Etching Concrete Block

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Old 01-20-15, 08:23 AM
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Etching Concrete Block

What etching products have people has success with? Most I've seen are acids that require rinsing, but I have also seen some "eco" products that do not require rinsing. Want to make sure I properly prep the block before coating. Thanks
 
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Old 01-20-15, 09:54 AM
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Normally block do not require etching before applying a coating. What are your coating plans?
 
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Old 01-20-15, 10:15 AM
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You will have trouble with the control of the uniformity and depth of the "etching" without something to stop the action.

I have seen many similar appearances, but they were done in the plant where the block were made. - Either mechanically sand blasted or chemicals for exposed aggregate appearances. There are also abraded (ground) faces for block.

Trying to do it on a few block and get some uniformity will be tough since you will not have any way for uniformity and controls.

"Eco" materials will not be aggressive do a good job.

Dick
 
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Old 01-20-15, 11:35 AM
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Planning to apply Drylok Extreme to the walls, to a house built in the 1940's. I removed all the old paint with a rotary hammer and bushing tool. I am just worried about salt causing an issue with adhesion of the coating. There are spots on the walls that look rusty, like iron was leaching out of the block.
 
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Old 01-20-15, 12:06 PM
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I have tried prepping walls to varying degrees before applying Drylok. Even pressure washing unpainted walls just to get them clean, applied muriatic (hydrochloric) acid then pressure washed again to remove... Still, I can not recommend expending the effort or money. I'm not saying it can't work. I have seen it hold up well on dry walls. On those with moisture problems It started having problems in a few years. So, in my opinion there is only one way to stop water from entering a home and that's to stop it outside and preventing it from entering the walls in the first place. Once it's (water) in the walls you're trying to seal a leaky boat with a coat of paint on the inside.
 
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Old 01-20-15, 12:52 PM
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I agree that waterproofing is best addressed on the exterior!!

All the drylok I've applied has been to unpainted masonry and I've never had any issues with it peeling unless the moisture problem is severe. IMO drylok is best used as a primer for painted block below grade or an insurance policy for a dry basement prior to being finished. Drylok is formulated to fill the pores in the masonry and it's ability to expand in those pores is what gives it water resistant qualities. While I've always warranted my painting, I've never guaranteed that drylok would keep a customer's basement dry!
 
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Old 01-25-15, 04:23 AM
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read all this thread but have no idea yet WHY you want to do this work ? imn-s-hfo, d**l*** is a terrible mtl foisted on the ignorant & sold by the uncaring but that's just my opinion,,, hearing they now have an 'extreme' version may be an attempt to erase bad memories of the original formula &/OR just get more $$$

pls post why & maybe we can direct you towards proper mtls,,, most everyone knows the improper ones by now
 
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Old 01-25-15, 10:32 AM
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Stadry, go back and read post #7 and tell me you understand it completely. Your abbreviations don't make sense to anyone.
imn-s-hfo, d**l*** is
And if you wouldn't want your grandchildren to read what the abbreviations mean, leave them out.
 
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Old 01-25-15, 10:59 AM
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Stadry - I recently removed all the old paint on my basement block with a rotary hammer and bushing tool as you suggested in a previous post. A large section of the basement floor was in poor shape so we excavated the floor and will pour new. When excavating the floor, I found an old, make-shift weeping tile. There is a crack in the footer and a previous owner installed a 6 foot piece of perforated PVC and connected it to the terracotta house drain system. I plan to replace and expand this weeping tile system since we will be pouring a new floor anyway. The walls will be insulated with 2" rigid foam and framed in, likely using DRIcore product for the subfloor. I want to coat the walls with a Drilock/Thoroseal product to keep the moisture off the walls. The walls do have spots where there are salt deposits that need to be removed. However, I am hesitant to use muriatic acid in the basement given that I won't be able to thoroughly rinse it. I am concerned with product adhesion if I don't remove these salt deposits.

Thanks the background, thanks for the input.
 
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Old 01-25-15, 11:22 AM
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Since pressure washing is rarely an option in a basement, I've always just used a wire brush to remove the excess deposits. It doesn't have to be perfect.
 
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Old 01-30-15, 05:33 AM
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my opinion - no muriatic - it eats lime - dry wire brush, wet scrub w/5gal wtr+handful tsp solution - rinse well - thoroseal, zypex, or aquafin ( for hi build qualities )
 
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Old 04-02-15, 03:52 PM
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So once the walls were chipped free of old paint, I scrubbed the walls with a TSP solution and rinsed with water. After drying for a day, I applied the first coat of Thoroseal. 5 days later the 2nd coat was applied. All seemed well I was pleased with the result. A week later (this week) the new floor was poured. Today I go in the basement and notice a sparkling on one section of the wall. This section felt chalking and a dusty film fell from the wall when brushed with my hand. At the bottom of this section near the floor, the Thoroseal was damp, bubbled in spots and flaked off with my fingers. There are also rust colored stains coming through in this section of wall.

I assume the TSP did not do the job prepping the wall and the salt deposits prevented the Thoroseal from binding? Obviously, I am less than pleased with the prospect of removing the Thoroseal and starting over...
 
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Old 04-03-15, 04:09 AM
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I've never used Thoroseal so I can't say about that but TSP needs to be rinsed well or the detergent's residue can cause issues with the coating's bond. Did the block appear to be dry before you applied the thoroseal? did it look like all the efflorescence was removed?
 
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Old 04-03-15, 06:35 AM
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I rinsed the TSP with water, allowed to dry, then dampened the block prior to applying the Thoroseal. I used the same process on the other walls and they are fine. It appeared that the efflorescence was removed, but perhaps it wasn't.
 
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