Spoke with the man again yesterday who mixes 1 1/2C oxalic to the gallon. He told me that his method gets 100% of the rust stains off of his concrete drive and sidewalk. So I pumped him a little for more information. His novel method of application is applying the oxalic with a long nap roller. No wandering sprays and a much thicker coat that he doesn’t need to brush in. He tells me he can cover a lot more ground in less time as well.
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I’m willing to test it… I thought about it today when I had to hit this with F9, but no rollers.
It’s hard to believe it works faster than pump sprayer with a fan tip though.
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That would help on the problem with getting it spread even on concrete. It can look real splotchy sometimes if you don’t get dispersed well.
I went and bought an 18" long nap roller today. I’m going back over some sidewalk that has thus far gotten the better of me. I expect that Brodie is right about the last 10% of rust stains being PFMagic, but I’ll give an update tomorrow night.
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Does anyone remember radio contests?
After initial PW
Rewmember this? Part done with 1/2c/gal, the other 1c/gal
Two treatments in, and still looks like crap.
NO MORE CALLS PLEASE, WE HAVE A WINNER!
18 " Roller, Long Nap. 1 1/2c Oxalic/Gal. Rolls on very wet, soaks in, does a beautiful job.
If you look closely at this last pic you’ll see the ghost of one mother of a rust stain. I guess Brodie @squidskc is right , takes PFM to get rid of it all!
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[quote=“MrSparkleVA, post:5, topic:9462, full:true”]## If you look closely at this last pic you’ll see the ghost of one mother of a rust stain. I guess Brodie @squidskc is right , takes PFM to get rid of it all!
[/quote]
Im goin’ back tomorrow and get me that frikkin’ ghost.
I ain’t afraid a’ no ghost!
!!!UPDATE!!!
Rust came back. Since I began this thread I have worked with oxalic often and discovered that without brushing the oxalic into the rust it will bleach the top surface and as soon as the rains come and wash away the bleached oxidation, the orange will show through**. SO**, I recommend applying the oxalic acid, and the 14" roller is fine, but follow up by brushing the oxalic vigorously into the surface so that it gets beyond the surface.
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Sorry if this is common knowledge, but who knows, maybe it isn’t.
There are oxalic based formulas in the paint department that may work well in this application. They are called Wood Brightener. After you strip paint/stain off of wood…well certain woods, the tannin’s get angry from the caustic and come to the surface and the wood looks horrible. Painters apply the wood brightener and it calms the tannin’s back into the wood. It does also brighten wood without a caustic precursor, specifically it helps old gray wood look brighter. Check the label to make sure it’s oxalic based. These often have oxalic, surfactant, and possibly another weak acid like phosphoric. Some are even thickened so they have a longer dwell time.
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Google it. You want the “internet slang” definition 
Pure Magic, you can fill in the “F”
I’d like to stress several things about bleaching rust in this thread:
- Some stains just won’t bleach. Accept this and never promise to remove more than 90% (THX @squidskc)
2)Some stains come out without brushing, and some come out with brushing, and some won’t come out either way (see #1) - Keep spraying or rolling, once dry the oxalic stops bleaching.(THX again to @squidskc)
- Be patient, and keep spraying (and brushing).
OOPS! See I’ve got the before/After backwards. Let me fix that!
\
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Looks great! What is your method for applying? Apply coat and let dry then reapply x2? No Rinse?
Do NOT let dry, it’ll cost you momentum. Just keep wetting it, lightly brush until the stain disappears. Novel application is an 18" roller, lightly brush, continue until the stain is eliminated, or 90%. The other 10% should NEVER be promised. That, my friend, is in the hands of the gods.
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Muratic will have that rust gone 99% within 10 seconds of contact
I just spray the OA and within seconds, it’s gone! Rinse afterwards.
What do you spray it with? Have you ever gotten blotchy results when spraying?
Pump sprayer; at first until I figured out it had to be an even spray.
Same here. I used the roller successfully
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