# Etching



## Rich (Apr 26, 2007)

Got this idea from a thread over on C-talk.

Etching-it is mainly done with acid correct? for concrete right? 

do some guys call sanding or deglossing, etching?

just curious


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## Bushdude (Apr 17, 2007)

As far as I know etching means scrubbing the concrete with muriatic acid, then nuetralizing the acid before finishing the surface. Many contractors that specialize in epoxy floors are using shot blasting and or grinding with a diamond wheel, the latter causing a huge amount of fine dust.


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## Wolverine (Apr 17, 2007)

I've never heard of anyone referring to sanding or deglossing as etching...

Etching is the chemical attack of a substrate that semi-dissolves a portion of the top layer. It relation to coating, it serves to increase the surface area of the substrate to provide more opportunities for bonding of the polymer. Etching is also done on metals like Aluminum, Carbon Steel, and Stainless Steel with inorganic acids such as Phosphoric Acid.


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## ibsocal (Apr 17, 2007)

Some type of acid is always used but i have heard that one can use vinager to etch galvinized coated steel or was it aluminum to get a good anchor tooth profile for better coating adhesion.i used to use alot of hydrofloric acid to etch porcelian and ceramic tile surfaces but now only use silanes which do not etch but bond onto the microscopic pores of the surface creating a primer coat which then require a top coat or a cap for your tooth that is being repaired at your local dentist.


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## Wolverine (Apr 17, 2007)

You are right ibsocal... Vinegar IS acid... Depending on what you buy... acetic acid, tantaric acid and citric acid... The acid content is mostly acetic acid

Commercial silanes are typically a Silicone Molecule bonded to two organoreactive groups. They form a coupling agent. IOW, one of the reactive groups bonds to the substrate while the other bonds to the coating being applyied over the substrate that is normally hard to coat. (It's kind of like politics in the late 70s... Jimmy Carter (who had a good relationship/bond with Egypt AND Israel) is the Silicone molecule and the other two reactive sites are Egypt and Israel. E & I could not get together with out the mediary.) In general, the hard to coat substrate must be inorganic. SO, it is important to ensure that the ceramic is NOT sealed or is sealed with a silica (or other inorganic based) based glaze. 

Silanes DO NOT rely on pours to get good adhesion although they will wet and bond inside any pours that may exist. Paint that is not chemically modified to react with it's substrate DO rely on pours for bonding as the liquid fills the pours and then hardens. 

A liquid that fills pours and hardens forms a physical bond. Silanes and other organometallic coupling agents that chemically react with a substrate form a chemical bond. A chemical bond is MUCH (at least 10 times) stronger than a physical bond.


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## Brushslingers (Apr 11, 2007)

Dude.. like you should like listen to this man dude, I played with him once, he's an awesome drummer... :stuart:

He makes my head hurt though....


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## ibsocal (Apr 17, 2007)

awesome,you are blinding me with science.as much as 10x that is impresive.so where is a good source to get the silanes for porcelian/tile.can i make my own with your guideance.can it form a chemical bond on old epoxy/polyurathane coated surfaces and top coated with a linear or aliphatic polyurethane or or or see now ya got me thinking of new methods for me madness.i love this stuff (expiermenting) looking at polyureas right now to expand my coatings experince.lots to learn and loving it.


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## Wolverine (Apr 17, 2007)

No Problem... There are TONS of places to get them... 

Here is a start... Just Google these and you should be able to find a distributor in your area... We buy most of our from Degussa and ShinEtsu

Dow Corning Silanes
Degussa Silanes
ShinEtsu Silanes


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## ibsocal (Apr 17, 2007)

Master why must i work so hard for my quest of silane knowledge.please help me to the promised land,grasshopper.
ok so im feeling a little lazy right now to do the research.youz were good in red dawn.


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## jamgigo (May 15, 2007)

Dude, this hot stuff.I can relate to the etching and physical bonding stuff you mentioned.I reglaze bath tubs and always use the etching process.I would love to know more about the silane and chemical bonding.Imagine the edge I would have if I could give my customer 12-15 years warranty.All my competition use the etching method.


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## ibsocal (Apr 17, 2007)

Dude what type of coatings are you using ,from who.dude makes you figure it out yourself but i will tell you i use verbindung silanes from midwest chemicals for all my porcelian tub/sink and tile refinishing jobs.


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## walkerpainting (Sep 17, 2015)

This is good stuff, the bathroom reglazing is always hard to teach my new guys, but once they get it they see what a difference it makes.

Awesome post, I'm new so I'm starting from the beginning 

Rockville Centre Painter


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