ACID TREATING - Crust/Rust to Primer

[rte592]

SO how about those before and after pictures?

I Think I might have to try some on these steel parts.

[MNAirHead]

Good start..

I've learned that using a weak dilution works great... let them soak longer.

T.

[hpw]

I am so sorry Idid not get back to this. Just saw it today. Yes!.....I have done heater channels with acid.
I also used an engine cleaner syophon just like what you are talking about.

I warn you though. be very careful of mist generated.

It also needs to be done during tehheat of the summer....because you are going to need to flush out the heater channels with a garden hose. Water will get into places like the floorboards. Thats no big deal. Just let it drain and leave teh windows down out in the heat...and everything drys and rust films over retty quick. Then using the wand...spray phosphoric acid up into the channels. Rust will bother you no more.

You can even get paint coatings into the channels with this technique. Ray

Okay, I'm getting ready to treat my heater channels, so can we review what we/I have learned ? The muriatic acid is

quite a bit cheaper than the phosphoric acid. So I was planning on using that. I have my body off the pan (1966 ghia).

Want to see how much liquid it actually takes to fill up the channel. I'm going to take plumbers putty and seal all the bolt

holes, foot vent and seams. Measure out a couple gallons of water and fill up the channel with a funnel using the fresh air

tube that goes from the heater channel up to behind the dash. Once I determine how much water it takes to fill up

completely, drain all the water out. Then I will mix up a 50/50 muriatic acid/water and pour into the heater channel and

allow to soak for a 1/2 hour or so. After draning then I will rinse thoroughly allow to dry using either compressed air, electric

leaf blower, hair dryer to remove all traces of moisture. After this is where it gets a little fuzzy for me, you say

Then

using the wand...spray phosphoric acid up into the channels. Rust will bother you no more.

Is this all I have to do

or should I use some thinned master series(cheaper version of por15) sprayed/poured into the channel? Or as you say just

use the phosphoric acid and be done with it. I called the tech line for the phosphoric acid and they recommend against just

leaving the phosphoric acid as they said rust would return if not treated with a coating of some type.

Now all this probably sounds crazy, but we all know that fixing rust damage is very expensive and time consuming, so I am

trying to avoid this by doing all this.

ANY insights/comments are greatly appreciated. Also I have a tendency of over analyzing stuff, thinking something to

death, so that I can avoid any unforeseen pitfalls as much as possible. Also I don't want to do more damage than good.

I apologize this turned into a book

[hotrodsurplus]

The muriatic acid is quite a bit cheaper than the phosphoric acid. So I was planning on using that. I have my body off the pan (1966 ghia). Want to see how much liquid it actually takes to fill up the channel.

Yeah, the muriatic will work; however, before you do what you're talking about, take a few pictures of the channels and say a few last words of respect to them because they won't be there for long afterward. Muriatic tends to work for a lot longer than you expect. It's not so bad in a highly exposed areas where you can effectively neutralize it, but it's borderline impossible to neutralize when it's in a confined space.

Water alone won't flush out the muriatic and your chances of neutralizing it in such a confined space with even a highly basic solution are somewhere between impossible and never. Trust me on this one; at $13 a gallon for phosphoric, you could buy 10 gallons and not be where it would take to buy one good-quality heater channel (you can reclaim and reuse the phosphoric over and over too).

I've de-rusted enough stuff with muriatic to know that it's too destructive in anything but highly exposed areas where you can really neutralize it or on very thick material. Diluting it won't reduce the risk, either; it'll just make the stuff work slower than snail sh!t.

I'm going to take plumbers putty and seal all the bolt holes, foot vent and seams. Measure out a couple gallons of water and fill up the channel with a funnel using the fresh air tube that goes from the heater channel up to behind the dash. Once I determine how much water it takes to fill up completely, drain all the water out.

