Hakko 936-12

[bigbeark]

I have not been successful in tinning the tip (chisel) of this iron. It seems to repel the solder. I use the standard chisel tip that came with the iron.

My experience with this iron is that it works well only at the highest setting. Anything less and the solder refuses to flow into the joint. Just replaced a "nest" of 6.3v 1000uf caps on an old SOYO board and found the heat available was only just sufficient.

I seem to be getting good joints and have successfully recapped about 10 boards.
I like it when my solder joints resemble the factory joints, but I sometimes find the solder wants to flow onto the cap leads and not into the joint. This is minimized if I trim the leads to a short length before soldering in the new caps.

Do I need to service the iron in some way?

I also have an inexpensive 50watt needle tip iron, works well, but totally inadequate heat for attaching caps. I use my solder sucker on the front of the board, and briefly hold the needle tip on the solder in the hole on the back of the board. releasing the button results in clearing of the hole. I'm sure my technique will make a purist wince, but it's quick and effective, but perhaps removes too much solder.

Occasionally in tight locations I will use the heated pin technique. This seems to move the solder out of the way, but leaves it near the hole, so the new cap can use it.

Seems like a nice method but more fiddly

So please offer suggestions/criticisms of my soldering technique or lack thereof,

[shadow]

Re: Hakko 936-12

It seems like your tip has oxidised.
This can be attributed to a very large number of factors.

If you storing the soldering iron for a extended period of time, it will corrode slowly due to being in air and/or moisture in the air. What I do to help prevent this problem is to ensure that the tip is tinned before I store the soldering iron. The solder (which tins the tip) will corrode, however when you use the soldering iron again this can be removed. The heat from the iron will melt the solder and it can be wiped onto a sponge.

I am unsure about your soldering habits, however forcefully cooling the soldering iron in water is a huge no no as well.

There are probably a huge number of other attributes which contribute towards the tip oxidising.

My suggestion is to replace the tip with a new one and try your best to preserve the integrity of the new tip. If you do not care about damaging your tip, you can try gently filling the tip so that the rust is brushed off. There are consequences for this, however you will be able to use the tip under normal temperatures for a while.

[i4004]

Re: Hakko 936-12

use higher temps only when you need them...once done with mobo work, decrease the temp to 200, then tin it, and turn it off...

too much heat means tip will become very black very fast...
and then you use higher and higher temps, which only makes things worse.

also, follow the mfrs manual when it comes to first-time tinning....
it's important to tin it as soon as it can melt solder, because if you wait for too long it'll burn and then solder won't stick to it.

there should be some things to clean the oxidized tips..check 2nd and the last link here
http://www.cooperhandtools.com/brand...=Miscellaneous

[willawake]

Re: Hakko 936-12

tip tinners or refreshers are good
i use the goot one

quite a good article about tips https://cdn.badcaps-static.com/pdfs/...0f3c5eebaf.pdf

need to be careful filing the tip or will damage it. if you see copper you just did. i dont recommend

[Krankshaft]

Re: Hakko 936-12

I recommend one of these to anyone soldering.

http://www.hakkousa.com/detail.asp?PID=749&Page=1

Hakko included it with their FX-951 and I love it. I just plunge the tip into the brass shavings and tin the tip before I return the iron to the holder and it cleans the tip perfectly. It doesn't scratch the tip because brass is a softer metal.

Just open the bottom every now and then to to dump the solder deposits.

Also my optimum soldering temperature on my Hakko is 350 C or 662 F I just leave it there almost all of the time when soldering small boards like PSUs and TV/Monitor PCBs. Higher temps will cause serious oxidation.

Cleaning your tip regularly during use will also help heavy oxidation deposits from accumulating. Just be sure to re-tin when you do. In any case always clean and re-tin before you turn the iron off.

[Krankshaft]

Re: Hakko 936-12

I agree with the others the reason the heat seemed "just adequate" is probably because the tip was so badly oxidized that it was blocking efficient heat transfer into the PCB.

You're lucky your tips are like 6 bucks my tips for my 951 start at 14 bucks all the way to 70 (integrated heating element) . I am very careful with my tips.

Hakko tips are pretty robust with a thick iron coating treated properly they seem to last a real long time.

[larrymoencurly]

Re: Hakko 936-12

I think the tip is contaminated or oxidized because I can unsolder mobo caps OK but not well with a 40W iron and have no problems at all soldering in new caps with it. This iron works better than my adjustable 10-60W at 40W, so I thought the former was drawing more than its rated power, but a Kill-A-Watt showed that each iron drew almost exactly 40W. OTOH dirty tips have prevented solder from sticking at all or sometimes even melting

I quit using sponges to clean tips because they either don't remove enough junk, or something from the sponge gets onto the tips. I've had much better luck with dampened paper towels, but that curly brass wool that Willawake mentioned works better than anything. I get it at dollar stores, which also carry copper and stainless steel versions.

[bigbeark]

I cleaned the tip

I used some fine steel wool to clean the tip, then tinned it at the lower temperature. It wasn't heavily corroded, just slight oxidation. so no damage done.

Seems to work better now, although there are places on some boards where the heat is no more than adequate.

So I am able to use somewhat lower temps. My model does not have a temperature readout. I know when the solder "smokes" that the iron is too hot, so I turn it down a bit.
Don't know what's in the smoke, but can't be good for you.

When I remove the smallest caps they feel a little warm, but definitely not 105C!

Thanks for the soldering advice!

[Krankshaft]

Re: Hakko 936-12

That smoke is burning flux it's the flux keeping oxygen away from your joint and removing oxides on both the trace and the component lead from oxygen exposure prior to soldering. When it stops smoking and is depleted is when you need to worry about bad joints .

I forgot to mention the size of your tip affects heat transfer as well if it's too small you will have heating problems.

For example using a 1.0mm needle tip for SMT work on through hole is not a good idea and will produce crappy joints.

I tend to prefer the conical tips for through hole.