Tapping broken taps (a.k.a. I'm all tapped out)

[Astronouth7303]

Originally Posted by sanddrag

I saw this thing on a show called Trucks! that was like a big bowl of nut shells or something and it vibrates a lot and you put your parts in there and they come out real nice after like a day. I think it was pretty expensive though.

An ultra sonic cleaner. Usually used with jewely.

The problem with mechanical means of removing R&C is that you actually remove material. They won't fit together as well any more.

[dez250]

Originally Posted by RogerR

if i recall corectly, soda does remove rust and grease (to an extent) but not as well as rust and grease removers

The truth behind this "urban myth" is the soda doesnt remove the filth, its mainly one ingredient in the soda that wil clean filth. This main ingredient is Carbon Acid. When you try to clean with soda, you gave the sugars, dyes, additives and syrups that will go onto what you try to clean and thus its dirty once again. When you use plain carbonic acid or really old soda (where the ingredients have broken down and carbonic acid is still there), you will get a clean surface and it will help prevent future deterioration. So if you are looking at cleaning it with a "soda bath" i would reccommend going to a beverage distributer and seeing if they have any plain carbonic acid that you could purchase. Other wise i would suggest you going a different route and first try a pressure washer with a degreaser or cleaner.

[Astronouth7303]

So carbonated water is the best bet?

[sanddrag]

I heard Hydroxic Acid works really well.




j/k LOL sorry, couldn't resist.

[Tristan Lall]

Originally Posted by sanddrag

I heard Hydroxic Acid works really well.

I hope that you aren't referring to the dreaded H-O-H....
+

[UCGL_Guy]

Originally Posted by Elgin Clock

NIce tip. I'll have to remember that for next year.

Anyways, speaking of cool metal related tips and tricks, does anyone have a good way to remove rust and corrosion from nuts and bolts, or large pieces like car body panels - in case you do want to finally take a chance at fixing up that '68 Chevy Engine that is sitting in your living room - (or '79 Mopar 360 as it may be in my case).

I was thinking just buying a cheap barrel tumbling kit from the craft department of the local store for the nuts and bolts, but will that work?

Is there a chemical way to remove rust and corrosion that would be faster, or easier - more for the bigger parts that won't fit in a tumbler?

I don't mind using a little (or a lot) of elbow grease, but if I can just let things get clean overnight in a solution of whatever, or in a barell tumbler, then that would be great.

You can still find places that "Hot Tank" parts for you - which depending on your part is either an acid bath or caustic. I had an engine block done about a month ago. Saw an episode of "Overhaulin" wher they acid dipped an entire car. Galvanizing places usually have a huge hot tank.
For home use there is Naval Jelly - been around for years and works pretty well. For bolts and small parts I use a grinder and a wire wheel, these throw off the bristles pretty well so make sure you wear a face shield.
But the best is a sandblast cabinet and is enviromentally friendly.
Word of caution when using chemicals of any kind. Make sure you know the hazards before you proceed. Look up the MSDS for that material on the internet or find an expert ( and then check the expert to make sure they told you right). Acid and Bases can create strong exothermic(heat releasing) reactions.
Ken

[Adam Y.]

This main ingredient is Carbon Acid

Carbon acid?? Are you sure it isn't carbolic acid? Also I just checked and there are a variety of acids in soda but nothing that starts with a C. Opps. There is an acid that is formed when carbon dioxide is in solution. Is that what you are thinking of.

[dez250]

Originally Posted by Adam Y.

Carbon acid?? Are you sure it isn't carbolic acid? Also I just checked and there are a variety of acids in soda but nothing that starts with a C. Opps. There is an acid that is formed when carbon dioxide is in solution. Is that what you are thinking of.

I mant to type carbonic acid, check later in my post, later in that sentence and you will see thats what i meant. Carbonic acid will form and remove many forms of oxides, including Calcium Oxide.

[dlavery]

Originally Posted by patrickrd

So, I'm thinking of two possible errors:
1) I didn't put in enough alum (what are the correct proportions of alum to water?)
2) The water quickly cooled to room temperature... Maybe I should keep it boiling like the instructions say.

