Thread: Rust on Lathe parts.

Originally Posted by Avery

Caustic soda has lots of uses. If you know how to handle it i am sure that it can be used safely. Someone suggested paint stripping - I am sure it can be a goodagentfor that.


For electrlytic rust removal on bits of your lathe , i would say DON"T DO IT.

Electolytic rust removal requires some dissolved salts to make the process work, Sodium carbonate , or similar, is relatively inert - very safe , and will get the job done.

Ihave no idea what would happenif you run an electric current through a bath of caustic soda, but I am guessing that the resultant gasses and liquids might be just a little bit nasty.

Any chemists out there??

I am certainly not a chemist but I have done quite a lot of reading on this matter in the last 24hrs. Some of the methods I have read about use caustic and at least one used a mix. It appears that the solution used is only to allow the water bath to be conductive and does not have any chemical relation to the process. The formula for caustic is NaOH. Nothing very dangerous there. Sodium is the worst and you eat that all the time. The only gasses as far as I am aware are the usual Oxygen and Hydrogen.

If you have read the thread mentioned in my last post you will see that paint removal is possible with caustic.

Dean

Sodium Hydroxide - NaOH - Caustic Soda

Not dangerous? Please have a look at these images.

Caustic burns on skin

Originally Posted by Big Shed

Sodium Hydroxide - NaOH - Caustic Soda

Not dangerous? Please have a look at these images.

Caustic burns on skin

Quite correct Fred. I phrased that poorly. I was referring to the nastiness of the gasses given off in the electrolosis process only. Of course the actual caustic soda itself is quite dangerous and the gasses can be explosive if confined to a restricted space so this process should only be carried out in a well ventilated area. These are the same gasses regardless of the conductive solution used.

In regards to the gasses given off there is possibly a comparison that can be made with a lead acid battery. The sulphuric acid in these could conceivably produce a more dangerous gas than caustic can under abnormal use. Sulphur dioxide is one rather nasty one that I also have to deal with at work. In normal use lead acid batteries only give off the same gasses, oxygen and hydrogen. This is my understanding of the matter but I am willing to be convinced otherwise if evidence can be provided.

Dean

Originally Posted by Oldneweng

Are you planning on a complete restoration of this lathe? Have you read Ken's thread https://www.woodworkforums.com/f65/we...ll-not-161795/? Not a very descriptive title but some great info on cleaning up and painting a lathe and some useful links.

If I get it, yes. Full strip down and going over.The vapours from caustic when mixing it are pretty nasty if you get a whiff.

Originally Posted by Oldneweng

I am certainly not a chemist but I have done quite a lot of reading on this matter in the last 24hrs. Some of the methods I have read about use caustic and at least one used a mix. It appears that the solution used is only to allow the water bath to be conductive and does not have any chemical relation to the process. The formula for caustic is NaOH. Nothing very dangerous there. Sodium is the worst and you eat that all the time. The only gasses as far as I am aware are the usual Oxygen and Hydrogen.

If you have read the thread mentioned in my last post you will see that paint removal is possible with caustic.

Dean

Nothing very dangerous with NaOH??.. what a stupid thing to say!

What you eat is sodium chloride (NaCl). basically harmless unless you have a whole range of health conditions that can make it quite dangerous.

Both the elements involved , Sodium and Chlorine, on there own are quite lethal.

Are you suggesting that you could handle sodium? It explodes violently at room temperature. H explodes with very little encouragement and O makes them burn all that much better

Any one of those elements N, O and H can kill.

There is nothing too dangerous in H2O, but if you apply it with enough vigour it can be real killer.



sodium hydroxide is a dangerous compound. it is use every day in all sorts of industries to accomplish all sorts of tasks. it is sometimes used in the domestic kitchen for cleaning, unblocking drains etc.

It is still a dangerous thing to use.

If you throw a handful of NaOH into a bucket of water to dissolve it, you will probably find that the exothermic reaction causes the water and salts to explode all over you, it could burn you, it could blind you, it could kill you.

Why would you want to use this stuff in a solution that just has to conduct electricity to remove rust?

It would be a very stupid thing to do when there are much safer, much simpler, less expensive compounds that do an excellent job.

If caustic is mixed at the recommended rate it is very dangerous.....But at the rates needed for electrolysis it is so weak it will not burn the skin, an i have not noticed any fumes like one gets when mixing it full strength.

Avery, i get you point but have you tried it? Caustic is MUCH MUCH better at removing paint, oil, grease, bog etc than washing soda. Actually a mix of both works the best.

The real point is that all Dean wants to do is stop the machine getting worse over the next few months......slather on any rust inhibitor and let it sit!

Originally Posted by Avery

Nothing very dangerous with NaOH??.. what a stupid thing to say!

What you eat is sodium chloride (NaCl). basically harmless unless you have a whole range of health conditions that can make it quite dangerous.

