WHo has done media blasting?

[Le Poisson]

We have a house (built in 1875) with soft clay brick. The back of the house is an addition (1986) that we have gutted and are rebuilding as a bachelor suite. We took down the drywall on the shared wall of the addition and found some lovely looking brick behind the drywall.  Since exposed brick is all the rage this week, we though we'd save ourselves the trouble of re-doing that wall, and just leave the brick exposed.

Since we are going down that road, we need to clean the brick of 100 yrs of grunge. I called a restoration company and they quoted me $2500 to clean the 8' X 8' square of brick. This sounds unappealing. On Amazon or at Princess Auto I can buy a media blast gun for $25 and a couple bags of media (the restoration folks said to use 30/60 recycled glass) at $40 each.

For folks who have done this before, a few questions...

1. That hopper on the gun looks small for the job I'm doing. Should I think about getting one of the guns with a siphon tube and just having a bucket of media to siphon from? Should I pay $200 for the full-on sandblaster?
2. How much of a mess will this make indoors? The restoration guy said to just build a tent around the workspace and not worry about it, do the job and sweep up after.
3. How much should I worry about damaging the brick? It is pretty soft, and I don't want to gouge it.

[Sibley]

Haven't done it, but yes, you could damage the brick. It's soft. At a minimum, plan to tuckpoint afterwards.

And really, you want to spend all this time and money, potentially damaging your house, for a fad? That will be gone in a few years and then will just make your decor look dated?

[Le Poisson]

Haven't done it, but yes, you could damage the brick. It's soft. At a minimum, plan to tuckpoint afterwards.

And really, you want to spend all this time and money, potentially damaging your house, for a fad? That will be gone in a few years and then will just make your decor look dated?

$200 for the setup is cheaper and faster than building out the wall and drywalling.

[lthenderson]

What exactly is "100 years of grunge"? Have you tried cleaning it by hand first?

I haven't done an entire room's worth of brick, but I have cleaned some around old fireplaces just using something acidic like vinegar and a bristle brush. It cleans quite effectively with a little elbow grease. Once done I just neutralize the acid with some baking soda mixed into water that I use that to clean the area.

[lthenderson]

Having just got done drywalling, sanding and texturing in my own home and how much of a holy mess that creates even with hours spent putting up plastic to try and control it, I can't imagine sandblasting inside a home.

[Fishindude]

Most rental houses rent sand blasters but it will be a messy operation.

[Sibley]

Haven't done it, but yes, you could damage the brick. It's soft. At a minimum, plan to tuckpoint afterwards.

And really, you want to spend all this time and money, potentially damaging your house, for a fad? That will be gone in a few years and then will just make your decor look dated?

$200 for the setup is cheaper and faster than building out the wall and drywalling.

Yep. Until you spend $200 now, and $300 in 5 years because the fad of exposed brick dies out. It's a fad. If you want to follow it, sure. Do it. But understand that you WILL be judged in however many years (not that long) for having a dated exposed brick wall.

[Le Poisson]

So has anyone actually done this, I mean I appreciate the opinions, but if anyone has actually cleaned off brick, I'd love your input.

[Le Poisson]

What exactly is "100 years of grunge"? Have you tried cleaning it by hand first?

I haven't done an entire room's worth of brick, but I have cleaned some around old fireplaces just using something acidic like vinegar and a bristle brush. It cleans quite effectively with a little elbow grease. Once done I just neutralize the acid with some baking soda mixed into water that I use that to clean the area.

We have an area about a foot wide and 8' high of old paint, and at the far end some soot.
The rest of the wall is just dirty.

Luckily our fireplaces are painted brick and look really good.

[Sibley]

Brick is porous. That stuff may have literally soaked in. It's like painting brick. Once you paint brick, you are never getting it back to pre-painted state. You can get close (depending on specifics), but it won't be 100%.

So, my hunch is.... it won't be uniform. And you'll probably do some damage in the process. I had a neighbor long time ago who had the exterior brick face sandblasted. It did brighten up the brick color. But it also damaged the face. Not much, and you had to be within a few feet to notice it. But it had been abraded. And same neighbor had to do tuckpointing. Some of that was usual maintenance/repair over time, but I'm sure some was also from the sandblasting.