Hey, wait a sec. Rusty heater channel means you have gaping holes everywhere. If you can seal up a heater channel that way it's not a rusty channel. It might have some surface rust but that doesn't necessarily mean bad things. If that's the case, leave it alone. Pour some OSPHO in there if you're really scared of it and then just seal it with Rust-Oleum alkyd enamel or something like POR or Rust Bullet or Master Series.

Or as you say just use the phosphoric acid and be done with it. I called the tech line for the phosphoric acid and they recommend against just leaving the phosphoric acid as they said rust would return if not treated with a coating of some type.

The tech line is right. You definitely have to seal the metal after you've eliminated the rust. There's no paint on it, remember? And now it has more surface area because of the rust that pebbled the metal, so it'll rust faster than ever. I vote phosphoric acid bath, drain, rinse like crazy, maybe even neutralize with a few gallons of water with sodium carbonate (go to the pool shop), dry in hot weather or with a torch on the outside and a shop vac pulling air through the inside, and then coat with cheap-assed Rust-Oleum. Thin it a bit with mineral spirits and make it last longer. Reclaim what doesn't stick and use it in the other side.

Also I have a tendency of over analyzing stuff, thinking something to death, so that I can avoid any unforeseen pitfalls as much as possible. Also I don't want to do more damage than good.

That's a good trait. Otherwise you'd be looking at a pile of flakes in the shape of a heater channel.

Seriously, the phosphoric is a good investment and is very safe. I de-rusted a very crummy tank that's in my wife's baja. After I rinsed the phosphoric I coated it with OSPHO and left it alone. Since it's always filled with gasoline it won't rust--at least rust quickly (stock VW tanks are uncoated). I did this to the tank in my '56 Ford about 10 years ago and this spring I did it to a '32 Ford tank with perfect results--and gennie, dent-free Deuce tanks are way too expensive to risk. It's been sitting empty ever since and doesn't have a lick of surface rust.

[hpw]

The muriatic acid is quite a bit cheaper than the phosphoric acid. So I was planning on using that. I have my body off the pan (1966 ghia). Want to see how much liquid it actually takes to fill up the channel.

Yeah, the muriatic will work; however, before you do what you're talking about, take a few pictures of the channels and say a few last words of respect to them because they won't be there for long afterward. Muriatic tends to work for a lot longer than you expect. It's not so bad in a highly exposed areas where you can effectively neutralize it, but it's borderline impossible to neutralize when it's in a confined space.

That is the response I was looking for and I thank you for it.

Water alone won't flush out the muriatic and your chances of neutralizing it in such a confined space with even a highly basic solution are somewhere between impossible and never. Trust me on this one; at $13 a gallon for phosphoric, you could buy 10 gallons and not be where it would take to buy one good-quality heater channel (you can reclaim and reuse the phosphoric over and over too).

I've de-rusted enough stuff with muriatic to know that it's too destructive in anything but highly exposed areas where you can really neutralize it or on very thick material. Diluting it won't reduce the risk, either; it'll just make the stuff work slower than snail sh!t.

I'm going to take plumbers putty and seal all the bolt holes, foot vent and seams. Measure out a couple gallons of water and fill up the channel with a funnel using the fresh air tube that goes from the heater channel up to behind the dash. Once I determine how much water it takes to fill up completely, drain all the water out.

Hey, wait a sec. Rusty heater channel means you have gaping holes everywhere. If you can seal up a heater channel that way it's not a rusty channel. It might have some surface rust but that doesn't necessarily mean bad things. If that's the case, leave it alone. Pour some OSPHO in there if you're really scared of it and then just seal it with Rust-Oleum alkyd enamel or something like POR or Rust Bullet or Master Series.

The plumbers putty was just to keep the phosphoric acid inside the heater channel. No there isn't any rust holes(yet).

Or as you say just use the phosphoric acid and be done with it. I called the tech line for the phosphoric acid and they recommend against just leaving the phosphoric acid as they said rust would return if not treated with a coating of some type.

