Video - quick capacitor replacement using liquidized lead

[Agent24]

Re: Video - quick capacitor replacement using liquidized lead

Interesting, I notice that the cheap Chinese solder pots are at least 100 watts for 38mm and 300 watts for 100mm diameters.

Not sure how big yours is on the outside, but it sounds likely you need a more powerful heater. 20 minutes sounds long enough, the Chinese ones list about 5-10 minutes.


The one I made certainly gets hot enough but with it sticking up in the air as it is, using it is a bit annoying - and because of the small size interfering with component leads, sometimes can't be used at all.

I think one similar to that from the first video would be even better - short and low, for easier use and wider to clear the leads well. But to just get the feel of it, one on the end of a beefy soldering iron works OK!


Worth noting that brass\copper\bronze etc will be useless as it will dissolve into the solder, stainless steel is OK but won't handle lead-free. Gray cast iron or Titanium is apparently much better.

Also seen some solder pots that appear to be completely non-metallic, made from some kind of ceramic compound, and also a cheap Chinese one that looks suspiciously like a standard glazed cup.
(http://sanshinetechnology.en.made-in...older-Pot.html) - although with such a small photo it's hard to tell, but it does seem a lot more shiny than the other ceramic pots from more well-known manufacturers.

[momaka]

Re: Video - quick capacitor replacement using liquidized lead

Just to report back on my implementation of the solder pot...
I tried it last week and the clay was still very wet so obviously it didn't heat enough to melt solder. Tested it again today and I think the clay is finally dry. But given the mass of my solder pot, looks like 50W may not cut it. After running for about 20 minutes, it was still not hot enough to make a drop of water sizzle. There was a bit of smoke coming from the sides, though (probably moisture or foreign particles burning). I stopped testing it because it didn't smell very good and because I was impatient. I will try it again in a few days in the garage, and if it still doesn't work, I'll try hooking it with 80W or even 125W - at this point I don't care if the heating element burns. I just want to see some results (either success or failure).

Looks like the solder pot Agent24 built is a lot less hassle than what I have. It's likely I'll be building one like that, too.

[Agent24]

Re: Video - quick capacitor replacement using liquidized lead

In case anyone is looking for ideas or such, I found some pretty interesting stuff here: http://www.air-vac-eng.com/pcbrmsupport.html

User manual etc for solder fountain machine, quite informative as to how such a machine is used and designed.

[Agent24]

Re: Video - quick capacitor replacement using liquidized lead

Nice!
That's basically my second idea (if my original solder pot doesn't work).
Of course, yours definitely looks better than what I have (and probably works better too).

I think yours should work fine as long as your heater is powerful enough. With a large clay pot it might work better than mine for thermal mass.

Just another note, it would be wise with one like mine to put some kind of shield around the base of the soldering iron, as solder drips down there often. I thought it wouldn't matter too much but as it turns out I don't think it's a good idea. (might run inside the handle and short\melt something) I will post a photo once I make one.

Here's how i would do it:



the whole thing sits on a block of ceramics or something that insulates it.
between the insulator and the metal bottom some heating element
separate two sides of the container with the pipe going up, on one side cut a small hole at the bottom of the pipe so that liquid solder can come up the pipe
connect the two sides with a tube that has some kind of locking or a one way valve on it.
on the pipe, weld a funnel in such a way that the solder coming out the slightly U shaped tip is forced to flow to the right and into the other container.
Now just push air inside the left container (water pump from a larger fish tank maybe) and the air pressure would push the solder out the pipe forming a natural dome, solder flows on all sides but the funnel will push it in the right container.
When done, remove air pressure, allow the air to come out,unlock the tube at the bottom and lift the right side a bit - gravity will push the liquid solder through the unlocked tube back into the left container.
You just need to make the left container a bit higher because you don't want the solder to reach the air pipe.

You could theoretically refine the design by using some mechanical gates at the bottom of the pipe, like they use in river dams - put down the gate when pushing solder out, push it up and close the top hole and tilt the whole thing to the left to have the solder flow back in the left container.
But I guess this would be more complex and would make it harder to do some pressure in the left container.

actually you don't even need a tube with valve, you can just design a cool door... (damn, drawing in paint is hard ):

I like the idea of using an air pump system but I think the door idea might be a bit tricky. You'd need to make sure you get a good seal or the solder might prefer just squeezing out through cracks etc into the right hand tank instead of bothering to go up the nozzle. Or maybe it wouldn't. I don't know.

The bit about tilting it seems a bit dodgy though... The idea of handling a heavy metal tank heated to 350+ degrees full of liquid solder doesn't really appeal to me a huge amount...

