Bridge City Tools followup

[iublue]

I want to thank all that responded to my earlier post about Bridge City Tools customer service.  I started a new thread to post the resolution of the problem.  Here is a link to the original thread.

https://www.forums.woodnet.net/showthrea...id=7337520

After posting my problem here and photobug (thank you) linking that thread to BC., I was in contact with Consuelo Cao the Customer service manager.  She is the one I originally spoke with when this whole process started.

She stated that the guy who did the repairs/cleaning was not available at that time and he would be back in a couple of weeks and he would look at the tools at that time.  She contacted me when he returned and I was told there was nothing that could be done with the black spots on stainless steel components but the other tools (brass-rosewood) could be cleaned and re-calibrated.  I was also asked if I wanted the tools that couldn't be cleaned back or wait until they all were returned.  I waited.

It was about 2-3 weeks later she contacted me and said they were all done and they would be shipped out.

I received the box and the tools were well packed.  The brass/rosewood tools were all cleaned and mostly looked like new.  The stainless items, rules and straight edge, which I had already been told they couldn't do anything about, were untouched.  The only small issue I had was the adjustable square that had a brass/rosewood head with a stainless steel blade had not been touched.  I guess he didn't do anything to it since it had a SS blade.   I can clean the head, not a big deal in the scope of things.

I want to thank Consuelo Cao, the service manager, for resolving this issue, getting my tools looked at and returned.

For the record, it was $45 that I paid for the Founders Club, not $75.  When I originally checked on the FC, it was $75 but when I signed up, like two years later, they did have the lower level that I paid.

[Alan S]

You should post this at the end of the other thread (a link to this would do) so people who find that thread know the outcome.

[Cooler]

Our company works with stainless steel (production parts) on a regular basis.  Bridge City Tools' response about the black mark on the stainless steel is accurate--to a degree.

Note:  The original response to this got too long-winded and this is the heavily edited version--I don't think I left anything critical out of this.

It is important to understand that stainless steel is not entirely rust proof--it is merely corrosion resistant.  

There are two basic types of stainless steel we encounter:  300 series and 400 series.  The 300 series is more corrosion resistant, but cannot be heat treated.  The 400 series is less corrosion resistant but can be heat treated and it is the type used for cutting implements like knives.

All stainless steels are regular steel alloyed with chromium and nickel and sometimes some other elements.  It is the chromium oxides that create the corrosion resistant barrier.  Chromium oxides are naturally occurring, but to make sure the entire surface is protected by the chromium oxides a either of two processes are employed:  Passivating or or electro-polishing.  

For many applications no additional passivating or electro-polishing is required.  Most tools would use the stainless steel "as machined" or "as stamped".  Medical parts and stainless steel mugs, for example would be passivated.

Passivating is done by immersing the component in acid (citric acid and nitric acid are the most common types of passivating) and rinsed.  The acid removes a minute amount of the surface leaving a pristine layer of stainless steel with an uninterrupted surface of chromium oxide.  

It also removes contaminants.  

Minute amounts of the tool steel used to form or machine the parts can get embedded in the surface of the stainless steel.  Those minute particles of iron rust and leave dark spots.  

The only real ways to remove those spots and make sure that they do not happen again is to have the parts passivated or electro-polished. 

But since the component was not originally passivated, Bridge City Tools' response should have read, "There is no way for us to eliminate the dark spots with processes we do in-house".  

The parts could be passivated.  That would require an outside vendor perform the work.  Most of these vendors have a minimum to do any work that varies from $50.00 to $250.00.  Our passivation vendor has a minimum of $75.00 the last time I checked.

Passivation removes a minute layer of the material.  It does so fairly evenly, so scratches and imperfections will remain.  They will just be cleaner and brighter.  A smooth surface of 300 series stainless steel will rival the appearance of chrome after passivating.

If that dark spot is really objectionable you can try to locate a local plating vendor that does passivating.  If you tell them you are restoring an old tool they might cut you a break.

The other alternative is to electro polish the parts.  The is like electro-plating with the polarity reversed.  You are plating "off" from the part onto the electrode.  The electro polish results in a higher degree of polish than passivating, but it also will not eliminate any surface scratches.

About two pages of typing are on the cutting room floor--eliminated from this post.  

If you go to get this passivated you must request "nitric acid" passivation.  The citric acid passivation will protect the surface from corrosion but will leave an ugly dull finish with highlights of grey, muddy blue and muddy green.

As a side note the reason stainless steel mugs come with the advisory that you should not use chlorine bleach to clean them, is because the chlorine bleach will damage the chromium oxide layer and will invite rust.

[iublue]

Our company works with stainless steel (production parts) on a regular basis.  Bridge City Tools' response about the black mark on the stainless steel is accurate--to a degree.

Note:  The original response to this got too long-winded and this is the heavily edited version--I don't think I left anything critical out of this.

It is important to understand that stainless steel is not entirely rust proof--it is merely corrosion resistant.  

There are two basic types of stainless steel we encounter:  300 series and 400 series.  The 300 series is more corrosion resistant, but cannot be heat treated.  The 400 series is less corrosion resistant but can be heat treated and it is the type used for cutting implements like knives.

All stainless steels are regular steel alloyed with chromium and nickel and sometimes some other elements.  It is the chromium oxides that create the corrosion resistant barrier.  Chromium oxides are naturally occurring, but to make sure the entire surface is protected by the chromium oxides a either of two processes are employed:  Passivating or or electro-polishing.  

