Erasing 2 mile painted line

Good afternoon.

We’re a small business in Canada (Ottawa, On. area) and do mostly residential but we are interested in growing and have been invited by the city several times lately to bid on jobs. We have done 2 graffiti removals for them which went well.

I’m preparing to bid on a project for the city, larger than we’ve ever done and i’d like some input and practical advice as we’re already very busy and I’m only interested to do this if it goes relatively smoothly and is really worth the hassle.

The project consists of erasing a painted line on the sidewalk/street/crosswalks that has been painted on, a year ago, as part of an ``artistic’’ thing. It is red acrylic paint. It is 6 inches wide and about 3.2km /1.8 miles long.

I have already sent a bid earlier this summer and there was only one other contractor bidding. He won it but now he has not been able to get the paint off with satisfactory results so the city is asking for bids once again. This other contractor is a 78 year old gentleman that has been doing this for 30 years and has all the best equipment so if he couldn’t get it done i’m really scratching my head on how it can be done. I plan on bidding plenty high to allow for unexpected problems that will arise. I expect to rent or buy equipment and will factor this in the price. The line crosses streets and sidewalks and the work must be done at night. Some areas are asphalt, but a lot are concrete or interlock.

So far as a test I have tried pressure washing (4000psi/4gpm with turbo nozzle) with good results on asphalt but barely does anything to the paint on concrete or interlock. I plan on doing a test with a wet sandblasting kit and also try a scarifier. Are there other options that exist and would likely be approved by the city (environmentally safe etc). Keep in mind this line is downtown in the city.

There are also 7 pieces of ‘’‘art’’’ on the asphalt/concrete/interlock that have been painted with the line and need to be priced separately. Probably 200 sq feet on average each.

So, what would you recommend to remove this paint efficiently, with satisfactory results and without damaging the surfaces? The other contractor used high-end sandblasting equipment but the city did not approve the results.

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I can’t load the pics. Any chance of uploading them to the forum using the built in upload feature?

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Wow, that is a job.

I would think you could use a pot blaster and some “baking powder” (industrial not kitchen). The problems with acrylics is once they dry they are kind of resistant to water. I would think blasting it and then PW it would solve the problem, but I’ve never tackled something that size.

My other spitball idea is

rent a vapor blaster unit, like sandblasting but no big mess to deal with. THe problem with using strippers is you would have to keep them from drying. You could make a paste with stripper and cover it with plastic, but I really think blasting might be the way.

When the other guy did these things, was there a shadow on the concrete afterwards? THe problem, as always, isn’t the surface removal, but getting it out of the pores.

Also, 3.2km= 2mi. That was bugging me :rofl:

What was, the km part or the 1.8 part? :face_with_monocle: @Infinity

@dirtyboy vapor blaster? Will look into this right now.

Heat gun and a drop cord.

The 1.8 part. My apologies for derailing your thread over such a minor error :smirk::rofl:

We all needed a math tune-up anyway.

Honey bring an extension cord, a really long one. Oh and forget Christmas Eve plans …

Does anyone have experience shotblasting on a similar job?

here is a very short review

I believe arm and hammer makes several types of media for vapor blasting.

My recommendation for the vapor blasting is that it isn’t as aggressive, which I would think (not know) would not leave marks on the concrete. You gotta check into it, it was an idea for your collection of ideas on how to tackle that job.


My concern is the various surfaces it was painted on. You can blast paint off a concrete sidewalk, but cross over to pavement and I can see a nice stripe left over.

Sounds like he has the knowledge, equipment and experience to do it. Concerns me he couldn’t get it done.

Have you thought about asking him what he tried? And what he’d do different if he did it again?

What happens if you win the bid and buy new equipment and then can’t get it off? I can’t expect they’d pay twice for a job that couldn’t be finished.

Baking soda and those types of media are very slow and tedious for large jobs


Wet sandblisting is a huge mess and cleanup of heavy wet sand

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Yes i went to have a chat with him last week. He says he “used sandblasting, damn paint wouldn’t come off, and he realized he bid too low and he hates working nights so he just said f### it”.
But i notice he probably uses the same techniques from decades ago, doesn’t have a website or use email and all that although his company is well established. So i thought maybe there’s something better for this job out there.
The thing is we have a very good chance of getting this job and it could be quite profitable IF we find the best way to do it and get it approved.

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So far i’m planning to rent a shot blaster to test results. I’m guessing it would be less damaging to surface than say, scarifier. Anyone has experience in this?

Methylene chloride based stripper would have that bubbled loose in minutes. Unfortunately you can’t buy it anymore, unless you know somebody who bought it all up before the ban hammer swung. But even then, not feasible for two miles.

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wet blasting or vapor blasting, not the same thing. One uses much less water and material than the other. Just not sure we are talking about the same thing.

I get what you are saying, but he isn’t doing a wall or a storage tanks, he is doing a 6" line. I was thinking, thinking here, that he could get a portable unit and walk that line so to speak. The vapor blasting wouldn’t cause a lot of dust and would reduce the water. He could later on PW or surface clean the material away.