Video - quick capacitor replacement using liquidized lead

[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

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

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.

[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 ):

[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

[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.

[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

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.

[Agent24]

Re: Video - quick capacitor replacement using liquidized lead

Try wrapping one of these around it:

http://www.ebay.com/itm/Wires-Leadin...-/370579532925

Even at 110v you'd probably find it did the trick!

[Evil Lurker]

Re: Video - quick capacitor replacement using liquidized lead

One technical problem I see... what are you going to do about those tiny decoupling monolithic ceramic capacitors on the back of the motherboard? I'm sure those will come right off as soon as the board touches the molten lead.

[Agent24]

Re: Video - quick capacitor replacement using liquidized lead

Yes that will be a problem if the board has those near the component you want to replace, however I have not seen a lot of boards that even have them, and even then, they are usually around the back of the CPU and NB\SB etc, nowhere near the electrolytics you want to remove.

[mstbone67]

Re: Video - quick capacitor replacement using liquidized lead

I used to use a metcal rework station at my old work and man that is the best. it sucked the solder out while heating. http://www.element14.com/community/v...50-desoldering this is the newer version.. I had one that was an all in one unit so no air line required the pump was in the base. this is similar but a different brand.
http://www.ebay.com/itm/PACE-ST65-DE...item19cd3f3b54

I still have a metcal soldering base and use it all the time..just need to buy some bigger tips..

Oh and that chiquik stuff is the bomb.. for big ic's if you dont have a flatblade available.

[momaka]

Re: Video - quick capacitor replacement using liquidized lead

I just want to see some results (either success or failure).

And I have them finally... IT WORKS!!! And as promised (a very long time ago), I attached some pictures of this "invention" (okay, I won't lie, it's a straight-up kludge). Let's call it a clay solder pot .

To get it to work, though, I had to up the voltage a bit to get more heat. Had a 31.5V and a 15V power supply in series for that which amounted to an output of about 100 Watts. And even with that, it still took about 10 minutes (if not 15... I didn't really time it) for the solder in the pipe to finally melt. Actually, the solder balls and pieces I put in there originally didn't melt at first. But then I touched the side of the copper pipe with some regular rosin core solder and that melted fine. Once that happened, the melted solder fell down and caught the other solder balls. In no time, they melted as well. After that, it was pretty much unstoppable - I could put all of the solder I want in it and it would melt without problem.

The only big problem I have with this clay solder pot is the smell - for some reason, the fumes from it smell really bad. I don't know if it's the can or the clay, though. I'm guessing most likely the can, as I do know that those aluminum cans are sprayed with some type of polyurethane or something similar on the inside to prevent them from oxidizing. Or maybe not.
The fumes had a "sweet" type of smell to them. Made me somewhat sick after 10 minutes . Good thing I decided to test this in the garage. Had to open the garage doors after I was done - it was that bad!

I'm thinking of breaking the solder pot down and rebuilding it again. When I built it originally, I first put some clay on the side of the can and pushed the heating element in it, leaving a hole in the middle for the pipe to go. But I think the heating element is too far from the pipe and too close to the can, since the outside of the can seems to get hot much faster than the copper pipe. Another reason for me to rebuild it is to set the space between the turns of the heating element more evenly... As I started inserting the heating element in the bottom, I was doing so in a fairly tight spiral. But the heating element got used up much faster than I anticipated, so I began putting more space between the turns of the spiral towards the top. Therefore, the top heats up much slower than the bottom. This also creates a problem of where the heat goes - right now, a big portion of it actually get dissipated by the metal plate I was using as holder. In fact, the metal plate got so hot, I couldn't even touch it. Probably close to 60-70C.

After the rebuild, hopefully there will be less heat losses and less area to heat (I'm thinking of not using the can at all and making the clay pot much smaller in diameter). That way, perhaps I'll be able to use only the 31.5V PSU (back to 50W output). I'm not sure if the heating element got damaged after I ran it at 100W for so long. It is a pretty short heating element. I guess I will find out when I break the thing down. Stay tuned.

By the way, I tried desoldering some caps from junk motherboard. It definitely wasn't as easy as some of those videos showed, but it worked. It might have been that my solder wasn't hot enough, though. After melting all of the solder in the pot, I had the pot turned off for about 5 minutes or so (had to go get the motherboard from my room). At least this solder pot has a really good heat capacity. Even 10 minutes after turning it off, the solder in the pot was still malleable.