You want the alum solution to be pretty well saturated. The last time I needed to do this, I dumped the entire container of alum - one of the little ones from the spice rack in the grocery store - maybe three ounces? - into about a pint of water. Heated it up to simmering, dumped in the part and walked away. It worked just fine, and after a few hours the part was tap-free.

Originally Posted by sanddrag

I saw this thing on a show called Trucks! that was like a big bowl of nut shells or something and it vibrates a lot and you put your parts in there and they come out real nice after like a day. I think it was pretty expensive though.

That is exactly what it was. Vibrating bowls are used to provide a number of finishing operations for metalworking. A number of different materials are used, based on the finish desired or the rust/scale/crap to be removed. Ground walnut shells and fine playground sand are two of the more common materials. Left in the vibrating bin long enough, ground walnut shells will provide a nice polish to most metal parts.

[EDIT]There is a simple tumbler design here that will work very well for cleaning and polishing small parts.[/EDIT]

Originally Posted by Astronouth7303

An ultra sonic cleaner. Usually used with jewely. The problem with mechanical means of removing R&C is that you actually remove material. They won't fit together as well any more.

Ultrasonic cleaners will work real well to remove grease, oil and even old paint. They ususally don't do so well will rust and scale.

If you are specifically looking to remove rust, there are several ways. For small parts, or light rust, several methods already mentioned (Naval Jelly, steel wool, sandblasting, etc.) work quite well. If you have a lot of items to de-rust, or it is very deep into the part, you can try rust removal by electrolysis. For this method, you place the iron/steel part in an alkaline solution, pass an electric current through the solution, and blast some of the ferrous oxide back into good metal (you hope). There are good instructions on how to do it here and here. I have used this method once, and have a friend who does this a lot when restoring old machine tools, and it works quite well. And, yes, the resulting solution really is as nasty looking as that crud in the second link...

-dave

[Adam Y.]

I mant to type carbonic acid, check later in my post, later in that sentence and you will see thats what i meant. Carbonic acid will form and remove many forms of oxides, including Calcium Oxide.

Hmmm... If you really want to use something like carbonic acid in large amounts why not get dry ice. It's easier to use.

[Lisa Perez]

Originally Posted by Adam Y.

Hmmm... If you really want to use something like carbonic acid in large amounts why not get dry ice. It's easier to use.

.. Dry ice is CO2 and carbonic acid is H2CO3, though. They wouldn't react in the same manner. In fact, dry ice would sublimate way too quickly to have any kind of reaction with a metal oxide

[Adam Y.]

.. Dry ice is CO2 and carbonic acid is H2CO3, though. They wouldn't react in the same manner. In fact, dry ice would sublimate way too quickly to have any kind of reaction with a metal oxide

Carbonic acid is CO2 dissolved in water. Thus dropping dry ice into water will form the acid. I have seen this done before though I never knew that the acid was strong enough to do anything.

[Lisa Perez]

Originally Posted by Adam Y.

Carbonic acid is CO2 dissolved in water. Thus dropping dry ice into water will form the acid. I have seen this done before though I never knew that the acid was strong enough to do anything.

Yeah, that's true, I thought you meant just direct application of the dry ice . Plenty of CO2 gas would escape, though. To make the weak acid a little bit stronger and thus more effective for the reaction.. one could increase the solubility of CO2 in H2O by altering the temperature/pressure of the room, I believe




Whoa. Yeah. On the topic of dissolving broken taps, couldn't one find an ion solution in which the ions had a greater (or lesser? ) standard potential than the ions of the metal used for the tap, but a lesser (or greater?) standard potential than whatever material is being used for the robot? And then just pour that solution over the tap for a redox reaction?

[Spaztik Duck]

Originally Posted by Lisa Perez

one could increase the solubility of CO2 in H2O by altering the temperature/pressure of the room, I believe

alteing temp or pressure will work.

a lower temp allows more gas to disolve in a liquid and a higher temp allows more solid to disolve in a liquid.

I cant think about pressure now though... brain is too tired.