[JimB]

I'm anxious to get started on my AKSA 100n. I will need to buy a soldering iron. I have found there are quite a few choices out there. Does anyone have a recommendation on the most appropriate type?  I'm leaning toward a 25 amp Weller or Hakko. Would a variable wattage set-up be worth the extra money?

Thank in advance for any replies. (I'm new here.)

-Jim

[AKSA]

Jim,

Go for the Hakko.  The Weller approach is rather dated now, and I've never much cared for them.  I use a Hakko 905, I think it is.  Nice iron, well priced, beautifully balanced, warms quickly, controllable, tips last pretty well.

Cheers,

Hugh

[EchiDna]

I'm anxious to get started on my AKSA 100n. I will need to buy a soldering iron. I have found there are quite a few choices out there. Does anyone have a recommendation on the most appropriate type?  I'm leaning toward a 25 amp Weller or Hakko. Would a variable wattage set-up be worth the extra money?

Thank in advance for any replies. (I'm new here.)

-Jim

Hi JimB, Welcome aboard!

I bought a pair of Hakko's (not the one Hugh has unfortunately) of 30watt and 60watt values. Combined cost, including a pair of spare tips, was under US$12 here in Singapore. These allow me to cover almost any need - everything from surface mount to moderately size power capacitors like in the AKSA 100 power supply. There is no need for anything bigger when building amps IMHO unless you plan on building big power supplies with copper "buzz bars" linking the capacitors together.

[JohnR]

Funny, I just looked at a Hakko in Dick Smith this evening. Late nite shopping and all that. I damn near fainted, or would have if I wasn't a tough sort of bloke and didn't go in for that kind of nonsense, the darn thing was nearly $300!!!

It was the 936, if memory serves you can get these in the US for like a hundred bucks  

[EchiDna]

Funny, I just looked at a Hakko in Dick Smith this evening. Late nite shopping and all that. I damn near fainted, or would have if I wasn't a tough sort of bloke and didn't go in for that kind of nonsense, the darn thing was nearly $300!!!

It was the 936, if memory serves you can get these in the US for like a hundred bucks  

   woah...

I gotta check out the prices here on that model now

[JohnR]

Hey, is Singapore 240V?

[EchiDna]

Hey, is Singapore 240V?

well 230v... close enough for government work  

[AKSA]

well 230v... close enough for government work  

Ya know,

Having worked for Government (well, Defence, almost the same!) for twenty years, I find I really relate to this comment......

Since working with AKSAs, I've had to notch up my standards quite a ways since those days!  

Progress:  Yesterday completed the first pass at the picking slips for the GK-1R parts, and the first package is in front of me now.  Last night and early this morning completed the instructions, except for two photos which Sri (my wife) will help me with in a few minutes.  Just spoke with Ben, who I will visit this afternoon at 2pm, and the software is being tweaked and a few micros are being programmed as we speak, so things are looking pretty good.  We are now looking for the final piece - a half inch acrylic disc for the IR remote sensor window on the front panel - that's it - and it's done!!  WOW!!  

I'm VERY pleased with these instructions.  They draw on lessons learned, and are very clear.  Here's hoping you fellows like them.......

Cheers,

Hugh

[Regis B]

I'll put my vote for the hakko 936  or a xytronic about 100 us each.

[fred]

I recently bought a Hakko 936 (on eBay, it was fairly cheap). I haven't used it yet; the GK-1R will be it's first use    

But I have a question for those who have one: what setting do you recommend for such assembly? I don't want to destroy components due to my lack of experience with this unit.

[Regis B]

I recently bought a Hakko 936 (on eBay, it was fairly cheap). I haven't used it yet; the GK-1R will be it's first use    

But I have a question for those who have one: what setting do you recommend for such assembly? I don't want to destroy components due to my lack of experience with this unit.

350-375 Celcius.  And get some decent flux.

[AKSA]

Fred,

I checked my numbers;  I actually have a 926 and a 936 Hakko!     I pay little attention to my soldering irons, just expect them to work on demand!

NOTE I HAVE CHANGED THE TEMPERATURE RATINGS FROM F TO C!!  

The heat output of an iron on any given solder joint depends on just two factors.  Temperature of the tip, and time exposure on the joint.  In photography, you could say the temperature of the tip is the aperture, and the time at the joint is exposure.  It is the product of the two - temperature and exposure - which determines the heat flow to the component above the joint.  So, you could set your iron to 350C and spend three seconds at the joint soldering, or you could set your iron to 450C and spend maybe one second at the joint.  The result would be similar.  And there's the rub;  it's personal choice.

At the low end of the scale you risk the solder not wetting the component wire and pcb pad probably;  at the higher end you risk overheating the solder and the component and boiling out all the flux, leaving a potentially dry joint.  Like everything, it's a compromise....

I personally go for very high temperatures, and I wipe clean the tip on a wet sponge before each and every use.  This way I'm in and out of the job in a second, and can move quickly along the pcb.  I always add that tiny bit of extra solder to the joint to ensure flux is visible at the edges of the joint when I'm finished;  this means there is still flux left over after the job and it's unlikely to be a dry joint.  Because this intense heat is applied so quickly, the number of calories injected into the joint is actually quite small, and consequently it quickly dissipates in the thermal mass of component lead and pcb pad.  Therefore there is little danger of damaging a sensitive component.