If the rebuild of the solder pot is successful, I might post some instructions (with pictures) on how to build one. (As you can imagine, though, it's pretty simple and straightforward.)

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.

Well, let's see how long mine lasts then. I did have some steel pipes, but those had very thin walls and were painted, so I didn't want to use them.

[Agent24]

Re: Video - quick capacitor replacement using liquidized lead

On first glance I thought that was some really weird firework!

Looks good though, but the smell you described seems a bit worrisome. Maybe you can remove the can after drying and just run it with the clay by itself?

Yeah the guys on those videos make it look real easy, but I found with mine you had to really make sure the board was lined up properly - without good contact it was much harder to do anything. A wider pot would probably help more there. (Good reason why I think a fountain would be better)

Would probably be good too to see what actual temperature it was at if you can. Remember just because the solder melts in the pot doesn't necessarily mean it's hot enough for easy soldering.

Did you put flux on the board beforehand?


I wonder how it would go if you remove the pipe insert and use just a clay pot? I see some of the latest commercial solder pots are in fact ceramic coated, apparently to provide more resilience to lead-free solders. You'd probably need a good quality clay though, and I'm not sure about glaze.

I say this because of course you have these: http://www.durhamgeo.com/testing/lab...-crucibles.htm

Surely material that could be used in a furnace could be used for melting solder at lower temperatures!

[Koda]

Re: Video - quick capacitor replacement using liquidized lead

I found this on DX

http://www.dealextreme.com/p/250w-te...den-220v-48763

For 22$ its worth a try

[Agent24]

Re: Video - quick capacitor replacement using liquidized lead

Thing with those though is you need a lot of solder to fill it, and the top is big, probably too big.

If you made some kind of insert or got a smaller one then yeah, it might be OK. I think the smallest one in that style is 38mm diameter pot, that might be small enough not to be overkill but big enough to be quite effective.

[Koda]

Re: Video - quick capacitor replacement using liquidized lead

You need to fill it only once, and you can buy solder in bars which is far cheaper

[momaka]

Re: Video - quick capacitor replacement using liquidized lead

On first glance I thought that was some really weird firework!

Yes. Like I said, it looks .

Would probably be good too to see what actual temperature it was at if you can. Remember just because the solder melts in the pot doesn't necessarily mean it's hot enough for easy soldering.

Unfortunately, I don't have a high-temperature probe or a thermocouple at the moment so I can't check. We do have one at work, but I would rather not bring it there - it would stink up the place pretty badly.

My guess would be it was running probably between 180 and 210 somewhere since the leaded solder balls I was adding to fill the pot would melt easily but the lead-free solder would take several seconds to melt. So you are right - for easy soldering, I would probably need the temperature up to at least 250C.

Did you put flux on the board beforehand?

Yes. MG Chemicals RMA liquid flux. Without it, the solder in the pot wasn't sticking at all to the capacitor leads (as expected).

I wonder how it would go if you remove the pipe insert and use just a clay pot? I see some of the latest commercial solder pots are in fact ceramic coated, apparently to provide more resilience to lead-free solders. You'd probably need a good quality clay though, and I'm not sure about glaze.

Interesting idea. But yes, I would need good quality clay and I would also need to bake it properly. What I have right now is mud. The soil here is very reddish and very close to clay though. The solder pot is actually pretty hard right now.
I don't think I will get rid of the copper pipe, though. It definitely helps spread the heat evenly. Without it, the clay may require a lot more heating before the solder in it melts.

I found this on DX
http://www.dealextreme.com/p/250w-te...den-220v-48763
For 22$ its worth a try

That's pretty cheap. Definitely worth it if you don't want to build one yourself.

[Agent24]

Re: Video - quick capacitor replacement using liquidized lead

Yes. MG Chemicals RMA liquid flux. Without it, the solder in the pot wasn't sticking at all to the capacitor leads (as expected).

Have you thought to try paste flux? The liquid flux I've tried just evaporates really quickly... paste flux stays on much longer (until you clean it off of course)

Not sure if it would make a difference though

[momaka]

Re: Video - quick capacitor replacement using liquidized lead

Have you thought to try paste flux?

Yes, but I don't have any at the moment.

By the way, I'm thinking of building a solder pot similar to yours to use with my 35W Radio Shack iron since it looks pretty easy - either this or next week. The clay solder pot rebuilt project is on the back burner for now since I'm out of clay (I used the dirt to plant several apple seeds, lol ). Also need to wait until it's warmer outside so I can break the clay solder pot in my backyard. This will likely be messy since the clay is rock-hard right now.