The tech line is right. You definitely have to seal the metal after you've eliminated the rust. There's no paint on it, remember? And now it has more surface area because of the rust that pebbled the metal, so it'll rust faster than ever. I vote phosphoric acid bath, drain, rinse like crazy, maybe even neutralize with a few gallons of water with sodium carbonate (go to the pool shop), dry in hot weather or with a torch on the outside and a shop vac pulling air through the inside, and then coat with cheap-assed Rust-Oleum. Thin it a bit with mineral spirits and make it last longer. Reclaim what doesn't stick and use it in the other side.

That will be my game plan and will report back after it is all said and done^

Also I have a tendency of over analyzing stuff, thinking something to death, so that I can avoid any unforeseen pitfalls as much as possible. Also I don't want to do more damage than good.

That's a good trait. Otherwise you'd be looking at a pile of flakes in the shape of a heater channel.

Seriously, the phosphoric is a good investment and is very safe. I de-rusted a very crummy tank that's in my wife's baja. After I rinsed the phosphoric I coated it with OSPHO and left it alone. Since it's always filled with gasoline it won't rust--at least rust quickly (stock VW tanks are uncoated). I did this to the tank in my '56 Ford about 10 years ago and this spring I did it to a '32 Ford tank with perfect results--and gennie, dent-free Deuce tanks are way too expensive to risk. It's been sitting empty ever since and doesn't have a lick of surface rust.

I checked the price on the OSPHO and it was 109.00 a gallon, is that what you paid?

Thanks again for the great education, I learned a lot

[hotrodsurplus]

The plumbers putty was just to keep the phosphoric acid inside the heater channel. No there isn't any rust holes(yet).

Is it wet where you live? Do you drive it daily? If the answers are no, you might want to just leave it alone. A bit of surface rust is totally normal and you may actually cause more problems than you solve.

I checked the price on the OSPHO and it was 109.00 a gallon, is that what you paid?

Lordy no! I remember grumbling that a quart of the stuff was almost as much as a gallon of phosphoric. I want to say that it was $10 a quart at my local Ace or True Value. Boat places carry it too.

You're welcome on the tips. I hope they work for you.

[hpw]

Is it wet where you live? Do you drive it daily? If the answers are no, you might want to just leave it alone. A bit of surface rust is totally normal and you may actually cause more problems than you solve.

No I don't drive it daily and it is tore down while I "restore" it. And I knew now is the time to do something to the heater

channels while it is all apart. I have had a couple pin holes in front of my right front tire(where the crease is at the bottom of

the fender). I have treated and sealed it( can't weld and it wasn't that bad) so it got me to worrying about my heater channels.

I wished I had access to one of those boro scope with about a 3' lead so that I could actually see what is going on.

[hpw]

hotrodsurplus, was having trouble trying to send a pm, you may have gotten it 3 times

[Piledriver]

Home Depot/Lowes have the Kleen-Strip for about $15/gallon, it's no different than OSPHO.
OSPHO sells for about the same price, marine (Boat) stores sell it, generally.

It's the same stuff.

$109/gallon must have been a typo, even POR15 is less than that

[raygreenwood]

The muriatic acid is quite a bit cheaper than the phosphoric acid. So I was planning on using that. I have my body off the pan (1966 ghia). Want to see how much liquid it actually takes to fill up the channel.

Yeah, the muriatic will work; however, before you do what you're talking about, take a few pictures of the channels and say a few last words of respect to them because they won't be there for long afterward. Muriatic tends to work for a lot longer than you expect. It's not so bad in a highly exposed areas where you can effectively neutralize it, but it's borderline impossible to neutralize when it's in a confined space.

Water alone won't flush out the muriatic and your chances of neutralizing it in such a confined space with even a highly basic solution are somewhere between impossible and never. Trust me on this one; at $13 a gallon for phosphoric, you could buy 10 gallons and not be where it would take to buy one good-quality heater channel (you can reclaim and reuse the phosphoric over and over too).

