Desoldering question (Miller XMT welder repair)

What a shame lead-free doesn't do the same ... d;~}

Seriously though, most soldering iron tips have been made from nickel plated iron rather than copper, for many years now, and they get just as pitted as the copper ones did, but at least you could file the copper ones down. I never used to put a new bit in my old Adcola, until it was a 'stump'. I am more of the opinion that tip erosion, both back then and now, is caused mainly by the mildly corrosive action of the flux in the solder core, and that the nasty gob of metal that you find on the tip when the iron hasn't been used for a while, is oxidised components of the original solder almalgam. Smitty, what thinks you ?

Arfa

For many years, I used a desoldering pump with great success. Then I took on a contract that required me to have the desoldering station running just about all of the time. It became easier to just pick up that iron 'ready to go' than to start hunting around for the hand sucker, so that's what happened ! Using it all of the time like this, you develop techniques for 'making it work' on just about any sort of joint, but I do agree that it does sometimes take a couple of attempts to get enough solder off the joint, and it has to be kept well maintained. I do still use a good quality solder wick - expensive, but worth every penny - to 'clean down' in preparation for placing a s.m. IC for instance, and occasionally, for clearing out a stubborn thru' hole that just won't suck clear, no matter how well your iron or sucker is working, and how much new solder, you get into it. Bet you've been there ... !!

Arfa

If they are anything like the felt wads fitted in the same place in my Weller vacuum desoldering station, you can recover them once, sometimes twice, by just running a curved, blunt scalpel blade over the surface as a scraper. The surface layer thats stuffed with solder dust, just falls away re-exposing clean, uncontaminated felt. I would guess that you perhaps lose a half a mm from the pad's thickness.

Arfa

Dracula? Rotwang?

Are all desoldering tips (such as 1/8" tips) compatible? I need to buy a few and am a little confused about brand compatibility.

Do like I did on my 220W dual heat Weller. I made a tiny ceramic piston, 2 stage, vacuum pump and inserted it in the light bulb socket. A teflon tube coiled around the tip supplies suction to the work. The tip is hollow and flux is pumped through it in calibrated amounts from another small pump in the light bulb socket. Solder and flux is effectively sucked up (cleaned) from the work in such a way that only an "amalgamate film" is left.

Bob Swinney

For many years, I used a desoldering pump with great success. Then I took on a contract that required me to have the desoldering station running just about all of the time. It became easier to just pick up that iron 'ready to go' than to start hunting around for the hand sucker, so that's what happened ! Using it all of the time like this, you develop techniques for 'making it work' on just about any sort of joint, but I do agree that it does sometimes take a couple of attempts to get enough solder off the joint, and it has to be kept well maintained. I do still use a good quality solder wick - expensive, but worth every penny - to 'clean down' in preparation for placing a s.m. IC for instance, and occasionally, for clearing out a stubborn thru' hole that just won't suck clear, no matter how well your iron or sucker is working, and how much new solder, you get into it. Bet you've been there ... !!

Arfa

Heh heh - even Pace tips ain't compatible across model ranges. Think they use Microsoft for design work.

stage, vacuum pump and

supplies suction to the

from another small pump

from the work in such

Do you have an photos of this contraption?

Michael

Just trim a bit off the end pointed towards the solder side. I liked to use a sharp pair of dikes (take several nibbles) or a good utility shear. You only need to take off a 1/32 or so. You can do that trick several times before you have to replace the wad/filter.

A piece of stainless steel antenna rod works good for poking out the hollow tip. Put a little wiggle in it so it looks like this:

-------------^---------- | | ---

The little wiggle/bump will help burnish down the burr that builds up inside after use (and filing). You can also use a flat-file to straighten the end after it wears a bit. I use to give up on a desolder tip when if developed a hole farther upstream inside the heater area :)

A small straight screw driver with about a 1/16 inch diameter shank and 6 inches long works really good to take nasties out of the heater area. Run it in with the tip out and the heater on/hot. Be quick about it so you don't melt the handle down on the driver.

I had all the proper tools/brushes available for cleaning, but these little guys did a better job in my opinion.

He doesn't do things the right way.

To be fair desolder stations were incredibly expensive once and even now secondhand reasonably recent Pace etc still fetch big money. I ended up making my own. ;-)

It is a conformal coating. General Cement in Rockford, Illinois, makes a silicone based version called "Print Koat", as well as the solvent.

Part No. 22-203 - Print Kote Conformal Coating The ultimate coating for PC boards. Provides a protective shield to resist environmental contaminants. Prevents arcing and shorting. Air dry

and

Part No. 22-209- Print Kote Solvent A solvent to remove silicone and other types of protective coatings from PC boards. Required when modifying PC boards or replacing components where the protective coating interferes with the desoldering and resoldering operation.

Allied Electronics stocks it.

