphasis but instead related to as 'Which is right for the job'.

This is pertinent to the way these bleaches are used and to what they are effective on and in what conditions based upon their individual chemical scope of capability.

The article is a good one albeit the writing style looks very familiar but the point getting across to the reader is valid.

Rod!~

[James 625]

R od, I agree !!!!

[Phil H 14]

Hi everyone, first post here!

A few other plus factors for percarbonate are that it's an antifungal and antimicrobial - translate mold and mildew killer yet it does not harm plants in modest concentrations.. On roofs we spray an initial coating at about 2 to 4 ozs per gal after removing heavy growth with a mild 2 - 300lb wash. We either wash the rest of the property while it soaks or leave the property and go wash something else. A final rinse is ok but really not required as the chemical actually becomes inert after about 6 hours and leaves no discoloration. We're in New England so obliging rainstorms wash off the residual dead particles. Drier climates may need a standard garden hose rinsing after treatment. Beware of strong concentrations on paint. Vinyl siding mild solutions neutralize most mold problems. Super on decks but coat evenly and go do something else for an hour or so while it works but make sure it stays wet. Dry outs can create patchy appearance. Percarbonate - GREAT STUFF!!!

Phil H

ColorMasters

Power Washing Service

www.colormasters.org

[Beth n Rod 1,279]

Thanks Phil for the post.

From my personal experience, a percarbonate can also cause a whitish haze to form on glass if allowed to dry. Fortunately, the cause is the cure but thorough rinsing is needed to assure no residue is left behind.

.02

Rod!~

[WEW 14]

Mmmmm aaaa?????

[hydrtequniclychallanged 14]

intresting Tampa. All I know is when I was a kid we would run clorox through the pressure washer and go through 10 bottles and cover a house with it. As far as oxalic acid goes, I perfer it over hydrochloric when removing staines on yachts and boats. Its truely amaising how, If applied correctly can turn a hunk of yard trash boat into a gistening white gem. Just got to de oxadise and wax and your sitting pretty

[steve r 14]

Rinse Man Rinse And More Rinse

[PLD 14]

Any chemical alone or in compound form that becomes a strong oxidizer is considered a bleaching agent.

Not quite. Bleaches are generally strong oxidizers, but strong oxidizers are not neccessarily bleaches. For example, sulfuric acid and ammonium perchlorate are strong oxidizers, but neither is a bleach.

[Beth n Rod 1,279]

Bleach is a term we use to refer to the effect of whitening or any degree thereof. In the same process, the removal of ions contributing to color are the basis of the effect as I understand it. Oxidation happens at this level and involves the removal of ions but not necessarily those associated with color but an increase or decrease in the valence of the molecules when combined or replaced with hydrogen or chlorine atoms. (god, I can't believe I remember some of this stuff from H.S.)

Oxidation is a combination with oxygen which can also increase or decrease the valence of an ion. This can be seen as a change in color or elimination of color.

The effect is technically bleaching.

Sulfuric acid and ammonium perchlorate combination will also result in an explosion due to the rapid combination with oxygen. I have seen this in the explosions outside of Henderson NV. when a plant blew up knocking the town a few inches away...literally! Actually, there were 2 major explosions which registered 3-3.5 on the richter scale and I lived about 3-4 miles away. This was pepcon...

reviewjournal.com -- News: Pepcon Explosion Anniversary

http://www.reviewjournal.com/news/pepcon/misc.mov

Rocket Fuel Plant Explosion Investigation, accident Reconstruction

Scared the (*#&$(*#) out of me!

Rod!~

[PLD 14]

Sulfuric acid and ammonium perchlorate combination will also result in an explosion due to the rapid combination with oxygen. I have seen this in the explosions outside of Henderson NV. when a plant blew up knocking the town a few inches away...literally! Actually, there were 2 major explosions which registered 3-3.5 on the richter scale and I lived about 3-4 miles away. This was pepcon...

I must add that the pepcon explosion was a very rare set of circumstances that culminated in an explosion. As a rule, AP compounds are not explosive in nature. I personally have burned several hundred pounds of APCP under extreme temperatures and pressures. (My rockets)

FWIW, the space shuttle boosters are 90+% AP. If you will recall, when the Challenger main tank exploded, the attached boosters flew away still burning as expected. If a million pound hydrogen explosion at point blank range can't make a few million pounds of already burning AP explode, not much can.

[Beth n Rod 1,279]

That is really cool stuff Philip.

So does this mean literally you are a rocket scientist? Now I can say I have made ones acquaintance.

I flew some model rockets in my day but they used CO2 cannisters for propellant. Some used the (I forget what they are called) ignitable engines, but on a limited budget as a kid it was a short lived hobby. Balsa wood planes were more in the budget. :)

Very interesting though. Thanks for sharing.

Rod!~

btw, congrats on your getting publication in Extreme Rocketing Magazine.