Duratool Desoldering Gun Filters

[Ti Pwun]

This desoldering gun is an invaluable tool, especially for older gear where excessive heat can easily lift traces off the PCB. But I'm definitely not a fan of the price of replacement filters; if you have one and use it as much as I do, or are considering getting one, you will need to replace the filters quite regularly in order to keep it working properly.

A very cheap alternative, and one I've used for months now, is to use 'pure cotton wool pads' The mrs picks them up from Morrisons for me and they cost £1 for 100. I can comfortably get FOUR filters out of just ONE pad for the gun itself. Nothing has ever got past this first filter to the second filter at the other end of the tube so I've never replaced it.

In the photos I would normally replace the filter more regularly but I left this one until the gun became inefficient so I could show how clean the back of the filter is. These homemade filters work very well.

Just passing this on for anyone who is interested - saves a small fortune!

Jon.

[Herald1360]

Nice bit lateral thinking, that. Now you just need a suitable size of wad punch to save fiddling about with nail scissors

Something like

http://www.amazon.co.uk/Toolzone-Pun...ords=wad+punch

[Ti Pwun]

Yes, I'm sure the 19mm punch in that set would be perfect. I don't have any but the savings on making the filters justify the cost to make the job simple.

[G6Tanuki]

My only angst would be the flammability of your replacement filters !!

[McMurdo]

I think I've only changed 4 in 3 years, and it's in daily use!
On my first gun (replaced after the element went open) it was assembled incorrectly; the little metal plate was the wrong side of the filter so all the solder stuck to the filter and soon clogged it. Of course the metal plate goes between the filter and the spring

[Ti Pwun]

Well, cotton wool is flammable, of course, but it's compressed when it's in the gun and highly unlikely to encounter a spark, so I'm not concerned about it.

I use mine for component salvage as well as repair work so 4 in 3 years is light use by comparison. I can replace two filters a week.

Mine came with the plate on the vacuum side of the filter as well and that's the way I still use it. With it attached the way it should be, the four exposed parts of the filter clog very quickly and I find that more speckles of solder dust then find their way past the filter. With the filter against the spring, it does clog up but I have found that there's a clump in the centre and the dust is contained within the fibres of the filter, not around the edges.

Maybe it's down to how much I use it but I've tried it both ways and spring, filter, plate, seal leaves me far less worried about solder dust reaching the tube, and therefore the vacuum pump.

[McMurdo]

the four exposed parts of the filter clog very quickly

I think the idea is that the solder hits the plate and cools quickly, the air & fumes only goes down the sides of the filter. On the original versions, there was a conical spring which was so strong it would compress the filter and it soon blocked. The later ones have a light spring so the plate just touches the filter and doesn't compress it.
Properly set-up, the glass solder tube can fill to capacity before emptying. When I had the filter the other way, it would block up every hour or so and need fiddling with when the solder covered the filter.

[G8UWM-MildMartin]

I prefer Kevin's way for the plate position. The filter on the air inlet on the machine is still clean enough after a couple of years of frequent use.

I was having a marathon rework session at work (wrong component fitted); 15 boards to do, with eight 16-pin ICs each. Going beautifully, with ICs dropping straight out after desoldering.
Then, after about 30 ICs virtually non-stop: no suction and a sucking noise.
Nothing obvious. The solidified solder had melted a hole in the underside of the tube!
Replaced it with one from a scrap one (I tend to break the bakelite element mounting ring by dropping the tool, good job they are cheap from CPC) and promptly did the same again...

[Ti Pwun]

Originally Posted by McMurdo

Properly set-up, the glass solder tube can fill to capacity before emptying. When I had the filter the other way, it would block up every hour or so and need fiddling with when the solder covered the filter.

Mmmm - I may have to rethink this. My plate is slightly cupped, which is how it came. Is yours the same or is it flat? I can see how being flat it might make sense to have it spring side and the cooling does make sense,

I wonder if I should tap the plate with a hammer to make it perfectly flat. It certainly performs best the way I have it, even though I do go through filters. That would be cup toward the seal with the filter between it and the spring. You may just see the slight dome in the photo. It is slight but it does make a difference which way I have it.

