ACID TREATING - Crust/Rust to Primer

Need help straightening that dent? Or painting your car? This is the place to be!
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MNAirHead
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Post by MNAirHead » Mon Mar 24, 2008 11:11 am

Daniel...

Do you care about the colors etc.

If it's a quick and temporary, there are some industrail "coating" paints (not oil) that will hold your steel until it can be restored.

Looking to help.

T.

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Daniel G
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Post by Daniel G » Wed Mar 26, 2008 1:51 am

MNAirHead wrote:Daniel...

Do you care about the colors etc.

If it's a quick and temporary, there are some industrail "coating" paints (not oil) that will hold your steel until it can be restored.

Looking to help.

T.
Well, I am not really particular about the color, provided it's not hot pink or neon green... :lol: ...But black or gray is what I would like to have, since I will be driving the bus and want it to look nice underneath.
I thought about it some more, and for all the trouble I would have to go through with the acid and everything else, it would probably be worthwhile to just use por-15 in the first place. I could always just do a section at a time as I do the rust repairs...and it could take longer than expected for me to be able to redo the undercarriage, so that would probably be the best route...


But for my rusted engine tin, etc, acid is going to be the way I go...I got a couple gallons of acid, diluted it 50%, and put it in a plastic tub with my engine tin...Rust, paint, and most of the grease was gone after a couple hours of soaking. I used ammonia to neutralize the acid, and it worked great...But it did make some fumes which I am assuming aren't good for me...But I was outside, and I avoided breathing them. The only downside is that the backyard now looks like a meth lab... :lol:

I have another question...Would the hydrogen embrittlement be an issue on a sandrail frame? I'm assuming it will...

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MNAirHead
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Post by MNAirHead » Wed Mar 26, 2008 2:09 am

For your temporary touchup..

I'm a big fan of zero rust.. it's low cost and comes in small containers or ratttle cans... not an appearnace grade product but works good for this type of use.

Tim

hpw
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Post by hpw » Sat Mar 29, 2008 6:29 am

Kinda of a shot in the dark, but has anyone tried to spray the inside of

heater channels using this muriatic acid technique?

I have a pretty rust free 66 ghia vert and want to keep

it that way. I have been searching like crazy trying to figure out a way

to get in there and treat for rust. Was looking to use something

like this to get into the cavities.

http://www.chemicar.com/spraygun_under.php

Image

Drilling holes to get in between the

extra plate used for stiffening the convertible. After letting it all

dry(blow dryer?) using either por-15 or the ospho to treat the inside.

Than using rubber plugs to seal the holes.



http://www.eastwoodco.com/shopping/prod ... uctID=1110

ANYONE have any insight on this subject that has attempted this or am I

an idiot for trying to come up with a idea like this?


By the way that gun is 200.00, not cheap.

These are the rubber plugs from eastwood.

Image

ckiablick
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Post by ckiablick » Sat Mar 29, 2008 9:40 pm

I am pretty ignorant as to the chemical part of this (hence, why I am reading this). But I do have an idea to use as an alternative for your expensive spray gun (that can also get into tight places).

I've painted tough to reach places with an engine cleaning wand. I know it sounds crazy, but it actually works ok. From the few times I've had to do it, I like running a high pressure with lower paint feed to make what I am spraying reach far into the channel. Also with one of these wands (if you were acid treating), you could attach a rubber hose and pull it out of the channel as you are spraying. I'm not sure how the hose would react to the acid. Also, cleanup is a breeze because all you do is take the siphon hose from the wand and dip it in your cleaning agent (paint thinner, water, etc...)

Obviously not ideal, you will be suprised at how well it does work. If painting a surface you cannot hit at 90 degrees, just remember to do thin coats. Also, HPW, in your specific case I would be weary as to the effects of the acid on your existing paint (the other guys were talking about this stuff eating up concrete).

