Caustic and wood cleaning

Richard Fleming

New member
I have heard alot about cleaning wood with caustic. What is a good caustic mixture to use? I assume the ones using caustic are mixing their own solutions to clean with. Any help or advice greatly appreciated.
 

Doug Dahlke

New member
Most people are probably using a sodium hydroxide type cleaner. Check with vendors on the boards for products they sell. There are other products that can be used with wood that has not been stained previously and just needs to be cleaned.
 

Big Mike

Member
I have heard alot about cleaning wood with caustic. What is a good caustic mixture to use?

Caustic is used for stripping oil based stains from wood, not cleaning. Caustic MUST be neutralized with an acidic solution (oxalic acid or equivalent) or the wood will be extremely dark (tannin bleed), and new stain will fail prematurely. We do formulate our own mixture of wood stripper.

For simple cleaning we like a mild bleach/water/dawn mixture, followed by a low pressure rinse.
 

DynamicDetails

New member
I used Bleach and ammonyx Lo but it is a grayed old dark fence. it did not do much. I want dramatic results! I mixed 5gal bleach to a 55gal drum and 1/2 cup ammonyx Lo.

*maybe it was to weak?

Now I'm thinking if I put 1 cup of caustic and some surfactant in a 2gal pump up
sprayer let sit for 15min. Than come back and use ox to neutralize. just don't know how much to mix for the OX to neutralize.

I think 6-8oz would work per gal for the ox?
 

Chesapeake

New member
Use 4-8oz per gallon if you're applying with a pump up or dedicated chem pump. Use around 8-16oz per gallon when downstreaming. That goes for the sodium hydroxide and the oxalic.
 

Big Mike

Member
*maybe it was to weak?

Yes too weak. We usually downstream 12.5% & dawn for basic cleaning. I'm not sure what the exact ratio is when it hits the wood, but it's got a little bite to it. we use Allison injectors that draw at 20%.
 

rmhinkle

New member
What would the correct method be? I'm assuming the majority of your grime is on top of the decks stain/sealer? Or does the grime usually penetrate the sealer/stain?
So would you clean first, strip the sealer/stain, neutralize, rinse.... wait 48 hours and then seal?
Or would you strip first, neutralize, wash, rinse?
Or strip, wash, rinse, neutralize...?
 

B.A.

New member
are we talking about cleaning wood or stripping? I use a basic house wash for cleaning, and varying degrees of sodium hydroxide for stripping.
 

rmhinkle

New member
I'm talking about complete deck renewal. From strip to seal. Does the stripper get the deck clean alone? I thought even after it was stripped it would need to be cleaned.
 

John Orr

Member
After the application of the stripper, a low-pressure wash is needed, followed by the neutralizer. As for when to stain/seal, it depends on the weather, but 48 hrs is about right for my area of VA. Fences can usually be done in 24 hrs as they dry much faster.

Cleaning a deck (speaking about pt pine) usually involves emulsifying the top layer of dirt and the killing of mold/mildew/algae. Using either bleach/chlorine (diluted, of course) or a sodium hydroxide stripper allows for the use of low, or at least lower, pressure to clean.

A 20 year old deck that has never been maintained will have crusted-on green gunk (a technical term) that will likely require the use of bleach/chlorine. Dwell time is important, regardless of how or what you are cleaning and this knowledge will come with experience. I will say that when the label says to keep the stripper wet, a light misting of water is all that's needed - you don't have to keep reapplying stripper. If the stripper dries, simply misting will re-activate it.

Regardless of how you clean, neutralizing is a must. How strong mix of oxalic? The best way to tell is that when applied at the proper rate, the wood will almost immediately lighten in color. Neutralizing must be done to stop the chemical reaction of the stripper/cleaner. If not done, the wood will tend to "fuzz". A too strong mix of sodium hydroxide will also tend to "fuzz" the wood.

Again, dwell time, strength of chem, pressure used and proper neutralizing as well as washing technique (its all in the wrist action!) all affect the outcome, so it's best to practice - on your on deck if possible.

I have helped local pwers with washing/stripping decks and fences. I'll extend that offer here as well. My phone is always on.

* In all fairness, I don't consider myself a "woody". I wash houses and many of my customers have decks - mostly PT Pine - and want to keep them looking nice. In 10 years, I have used a sander a few times, replaced a few boards and pounded more than a few nails but I don't consider myself a deck restoration expert...though my customers are always satisfied with my work and refer me constantly. I have many decks that I have been maintaining for years, so I know how to do what I do and don't mind sharing.
 

rmhinkle

New member
After the application of the stripper, a low-pressure wash is needed, followed by the neutralizer. As for when to stain/seal, it depends on the weather, but 48 hrs is about right for my area of VA. Fences can usually be done in 24 hrs as they dry much faster.

Cleaning a deck (speaking about pt pine) usually involves emulsifying the top layer of dirt and the killing of mold/mildew/algae. Using either bleach/chlorine (diluted, of course) or a sodium hydroxide stripper allows for the use of low, or at least lower, pressure to clean.

A 20 year old deck that has never been maintained will have crusted-on green gunk (a technical term) that will likely require the use of bleach/chlorine. Dwell time is important, regardless of how or what you are cleaning and this knowledge will come with experience. I will say that when the label says to keep the stripper wet, a light misting of water is all that's needed - you don't have to keep reapplying stripper. If the stripper dries, simply misting will re-activate it.

Regardless of how you clean, neutralizing is a must. How strong mix of oxalic? The best way to tell is that when applied at the proper rate, the wood will almost immediately lighten in color. Neutralizing must be done to stop the chemical reaction of the stripper/cleaner. If not done, the wood will tend to "fuzz". A too strong mix of sodium hydroxide will also tend to "fuzz" the wood.

Again, dwell time, strength of chem, pressure used and proper neutralizing as well as washing technique (its all in the wrist action!) all affect the outcome, so it's best to practice - on your on deck if possible.

I have helped local pwers with washing/stripping decks and fences. I'll extend that offer here as well. My phone is always on.

* In all fairness, I don't consider myself a "woody". I wash houses and many of my customers have decks - mostly PT Pine - and want to keep them looking nice. In 10 years, I have used a sander a few times, replaced a few boards and pounded more than a few nails but I don't consider myself a deck restoration expert...though my customers are always satisfied with my work and refer me constantly. I have many decks that I have been maintaining for years, so I know how to do what I do and don't mind sharing.

Great advice, thanks a lot. That was a very thorough answer and it is much appreciated. You really cleared everything up for me. Now I'm ready to do some test's on dwell times and concentrations and see what works well. Thanks again
 
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