Still, I reckon it would probably be one of the easiest and probably cheapest ideas, which isn't a bad thing at all

[mariushm]

Re: Video - quick capacitor replacement using liquidized lead

Here's how i would do it:



the whole thing sits on a block of ceramics or something that insulates it.
between the insulator and the metal bottom some heating element
separate two sides of the container with the pipe going up, on one side cut a small hole at the bottom of the pipe so that liquid solder can come up the pipe
connect the two sides with a tube that has some kind of locking or a one way valve on it.
on the pipe, weld a funnel in such a way that the solder coming out the slightly U shaped tip is forced to flow to the right and into the other container.
Now just push air inside the left container (water pump from a larger fish tank maybe) and the air pressure would push the solder out the pipe forming a natural dome, solder flows on all sides but the funnel will push it in the right container.
When done, remove air pressure, allow the air to come out,unlock the tube at the bottom and lift the right side a bit - gravity will push the liquid solder through the unlocked tube back into the left container.
You just need to make the left container a bit higher because you don't want the solder to reach the air pipe.

You could theoretically refine the design by using some mechanical gates at the bottom of the pipe, like they use in river dams - put down the gate when pushing solder out, push it up and close the top hole and tilt the whole thing to the left to have the solder flow back in the left container.
But I guess this would be more complex and would make it harder to do some pressure in the left container.

actually you don't even need a tube with valve, you can just design a cool door... (damn, drawing in paint is hard ):

[momaka]

Re: Video - quick capacitor replacement using liquidized lead

Nice!
That's basically my second idea (if my original solder pot doesn't work).
Of course, yours definitely looks better than what I have (and probably works better too).

As for the solder fountain, you'll need a very powerful heater. The pump is another issue too - needs to be strong enough to push the melted solder and at the same time be heat-resistant so it doesn't overheat and melt. Not sure how that one can be made.

[Agent24]

Re: Video - quick capacitor replacement using liquidized lead

I finished mine

Gave up on the idea of making it from brass and after that it dawned on me how to do it - it also helped realising that I didn't have to make a great job of it, in case it didn't even work anyway.


Well, the soldering iron I was using for a heater killed its own tip in about 15 minutes due to sheer overheating last time I used it (80 watts)

So, I cut the highly pitted and useless end off the tip and was left with a copper shaft. I then took a piece of 14mm steel bar and cut a 30mm length from it. In one end I drilled a hole into which I fitted the old tip shaft.

In the other end I drilled a larger hole, about 10mm diameter and about 10mm deep (biggest drill bit I had) - don't forget to file the top end of the pot so you don't scratch or otherwise damage any PCBs.

I also threw together a basic wooden stand for the iron (heavily based on the design I posted earlier)

(See attached photos, excuse the mess with everything else shoved out of the way!)


I powered the iron from my light dimmer controller I built a while back at 50% to start with but increased power a bit as I think it lost a bit heating up some boards. I don't know what the actual temperature was as I don't have any way to measure it at the moment.


Method of operation was much the same as the device on Youtube, nothing special there so I didn't go to any hassle making a video or anything.



However, some points I think to be observed:

1) Overfilling the pot causes dripping when the board is placed on the pot. This is not so bad but there is a side effect - when testing on an old motherboard I found that some tiny (0.1-0.2mm or so) vias next to the capacitors acted as a nice pipe for the solder and left a lovely ball on the component side of the board. This is obviously not good

2) under-filling the pot or leaving the surface flat results in bad heat transfer and failure to melt the solder - having a very slight dome on top but not too much seems the way to get best results.

3) Get the board flush with the pot. I get the feeling the liquid solder needs to come into contact with the board and not just the pads to allow for best heating.

4) USE FLUX. If you do not apply flux to the board before attempting this, you will get solder stuck not just on the pads but everywhere else as well! I used a cheap paste flux from eBay which worked very well. Liquid flux would probably burn off too quick actually.

5) Be quick. With the large surface area and the high heat output this thing heats the board pretty well, so don't leave it too long or you will most certainly overheat something.



It took me a few components but I got the hang of it pretty well. After about 8 capacitors and a few other things on my test board, it seemed pretty easy, but holding the board up was kind of annoying.

Also, the large(?) 14mm size of the pot did have some problems interfering with some leads, which meant some groups of capacitors had to be done in a certain order. Some components on another board (old modem) were un-removable due to other components too close.

I think in this respect the solder wave\solder fountain idea would be better.


In any case: The final word - does it work? For now it seems so! I am a bit worried about the copper tip oxidizing but it is just a prototype and if it fails I will try to get another one professionally made from stainless steel on a lathe, assuming I find no faults with it.

The cogs in my brain are still turning on how to make a cheap solder fountain!

[momaka]

Re: Video - quick capacitor replacement using liquidized lead

How big is the actual pot?

It's the size of a small soda can. The actual "solder pot" where the solder will go is made of a copper pipe about 15mm in dia. It looks pretty . I'll get some pics when the clay dries in a few days and I clean it up a bit.

[Agent24]

Re: Video - quick capacitor replacement using liquidized lead

Sounds interesting, would love to see some photos

How big is the actual pot?

[momaka]

Re: Video - quick capacitor replacement using liquidized lead

I might try building something like is shown in the first video either this or next weekend.