I've de-rusted enough stuff with muriatic to know that it's too destructive in anything but highly exposed areas where you can really neutralize it or on very thick material. Diluting it won't reduce the risk, either; it'll just make the stuff work slower than snail sh!t.

I'm going to take plumbers putty and seal all the bolt holes, foot vent and seams. Measure out a couple gallons of water and fill up the channel with a funnel using the fresh air tube that goes from the heater channel up to behind the dash. Once I determine how much water it takes to fill up completely, drain all the water out.

Hey, wait a sec. Rusty heater channel means you have gaping holes everywhere. If you can seal up a heater channel that way it's not a rusty channel. It might have some surface rust but that doesn't necessarily mean bad things. If that's the case, leave it alone. Pour some OSPHO in there if you're really scared of it and then just seal it with Rust-Oleum alkyd enamel or something like POR or Rust Bullet or Master Series.

Or as you say just use the phosphoric acid and be done with it. I called the tech line for the phosphoric acid and they recommend against just leaving the phosphoric acid as they said rust would return if not treated with a coating of some type.

The tech line is right. You definitely have to seal the metal after you've eliminated the rust. There's no paint on it, remember? And now it has more surface area because of the rust that pebbled the metal, so it'll rust faster than ever. I vote phosphoric acid bath, drain, rinse like crazy, maybe even neutralize with a few gallons of water with sodium carbonate (go to the pool shop), dry in hot weather or with a torch on the outside and a shop vac pulling air through the inside, and then coat with cheap-assed Rust-Oleum. Thin it a bit with mineral spirits and make it last longer. Reclaim what doesn't stick and use it in the other side.

Also I have a tendency of over analyzing stuff, thinking something to death, so that I can avoid any unforeseen pitfalls as much as possible. Also I don't want to do more damage than good.

That's a good trait. Otherwise you'd be looking at a pile of flakes in the shape of a heater channel.

Seriously, the phosphoric is a good investment and is very safe. I de-rusted a very crummy tank that's in my wife's baja. After I rinsed the phosphoric I coated it with OSPHO and left it alone. Since it's always filled with gasoline it won't rust--at least rust quickly (stock VW tanks are uncoated). I did this to the tank in my '56 Ford about 10 years ago and this spring I did it to a '32 Ford tank with perfect results--and gennie, dent-free Deuce tanks are way too expensive to risk. It's been sitting empty ever since and doesn't have a lick of surface rust.

I wish I had seen your reply back in November. You are incorrect on the issues with Muriatic acid. Its no harder to neutralize in confined areas than in the open. Its a chemical issue not a confinement issue. Simply flush it with water for quite a period of time...which is exactly why I cautioned to do this in warm weather instead of cold....if you read what I wrote.
Stick the hose in the hole and let it run. When in doubt mix 1 lb of arm and hammer in 2 gallons of water and flush it. It will be 100% neutralized then if it sets your mind at ease.
But the problem with flushing with baking soda is that its sodium. It will require as much flush time as muriatic acid will.
Muriatic acid is NOT destructive to steel. its destructive to rust. The very worst you could do is create a slight hydrogen embrittlement to the surface....not a problem in a heater channel. It makes the surface very susceotable to rust....which is exactly what we want.

Its not an option whether you use phosphoric acid or muriatic acid....its not an either or. The muriatic acid has one use only....derusting.
The phosphoric acid has one use only as well.....converting surface flash rust to iron phosphate. Iron phosphate will not readily rerust. It stays unrusted for nearly ever if you then paint it. Its a better primer than zinc diphosphate.

Phosphoric acid is lousey by itself for derusting. Its far too weak of an acid to penetrate more than .001" into flaky rust. ....and it has "0" anti-rust properties on bare metal. Leaving thick flaky rust on....means that its still growing underneath...even if you convert the surface to iron phosphate with phosphoric acid.

