Sunday, January 20, 2008

More Brick Stripping Fun

The brick wall was wire brushed (used a brush from the grill), and then used muriatic acid diluted 10:1 with water. It worked great to get the plaster and mortar off the face of the brick. Watching the water and lime in the mortar fizz on contact was a bit disconcerting, but all part of the fun. It took a fair amount of elbow grease but the mortar all came off.

For now I am reasearching how to seal the brick. There is quite a debate regarding this topic online. Some people saying not to say it at all, while the other camp say to seal it but don't agree on a sealer to use. I've seen some brick in Baltimore that has a shiny look to it, which I don't like. I may just keep it unsealed for a while unless somebody can tell me a good matte sealer that can be purchased locally. That or until the dust from the wall bothers me too much and I pick up whatever Home Depot (HD) carries...

Lesson Learned: Be careful of what sprayer you put muriatic acid in. The sprayer bottle I purchased had metal in it for the pump spring, or some other metal in it associated with the pump. After about 20 minutes the sprayer wouldn't pump, as I assume the metal corroded out. A trip to HD later and I had a more expensive spray bottle for rougher chemicals - no metal at all in it. Of course being at HD allowed me to also purchase a much needed shop vac. :)


Jon said...

Corey - had a question about the brickwork.

After the brick is exposed, I assume you went through the process of 'scrubbing' the bricks first to remove the bulk of the plaster. Can you describe the muriatic acid process a bit more? Is it just spraying the chemical on and allowing it to etch on it's own? What about cleanup?

-Jon at ProjectRowhouse

(Also, so sorry to read about Loki - it's admirable that you guys provided for him and tried as much as you did.)

Corey said...

Hi Jon,

You are quite correct about scrubbing first. I first used a wire brush to get most of the plaster off. Try to get as much material off during this stage before the chemicals or you will be scrubbing a lot more with chemicals using a less stiff brush (more on that to follow).

For scrubbing the chemicals I used a small tile brush, one used to clean grout (mine had black bristles and a white handle) to scrub the tiles. Get a lot of the brushes, as the bristles will quickly deform. Also note that the tile brush must be all plastic, as the acid will eat away at any metals (so don't try the acid with the metal brush above).

Once you have wire brushed the brick to get most material off, I mixed the muriatic acid (which you should do outside!) in the dilution noted above. Note that it is best to error on the side of too little acid as opposed to too much acid - with too much acid it can start to stain the brick an unappealing green color. Not pretty.

Once the spray bottle was full, I put on thick rubber gloves, wrap around safety glasses, long sleeves and you should wear a respirator (though I didn't - just too much gear). Just make sure you have decent ventilation. I sprayed down the bricks, one at a time, usually taking about 2 sprays or so per brick. Make sure you spray the brick at an angle to you as any back-spray will burn your skin. It's not an excrutiating pain or anything, but it's unpleasant and will cause an irritation. The acid will especially attack the plaster, desintegrating it into nothing, but will only mildly eat away the the lime-based mortar used in our rowhomes. If you spray heavily onto the mortar it wille at away more, but you'll get a feel for this as you go...

All you have to do is just spray one brick at a time, and scrub away with the tile brush. It's a slow process, but rewarding overall. If you don't scrub and just let it naturally etch you won't get all the schmutz off the brick, and you will be eating a lot of the mortar away. Not good.

For clean-up, I suggest laying a plastic sheet below. Keep in mind you will have overspray from the acid, so make sure you have baking soda around to neutralize the acid. After doing a section sprinkle some powder to neutralize the area. Also, if you were to spill some acid on your skin use the baking soda ASAP to neutralize the acid.

I don't want you to think muriatic acid is the only way to go. There are many alternatives to muriatic acid, but I had used it before so wasn't too worried about it. A lot of places recommend phosphoric acid, but I didn't have any experience with it. If you want, I even have some muriatic acid that I'll give you for free. It's not exactly stuff I want sitting around my house now. :-)

And thanks about Loki - it's been tough but we're doing our best to move on. :-(

Jon said...

Corey, you still got that acid sitting around? I'll take it off your hands if the offers still on the table. I finally got the scrubbing done (yeah, I've been moving a bit slow on it).

Shoot me an email and we can figure out a way to meet up -


Mike said...

Hey Corey - I don't know if you ever gave the acid to Jon, but I understand that Home Depot no longer carries it (it's too caustic). I'm pretty sure I must live less than a mile from you - so if you've still got the acid on hand, let me know. Thanks!


Mr. Nichols said...

Hey there...
I'm wondering what the process was like for the edges of the brick wall. I exposed the brick in my kitchen, and am beginning the wire brush scrubbing today (prior to phosphoric acid) and have 2 walls and a ceiling where the plaster meets the brick in a not-so-pleasant way. Did you trim it out or just leave it rugged looking?

Corey said...

We ended up going with this matte sealer by behr, which worked great. I even tried to use a mixture of elmer's glue and watter for a more matte look, but this just ended up looking like elmer's glue on the wall. Not pretty. If you want more of a wet look, behr also has a wet look sealer. Why folks would want a wet look inside a house is beyond me, but seeing lots of houses with this makes me think some people like it...