[marble_faun]

Why not try to clean it as best you can, then do a "German schmear" instead?  It gives a quasi-exposed look but may cover up some of the grime.

[Le Poisson]

Why not try to clean it as best you can, then do a "German schmear" instead?  It gives a quasi-exposed look but may cover up some of the grime.

Can german Schmear be sealed? our plan was to clean, seal, and then use as backsplash for a kitchenette saving us tiling and finishing.

Edit to add schmear video for future reference: https://youtu.be/7KHjri0Trik

I like the look, but the smoothness of the brick makes it a good match for a backsplash - I worry that the unevenness of the schmear finish would make it harder to wipe down. On the upside though, the schmear would take away the step of repointing some of the sections that need attention.

[lthenderson]

For that small of an area, I seriously would get a bottle of vinegar, a bucket of water and a stiff bristled brush and go to town. Would probably take just a few minutes to see if it was working and less than an hour to do the entire area.

[Le Poisson]

For that small of an area, I seriously would get a bottle of vinegar, a bucket of water and a stiff bristled brush and go to town. Would probably take just a few minutes to see if it was working and less than an hour to do the entire area.

Can't hurt to try...

[TomTX]

I've done some blasting and overseen a lot of blasting - though industrial, not brick. Mostly steel, some concrete.

Glass blast media(grit) is going to be too hard/aggressive for brick. Full stop.

Ideally I would do pelletized dry ice blasting as the gentlest (presuming you have adequate ventilation) but that would mean either hiring someone, or renting specialty equipment. I got to use a rig one time to clean off 70 year old structural concrete and it worked fabulously - cleaned the grime/mold, left the concrete pristine. You could see the imprint of the original wood formwork was still very well defined.  Brick's going to be even softer than my old concrete.

Second choice would be conventional blast equipment, but using baking soda as the blast medium. Not as gentle as dry ice, but way more gentle than glass or mineral blasting. Yes, regular baking soda you can buy from the grocery store or Costco.

Third choice would be something like Sponge-jet. Read up on their different grades. Not cheap though

Use a respirator and eye protection for any blasting, preferably N100 or P100.

[Le Poisson]

Thanks Tom. Valuable information there.

[BDWW]

Just re-reading through this, and one thing I don't see mentioned is your compressor.

You generally need some serious CFM to blast with. Just something to be aware of, most small homeowner compressors won't cut it, and even if they have the CFM required, they aren't rated for continuous duty.

[Le Poisson]

Just re-reading through this, and one thing I don't see mentioned is your compressor.

You generally need some serious CFM to blast with. Just something to be aware of, most small homeowner compressors won't cut it, and even if they have the CFM required, they aren't rated for continuous duty.

Good point - mine is 26 Gal, with Rated air flow of 5.2 CFM @40PSI, 4.2CFM @90PSI (cut-n-pasted from Canadian Tire website). I'm a little worried about the CFM, but I got a media blasting wand from Princess Auto that is rated at 6CFM at 80PSI, so obviously I will be underpowered, and the compressor may cycle more often than is ideal. So far I have $60 invested in the venture (gun and media).

[Le Poisson]

So I've done about 1/3 of the wall. Observations so far...

+the air compressor is struggling to keep up. It's running nonstop. But it is putting out enough pressure that the abrasive can do its job.

+paint is not coming off well. I need to find another method there. It's two layers, an only some of it is coming off.

+the abrasive isn't eating into the brick unless I hold it in one place quite close. This hasn't been an issue.

+The mortar is much softer than the brick and holds dirt differently. It takes two passes from different angles.

[Sibley]

Well, you get to learn some masonry next. You're removing pretty much all the mortar it looks like, which means you will have to replace all of it. You also need to be careful with what type of mortar you use. Many modern mortars are quite hard, and will cause long term damage to old, soft brick. While it might sound like a good idea to have really hard mortar with soft brick, is really isn't. So you'll need to do some research and use the right type.

Re the paint not coming off, I'm not really surprised. You can try some stripper to see if it helps, but realistically the brick has absorbed some of the paint and it's permanent.

This Old House has a mason who seems to know his stuff, so check their site.