For many applications no additional passivating or electro-polishing is required.  Most tools would use the stainless steel "as machined" or "as stamped".  Medical parts and stainless steel mugs, for example would be passivated.

Passivating is done by immersing the component in acid (citric acid and nitric acid are the most common types of passivating) and rinsed.  The acid removes a minute amount of the surface leaving a pristine layer of stainless steel with an uninterrupted surface of chromium oxide.  

It also removes contaminants.  

Minute amounts of the tool steel used to form or machine the parts can get embedded in the surface of the stainless steel.  Those minute particles of iron rust and leave dark spots.  

The only real ways to remove those spots and make sure that they do not happen again is to have the parts passivated or electro-polished. 

But since the component was not originally passivated, Bridge City Tools' response should have read, "There is no way for us to eliminate the dark spots with processes we do in-house".  

The parts could be passivated.  That would require an outside vendor perform the work.  Most of these vendors have a minimum to do any work that varies from $50.00 to $250.00.  Our passivation vendor has a minimum of $75.00 the last time I checked.

Passivation removes a minute layer of the material.  It does so fairly evenly, so scratches and imperfections will remain.  They will just be cleaner and brighter.  A smooth surface of 300 series stainless steel will rival the appearance of chrome after passivating.

If that dark spot is really objectionable you can try to locate a local plating vendor that does passivating.  If you tell them you are restoring an old tool they might cut you a break.

The other alternative is to electro polish the parts.  The is like electro-plating with the polarity reversed.  You are plating "off" from the part onto the electrode.  The electro polish results in a higher degree of polish than passivating, but it also will not eliminate any surface scratches.

About two pages of typing are on the cutting room floor--eliminated from this post.  

If you go to get this passivated you must request "nitric acid" passivation.  The citric acid passivation will protect the surface from corrosion but will leave an ugly dull finish with highlights of grey, muddy blue and muddy green.

As a side note the reason stainless steel mugs come with the advisory that you should not use chlorine bleach to clean them, is because the chlorine bleach will damage the chromium oxide layer and will invite rust.

This has been a good day since I learned something from you!  Thanks.

A question, Two of my SS tools are rules.  Would passivating those destroy the measuring marks?  I am pretty sure they are engraved/etched into the metal.

TIA

[Cooler]

This has been a good day since I learned something from you!  Thanks.

A question, Two of my SS tools are rules.  Would passivating those destroy the measuring marks?  I am pretty sure they are engraved/etched into the metal.

TIA

Passivating will remove everything that is not stainless steel.  So the paint will disappear but not the engraving (if it is engraved).  If it is engraved you can fill in the engraving with paint.  

I'm not sure that passivating a rule is a really good idea.  Most stainless steel rules have a matte finish to improve readability.  The extra shine from passivating may make that less readable.  I really don't know if it will or will not.  I would skip the rule unless you are seeing rust spots.

I was in the Farberware factory in the Bronx, NY in the early 1970s.  They were stamping out pots and pans.  I expected to see big tool steel forms that the stainless steel sheet was formed over.  But the forms were made from Anco bronze (a very hard grade of bronze).  The engineer told me that the heat generated in the stamping process would forge weld bits of the surface of the pan to the tools if they were made from tool steel.  The bronze solved that issue.

Stainless steel has a property that I've heard called "galling".  It is discussed here in relation to nuts and bolts:  http://www.atlanticfasteners.com/tech-ti...fasteners/

Thread galling seems to be the most prevalent with fasteners made of stainless steel, aluminum, titanium, and other alloys which self-generate an oxide surface film for corrosion protection. During fastener tightening, as pressure builds between the contacting and sliding thread surfaces, protective oxides are broken, possibly wiped off, and interface metal high points shear or lock together. This cumulative clogging-shearing-locking action causes increasing adhesion. In the extreme, galling leads to seizing – the actual freezing together of the threads. If tightening is continued, the fastener can be twisted off or its threads ripped out.

I suspect that galling is the cause of your dark spots.  Some of the tool steel used to form the component got embedded in the surface and that bit rusted.  

Was this 400 series (probably only the blade was 400 series) or 300 series (300 series polished up much nicer and is preferred for that reason).  The 400 series will stick to a magnet pretty well.  The 300 series will have only the slightest pull to a magnet.

The hot water pot I got for my induction cooktop has a 400 series (magnetic) bottom and the balance is 300 series and has a high polished finish.

As an aside, those tablets that are used to clean dentures and fizz like Alka Seltzer generate sodium peroxide, and that will eliminate all organic materials.  You can safely use that on the stainless steel mugs that say "no chlorine" and they will clean just as well.  They will also clean pitch off of saw blades (but oil them afterwards).  It will also safely clean tea stains from cups and saucers.  It is a safe and handy chemical to keep around.

Very strong solutions of hydrogen peroxide are sometimes used for passivating.  I don't know what the appearance is for that process.  It is supposed to be relatively "clean".

A salesman tried to sell our company hydrogen peroxide so we could passivate in house.  He he said that we could legally flush hydrogen peroxide down the drain and no EPA filing was required. True if you are flushing un-used hydrogen peroxide, however once it is used it is loaded with chromium, a heavy metal that that is not permitted.