Soldering iron tip treatment

[kotlec]

Hi everyone

I have bit strange question. How it is possible to make  some solder tip parts not stick with solder ?  I mean parts that has not to stick. I have problem solder running up the tip and making blob there. The very tip at thet time has very little solder left.
Im using chinese T12 tips. They are cheap but I am already tired exchanging them every few days.
 I hope you can understand my problem and share your insights. 

[kotlec]

Right one ilustrates my problem

[donlisms]

I am not very sure what is wrong, but I will say this:

I don't see anything wrong with the tip in the right.  It looks normal to me; there is not too much solder on there.

Are you able to make good joints anyway?

[kotlec]

There is no solder at the moment. I want to show that spot below ‘contact zone’ so to call.  This spot acumulates aditional solder and when i touch pcb all that solder dumps down and makes bad things. New tip like on the left hasn’t that additional solder sticking spot and works very well. I would like to "spoil" that problematic spot so that it would not receive solder anymore. Just i dont know what stuf to use .

[Benta]

Just clean the tip before soldering.
Most solder stations have a "moist spnge" for that, or just wipe with moist toilet paper. No big deal. You'll always have old and oxidised solder sticking to the tip after use.

[Solder_Junkie]

That soldering iron/station tip looks a little strange. Mostly we use either a pointed, angled or chisel shaped tip. I mostly use a Weller tip as shown below.

However, I think the issue has more to do with your technique than with the tip...

SJ

[wraper]

It wets because there is exposed iron with no other plating on top of it. To make it not wet, there is quite simple thing you can do. Clean that part from solder, for example with wet cellulose sponge (and precisely re-tin what needs to be tinned), then burn a small piece of ABS plastic on area that shouldn't attract tin at like 400^oC. There will be nasty fumes, so better to do it outside or near open window. Once it burns for like 10 minutes, you can wipe it off while still hot. It will be extremely hard to restore wettability in that area.

[kotlec]

Hey wraper

You get it. That is exactly what I was asking for .
Thanks a lot.

[kotlec]

Tryed wrapers suggested method. It worked initially as supposed. Unfortunatelly that coating wears away too fast and problem returns.
Need some better method to "spoil"  tip area that is not supposed adhere with solder.

[wraper]

Are you sure it was ABS plastic? Also it could be there was some solder left before you applied it. It needs to be done on bare tip with no solder.

[kotlec]

Yes I am sure it was ABS. Took from 3d printer reel.
I will try once more and clean more vigorously.

[Vovk_Z]

If tip of my station became 'poisoned' by something (plastic, aluminium) I just use a toilet paper and a solder with a flux. Repeat cleaning and then pouring in flux solder untill it became almost good.

[p.larner]

the issue i get mostly with small tips is then not wetting,i assume its due to poor quality ebay tips,worst is needle pointed tips i find.

[Jwillis]

You don't need a lot of knowledge in metallurgy, but a basic idea can help. All of these tips are basically copper in a stainless steel shell. Some of the more expensive tips also include a shell of chromium from the exposed steel part back to the base. Regardless of the type,  the part you want to repel the tin is case hardened steel and the part that excepts tin is not. This area of case hardening, there is more carbon contain int the alloy . So what needs to happen is the spot where the tin is wandering needs to be scraped off back down to the steel. And then Case Hardened again by dipping the hot iron into something containing lots of carbon. So Wraper's suggestion of using ABS is valid.
Basically you want to get that bit of tin off the steel so the steel can be case hardened again.

This method I use to completely recondition a really bad tip.
 I've gotten impatient with scraping and sanding and just lightly use a Dremal  to grind away the tin you don't want back down to the steel underneath. You have to be patient and careful not to grind to much, as the steel shell at the tip is quite thin. A Exacto knife and fine sand paper works just as well. You just need to get the tin off.
I turn the iron up as high as it will go and dip the tip into mineral oil and let it smoke. The little bit of tin left on the part of the tip that you want won't except carbon very well but the exposed steel will. Clean up the tip with cotton or paper towel and re-tin the tip. I've even gone as far as resharpening the tip to get a bit more life. But this will expose the copper core of the tip. If I can get another year or 2 out of a 5 or 6 year old tip then I'm happy. I use the TSS02-K  tips for the Quick TS1200A which are similar to the T12. The TSS02 tips range from 15 dollars to as much as 25 dollars each,so you can probably understand me wanting to get as much out of them as i can. 

[floobydust]

If any buildup is really bad, I use a wood block as the abrasive and rub the tip on that. There is some smoke of course but it's softer than metals. I have never used sandpaper or more since the old days of solid copper tips.

Soldering iron tip cleaner/paste might be useful? It seems to be a strong acid flux. Noob engineers love the stuff.
https://hakkousa.com/products/accessories/tip-cleaners.html

[wraper]

You don't need a lot of knowledge in metallurgy, but a basic idea can help. All of these tips are basically copper in a stainless steel shell

It's iron, not stainless steel that surrounds copper core.
Also did last four commenters even read the question. OP wants tip to not attract solder, so suggestions of how to regain wettability are exact opposite of what OP wants.

[Jwillis]

You don't need a lot of knowledge in metallurgy, but a basic idea can help. All of these tips are basically copper in a stainless steel shell

It's iron, not stainless steel that surrounds copper core.
Also did last four commenters even read the question. OP wants tip to not attract solder, so suggestions of how to regain wettability are exact opposite of what OP wants.

