cadmium coating - i got fooled?

[whiz115]

Hi

Recently i've noticed that my favorite soldering iron tip, peeled off a little and since it's hard to find locally,
i decided to go to a shop which anodises metals and ask for a new cadmium coating.

I was in front watching the procedure, the guy covered with electric tape the part that shouldn't
get coated placed a wire around the tip and deeped it into the water to do the electroplating,
after around 5 minutes it was done he transfered the tip to another machine which looked like
a barel (don't know what that is... i guess it stabilizes the coating with heat or pressure?) for around
one minute and then he gave the tip to me.

problem is when i tried to use the tip, it started to peel off again this time right away! and i wonder what
went wrong? is it possible he used non cadmium coating? because he asked me "why we should use cadmium
and not tin?" (he initially didn't understood he was holding a soldering iron tip!!!)

 

[JimB]

That is the first time that I have heard of soldering iron tips being cadmium plated.

Usually they are iron plated.

JimB

 

[whiz115]

That is the first time that I have heard of soldering iron tips being cadmium plated.

Usually they are iron plated.

JimB

hmmm...because of your comment i did a small search and i understood that for years i knew wrong
that tips are cadmium plated.... there are layers of iron, nickel and chrome!

so i asked for a wrong coating? or do they also get cadmium coated?

 

[Ian Rogers]

If the iron coating has lifted, just put a new tip in... Replating a tip is "over the top" It'll take an hour or two... My tips are 3 for £4 (ish)

 

[whiz115]

If the iron coating has lifted, just put a new tip in... Replating a tip is "over the top" It'll take an hour or two... My tips are 3 for £4 (ish)

as you can see in the photo i guess only the (chrome?) layer got peeled off.

 

[unclejed613]

if the iron and nickel layers are compromised, re-plating isn't going to help. in fact what often happens is you get a small hole or crack in the plating, then oxygen begins corroding the copper core, and soon after, you go to solder something, and the iron plating crumples like a piece of tinfoil....

cadmium is one of the last things you want in contact with solder as it can badly effect the way solder flows. https://www.kester.com/Portals/0/Documents/Knowledge Base/EffectsofMetallicImpurities.pdf

 

[whiz115]

for many years i had no reason to doubt the knowledge of a good friend of mine who told me
about the cadmium coated tips...

fact is cadmium coatings are used to resist corrosion and look very similar to chrome so i had
no reason to search if indeed tips are coated with it.

if the iron and nickel layers are compromised, re-plating isn't going to help. in fact what often happens is you get a small hole or crack in the plating, then oxygen begins corroding the copper core, and soon after, you go to solder something, and the iron plating crumples like a piece of tinfoil....

You can see the exact condition of the tip in the photo.

 

[Nigel Goodwin]

for many years i had no reason to doubt the knowledge of a good friend of mine who told me
about the cadmium coated tips...

Like the others, I've never heard of any such suggestion - I presume he just made it up?.

Historically tips were copper, and didn't last long at all - so iron plating was added, and the Antex ones I use seem to last for ever?.

 

[whiz115]

Like the others, I've never heard of any such suggestion - I presume he just made it up?.

maybe he was also misinformed from somebody else, but despite that.. should the cadmium coating
peeled off so easily? i guess that's another matter right? maybe it can't last long on the nickel?
(presumably undeneath the chrome there's nickel layer).

 

[Nigel Goodwin]

maybe he was also misinformed from somebody else, but despite that.. should the cadmium coating
peeled off so easily? i guess that's another matter right? maybe it can't last long on the nickel?
(presumably undeneath the chrome there's nickel layer).

I've no idea what cadmium needs to plated on to?, but it seems a silly idea to try and have a soldering iron bit re-plated anyway.

 

[whiz115]

but it seems a silly idea to try and have a soldering iron bit re-plated anyway.

what if the bit costs 17 euro and you have to wait for days or even a month after you order it?

 

[dr pepper]

Looking at some new tips I've used there is a kind of drip on the end as if they were iron dipped rather than plated.

 

[Nigel Goodwin]

what if the bit costs 17 euro and you have to wait for days or even a month after you order it?

Buy a decent soldering iron in the first place!

 

[whiz115]

Buy a decent soldering iron in the first place!

it's a 65W pen style soldering iron with oled display on the handle, sleep mode function (when not in use
the temperature falls to a user preset value and heats up again when you lift it up, has accelerometer inside)
voltage / power consumption indication fast heat up times (less than a minute for 400c) with the 65 Watts it
can solder on large enough surfaces can do more than SMDs that i'm usualy doing, portability (can be used
with many different power supply ways, even LiPo batteries and there are options to limit power dissipation
when it's on batteries.

i think i only said few of its capabilities...what more you want from a soldering iron? i guess durability...
many times falled on the floor, i don't know if it has to do with the tip damage.

 

[Ian Rogers]

Can the tips be replaced?? Do not run an iron at 400°C unless necessary... I keep mine at 325 ~ 350°C for ever... The higher you go the more oxidization.. Cut a piece of denim to dry clean the iron and get a small tub of tip restorer..

 

[whiz115]

Can the tips be replaced?? Do not run an iron at 400°C unless necessary... I keep mine at 325 ~ 350°C for ever... The higher you go the more oxidization.. Cut a piece of denim to dry clean the iron and get a small tub of tip restorer..

has boost mode up to 450c with good accuracy and yeah generally i'm usually working with it near the temperatures
you also said, in fact 450c up to now it was useless temperature range for me...it only deteriorates the tips, of course
the tips can be replaced there's a variety of tips and i have one conical which i never use and the tip you can see
in the photo.

Guys just one thing i wanna now, despite the cadmium coating was wrong...do you think it was normal it didn't lasted
not even a single soldering?? i wanna know that because still it's metal coating and it was done with electroplating.

 

[JimB]

I have done a bit of googling and found this little snippet:

It was here:

An Introduction to Biomedical Instrumentation

An Introduction to Biomedical Instrumentation presents a course of study and applications covering the basic principles of medical and biological instrumentation, as well as the typical features of its design and construction. The book aims to aid not only the cognitive domain of the readers...

books.google.co.uk

in a book about biomedical electronics, first published in 1966, second edition 1976.
I remember 1966, oh the nostalgia!

As to why the new cadmium plating did not stick to the tip?
Who knows?

What preparation was done to the tip prior to plating?
It is usual to go through several stages of cleaning and preparation before electroplating.
Was that done in this case?
Or did the guy just do a half hearted job so that he could go back to doing something more important (to him).

JimB

 

[whiz115]

What preparation was done to the tip prior to plating?
It is usual to go through several stages of cleaning and preparation before electroplating.
Was that done in this case?
Or did the guy just do a half hearted job so that he could go back to doing something more important (to him).

JimB

No prepation at all! he just did what i describe in the first post...
i don't have knowledge on metallurgy, just now i'm searching details just because of the issue and i think he
had to remove the old coating and then deep the tip into hydrochloric acid before electroplating it.

so as i said earlier that's the reason i care to know if the cadmium coating should last or it peeled off
because he didn't cared to do proper work.

 

[unclejed613]

so as i said earlier that's the reason i care to know if the cadmium coating should last or it peeled off
because he didn't cared to do proper work.

it peeled off because it has a melting point of 321 deg C, and most solder melts between 350-400 deg C, so cadmium isn't something you would want for a coating on a soldering iron

 

[alec_t]

I've no idea what cadmium needs to plated on to?

I remember there used to be Cd-plated screws/bolts sold back in the ~70's.