Cheap solder suckers with the spring in the chamber can be much improved by adding a wiper to keep as much solder dust as possible away from the piston seal(s). The difference is incredible - you can reduce the cleaning interval by anything up to an order of magnitude and still get a better seal than it has with the normal cleaning interval. To test how good the seal is, simply moisten your fingertip and hold it tightly over the tip while triggering the solder sucker - the plunger should move gradually, taking several seconds for its full travel.
To make the wiper, cut several disks of waxed paper (saturate copier paper with paraffin wax on a flat hot surface and wipe off excess before it cools) that are just a fraction larger than the barrel bore so they cup slightly and scrub the solder dust off the bore as you re-cock the piston. Use a hole punch to make the center hole for the spike that clears the nozzle and fit them between the spring and the piston. Its best to punch the center hole first through the rough cut disks then trim them to size so that their outer edge is concentric with the center hole.
You will find that the disk next to the spring wears the most and when it gets too tatty it can be discarded exposing the next one in the stack, but there should always be at least three left. When you clean the chamber, you should clean the O rings or cup seal on the piston with an old toothbrush if there is any buildup of solder dust, and occasionally apply a drop of light silicone oil (copier fuser oil is ideal) to keep the seal(s) and bore lubricated.
You can also improve the nozzle - a short length of fairly thin walled silicone rubber tubing pushed over the tip will let it seal to the board: Clamp the board vertically and heat the hole to clear from the side with the most copper, using a large hoof bit, with a little flux and fresh solder, sucking from the other side with the sucker normal to the board so it gets a good seal and all the suction is applied to the hole.
N.B. it wont be anti-static, but nor is the normal white Teflon nozzle. If working with highly ESD sensitive devices, buy a black carbon loaded static dissipative nozzle and *DON'T* add silicone tubing.
Another useful tool is a mounted steel needle fractionally thicker than the component lead. It can be inserted into a hole from the side with the least copper while heating the other side to clear the hole. After removing the iron keep rocking the needle fractionally in the hole as the solder cools to maintain enough clearance for easy withdrawal of the needle. If the resulting hole isn't clean enough, it can often be improved with a drop of flux and reheating next to but not covering the hole.
If you don't have a heat resistant miniature pin vice handy, you can make a mounted needle starting with a sewing needle. Use a thin wooden dowel for the handle, insert and remove the needle in the end to make a hole, then ligtly sand the eye end of the needle to roughen it, apply a drop of superglue to it and force it into the dowel for 1/3 of the needle length. The needle needs to be bright polished steel, not gold or brass plated, and should be kept lightly oiled or waxed so solder doesn't wet it.
If your iron cant supply enough heat to keep the solder molten all the way through the hole, with the biggest hoof bit you can get for it, you need a higher wattage iron. Temperature controlled is preferable - at least 50W, but with practice you can do a good job even with something as crude as a 100W Weller soldering gun - get the joint melted and sucked quickly before the high bit temperature has time to significantly cook the board.
When desoldering DIL package ICs in plated through hole boards, after sucking as much solder as possible from the hole, flex the pin slightly with a fine jewellers screwdriver or other blunt ended probe to hold it away from the wall of the hole so it doesn't stick as it cools. You may need to add a drop of flux and alternately reheat the pad and the pin while flexing it to clear any solder whiskers to get the pin free in its hole. If there is much solder on the shoulder of the pin you may have to use flux and braid from the top side after sucking the hole. The amount of care taken freeing each pin direct contributes to the odds of you avoiding signifiicant board damage.
Home
Help
Search
Login
Register