[Le Poisson]

The tarps are down and cleanup is in progress. For those who mentioned dust, the blasting sand didn't travel past the tarp, but the brick dust sure did. Negative pressure ventilation kept it down somewhat but we need to sweep all surfaces.

As @Sibley noted, there is a column of missing mortar. I suspect a chimney fire or something must have happened there in the past. With the sandblasting I was able to clean out the joints and now have some type O mortar on the way.

FYI, as good as This Old House is as a resource for restoration projects, the Journal of Light Construction and the (mostly archived) Fine Homebuilding forum are great resources to get input from tradespeople without paid product placement. Here's some technical information on mortars: https://www.finehomebuilding.com/forum/why-do-masons-hate-type-o

[Sibley]

Cool, you're getting there. Thanks for the resources, hadn't heard of those. Will check them out.

I haven't had to clean up brick dust, hope it's not as bad as plaster dust. But dust is just awful, whatever kind it is.

[Car Jack]

I'm a bit late on this thread, but when building a kit car, I built my own sand blaster box.  Big enough to put in an entire live axle out of a Mustang.  Something that really, really helped was to take a box fan and route it to blow out an opening in the wall.  This did not eliminate the dust but it really reduced it.

I hear ya on the compressor struggling.  I had a 25 gallon roll around oil free compressor and I could blast for all of 10 or 15 seconds before letting it recover. 

I used coal slag and play sand.  The play sand was easily available, even though not as good as the slag (called black beauty in some places).  I would also reuse the sand, doing some minor filtering and periodic gun cleaning.

[Le Poisson]

I'm a bit late on this thread, but when building a kit car, I built my own sand blaster box.  Big enough to put in an entire live axle out of a Mustang.  Something that really, really helped was to take a box fan and route it to blow out an opening in the wall.  This did not eliminate the dust but it really reduced it.

I hear ya on the compressor struggling.  I had a 25 gallon roll around oil free compressor and I could blast for all of 10 or 15 seconds before letting it recover. 

I used coal slag and play sand.  The play sand was easily available, even though not as good as the slag (called black beauty in some places).  I would also reuse the sand, doing some minor filtering and periodic gun cleaning.

Good tips - I used the ground glass, and it worked well, I tried to re-use it, but the flakes of paint clogged the gun instantly. At $12 per bag for sand, I was better off just using more sand. For this wall I went through 2 full bags and about 1/4 of the third one. If I were doing rust on clean metal, I think the sand would be able to be recycled though. I did hear in other places that if you re-use the sand too many times it gets dull and ineffective, but I have no opinion on that.

The box fan is a great tip. It's all about negative pressure in the workspace.

[BDWW]

I'm a bit late on this thread, but when building a kit car, I built my own sand blaster box.  Big enough to put in an entire live axle out of a Mustang.  Something that really, really helped was to take a box fan and route it to blow out an opening in the wall.  This did not eliminate the dust but it really reduced it.

I hear ya on the compressor struggling.  I had a 25 gallon roll around oil free compressor and I could blast for all of 10 or 15 seconds before letting it recover. 

I used coal slag and play sand.  The play sand was easily available, even though not as good as the slag (called black beauty in some places).  I would also reuse the sand, doing some minor filtering and periodic gun cleaning.

Good tips - I used the ground glass, and it worked well, I tried to re-use it, but the flakes of paint clogged the gun instantly. At $12 per bag for sand, I was better off just using more sand. For this wall I went through 2 full bags and about 1/4 of the third one. If I were doing rust on clean metal, I think the sand would be able to be recycled though. I did hear in other places that if you re-use the sand too many times it gets dull and ineffective, but I have no opinion on that.

The box fan is a great tip. It's all about negative pressure in the workspace.

How big were the bags and where did you get them? Are you actually using blasting material, or "play sand".  I've never seen blasting media for anywhere near that cheap.

[Le Poisson]

I'm a bit late on this thread, but when building a kit car, I built my own sand blaster box.  Big enough to put in an entire live axle out of a Mustang.  Something that really, really helped was to take a box fan and route it to blow out an opening in the wall.  This did not eliminate the dust but it really reduced it.

I hear ya on the compressor struggling.  I had a 25 gallon roll around oil free compressor and I could blast for all of 10 or 15 seconds before letting it recover. 