My plan for a Baja I'm working on (where we are no longer using the heater channels) is to spray hydrolic oil in the channel after it is painted. What some may call "ghetto" or "cheap" I think the hydrolic oil will climb unlike other rust prohibiting agents. If you still use the channels for heat, they do not get hot enough to ever ignite this low volume of oil. Reminder, if you plan to paint in the near future, the oils presence may raise havoc (fish eyes, etc...) wherever it gets. In my case, the car is going to be freshly painted prior to oil application.

hpw
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Post by hpw » Sun Mar 30, 2008 5:03 am

thanks for the reply, but the type gun you are referring to, is this it?


http://www.sjdiscounttools.com/mtn9344.html

ckiablick
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Post by ckiablick » Sun Mar 30, 2008 4:12 pm

Thats the ticket! Looks exactly like the one I used! With the tapered tip, it might take a little creativity (or alot of duct tape) to get working with an extension hose (more for oil, not paint). If using a paint type product, I'd keep a low volume feed of the fluid, with high relative pressure to reach the far areas... utilizing a couple coats. Plus, how can you go wrong for $10... and its easy to clean by siphoning a solvent.

(I know some of these points are repetitive... just thoughts in the process)

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raygreenwood
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Post by raygreenwood » Mon Apr 14, 2008 3:05 pm

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

ckiablick
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A couple questions

Post by ckiablick » Thu Apr 24, 2008 1:52 pm

Hello again.
I just used this stuff for the first time... and its awesome! I tried a few different materials to experiment with... and you were not joking about the aluminum!

My question now is, what is the best way to get rid of my used acid bath. I was going to drink it, but the rust flavor is not my cup of tea (joke). I don't want to poor it down a drain because I saw what it does to rust. What do you guys do? Another thought was to leave the bath exposed to the sun and see what evaporates to then hopefully over time have a solid or sludge that could be contained and disposed of.

P.S. If anyone wants the chrome plating from an old aluminum Mustang fuel cap... cap not included, let me know!

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MNAirHead
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Post by MNAirHead » Thu Apr 24, 2008 1:56 pm

I bring mine to the county recycler. I do them a favor and clearly label what the material is.

Our county does not charge for this.

Tim

ckiablick
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Post by ckiablick » Thu Apr 24, 2008 4:45 pm

Thanks Tim,
I'll see whats available in my area.

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MNAirHead
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Post by MNAirHead » Fri Apr 25, 2008 9:12 am

Thought some of you guys may be interested in this.

At work a customer wanted to know about "green" rust removal.


I've found a couple of methods that work well for removing corrosion. NOTE: These methods are neither degreasers nor paint removers. They may remove some grease and/or paint, but only if there is underlying corrosion. If you want to completely clean a part, remove the paint and/or grease before you tackle the rust.

Electrolysis:
I prefer to remove rust using electrolysis. This is a simple procedure that is particularly well suited to large parts and will not damage the original parts in the way that chemical or manual removal will. The method is simple: submerge the rusted part and an electrode into a "magic" solution, then pass a current between the two using the solution as a conductor. The solution is made of 1 tablespoon of washing soda (not baking soda) per gallon of water. Add the soda to the water, and use warm water to help dissolve the soda (it doesn't matter if the water gets cold later). The electrode can be made of any ferrous metal (iron) or stainless steel. I have used a railroad spike and an old steel dust pan; if it rusts, it's probably fair game. Don't use galvanized metal or aluminum. You want the electrode to as large or larger than the part you're working on (the bigger, the better); you can't use a nail to clean a bumper. Although the process will not harm the original part, it will destroy the electrode (unless the electrode is made of certain alloys of stainless steel), so don't use the wife's good pans.

To de-rust a part, place the part in a non-metallic container (garbage can, glass baking pan, plastic bucket, etc.). If you have an odd-shaped part, make your own container. I've used garbage bags inside cardboard frames. Place the electrode close to (but not touching) the part. You can put a sponge in between them to keep them apart. Any area that is to be cleaned must be submerged, and it works more efficiently on the side of the part closest to the electrode. If possible, form the electrode to go completely around the part.