On Thu, 31 Jan 2008 10:06:08 GMT, "Arfa Daily" wrote:

: :"Ross Herbert" wrote in message :news: snipped-for-privacy@4ax.com... :> On Thu, 31 Jan 2008 01:20:59 GMT, "Arfa Daily" :> wrote: :>

:> : :> :"Ross Herbert" wrote in message :> :news: snipped-for-privacy@4ax.com... :> :> On Wed, 30 Jan 2008 09:34:29 -0600, Ignoramus19508 :> :> wrote: :> :>

:> :> :On 2008-01-30, Ross Herbert wrote: :> :> :>

:> :> :> Your desoldering tool (like most) is probably fitted with a small :> :> diameter :> :> tip :> :> :> (approx 0.8mm - 1.00mm inside diameter) :> :> : :> :> :Yes. :> :> : :> :> :> designed for sucking solder from around small gauge component leads :> :> :> and IC pins where the tip make full peripheral contact with the :> :> :> board. When the solder melts around a pin all the air passes solely :> :> :> around the lead and maximum effect is achieved inside the through :> :> :> hole. :> :> : :> :> :Well, it does this pretty well with a real vacuum pump attached :> :> :instead of the "desoldering station pump". :> :>

:> :> Yes, of course it will. But the desoldering station pump is NOT a :> :> specialised :> :> 1/3HP vacuum pump. It is designed as being adequate to suck solder from :> :> around :> :> component pins ONLY when the nozzle completely surrounds the lead AND :> make :> :> 100% :> :> peripheral contact with the pcb solder pad. :> :>

:> : :> :Well Ross, I gotta tell you that I use my Weller desoldering station just :> :about every day, I keep the same sized tip on it with a 1mm hole at all :> :times. It is used both for pin sizes where the hole will fit over the :> pin, :> :as you describe, and also for any other joint that I need to get the :> solder :> :off as well. I have never had a problem with it developing enough suck to :> :remove solder from a joint that requires the tip to be applied in a way :> less :> :than your stated 'ideal', unless it has reached the point where it needs :> :servicing. I think that in common with most soldering / desoldering :> tools, :> :it depends on how often you use it, and hence how much skill in its use, :> :that you have developed. :> : :> :Arfa :> : :>

:> Yes Arfa, I agree with what you say. I also can use my Hakko to remove :> solder :> from around larger pins quite quickly, but due to the large amount of :> solder :> which often must be removed from large terminals, several attempts may be :> required and sometimes the tip requires a clean out to complete the job on :> a :> single switch. I can't say if there is anything wrong with the OP's :> desoldering :> station, although this may be the case. I find that for small number of :> large :> terminals the old Soldapult takes less time and requires less cleaning. : :For many years, I used a desoldering pump with great success. Then I took on :a contract that required me to have the desoldering station running just :about all of the time. It became easier to just pick up that iron 'ready to :go' than to start hunting around for the hand sucker, so that's what :happened ! Using it all of the time like this, you develop techniques for :'making it work' on just about any sort of joint, but I do agree that it :does sometimes take a couple of attempts to get enough solder off the joint, :and it has to be kept well maintained. I do still use a good quality solder :wick - expensive, but worth every penny - to 'clean down' in preparation for :placing a s.m. IC for instance, and occasionally, for clearing out a :stubborn thru' hole that just won't suck clear, no matter how well your iron :or sucker is working, and how much new solder, you get into it. Bet you've :been there ... !! : :Arfa :

I have sure been there... On those "difficult to totally clear" holes I concluded that the main cause was that the through-hole diameter was not quite big enough to allow sufficient lead displacement during the "wiggle and suck phase". The lead could not get clearance from the side of the hole to allow molten solder to pass by. That is one of my major complaints about some board designers - they seem to pride themselves on saving as much board territory as possible, even though the board is not crowded. My motto is to make lead mounting holes capable of allowing a fair clearance around whatever size lead is to be fitted, not the minimum size which will barely allow clearance for the largest pin diameter for any component on the board. One size doesn't fit all and if it means an extra drill size then so what. It makes for easier component removal, if needed, later on.

Sometimes adding extra solder and flux would assist but not always. When this happened I would resort to a pure liquid activated flux which sadly is no longer produced, Magna Alloys type 87. I still have a small quantity left but when that is gone...

As for final clean down of smt pads, yes, you can't beat a good quality solderwick, or as you would say, soderwick. However, much of the product around today doesn't work very well so it is best to pay for the quality brands such as that made by Multicore or ITW Chemtronics as Solder (or Soder)-Wick or Chem-Wick.

Snag is the most reliable solder joint is where there is minimum solder infill.

"Bob La Londe" wrote in news:47a015a0$0$26111 $ snipped-for-privacy@free.teranews.com:

Ghetto desoldering:

Heat up the solder and rap the board, usually edgewise, against the bench.

Works quite well but not recommended unless wearing lots of protection.

What did you make your desolder station out of? I'd be interested to see since I'd consider making my own as well.

Mike

I am not the party to whom this query was directed, but I too made a desoldering station; I used the vacuum pump from an IBM 360/30 mainframe and a new commercial head and filter unit (Weller?, I forget the brand and the unit is in storage) which at the time cost me perhaps $10.00.

For SMT work, see my homebrew solution at:

Regards,

Michael

:In article , : Ross Herbert wrote: : : :> I would resort to a pure liquid activated flux which sadly is no longer :> produced, Magna Alloys type 87. I still have a small quantity left but when :> that :> is gone... : :We use Kester 1544 for hand soldering, and desoldering as well. It's :fully activated and works very well. At 50% solids content, it's too :thick for a foaming flux bath, but works well in a capillary dispenser :for hand work. Maybe you have a Kester distributor there? They produce a :large and varied flux line.

Kester products not distributed in Australia as far as I can tell. We generally rely upon the Multicore range which is part of the giant German Henkel group. Multicore solder products are grouped under the Loctite brand owned by Henkel.

Basically I wanted something I couldn't really find on the market - or certainly at a price I could afford. So gleaned bits off Ebay, etc.

I like Antex handsets for soldering so wanted those. And easy selection of two with different bit sizes. Auto switch off after a period of time - I've set that at 5 hours. A good buy on Ebay got a Pace SX-80 handset new. Another a Pace pump from a non working base unit. All the electronics are home designed. To keep the size of the main unit down the pump is in an external box.

Pic here:-