removing mastic

[debushau]

I have a carport area and attached walkway that I wanted to prep for some concrete stain. The existing concrete area was covered in an indoor-outdoor carpet that I have removed. It's left behind a dry yellow mastic. In some spots the mastic is 1/4 thick and it's thin in others.

I am looking for suggestions for removal. I plan on doing an acid etch on the concrete before putting the stain down.

I've tried a few things to get it off - pressure washer wasn't effective. I have used Pearl turbocut discs on my angle grinder which is basically a carbide abrasive but that has been super slow, dusty and it just doesn't get rid of the glue in tiny cracks or some of the residue. I have seen concrete grinders mentioned here and elsewhere though none of the local rental stores carry one. From what I've read online, the adhesive removers are no good.

 

[thegarageguy]

We've used Been E Doo when grinding and dust was unacceptable and had great success.

http://www.franmar.com/shopping/index.php?main_page=index&cPath=2&zenid=8amejato03ctp7oo4sm3rn48a3

Let us know how it works

 

[Edger]

If you can get a product to dissolve it OK and scrape it all away a pressure wash immediately after will usually remove the soft mastic from the concrete cracks.

 

[debushau]

Thanks for the suggestions. I will try some Bean-e-doo.

 

[LegacyIndustrial]

I have a carport area and attached walkway that I wanted to prep for some concrete stain. The existing concrete area was covered in an indoor-outdoor carpet that I have removed. It's left behind a dry yellow mastic. In some spots the mastic is 1/4 thick and it's thin in others.

I am looking for suggestions for removal. I plan on doing an acid etch on the concrete before putting the stain down.

I've tried a few things to get it off - pressure washer wasn't effective. I have used Pearl turbocut discs on my angle grinder which is basically a carbide abrasive but that has been super slow, dusty and it just doesn't get rid of the glue in tiny cracks or some of the residue. I have seen concrete grinders mentioned here and elsewhere though none of the local rental stores carry one. From what I've read online, the adhesive removers are no good.

D:
Do not acid etch your floor before you use a "reactive stain". There will be nothing left for the stain to react with.

If you are going to acid etch you will have to use a litho type stain (water based) or an acetone dye (both are acceptable methods to color concrete).

If you do acid etch, the only remedy is to grind the surface all over again, nasty mess without the right equipment as you are already finding out.

Garage Guy is on the mark with the bean-e-doo.

 

[jdaallen]

Bean-e-doo will rarely affect the "yellow" carpet mastics. Bean-e-doo is for asphaltic mastics used for VAT and VCT flooring. Solvents strong enough to cut the yellow mastics usually end up creating a hazardous waste difficult to dispose of correctly.
Try dry ice. It will freeze the mastic and make it brittle enough that it will "chip" off easily.

 

[debushau]

Well, I tried the Bean-e-doo on the mastic and it wasn't great. I guess it softened the mastic a bit but it wasn't ideal. Maybe if the mastic was thicker (I have ground off most of already) it might have been more noticeable.

Did a little scraping, some pressure washing and I eventually just figured I had removed enough. It was hard to spot any remaining mastic, just a little spotting on the water test a tiny amount in cracks.

I etched using some citrus stuff and then had a second go at it with some kind of muriatic substitute based on hydrocloric acid.

I didn't see Legacy's post about the etch but the stain I used was H&C (Sherman Williams) which called for acid etch - so I figure it must be compatible, it's water based. Looks okay now though no idea whether it will last.

Only half the job done though - another 100 sq.ft to do.

 

[LegacyIndustrial]

D:

Sounds good. Many folks use acid stain and I assumed you were. Glad to hear it worked out.