old and new concrete

[jkevin]

ok i have done the search thing and did not really find an answer. i do concrete for a living and decided to try and add pressure washing to the mix so far slow but i guess that is the way it goes.. what i have is at a church that i poured a parking lot about 4 yrs ago needs to be cleaned and sealed easy enuff but the hard part i also have some sidewalk that is at least 50 yrs old dull and dirty would like to clean and brighten it before i seal it. i did look at envirospecs power stroke. and comment or suggestions? thanks kevin

[MudDuck]

I wouldn't think it should be any different if your using chems on it. HD80 wood stripper is supposed to be good for cleaning concrete but I haven't tried it myself. Check with Sun bright or Pressure Tek and see what they have for concrete. I'm sure it's all just about as good as anything else as long as you let it dwell a good while and keep it wet with solution. It's just a trial and error thing. At least it's concrete so you can't hurt it really. Watch overspray on plants, cars ect...

[Paul Kassander]

Powerstroke is a great cleaner degreaser that will lift the dirt and oil stains. If you a looking to brighten the concrete use the Rust-Away when you are done the Oxalic blend does a nice job of whitening the concrete.

[jkevin]

ok envirospec send me powerstroke and rust away to try can't wait to see what it looks like

[jkevin]

well finished up my concrete cleaning job and i must say was not impressed with the powerstroke cleaner cannot even tell it was used the water and pressure did all the cleaning as far as i can tell.. and now i see why i need a surface cleaner in all i think it was over 800 square feet with a wand not much fun. i know you save alot of time but do you also use less water?

[big mike]

Kevin,
Our company has used Powerstroke for the last three years with outstanding results. I have to believe that you're missing something in the process. It doesn't say in any of the above posts if you're using hot water? That's the single most important factor in cleaning concrete. We use minimum of 160 degree water, and many times that's all that's required. Powerstroke is great on oil stains, but following the directions on the packaging is vital to product performance (no cutting corners). We mix 55 gallon drums and then dilute that mixture 50/50 for downstream application. We pre-soak heavy oil areas with the undiluted mix first. Dwell time is important also. We usually let the downstreamed mix sit for at least 15 min. We have many satisfied commercial customers using this method.

[jkevin]

i did use hot water as well as cold did all the mixing per spec it is not that it did not work i guess i was expecting more. dwell time was anywhere from 15 min to 40 min. big area i did get a call from mike at envirospec we talked about it i am not going to give up on it i tried some more on my driveway. just have to keeping trying it. when you use surface cleaner do you prespray or run it thru surface cleaner? still lokking to get one of them after all the time i spent with a wand last night

[Paul Kassander]

Pre spray and then clean with the surface cleaner.

[MMI Enterprises]

Question.. is the part that seemed to not turn out well the old sidewalk or the stuff you laid 4 year back?. Perhaps the old stuff has a bunch of aggregate showing through and tricking the eye. Sometimes such stuff will never look very good or bright as a huge percentage of the viewable surface may be of darker rock that can't be whitened or lightened. If it is all cement skim that your looking at then it usually only takes the acids oxalic or phosphoric to brighten unless it has been soaked with motor oil spills or has a bunch of tuff mold growing in it. If oil is the case then the degreaser, heat, and sun/weather/leach time is in order. Can't count on shadow coming out without constant maintenance and time working on them. If mold then the 10-12% bleach cut down to about 4 to 6% should work. Pics may help..

[jkevin]

actually th old stuff turned out a little better when i sealed it at 530 this morn it did seem to be a little brighter after the sealer looked a little darker but sealer not drying to fast in this humid weather

[buc21jrs3]

who makes rust away? can it be purchased locally or is it mail order only?

[Paul Kassander]

Envirospec Makes the Rust-Away product which will ship UPS ground or truck freight only. Locally would be in Georgia or Wisconsin where there are distribution warehouses. The link will let you see current pricing.