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Old 06-16-2020, 07:33 AM   #1
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Default White film after pressure washing

After I wash the house I'm noticing a white film is left behind. Am I doing something wrong?

I wet the house down. I spray on a bleach solution, 1 gallon 10% bleach, 4 gallons water, 1 cup eLemonator, 1 cup cling on. I leave that on for 10 to 15 minutes. Rinse it off. Spray on wood brightener, (1 cup brightener to 4 gallons of water). Leave that on for 10 to 15 minutes. Then rinse thoroughly.

I'm staining the house with an Aborcoat solid stain and as of now it covers it with no issue. However if I was hired to just wash the house I would be embarrassed if i left it like that.

Too strong bleach solution, not enough rinsing, skip the brightener if it's just a wash, or ???

Thanks in advance
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Old 06-16-2020, 03:34 PM   #2
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Default White Film on Wood After Pressure Washing

Tough to say for sure without seeing a before pic of the same location, but more than likely what you're seeing is just dead wood cells/fibers that haven't been completely removed. If it were going a semi-trans, you'd definitely wanna remove all of it before proceeding with application, since it'd show through the semi-trans stain to some degree. Even though you'll be covering the look of the wood up with a solid stain, brightening with acid after rinsing your mix off is never a bad idea on homes to be stained, no matter which stain you use. Brightening restores the pH of the wood to neutral, making it fit for stain, and it also helps minimize the amount of fuzzies that happen sometimes when we apply sodium hypochlorite, sodium hydroxide, or sodium percarbonate to wood.

If the white spots appear fuzzy, then you know you've either used too strong of mix or you let the mix dry before rinsing. Judging by your ratios, if you downstreamed that mix, you'd be fine, since it'd be diluted even more by a ratio of approx 10:1, (the ratio at which most downstream injectors pull). However, if you applied your mix directly at those ratios, (like via pump-up sprayer), it'd be too strong, and would most assuredly be the reason for seeing fuzzies afterwards. Question is, how did you apply the mix?

As far as how to prevent that, again, tough to say without knowing if what we see is just remnants of oxidized dead wood fibers or if it's fuzzies. Either way, making sure to keep your mix wet between the time you apply and and the time you rinse it off is key. You can back off from the surface another 10' and just mist everything with water after you apply your mix in order to keep it wet, until you're ready to rinse it off. During the rinsing process, you've gotta be extremely thorough in order to remove as much of the fuzzies as possible. Sometimes fuzzies are inevitable though, and in cases where you'll be applying a semi-trans stain and fuzzies need to be removed, the easiest way is buffing them out via Osborn Brushes, like these:

https://www.loghelp.com/products/osb...ng-brushes.asp
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Old 06-16-2020, 06:09 PM   #3
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My guess is that you applied the wood brightener before the wood was thoroughly dry??

Although the following might not be 100% accurate, the oxalic acid in the wood brightener could have reacted with the residual sodium hypochlorite forming a stubborn white salt aka sodium oxalate. Although sodium oxalate is water soluble, it’s pretty difficult to re-dissolve/remove when dry, and also becomes embedded in the wood.

Edit: if it is an oxalate salt, a wet steam/hot water pressure/power washer might remove it.

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Old 06-16-2020, 08:57 PM   #4
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Sodium hypochlorite bleach becomes inert very quickly and doesnít need to be neutralized, the decomposition byproducts being sodium chloride and water...so I think..

Just to illustrate, below are photos of a piece of gypsum board which was wet with a 6% solution of sodium hypochlorite, not rinsed, and allowed to air-dry for 2 hours. When dry, I placed a few drops of deionized water on it and set a piece of litmus paper in it, the pH being 7 or neutral. I didnít want to use wood because most wood species are pretty acidic, and the resulting pH would be <7.

???
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Old 06-17-2020, 01:19 AM   #5
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Really why the need for a wood brightner?? That is only for raw wood. Your existing finish is clearly solid, so no need for that. And honestly your bleach solution sounds like a mix for downstreaming not for hand application, at least that is what I am inferring.
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Old 06-17-2020, 08:15 AM   #6
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Thank you all for your answers. I tried downstreaming with a bleach mix twice the strength. 2 gallons of 10% bleach, 3 gallons of water, 1 cup elemonator, 1 cup cling on. But it wasn't killing or bleacjhing out the algae or mold. It was still visible after the power wash. So I cut back to the mix I posted 1 gallon bleach to 4 gallons water and sprayed it on with my my4sons power sprayer (It's a kick ass sprayer). On the next portion of the house I'll cut that back to 1/2 gallon bleach and 4 gallons water. The temperature that I was working in was mild only 70 degrees and the house never fully dried between applications and rinsing. However I will keep a closer eye on keeping the structure consistently wet. There are bare spots on the house were there is exposed bare wood,but not the entire house. Regardless I wanted to make the whole house right so a sprayed it with wood brightener. It is what I was told, in this forum to do to ensure a proper structure to paint if i used bleach (or oxyclean) to kill the algae and mold. I don't mind taking the time and a little cost to do it and it appears it doesn't hurt and could help, correct? Maybe a bit of overkill by some comments. I want to do things right and thorough. Not looking to skip steps. However by Redux's experiment is it necessary?
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