Both the elements involved , Sodium and Chlorine, on there own are quite lethal.

Are you suggesting that you could handle sodium? It explodes violently at room temperature. H explodes with very little encouragement and O makes them burn all that much better

Any one of those elements N, O and H can kill.

There is nothing too dangerous in H2O, but if you apply it with enough vigour it can be real killer.



sodium hydroxide is a dangerous compound. it is use every day in all sorts of industries to accomplish all sorts of tasks. it is sometimes used in the domestic kitchen for cleaning, unblocking drains etc.

It is still a dangerous thing to use.

If you throw a handful of NaOH into a bucket of water to dissolve it, you will probably find that the exothermic reaction causes the water and salts to explode all over you, it could burn you, it could blind you, it could kill you.

Why would you want to use this stuff in a solution that just has to conduct electricity to remove rust?

It would be a very stupid thing to do when there are much safer, much simpler, less expensive compounds that do an excellent job.

You are missing my point. I am commenting about your concern re the following quote from you

Ihave no idea what would happenif you run an electric current through a bath of caustic soda, but I am guessing that the resultant gasses and liquids might be just a little bit nasty.

How about we stick to the subject on hand and keep within the context of what has been said. I am talking about the "gasses" given off by the process only. You asked if there were any chemists out there. I am happy to hear a professional point of view. Your comment about the dangers are quite true but way outside the context of this situation.

I think all the dangers have already been covered at this point and if you read my posts you will see that I am using washing soda. You seem to have a strong aversion to caustic and you are entitled to that but providing that proper precautions are taken I can see no problems with caustic.

Dean

Why not try molasses this is what it does to clean up my restoration car and it is safe.







Hope this helps/

Eddie

Another point I have thought of is that both caustic soda (Sodium Hydroxide) and washing soda (Sodium Carbonate) are caustic(alkaline/base) substances. The active constituent in an alkaline solution is OH- ions. Given an equal current in a comparison with the 2 chemicals used as we are discussing, that would suggest an equal number of OH- ion in each solution and so an equal alkalinity and equal risk of injury, at those dilutions. Both contain sodium and washing soda also contains carbon.

It would appear to me that the only risk would be with the handling of the chemicals prior to being in solution. Although it has been said that washing soda is harmless this is not quite true. The following is an exert from Wikipedia

Hazards

According to the MSDS, Sodium Carbonate could cause the following hazards:

• Potential Acute Health Effects: Hazardous in case of skin contact (irritant), of eye contact (irritant), of ingestion, of inhalation (lung irritant).
• Potential Chronic Health Effects: Slightly hazardous in case of skin contact (sensitizer). The substance may be toxic to upper respiratory tract, skin, eyes. Repeated or prolonged exposure to the substance can produce target organ damage.

Dean

Eddie. I have considered molasses but my understanding is that when using electrolisis the rust that is still bound to the base metal is converted back to good metal. This preserves a little of the surface. What I am cleaning up largely consists of precision ground surfaces which I would like to keep as intact as possible. The other point is that molasses will corrode the base metal. I have read of times when a component was forgotten and was somewhat damaged. I have also read that the electrolisis process will not damage the base metal and indeed you may leave components in the setup with the power on indefinetely and it will just keep rust off it. Electrolisis is used to protect metal boats from corrosion in salt water.

Again I stress that these points are just what I have read. I have to make a decision on what method to use and based on current understanding electrolisis appears to be best.

Dean

Sodium Carbonate (sold in Woolworths under the 'Lectric' name) does not appear to be harmful when used according to directions.

Let's get some balance here. Just because it's listed in the MSDS doesn't meant it's dangerous.

Everything in moderation.

Let's get some balance here. Just because it's listed in the MSDS doesn't meant it's dangerous.

It does not hurt to know what the potential issues are. Balance is having knowledge about all the materials you use. The MSDS is the document that lists these potential issues. Discounting its importance on a public forum is not what I would consider a good idea.

It is the responsibility of every individual to read the MSDS and decide for themseves just what precautions to take for their own safety.

A lot of people have mentioned the risks of caustic. I thought I would provide some balance by quoting the risks of washing soda. Maybe not as serious but still not to be completely discounted.

Dean

Originally Posted by murray44

Sodium Carbonate (sold in Woolworths under the 'Lectric' name) does not appear to be harmful when used according to directions.

Let's get some balance here. Just because it's listed in the MSDS doesn't meant it's dangerous.

Everything in moderation.

Hello,

Thats what I used and whats recommended in Australian Wood Review # 40. Worked very well. Can thoroughly recommend it.

Not sure why this discussion got diverted to Caustic Soda.

Bill

Well guys, my lathe purchase came off and if you look at the tool gloat thread you can see what I am going to de-rust pretty soon.

This is awesome.

Rob