Attach the negative lead from a battery charger to the part, and attach the positive lead to your electrode. NOTE: Polarity is crucial. You MUST attach the negative lead to the part. If you get the polarity wrong, you WILL destroy the part. As I mentioned earlier, this procedure does destroy the electrode. It will also destroy the clamp on your battery charger if the clamp is submerged. I suggest attaching a length of heavy gauge wire to the electrode, then attaching the lead from the charger to the other end of the wire outside of the solution. Turn on the battery charger, and watch the action. You should see small bubbles coming from your part, and you should see a small current draw (2-4 amps) on the ammeter of the battery charger. If you have an automatic battery charger, you may need to set it to the "start" position, as the small current draw will fool the charger into thinking its attached to a fully charged battery, so it will shut down. If you don't see anything happening, make sure you have good connections, make sure the parts are close, and make sure your charger is putting out current. You can also stick your hand into the solution (it's harmless). You will feel a slight tingle from the current.

After the process has been working for a while, you will notice that the solution is quite disgusting. It doesn't matter; it will keep working. Let it go for a couple of hours. You can't damage your part doing this, so you can't leave it too long. When you pull the part out, the formerly rusted areas will be black. You can remove this by rubbing lightly with your fingers, a plastic pot scrubber, or your wife's toothbrush. If the black doesn't come off, put it back in the solution for a little while longer. You shouldn't have to use steel wool or a scouring pad.
When you're done, you can just dump the solution out. It's harmless and non-toxic.

Vinegar:
If you have smaller parts, you can derust them using plain vinegar. Submerge the parts in the vinegar, then heat the vinegar on a stove or hot plate. This will stink. If you do not live alone, do it outside or when no one else is home. NOTE: Vinegar is acetic acid. After removing the rust, it will continue to slowly eat away at the part. It will also leave the part with a "pickled" or weathered look. As such, you must be careful if you're using vinegar (or any acid) to remove rust from parts that aren't destined to be painted. You should also note that the vinegar will have the same effect on any container used to hold it. Either use an old pot, can, etc., or use glass.

Final cleanup:
After the rust is removed, you must be careful that the parts don't immediately rust again. I have found that a quick dip (or wipe) in rubbing alcohol or paint thinner helps to displace any residual water. Follow this with a couple of minutes in the oven or a once-over with a hair dryer and you should be fine.


There is also a process using Molasses called “chelating”

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hotrodsurplus
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Post by hotrodsurplus » Wed Jun 04, 2008 2:42 pm

Hey there. My name's Chris and I post a bit to the off-road forum. Maybe Tim can vouch for me. This is a good topic. I have a few things to add.

I drove a car in bare metal for two years. Even in southern california it was a constant battle (and yes, I oiled the car regularly). Here are a few things I learned.

I really like phosphoric acid. As ray said it's the main component in ospho. It's also the primary component in automotive metal prep. It works a bit slower than muriatic (30%HCL), but it's considerably more friendly to use (it won't immediately burn you if you get splashed and you won't burn your eyes or lungs unless you really get down on top of the stuff). Kleen Strip offers it in gallon sizes. The last time I bought some at the Great Orange Mecca it was $13. It will not cause that residual flash rusting as muriatic will. Use a red Scotch-Brite pad and it'll cut through even nasty stuff. At the same time, I'd limit its use to removing heavy surface rust. You can also dip your hardware in it and it'll come out sparkly. Water is good enough to neutralize the effects of the phosphoric acid.

Kleen Strip also makes an automotive metal prep that's a bit more aggressive than the straight phosphoric. It also has zinc phosphate in it, which leaves a streaky white film on the bare metal that prevents rust from setting in for quite a while. The major paint companies have similar products, but for some reason they ain't as strong. Again, water will neutralize it.