I can't be certain but I seem to remember that the 'manual' was next to useless so I just played around with the parts until it performed the best. I definitely cannot let the tube come close to being full!

[Ti Pwun]

Well, after the comments I assumed the plate is meant to be flat. After a date with a hammer, I definitely hear (a lot) more suction and I have it with the plate next to the spring. We'll see...

[McMurdo]

Mine's flat.
This one gets some abuse as one of my constant day job tasks is repairing inverter drives with infineon power modules, (soldered into boards by its 1/4in faston tabs) and power amps with up to 32 TO-3 power transistors , and it all goes in that little glass tube!
The most consumable part for me is the tip. It's often on all day 8am-5pm or longer and it normally sits at 380C. As the tip wears it loses conduction and I have to have it a little higher.
I find short bursts of the pump work best because a long blast will cool the solder left in the joint and then the thru-plating can tear

I also fitted a quieter fan to the base unit. The original is a 12V fan on an unregulated supply that gets up to 18V, no wonder the original one sounds noisy. I fitted a 24V high quality thing that is quieter with no apparent detrimental effect.

[Ti Pwun]

Yes, I find the tips deteriorate. They can be filed flat for larger stuff, like point to point under a chassis, but for ICs, etc., it needs to be replaced. I also apply heat for a second or so and a short burst removes the solder easily.

I've actually found a problem with mine, though, that makes me think this wasn't new as stated when I got it; there is a leak near the seal that has silicon on it to stop air coming in from the side, preventing suction through the tip. I can see now why the plate was bent because in the position I had been using it, it forced the plate down onto the seal body so it didn't leak. Now, though, it's hit and miss. Or was - I have sealed it with some Gorilla epoxy.

Good call on the plate, though - I wouldn't have realised had you not pointed it out and I was obviously using a lot more filters than I needed to. Glad I wasn't paying for them!

I also replaced the fan for a silent one. That was the first thing I did.

Time to get a 19mm punch, I think. The filters work well but cutting them out with scissors is not my idea of fun.

[McMurdo]

great minds think alike Jon re-fan!

I admit to also adding a touch from the weller soldering iron if a little more heat is needed.
One time the solder tube got so full it extended into the tube that goes through the element and essentially locked the tube in place. After numerous attempts to release it I prised the tube out with the screwdriver and it broke, which is when I found out it was glass!

The new guns are so cheap I didn't worry too much

[G8UWM-MildMartin]

Interesting that your tube was glass.
Im sure the original on ours was, but the newer replacement handpieces have plastic ones, as I found out when they surprised me by melting.

[Oldcodger]

if the tips are suffering, and are similar to the hand pup type, I always found that a Hellermann sleeve on the tip extended the life and suction range .

[McMurdo]

a Hellermann sleeve on the tip ..

I'd probably have trouble melting the solder with that one!

[Ti Pwun]

Originally Posted by McMurdo

great minds think alike Jon re-fan!

Yes, they stuck a really cheapo fan in there didn't they? That had to go immediately!

My tube is plastic so it isn't going to crack but I hope it doesn't melt.

[PETERg0rsq]

Been reading these posts with interest.

I have a few of these tools (got a job lot!) and they are of completely different design!

Inside the plastic tube is a tight wound conical spring.

The suction sucks the solder through the spring, which cools it as it tries to get through the tight windings (as the conical spring fills up, the air is sucked through higher windings), untill it is full. Very little gets through the spring to the filter, and rarely needs cleaning.

New guns are available at CPC for £16 complete. They seem much better than the ones described here.

Peter

[Ti Pwun]

Interesting - I rely on this tool so much that a new one from CPC at that price is looking like a good option. The conical spring seems like a good idea.

I guess you could make a new tube out of metal, just a thought.