Ospho VS. Evaporust

woodchucker said:
yes, but the evapo rust can be re-used, the phosphoric acid is a one time brush on or spray on.
I have no problem painting after evapo rust. I clean it off with water, and use tsp before painting or mineral spirits. either works.

No I have not painted over phosphoric acid... good to know. But how do you stop it from being an acid if you just paint over it. I would think you would want to neutralize it.
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My understanding is that phosphoric acid doesn't need to be neutralized. Just rinsed well with water. I recommend some surface scrubbing also.

When using phosphoric acid, I pour out a helping, and then dunk the rusty parts in it. Commonly, bubbles will come off the part as the chemical reaction takes place. When the bubbles stop, the part is usually clean. I then pour the phosphate sauce back into the jug. A layer of smut will settle to the bottom of the jug, but the clear fluid on top is still active and ready for its next task. If it goes bad, I haven't found that point. With Evaporust, I've killed many a gallon; it looses effectiveness.
 
Dabbler said:
EDTA is a little slower than evaporust, but considerably cheaper. I use citric acid for a first pass because it is even cheaper and readily available. I then skip the EDTA and do a short pass in evaporust. Evaporust is way too expensive to do the whole job.

I stay away from muriatic acid as it etches the metal - i suppose it could be used topically rather than dip, and for a very short time only.
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where do you get EDTA that is inexpensive? what i can find on amazon is about the same cost as evaporust, well the way i buy it 5gal for ~~ $100.
 
EDTA powder was very cheap last October when I bought some from Amazon.com. Two teaspoons per litre of water was plenty. in the order of 1$, I'd guess.
 
 
wa5cab said:
Reporting acquisition of a new to you Craftsman 12" Lathe
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dabear3428 said:
https://www.amazon.com/UniClean-America-Diasodium-EDTA-Ethylenediaminetetraacetic/dp/B0D1Q7676P/ref=sr_1_36?crid=33YZ6X5DEDPJO&dib=eyJ2IjoiMSJ9.cuk7mo5jp66hv7L85lYA4c0u1oKChQRA7HRK4fRNxVSFt5_AGwdbPfHnL6hDjVGJrAx-FjCQ7iDNYIWG_1TRgZ8v_y56Uqk3cv1bZrZtTe-z_1KwuCE4cgjX_S0ByODYy8_PFiaCfGYiCGBqtONTxtxs8jhmAGJJoaELN39Cb9o9tJlZSk8PoMy-FF0uMpVwClNhlw7WFybHrhboD6C1c3nocxb_27DR2AHS_9ixz8vvN24PQaMySuR-hanTAUwKsTdeG4BauKWxyo6c5ZtFW4FSi2WgPN1n--aX_sjgrOU.I76vbT_45xIpB-zg7P69R9gAUkn7qtrDaLMA5Kugd_k&dib_tag=se&keywords=EDTA&qid=1718285451&sprefix=edta+,aps,103&sr=8-36&th=1is
this the correct type?
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As far as I know....

Mine was bought by a friend in the US and shipped to me.
It is a very similar price as I paid.

What you want is food grade EDTA.
 
Two very different things. I mainly use phosphoric acid, because I can source it pretty inexpensively.
 
jetlag said:
Two very different things. I mainly use phosphoric acid, because I can source it pretty inexpensively.
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i use both, phosphoric acid on my tractor equipment, automotive equipment and fencing. the evaporust for items that i do not want to change the precision surface on, things like the dovetails on my mill comes to mind
 
BTW, for a small part, just use coca cola. Its got a lot of phosphoric acid in it.

I have a pair of needle nose pliers for pulling fish hooks out of fish. I just stick them in a beer glass and pour 1/2 can of coke. They are like new in the morning.
 
Karl_T said:
BTW, for a small part, just use coca cola. Its got a lot of phosphoric acid in it.

I have a pair of needle nose pliers for pulling fish hooks out of fish. I just stick them in a beer glass and pour 1/2 can of coke. They are like new in the morning.
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i have 2 gal of it so about as cheap as coke besides the coke tastes better so i'm saving it for the rum.
 
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