[fierce_freak]

I sat down to change out some parts in my amp to change the gain, figuring it would be a quick job (i've changed parts on this board before), but it's not. Everything went fine except one joint was/is ridiculously stubborn. First, I couldn't get the lead out of the hole...it took about 5 minutes to get out. Now I can't get all the solder out of the hole to put the new resistor in. I've tried a solder bulb, desoldering wick, even adding more solder to the joint before using the bulb or the wick. Lastly, I tried using the soldering iron on one side of the board while trying to add solder from the other side.

The solder won't melt. Somehow I'm not getting enough heat through the joint (soldering iron goes to 825 degrees). Anyone have any ideas?

 

[nikongod]

add solder to the hole.

if the solder is below the surface (int eh hole, but not above or below it) it wont melt easily and will be harder for the de-soldering instruments to deal with. then try to wick or solder-bulb it out.

as a last resort, i have pressed the new part into the hole while holding the iron on the backside. it is a last ditch effort, but i have decent success with 2-leaded parts. if only 1 hole is plugged this is CAKE. you bend the leads to fit, and melt the stubborn solder as you slide the resistor into both holes. then the "open" hole gets soldered. if both holes are stuck you can go millimeter by millimeter. very careful planning is necessary to avoid "warming your fingertips" with hot things

but it can be done.

edited after re-reading the OP:
if you have a powerful iron, try to set it lower. i use 600*f for parts on PCB's. i use 700 for burning the crap off of cardas wires.
after you drop the heat, feed LOTS of solder into the hole, and suck it out.

 

[Tedro]

Try some flux, and or add more solder. Make sure to use Fresh solder solder baid.

Make sure the Iron is really clean or the solder joing is clean too.

 

[fierce_freak]

Thanks for the suggestions, guys.

 

[mono]

I would wonder if the soldering iron tip is dirty so it's not conducting heat well. You might try taking a needle in a pair of pliers, heating the needle or the hole with the iron (needle being better so as to not subject the hole & trace(s) to more heat than necessary since it has been heated quite a bit already) while pushing the needle through the hole. Keep moving the needle so it doesn't get stuck and be sure it is just a little larger than the part lead will be.

 

[Eokboy]

I would heat the joint and suck it out with a desoldering pump on the other side of the board.

 

[beerguy0]

I feel your pain. I do a lot of PWB rework, and I've had this happen plenty of times. Try twisting the solder wick into a point, so it can get inside the hole, add some flux to it, and place the iron on top the wick and see if that helps. Be sure the iron tip is clean, so it transfers heat.

The trick with using a resistor lead or needle has worked for me as well. Flux helps here, too.

 

[colonelkernel8]

Happens all the time to me, I have in the past simply taken a needle and used a small hammer to *gently* pound out the solder. It happens with dual sided PCBs with plated vias most frequently and most stubbornly. (Incorrect grammar?)

 

[fierce_freak]

Thanks again for all the suggestions, guys...about to face down the solder joint again, haha. I'll let you guys know how it works out.

 

[MN Ham Phones]

Often, blowing the molten solder out works well.
Fill the cheeks, heat the solder, and forcefully expel the air directly over the board hole.

 

[ericj]

If you have a Harbor Freight Tools in your town, buy their assortment of eensy carbide drill bits. Costs about $4.

Pick out the bit that's about the same diameter as the wire you pulled out of the hole and use it to drill out the solder.

Generally this does a lot less damage to the through-hole than trying to thermally desolder it. through-hole with groundplane on both sides can be nigh impossible to melt well enough.

 

[Mazuki]

For me, a hemostat has been an indispensable tool for desoldering, in addition to my desoldering iron, of course.

 

[fierce_freak]

Well, didn't exactly get it desoldered but got the new resistor in place. Things would have been easier had I had a screwdriver tip handy, I think. Thanks again for the help, guys.

 

[flashbak]

I agree with a previous statement that your iron tip just isn't getting hot enough. However, that's a double edged sword! The hotter the tip the greater the possibility of the pad lifting because it's been left on it too long!

 

[ziplock]

Hmm.. between a hot iron, flux, and a wick.. theres not much you can't desolder.

A lower wattage iron can cause all kinds of hell for sure, especially with the new crap solder they are manufacturing these days! Lead based solder is still the easiest and most enjoyable to use.

Make sure the tip of your iron is tightened down securely for optimum heat transfer. Also, keep the tip very well cleaned and properly tinned before doing any work.

With the lower wattage/cheaper irons, heavy soldering can cause the temperature to drop too low and will cause cold solder joints and difficulty during desoldering as well. If suspected, give the iron a short rest and allow it to regain it's peak temperature.

Good luck!

~Zip