The object is to remove all rust over about .001"-.002" thick with muriatic acid. Then rinse well....then dry and flash rust....then treat with phosphoric acid to prevent future rust. The ONLy use for phosphoric acid is to convert very thin, evenly applied surface rust....maybe .0005" thick...wherin it can penetrate this rust from top to bare metal....into iron phosphate....which makes a superior non-rusting primer.

I've done plenty of heater channels and internal body portions with acid. The acid once its spent itself against metallic corrosion its easy to netralize because the solution strength is low.

Also...you DO NOT rinse with water after using phosphoric acid. Thats the very worst thing you can do. That weakens the bond of the iron phosphate because the surface is porus...and it can absorb water.
In closed areas like heater channels...dry iron phosphate will stay rust free for some time....like years. In hot areas over 300F like on cylinder castings it will oxidize off in months. The proper rinse if you must (and its not necessary anyway)....is with mineral spirits. On non painted surfaces....you oil them or wax them. In an area like a heater channel....just paint it....don't rinse it. That mineral spirit rinse information is already contained in the directions for most phosphoric acid.

Though my explaination may be lacking...I went to great lengths to get the chemistry correct for this. There is no risk of using muriatic acid....but there is risk of using phosphoric improperly.
These methods have been known and used long before POR-15 was in existence. They have a great product...but they are not teh authorities on anything other than their product. POR-15 uses specific practices so it can work and be warranted. Its not teh only product..and not the only method. The steel industry has been using both phosphoric and hydrochloric for surface descaling and pickling since the beginning of steel. Ray

[perrib]

THIS IS IMPERATIVE:
(Quote from Hot rod surplus)
"Whatever you do, wear a full face shield, respirator, rubber gauntlet gloves, long-sleeve shirt and long pants, and closed-toe shoes when working with any of this stuff. Chemical burns are NASTY. It's not so critical with the phosphoric, but it's imperative with the muriatic. You will remember every little mishap you have with muriatic, all the way down to etching the concrete accidentally."

It would not hurt to have a plastic or rubber full length apron, limit access to your working area when using Muratic acid. Even phosphoric acids makes your finger tips rubbery and the skin rubs off. A five gallon pail of water or a water hose near by is also needed. I have used all three methods for removing rust. The nice thing about Electrolysis is you don't have to monitor it. It goes faster if you use enough consumable electrodes.

I have used all three methods with great results.

[hpw]

Ray, thanks for the reply.
I have been thinking on this ever since you posted trying to come up with a response for getting some more direction on doing this properly. As you can see in the picture below this is the
"rust" I'm talking about(none to very little surface rust). In case it isn't clear this is behind my passenger front fender with the mud sills removed. 66 ghia vert.


Knowing this and assuming my heater channels are in the same condition, would me skipping the
muratic acid and just using the phosphoric acid only be a good idea or not I like the idea of NOT introducing any water into this equation at all. Fill all the seams, holes and foot vent with plumbers putty and take a couple gallons of straight phosphoric acid and fill the heater channel up, leave for a good half hour, drain, blow out any residual with a leaf blower hooked to the back inlet with a flex able hose. Allow it to dry for a couple days in the summer heat, then apply my master series with a long flex able wand.

And again this is me over thinking this and making sure, as someone correctly pointed out, not making a good situation worse by what I do.

[raygreenwood]

If you are sure that all the rust is very thin surface rust...phosphoric will be just fine. The issue is where there is any deep crusty rust. The phosphoric acid will not convert more than than about .001"-.002" deep. Ray

[kyle_pc_75]

Electrolysis does work. This was my first attempt, and I just kind of winged it.

You can fool the auto chargers by keeping a battery inline:





Before and after...these spring plates were off the same car. I just wiped it off with a paper towel after about 4 hours.



Kyle

[davebuckholts]

How crusty of rust will muratic acid take care of w/o having been "descaled"? Reason I ask is that inside the tunnel of my 66 has some serious rust in it and I was wondering if I can get most of it neutralized with the acid.