Problem with suction in ZD-917 station

[dimkasta]

I got this about a month ago and it works very nicely.

However today it seems to refuse to suck any solder. I cleared the filter and waste barrel and made sure the pump works properly.
The unclogging pin goes in the barrel without issues, up until around 1cm into the plastic part of the gun.

My guess is there is some solder that got cold in a place that it should not and now cannot melt

Any suggestions on how to repair this?

[edavid]

A long drill bit in a pin vise.  Solder is soft enough that you can drill through it by hand.

If that doesn't work, you can buy a new gun fairly cheaply.

[dimkasta]

Ok for anyone having the same issue, the problem is that the heating barrel at its back end is thin and does not have enough mass to melt any solder stuck there.

I removed the waste barrel and saw a blob of solder sticking out from the back end.

I cut it with my cutters as close as I could without damaging the heating barrel.

I also removed the black seal and I was thinking to heat the back end with my soldering iron to let the solder run towards the front releasing the hole.

But as it seems, even leaving it like that for a minute or so is enough for the solder to melt just with the heat from the gun at 350C. It was probably the blob that was causing the problem.

Just be careful not to burn your hands handling the barrels

The gun is running perfectly once again.

[Muttley Snickers]

I've found that the trick with these units is to keep the trigger held for slightly longer after the pad is cleared and one particular board I was gutting required the gun to be dismantled three times over a few hours to clear the blockage using the technique that edavid described previously. The guns and spares for these units are reasonably cheap down here and readily available from Rhino Tools in Sydney which I have mentioned before.

I did a modification to my unit by adding a plate to the underside and fixing the soldering iron stand permanently, this station is not normally a permanent item on my bench and is regularly placed back in a cabinet when not in use hence the fixed stand, also on the first day of use I knocked it over a couple of times when placing the iron back in position.

Rhino Tools.
https://rhinotools.com.au/

[Gyro]

A couple of tips:

1. The unclogging pin is made of steel and is not very thermally conductive. A decent thickness piece of copper wire, preferably cut to a chisel tip with a pair of cheap (non flush) cutters works much better for transfering heat to the back of the tube. Note that it will try to transfer heat to you too at any opportunity!

2. Never operate the gun tip downwards. It's better to hold the board near vertical and the gun horizontal. This stops solder from the reservoir falling back onto the rear of the tube.