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cellardweller1234 t1_iug4rc2 wrote

Go to Home Depot and rent a concrete grinder and a good HEPA vacuum. It's basically an angle grinder with a diamond cup wheel and a dust cover with a vac attachment. Grind off all the glue down to sound concrete then use whatever thinset that Schluter recommends for this application. Have fun and wear a good respirator as well.

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SlimeQSlimeball t1_iug6jm6 wrote

Going to jump on this and say if you have a window in there, point a fan out that window and close the door behind you and you will get almost no dust in the rest of the house.

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Zenit_IIfx OP t1_iug79sz wrote

Unfortunately no window - interior room. Attached office has a window and nothing in it currently, so I will open that. Thanks!

EDIT: HD locally does not have any of these machines. Most HD's within 100mi show a stock of 0, but there is a single unit at a HD 35mi away. Are these normally hard to rent?

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cellardweller1234 t1_iugab2h wrote

My local HD has a few. If you own an angle grinder you can buy diamond cups and the shroud attachment on Amazon for not too much $.

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SlimeQSlimeball t1_iuhdoxz wrote

I was looking for my own project and it looked like it would be between $100 and $140 if you already owned an angle grinder which is another $50 to $150 depending on the tool brand. Plus a vacuum, another $40-100.

My neighbor did his whole floor with one during his COVID so it is possible to do a lot of work with one of those.

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threebicks t1_iuga37v wrote

Depending on the model—sometimes. Those dedicated concrete grinders can be quite large and are used for prepping large surfaces. If this bathroom is smaller you might be able to use an angle grinder with the appropriate (diamond) grinding wheel and lay it broadside onto the surface to get rid of the glue. This isn’t like a cutting blade. It’s built to grind on the face of the disc—not the edge.

There are also a number of handheld electric stripper/grinders that can be paired with various low grit sandpaper discs for this exact purpose. Maybe a wire brush wheel for a drill could work? My experience with those has been they sometimes don’t work well due to the type of glue

Dust collection will be an issue. Some grinders have a shroud to collect dust at the tool or they can be purchased on Amazon. You could have a 2nd person hold the intake pipe where dust comes off. You can buy most of this stuff at Harbor freight rather than renting for short money or even HD for reasonable price and is likely easier than renting.

As others have said, Negative air pressure in the room you’re working in should be used in addition to collecting dust right at the tool with a HEPA vac. The vac will not get everything and silica dust has a tendency to travel and linger and is also no joke health wise.

Does it have an old bath fan that works? It will likely get caked in dust though, but should do the trick. Struggling to think of an alternative if no window available. Maybe you can rent or buy a in line fan with a vent pipe?

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Zenit_IIfx OP t1_iugb27n wrote

Crazy thing is there was no vented bath fan, only a ventless fan. The builder stupidly ran the main HVAC plenum in a way that blocks outside access from this bathroom, but I found an alternate route out and am retrofitting a new fan.

Ventless fan is useless for anything except muffling noises.

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AlternatiMantid t1_iugkp56 wrote

Be careful with using a bathroom ventilation fan to vent out dust if you are sanding/grinding the remnants of the glue off. Those fans are really only designed to take humidity at most out of the room. The dust particles from this would be super sticky & gunk up the fan, those things are not generally designed to be easily cleaned besides just the cover, and you could blow the motor out pretty quickly if it gets too gunked up.

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JeNiqueTaMere t1_iujsgcf wrote

I did it myself with a small 4.5" grinder and a dust cover attached to a shop vac. No HEPA filter needed when you have a bag in the shop vac.

One downside is that you're always bent over and on your knees so your back and knees might hate you for it.

It takes a long time with a small grinder. Depends on the surface, obviously. I was doing half my basement.

A larger machine from home Depot might do it faster and also might allow you to control it while standing upright.

Also glue might gum up the wheel.

I had some tar-like substance under the paint and it took a long time to eat through that. The wheel would melt it and spread it around. I ended up using a lot of chemical/gel strippers to remove that tar.

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