Good Lord man. Seems you have a hard job reading. Tips can be Stainless steel, Hardened steel or iron. Some even have a layer of chrome , other have layers of other alloys It makes no damn difference .As I said , the part that you don't want tin to adhere to needs to be cleaned back down to the steel. Then case hardened again to prevent the the tin from adhering again to that spot  That's what case hardening will do. Applying plastic does the same thing as applying any oil based product. It incorporates carbon to the alloy which case hardens it. So applying the ABS, as you said, is an appropriate method. The carbon in the alloy prevents wettability.

[tooki]

You don't need a lot of knowledge in metallurgy, but a basic idea can help. All of these tips are basically copper in a stainless steel shell

It's iron, not stainless steel that surrounds copper core.
Also did last four commenters even read the question. OP wants tip to not attract solder, so suggestions of how to regain wettability are exact opposite of what OP wants.

Good Lord man. Seems you have a hard job reading. Tips can be Stainless steel, Hardened steel or iron. Some even have a layer of chrome , other have layers of other alloys

Forget what you've read in AliExpress listings. If they're even being honest about using stainless steel, which they only say on cartridge heater type tips, it's not used on the hot end of the tip.

Soldering iron tips have to be copper because of the thermal conductivity. Steel and iron are bad thermal conductors, and stainless is a terrible one. Additionally, it's extremely hard to tin stainless steel -- soldering to it requires specialized materials. In the past, tips were just bare copper. This dissolves and pits quickly, so all modern tips are plated. Iron is the key protective plating of the working end, chrome is used to create non-tinnable areas (like OP wants), nickel is used for overall protection. See the attached diagram from Ersa, a major manufacturer. (From page 44 of the 2023-24 Ersa catalog.)

[Doctorandus_P]

You are probably using the wrong tip. T12 comes in about 20 variants, so try some other tips for the sort of soldering you are doing. I most often use a conical tip with two very small flat sides so it resembles a screwdriver a little bit.

They are cheap but I am already tired exchanging them every few days.

That is not cheap then.

I can't remember what the tips cost that I bought some 10 years ago (Probably EUR15 or so, they don't have a built in heating element) but they last many years with the amount of soldering I do. And even with 8 hour/day a good quality tip should last between a bunch of months and a few years.

Those "cheap" tips are nice to have a few different models to have on hand (Just buy the whole set) and then, for the tips that wear out because you use them often, replace those with higher quality versions.

[Wallace Gasiewicz]

Tooki is correct....
Soldering iron tips were all copper or something close to copper initially.  Then someone put a protective iron coat on them to prevent corrosion since the small tips would corrode and destroy themselves.  I think Ungar was one of the first to use iron coated tips.   
You can make soldering tips out of good copper wire (for old fashioned electric soldering irons), I have and they do not last very long but you can fix them with a file....   I have used brass rod and it works OK. Still corrodes rapidly.
The further "stainless" coating is there to keep the solder from running up the tip and keep it on the only Iron plated tip. This is a further "improvement". It is very hard to solder stainless, ever try?  Stainless tools like old dental picks do not stick to solder hardly at all.  The Nickle plating is there to accept the stainless plating.  When plating steel or iron first a Copper plate then a Nickle plate and finally a Chrome plate was used. Chrome Bumpers..   
I do not think solder sticks to Nickle very well either....The nice shiny coating you see on stainless steel is actually an "Oxide" that forms on the surface, Same thing happens with just Nickle or Chrome.    Solder does not stick to this normal coating that forms in the air spontaneously.   
I once replicated old Nickle plated screws on an antique vehicle, we used stainless screws and polished them on a wheel very well, after a few days you could not tell the stainless screws from the original Nickle plated screws.
Stainless Steel has Nickle and Chrome in it.   

The suggestions to "Treat" the area that is not supposed to accept solder probably do work for a while but the problem is that the "Stainless Coating" is no good.   
I use Aluminum based anti Seize Lubricant on old soldering parts that I do not want to accept solder or parts I do not want to corrode and get stuck. Like the inside of solder suckers and solder sucker tips. And the base of solder tips.  You can buy this at an Auto supply store. It is made for exhaust manifold bolts (also used on jet engine parts).  It is kind of a gel and with heat from the soldering iron apparently forms an Aluminum coat on the part being treated.   
Perhaps try this?    You can apply it to the cold part and then heat it up in the handpiece. It smokes quite a bit for a short time, open a window.
I think there are Copper based anti seize and Aluminum based anti seize "lubricants" I don't think the copper based ones would be helpful here. 
The coating is kinda like an Aluminum "powder coat".

[JustMeHere]

Check out a bevel tip.  Its really good at holding solder.

[floobydust]

There are many different quality levels with the T12 clone tip offerings.

I think chrome plating is applied for the no-solder zone to stop "tin climbing". Some tips have the chrome plating in the right place, others do not.
If you don't have that, it's too late OP.

Best apparently are the "Taiwan black chrome" tips but I have not tried them.

[wraper]

It says "Taiwan" tip has better T2 cooper, while Chinese uses inferior T1. However it fact T1 is the best grade

T1 pure copper has the highest content and is the purest. T1 chemical composition: copper + silver CuAg: ≥99.95. T2 copper refers to copper-silver alloy, in which the content of copper + silver elements in copper is >99.9%, that is, silver + copper + silver CuAg: ≥99.9, and there is no requirement for phosphorus. T3 copper content is: copper + silver CuAg: ≥ 99.70. T4 has the lowest copper content.

Best apparently are the "Taiwan black chrome" tips but I have not tried them.