I used coal slag and play sand.  The play sand was easily available, even though not as good as the slag (called black beauty in some places).  I would also reuse the sand, doing some minor filtering and periodic gun cleaning.

Good tips - I used the ground glass, and it worked well, I tried to re-use it, but the flakes of paint clogged the gun instantly. At $12 per bag for sand, I was better off just using more sand. For this wall I went through 2 full bags and about 1/4 of the third one. If I were doing rust on clean metal, I think the sand would be able to be recycled though. I did hear in other places that if you re-use the sand too many times it gets dull and ineffective, but I have no opinion on that.

The box fan is a great tip. It's all about negative pressure in the workspace.

How big were the bags and where did you get them? Are you actually using blasting material, or "play sand".  I've never seen blasting media for anywhere near that cheap.

I used this stuff: https://www.princessauto.com/en/detail/50-lb-greengrit-crushed-glass-blasting-abrasive/A-p8223794e;jsessionid=uqDaXHu4pqdaOSk25dz0Co-s.pal-prod-com2

[BDWW]

Ah, nobody around here carries crushed glass, just glass beads. 

And it's about a 7 hour drive to Calgary, oh well.

[TomTX]

I used coal slag and play sand.  The play sand was easily available, even though not as good as the slag (called black beauty in some places).  I would also reuse the sand, doing some minor filtering and periodic gun cleaning.

Silicosis is a real risk with using actual sand for blasting.

[Le Poisson]

For those wondering how this is turning out, here's rough placement of cabinetry. Still need to point and seal.

[Dicey]

Nice progress...You know that most refrigerator doors are easily reversible, right? DH and look at tons of houses and it cracks us up how often we see them backwards.

[Le Poisson]

Nice progress...You know that most refrigerator doors are easily reversible, right? DH and look at tons of houses and it cracks us up how often we see them backwards.

Oh my gawk. Please don't bring that up.

I took the whole damn fridge apart trying to reverse this one only to find out it's pre-drilled as left-hand or right hand at the factory. I've never run into that before.

[Dicey]

Nice progress...You know that most refrigerator doors are easily reversible, right? DH and look at tons of houses and it cracks us up how often we see them backwards.

Oh my gawk. Please don't bring that up.

I took the whole damn fridge apart trying to reverse this one only to find out it's pre-drilled as left-hand or right hand at the factory. I've never run into that before.

How frustrating!! Do they sell lefts and rights or are they all the same?

[Le Poisson]

Nice progress...You know that most refrigerator doors are easily reversible, right? DH and look at tons of houses and it cracks us up how often we see them backwards.

Oh my gawk. Please don't bring that up.

I took the whole damn fridge apart trying to reverse this one only to find out it's pre-drilled as left-hand or right hand at the factory. I've never run into that before.

How frustrating!! Do they sell lefts and rights or are they all the same?

No, the issue was with the bottom screw for the fridge handle, and top screw for the freezer handle - the faceplate has to be supported behind. The installation instructions show that the door handle has to be reversed with the fridge handle (flipped upside down) and then you remove the protective cap to reattach the door. This is the point at which the instructions mention that for the SS model you order a new door. Which is frustrating since you now have the fridge in a billion bits and get to reassemble it.

I shouldn't complain too loudly though - I bought the fridge and stove from my last tenants for $100 when they didn't want to move them. This weekend I'll be tiling the floor and installing plumbing. While there I'll post an update pic. the brick turned out really nicely. everyone who sees this kitchen comments on it, so i guess we did it right.

[jpdx]

I love the look you've achieved! Here's an episode of Ask This Old House where the mason cleans brick using muriatic acid:

https://www.youtube.com/watch?v=jeYxjrMdAiw

[mrmoonymartian]

Trump.

[Le Poisson]

Trump.

We playing Euchre here? Dafuq you talkin' bout?

[Le Poisson]

I love the look you've achieved! Here's an episode of Ask This Old House where the mason cleans brick using muriatic acid:

https://www.youtube.com/watch?v=jeYxjrMdAiw

That's pretty cool. I wonder if it would eat up the paint. The job's done now though, so I'll back pocket this for another project, another time.