Primer Stains

[Callipygous]

while fixing some broken watering pipes in our backyard my dad kicked over the can of purple primer (the stuff you put on the PVC before the glue to get the joint all clean and stuff) and it spilled all over our brand new concrete sidewalk. the stuff is purple, and apparently stains. so now there is this big purple sploch on our white sidewalk and im curious if you guys know of good ways of removing it.

 

apparently the stuff is comprised of the following: methyl ethyl ketone, cyclohexanone, tetrahydrofuran, and acetone.

 

if that helps : P

 

would the same methods as removing oil stains do it? would bleech accomplish anything?

[Phi for All]

Try a wire brush and either alcohol or straight methyl ethyl ketone or benzene. Don't use any ammonia-based cleaners, they don't like each other.

 

You may remove the purple but still have a stain left. I don't know anything about acid stained concrete but these folks were at an architect's convention I attended. Pretty cool looking stuff. Coverup may be your only hope.

[Callipygous]

would bleech be an ammonia based cleaner?

[Phi for All]

No. I remember reading here at SFN that you never want to mix bleach and ammonia since it creates chloramine which is highly toxic.

 

You could try bleach but dilute it first, maybe a tablespoon or two per pint of warm water. Keep increasing the bleach concentration if that doesn't work. You just don't want to overdo the bleach right away. Definitely a multi-stage process to get it looking right.

[YT2095]

those solvents that you listed are already gone, leaving the dye, unfortunately those solvents will have carried the dye quite deeply into the concrete

there`s little to nothing you can do other than find out what the color agent is and try to alter it, OR paint over it, sorry dude, but that sucker`s there for the duration!

[RICHARDBATTY]

I know nothing of solvents or how they work in paint, so this is a guess at best. Could you try adding solvent to break the paint down, then use a vacum to draw the paint into rags. Use an old washing up bowl attatch a vacum to it. Fill the bowl with old rags and invert it. Wet the paint with thinners and slide the bowl over and apply vacum. You would want to allow air to leak in to the tube to keep the vapour concentration down. Completely fill the bowl with tight packed rags. Just a thought.

[YT2095]

only prob with that (esp the MEK and Acetone) one spark from the electric motor brushes and BANG!

[H2SO4]

I think his best chance is to mix MEK with acetone, and let it totaly soak that part of concrete like a puddle, then soak it up. Or is this the same thing that richard batty suggested?

[YT2095]

VERY expensive for such a minimal result though.

is the "sidewalk" is made of Slabs, it may just be prudent to turn the offending slab upside down and be done with, else hammer the offending section out and refill it again.

[H2SO4]

YT, you have to remember that the side walk was probaly poured onto gravel, or dirt, and probaly has a very, very, very rough surface, and probaly has some re-bar showing through also.

[Callipygous]

VERY expensive for such a minimal result though.

is the "sidewalk" is made of Slabs' date=' it may just be prudent to turn the offending slab upside down and be done with, else hammer the offending section out and refill it again.[/quote']

 

the sidewalk is in sections, but no quite what i would call slabs. the sidewalk is curved, and its a different curve on each side, which means if you flip it over it wont fit. not to mention the gravel problems mentioned above.

 

im not sure, but it seems like there may be some confusion in some of the other posts. its not really paint im talking about, its this stuff you smear all over the pipes before gluing them to get them all clean and ready to make a solid connection.

 

you said its just the dye thats left, in my experience, bleech will turn pretty much any liquid clear. could this work? is there a problem with getting the bleech to penetrate as much as the original mixture?

[H2SO4]

I know what you mean. It is not a paint. Ive used it before multiple times. It also stains skin bad (well, just about anything).

 

If bleach doesnt work, maybe conc. H2O2 (but this is very reactive, and good luck getting a hold of enough).

 

Ummm, oh , ya, maybe try some muriatic acid from the hardware store. The main purpose of this stuff is to clean bricks and concrete. I'd imagine muriatic acid (conc. HCl) will get below the stain, and eat a thin amount of concrete below it, and then the stain will be gone.

 

Now that i think of it, im very confident muriatic will work. Its like 4 bucks a gallon at the hardware store (although, you can get quarts of it).

 

Just realy follow instructions on the bottle, becuase muriatic is some strong stuff.

 

If that doesnt work, take a power sand, and put the toughest grit sand paper you can find (like 60 grit will work, otherwise the grit is like stones glued to cardboard) and sand the hell out if. Might work, but i think muriatic will work good.