View original topic: Phosphoric acid at Home Depot in Canada?
ovalhobo Fri Feb 25, 2011 12:53 pm

I went to Home Depot (in Canada) and asked about phosphoric acid. They looked at me like I had two heads. They had no idea what I was talking about.

Would any of you happen to know the name brand of this product in Canada (and if it can be purchased at Home Depot in Canada). I do know about Rust Converter etc (which are available and I have used); however, these products tend to come in small containers, usually in spray cans, and are quote expensive. I'm looking for the larger containers.

Thanks so much for your help.

c21darrel Fri Feb 25, 2011 1:05 pm

When i asked i got the same response...Its called "Prep and Etch" Gallon container for about $15 in USA.

ovalhobo Fri Feb 25, 2011 1:07 pm

I wonder if they have that product in Canada. I'll check this weekend.

Thrasher22 Sat Feb 26, 2011 2:32 pm

I got the exact same response :lol: Let me know what you find, I still need to pick some up.

ovalhobo Sun Feb 27, 2011 5:03 pm

Well, I went there today. I asked about Prep and Etch and Ospho. They had neither. Where else they might have this stuff in Canada?

hpw Sun Feb 27, 2011 5:47 pm

ovalhobo wrote: Well, I went there today. I asked about Prep and Etch and Ospho. They had neither. Where else they might have this stuff in Canada?
After a quick search on the Kleanstrip website, see if this helps.

ovalhobo Sun Feb 27, 2011 8:31 pm

Thanks. I'll ask for that product. I'll also check Wally Mart. I see that these products are available in USA nation wide, but I'm not so sure about Canada. I wonder if they'd ship this stuff over the boarder?

TonysGarage Sun Feb 27, 2011 9:10 pm

the problem with asking people that work at home depot is...most of them are IDIOTS!

ive asked for phosphoric acid before and they had no idea what it is---they'll stock it in the paint department..near acetone, laquer thinner, etc...just read the bottle...dont ever ask someone that works there

tspot100 Mon Feb 28, 2011 11:47 am

try tractor supply warehouse if you have them in canada. they stock gallons of "milk stone remover" guess what the main ingredient is???? phosphoric acid. highest percentage i have seen. cheap too, around 10$ per gallon. couldn;t find ospho locally ...i had to mail order a case...

guy dagenais Wed Mar 02, 2011 5:21 pm

Hi Ovalhobo

I live in Montreal and the product that you want is :

SURF-PRO Rust Buster and Primer (it's phosphoric acid).

I use it and it works well.

I've bought mine at Canadian Tire

This product is made in Ste-Julie, Québec (KOSMIC SURF PRO INC)


EV Carthago diesel

engineerscott Fri Mar 04, 2011 9:39 pm

Another product that Home Depot carries (at least in the U.S.) is Ospho. In a 1 gallon concentrate bottle. It is phosphoric acid and surfactants and is used as a metal pre-treat prior to painting.

This is what you are looking for:

ovalhobo Sat Mar 05, 2011 10:55 am

I asked for Ospho at Home Depot. They looked in their computer and came up with nothing. I'm guessing they don't sell this in their Canadian stores? I will search Crappy Tire for Surf-Pro next. Thanks everyone!

Thrasher22 Mon Apr 18, 2011 10:55 am

Though I'd bump this for other stuck Canadians.

I picked up a bottle of stuff called Rust-mort at a local autobody supply in Calgary last weekend. Its 75% phosphoric acid and seems to do the trick...

Wasn't cheap, I paid $40ish for around 700ml. This shop tends to have pretty high prices normally though.

guy dagenais Mon Apr 18, 2011 7:04 pm


That's really expensive, I paid around 10$ for same amount at Canadian Tire for the other product (Rust Buster)

Thrasher22 Wed Apr 20, 2011 10:46 am

I didn't see that last time I was at Can tire... The horrible music they're usually playing at the one near my house usually means I'm in a huge rush to get out haha. I have to go buy more MIG wire tonight, so I'll take a look.

chift Wed Oct 05, 2016 8:38 am


Any new update? I found RustMort at a local automotive paint shop but it's pricey (30$) for a pint.

Does the RustCheck product have enough phosphoric acid in it?

RustBuster isn't available at Canadian tire/Rona/Homedepot

raygreenwood Wed Oct 05, 2016 9:02 am

chift wrote: Bump.

Any new update? I found RustMort at a local automotive paint shop but it's pricey (30$) for a pint.

Does the RustCheck product have enough phosphoric acid in it?

Rust Check has less Phosphoric acid (listed as 15% to 30%....than Ospho which lists 45%.

But....Rust check also lists about 7% Tannic acid which is also the other chemical that does really well for converting. Some information notes that tannic acid converted rust...which is ferric tannate....may be a little more stable and rust resistant than those that use only phosphoric acid.

You should try some and let us know how it works.

Also....interestingly enough...I have noted that Jasco prep and primer is listed ...and appears to be so.,...about 2.5X stronger than Ospho.

In reality...its NOT a higher concentration.....its just more EFFICIENT.

Jasco lists 37.5% Phosphoric acid.
Ospho lists about 45% phosphoric acid.

However...the that Ospho is mainly water, a polymer solution somewhere in there and the phosphoric acid.

The Jasco and several other rust converters.....also have ethylene glycol monobutyl ether.....which is used as a wetting and flow agent to make the solution PENETRATE deeper into textures and microscopic fissures....and it has this in place of a lot of the water in Ospho.


W1K1 Wed Oct 12, 2016 11:52 am

I've had really good results with Picklex 20, I always have to order it.

available in Ontario from

raygreenwood Wed Oct 12, 2016 4:17 pm

Thanks for losting that. I could not remember the name of that product.

Picklex 20 has very little phosphoric acid ...less than 10%.....but ai believe it uses Tannic acid and wetting agents....and is also d3signed to be a,very sloooow soak. I have heard good things about it....but its slow. Ray

Digger89L Sat Nov 05, 2016 12:06 pm

Here's another one: 30% phosphoric acid: "Krud Kutter The Must For Rust Spray Gel Formula" its $12.99 for a 946ml bottle at Canadian Tire. Its apparently made by Rustoleum. Haven't tried it, and the instructions don't really say what to do with the surface after treatment, and befor painting ....

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