Well, I just finished building a solder pot today. Haven't tested it completely yet though, since the clay (read: mud) hasn't dried... Yes, I did actually use mud in this project! (along with many other common materials.) I'm not sure if it will work, but we will see. The designated PSU for this is putting about 53W of power into the heating element (1.7A at 31.5V). I'm hoping that's enough given the size of this thing.
If this doesn't work, I have another idea how I can build an attachment for my soldering iron.

[Agent24]

Re: Video - quick capacitor replacement using liquidized lead

This looks even better...

http://www.youtube.com/watch?annotat...7kU&feature=iv

I wonder how hard it would be to make something like that..

Turns out they exist as a commercial product under the name of "Solder Fountain"

They also cost quite a bit, too but I reckon you could make one for cheaper though, if you had the right tools.


Came across the name from this thread: http://bbs.homeshopmachinist.net/showthread.php?t=7194

Looks like brass might not be the best material for any kind of solder job either - stainless steel or cast iron seems to be a better idea, according to them...


Edit: loving the operating procedure for it! http://www.circuitmedic.com/features/517.shtml

[Toasty]

Re: Video - quick capacitor replacement using liquidized lead

I have the 33 watt & 45 watt heaters. Should be no problem as the surface area of the solder "bubble" will compensate. These sizes would be safer, IMO, than the large puddle the first one uses. Also, probably will be easier with some boards where you have SMDs in close proximity. Like Apple iMac PSUs. OIY!!

[Agent24]

Re: Video - quick capacitor replacement using liquidized lead

Ungar used to make "solder pot" type tips for their irons for DIP, SIP, TO.

I have the DIP & SIP ones yet. But, the TO types look to be the best and cheapest for doing cap replacement. I have the heaters too!

Time to give it a whirl...

http://www.ebay.com/itm/220772421243

Never knew anything like that existed as a 'proper' fitting.

I wonder if it would work OK for motherboards? 18 watts seems a bit on the low side, but do tell us how it goes though!

[Toasty]

Re: Video - quick capacitor replacement using liquidized lead

Ungar used to make "solder pot" type tips for their irons for DIP, SIP, TO.

I have the DIP & SIP ones yet. But, the TO types look to be the best and cheapest for doing cap replacement. I have the heaters too!

Time to give it a whirl...

http://www.ebay.com/itm/220772421243

Numbers/Sizes to look for: 6943 - 0.6", 6944 - 0.5", 6945 - 0.375", 6946 - 0.280"

Toast

[PlainBill]

Re: Video - quick capacitor replacement using liquidized lead

Personally I think some flux, braid, and possibly chipquik would work fairly well.

I've done a credible job using a 40 watt soldering iron and a dissecting pick. On a good day with an open layout I MIGHT be able to pull one cap a minute. Adding the time to install the new caps and clean up the board the time is probably about 4 minutes a cap. I would consider this perfectly acceptable if I were recapping a board a week, or less.

Recently I met a gentleman who recaps Dell GX260s and GX270s. He expects to turn around a pallet of them (200 computers) in a week. I'm not sure what kind of equipment he uses, but I'm sure solder braid is not a significant part of the operation.

PlainBill

[Evil Lurker]

Re: Video - quick capacitor replacement using liquidized lead

Personally I think some flux, braid, and possibly chipquik would work fairly well.

[Agent24]

Re: Video - quick capacitor replacement using liquidized lead

Yeah the mini solder pot thing looks like a clever idea, cheapest certainly.

They sell "Cartridge Heaters" on eBay which are very cheap, and start at about 100 watts and go from there. Looks like that's what he uses actually - not sure what the hot air is for, maybe it's to assist the heater

I guess for the real powerful ones you'd want a control circuit of some kind as well.


I'm also thinking of making something myself, but a bit differently (bigger) to theirs, inspired by the idea in the attached PDF. (source: www.qrpkits.com)

I'm going to assume since he used Brass I can use it too.. read that plain copper would be useless as it will just dissolve into the solder (That is why iron tips are plated!)

Also found some unverifiable evidence online that soldering iron tips used to be brass. Anyone know anything about that?

[momaka]

Re: Video - quick capacitor replacement using liquidized lead

I might try building something like is shown in the first video either this or next weekend. I doubt I'll succeed, but who knows. I got a heating element that I can probably push to 60-80W.
I've been removing caps from consoles and lead-free motherboards in the last few days - and it's not easy (at least not to me) even with good expensive equipment!

[PlainBill]

Re: Video - quick capacitor replacement using liquidized lead

Definitely the way to do it quickly. I like the laser pointer.

PlainBill

[Agent24]

Re: Video - quick capacitor replacement using liquidized lead

http://www.youtube.com/watch?v=RBeLnX7IDrY

This looks like the easiest way to make something like this.

Seems to be a block of metal with a heater inside, and a tube welded on top and filled with solder.