Twenty years ago active devices like transistors were not as robust as today.  Most semis are specced to withstand 300C for 10 seconds;  I solder around 400C with 175C solder, and am normally done after no more than two seconds.  I never use additional flux;  it's in the solder anyway and all my component and pad surfaces are normally clean and highly solderable.  This does not endanger anything, and in any event I set reasonably long leads when I fit transistors, further assisting with dissipation.

There are courses on High Reliability soldering conducted by industry and the military.  As a young Officer I once served in the Australian Army School of Signals where they ran a HRS course.   Like any technology, there are a few tricks but most of it is common sense, and a moderate approach.  I'm very impressed with both my Hakkos, nice irons, and would never use anything else now.

Most industry soldering, except on the very highly priced gear from the big boys, is wave soldered on a machine, often using surface mount components, which are completely immersed for a brief second or so in solder during the operation.  This operation is fascinating to watch if you ever get the chance;  a standing wave of molten solder is set up by a solder pump in a small container.  The position of the wave is adjusted so it is stationary, and a prescribed height, although the solder is moving through it at considerable speed.  The solder bath is constantly monitored for flux content to minimize dry joints.  The pcb is then inverted and passed across the crest of the wave, leaving a marvellous job.  Very elegant!).  Now this approach is quite traumatic, so components have had to get tougher to withstand it.  The problem with wave soldering is that human inspection is really required to ensure complete reliability, partially offsetting the benefit of using a machine anyway.  The other problem with SMD technology is heat generation, which can be so severe - as these components are tiny - that the solder can come unstuck!  In the design phase a heat profile of the board is calculated, and the boundary temperatures of every joint are computed.  As long as they do not exceed about 100C all is well.

Hope this gives you some pointers.  Nothing can really help you divine a good solder joint except experience, but, OTOH, a bit of experience does the job every time!

Cheers,

Hugh

[rwalton]

Hello All,

Just my two cents on Hugh's comments.  From my somewhat limited experience, I have found that tip geometry has some affect as well on the speed with which one can create a good joint.  Big wide tips that have a large mass seem to transfer heat more quickly because they have a larger contact area as well as a larger thermal mass (to limit temperature drop when they contact ambient temperature surfaces).  Of course the size tip you can use is specific to the task as well.

Also, my soldering station (Weller WTCPT) uses temperature controlled tips.  The most common tips are either 700F (371C) or 800F (427C).  I like the 800F tips best because they make faster joints.  Hugh's temperatures seem a bit too low to me.  (I think he must have meant C when he said F)

Rick

[rwalton]

Wow Hugh!  You corrected your message while I was still typing!  Sorry for the now obsolete post!

Rick

[fred]

Thank you all for the advice.  I have been practicing my soldering and am feeling reasonably OK about the results, and feel most comfortable with the higher temperatures.  As an added precaution, I've bought a couple of clip-on heat sinks to use.  I haven't used flux before, but it sounds like it might add an additional margin of error.  Is there any disadvantage to using flux?

[TG]

...  what setting do you recommend for such assembly? I don't want to destroy components due to my lack of experience with this unit.

I have a Hakko 936 with a 907 iron.  Usually I run it at around 380C for point-to-point work on valve projects but that's a bit hot for PCBs - I have lifted tracks from boards before now using that high a setting   .
For PCB work I've found 300C is a better temperature.

By the way - anyone looking for a Hakko station should keep an eye on Farnell's site  http://international2.farnell.com/AU/Welcome/welcome-frame-unregistered.jhtml as they occasiuonally have specials at very good prices - they had the Hakko 936 + 907 at Aust$175 earlier this year.

Cheers
TG

[SamL]

While we on soldering. I have a question to ask.
From the AKSA user inst, Hugh recommend not to over solder/overheat the capacitos. Well, due to trying to solder them quickly, I end up with bad join and need to desolder and resolder some of them... Now, what kind of "bad thing" will happen if I happen to over heat my caps?

Sam

[AKSA]

Sam,

Eventually, the caps will fail, depending on how much heat they absorbed, the type of capacitor, and how much voltage is across the cap.

Generally speaking, the most sensitive caps are the polystyrenes, followed by the block film caps.  Voltages less than 50V don't usually stress caps too much, but overheated electros operating at 300V need to be carefully watched as their failure mode can be almost explosive....

All this is a balance.  You need heat to do a good job, but not too much.
This means you must maximise heat contact with a hot iron, get in quickly, finish the job, and move on.  You have to be cruel to be kind!

Cheers,

Hugh

[econ]

Farnell in Australia have the Hakkos on special at the moment , actually they have them on special quite often . The 936 for $A 200 for the vanilla model and $A 240 for the ESD version.

They also have some nice 3U racks at half price BUT its for the bottom and sides only , the back , front and top have to be bought separately,hmm