To keep flash rusting at bay after I cleaned everything, I'd wipe it all down with automatic transmission fluid. Use Mercon if you're a Ford fan; Dexron if you like every other car in the world that has an automatic :) . Whatever you use, make sure it has no silicone in it. That will wreck a surface that you intend to paint. Contrary to popular belief, WD-40 is perfectly safe to use on any surface that will be painted. It has no silicone. I used WD at first, but it gets sticky fast and turns things into dirty, bearded stuff. The ATF is clean. In fact, it cleans the metal pretty well.

Now for muriatic. I've sloshed it on and dipped things in it. It works like magic...too well if you're not careful. It'll render a stamped part to lace in hours. I'm a crazy bastard and I use it full strength (muriatic is only 30% HCL; the rest is just water for a buffer). I dip a lot of hardware into the stuff with great results.

I hated the flash-rust problem so I'm one who neutralizes. I use sodium carbonate (wash soda) NOT sodium BIcarbonate (baking soda). I get it at pool supply stores. Look for something that increases the PH (PH UP! for one). You can probably find it pretty close to the muriatic if you buy it at a pool shop.

I mix a handful or two into a gallon pail and paint the stuff on or drop hardware in it. Even though I keep my acids well away from the sodium carbonate solution out of sheer principles, I've poured small amounts of acid into the sodium carbonate solution without catastrophic results. It just foams up and turns green. I'm sure it's on account that the solution is so weak that it's more of a buffer than anything. I'm sure mixing muriatic with a very high PH compound like bleach would be awful, if not fatal. Don't do it.

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.

I'm also a really big fan of the electrolytic rust conversion. I've done a fair bit. I lined a five-gallon pail with half a dozen strips of 1/8x3/4 strap for my anode (it's a line-of-site operation, so the more you have the better). It goes without saying that I use a plastic bucket, but I thought I'd bring it up nonetheless. My anodes bolt to the rim of the bucket and go to the bottom. I connect them with plain copper wire outside the bucket. Just make sure that your part to be derusted doesn't touch the anode(s). Use an ammeter to make sure that the current flow doesn't get too high. Some battery chargers have them. I've used the 10-amp current on my charger but I keep the actual current in the lower digits. Sodium carbonate concentration, number of anodes, distance from the anode(s) to the part, and part size itself will influence current flow. Oh yeah, you want to use the sodium carbonate (wash soda), NOT the sodium BIcarbonate (baking soda) for your solution. A few tablespoons to a couple gallons is enough. A stronger solution will not necessarily work better.

A few things to know about electrolytic rust conversion: it releases hydrogen. That's what made the Hindenburg go BOOM (oh the humanity!). It's not much, but you don't want to do it in a sealed, confined space and light a crack pipe, but that goes without saying too. When I do it, I just make sure to crack the garage door and window open so I get good circulation. Also, as long as you don't have oil or any other foreign substance in your de-rusting pail, the stuff is safe to dump. It's just sodium carbonate and a bunch of ferric oxide. It might even make your lawn nicer if you have low-PH soil. :)

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raygreenwood
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Post by raygreenwood » Tue Jul 08, 2008 11:07 am

The thing that is nice about the flash rust....is that it makes for a perfect bonding agent for the other ingredients in products like ospho.

Ospho is a combination of phosphoric acid and a couple other ingredients. It is not entirley designed to get rid of rust. It is designed to convert the rust to...I think iron phosphate.
Rust converted to Iron phosphate makes a better primer than ANYTHING known...except maybe zinc chromate.

So...don'tworry about that rust flash after using muriatic acid. Let it rust, then convert it with ospho...then paint it directly. Perfect. Ray

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MNAirHead
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Post by MNAirHead » Tue Jul 08, 2008 2:22 pm

Thank you..

Ray.. do you use an etch primer directly over the Muriatic acid .. or what exactly.

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