can you solder over old solder

Can you solder over old solder or should it be removed first?

Can You Remove Old Solder?

Yes. In fact, you should remove it completely before adding fresh solder to reserve the strength/integrity of the joint.

Can You Solder Over Old Solder?

You can solder over old solder, but it isn’t advisable to do so. Trying to solder over old solder won’t result in a perfect joint. You need to remove the old solder, clean the area, flux and solder afresh. While melting the old solder and attempting to add new solder can create a joint, it won’t be strong. It’s therefore critical that you remove old solder first.

How Do You Remove Old Solder?

You can begin by heating the old solder using a propane torch. Alternatively, you can use a hot soldering iron bit. Creating contact between old solder and a hot soldering iron will melt the solder, which can then be removed. Molten solder can be wiped away. However, you must be careful to avoid burns or damaging your components or work surface. Alternatively, you can use a special tool – a desoldering tool to remove the solder.

Methods for Removing Solder

Removing Solder using Solder Sucker/Vacuum

This method requires soldering tools such as a soldering sucker or vacuum that melts old solder and sucks it out of the joint in question. The solder sucker has suction power capable of removing old solder as soon as it melts.

This method is simple and begins by melting the solder and using the solder sucker to suck the molten solder. Depending on the types, soldering suckers can feature buttons for many operations, including quick suction and emptying the solder sucker.

Desoldering Using the Braid Method

As the name suggests, this desoldering method utilizes a copper braid for soaking up molten solder. However, to get the best result, you need a high-quality soldering braid with flux in it. The copper braid also needs to be clean.

This desoldering method requires a soldering iron and copper braid. The soldering iron also needs to be cleaned for a perfect result. Before getting started, select an appropriate copper braid size. Generally, the width of the braid should match or be wider than the solder joint in question.

To start, prepare the area you wish to place your copper braid by making a hole in the soldered joint. Proceed by holding your hot iron to heat up the joint. Your high-quality copper braid should soak up heat perfectly. You can use some flux to substitute for low copper braid quality. If you do this, ensure you put your flux before putting it on your joint. If the joint in question doesn’t have enough solder, you can add some new solder before removing everything.

When the solder melts and soaks into the copper braid, it will assume a tin color. Spool out as much braid as you need while moving to the other sections with old solder that you wish to remove. Continue removing until the joint is free of solder. Finish by lifting the copper braid and soldering iron together. Removing the iron first isn’t advisable as it may make the braid cool off and solidify on your work area.

Desoldering Using a Blow Torch

Old solder can also be removed using a blow torch. However, this method is only recommended for applications that won’t cause damage. Removing old solder from electrical components using a blow torch isn’t a good idea as it may burn the circuit board and other electrical components.

This method is simple. It begins by heating your target area using your blow torch or heat gun. This should be done cautiously, ensuring there are no flammable items or components nearby. To know when the old solder is ready for removal, observe the color. Molten solder is shinny. The solder can be removed using tweezers.

Desoldering Using Tweezers

It is possible to remove old solder using tweezers only. Desoldering using tweezers requires a heating source. Applying the tips of your tweezers to terminals can heat up the tweezers to the desired temperature. Provided the tweezers make perfect contact with the solder in question, the solder will melt away. Tweezers can either be free-standing or linked to a soldering station.

To remove the molten solder, use the tweezers to grab gently and lift the solder releasing it at an appropriate place. Tweezers are great for removing old solder from components featuring two terminals such as capacitors and resistors. Tweezers are a great alternative to a blow torch since they won’t heat and burn surrounding components or parts.

Conclusion: Can You Solder Over Old Solder?

Yes. You can choose to solder over old solder, but it isn’t advisable to do so since it compromises the integrity of the final joint. It’s better to remove the old solder first. Luckily, there are many desoldering methods discussed above you can use with ease.

FAQs on Desoldering (Removing Old Solder)

Can you reuse old solder?

Yes. However, it’s not recommendable to do so since it may contain impurities that will compromise the integrity of your joint. If the application in question isn’t sensitive, old solder can be reused.

What Material Absorbs Solder?

A copper braid or solder wick are perfect examples of materials that can soak up unwanted molten solder. Copper braid is sold in coils braided together using wire strands. Since copper conducts heat perfectly and molten solder is drawn to heat, heating up the copper braid sucks up the molten solder off the target area.

Can Old Solder be Removed Without Using Flux?

YES! Flux isn’t a must when soldering. However, you need something else (apart from flux) to get rid of the oxides that may be present on your metal workpieces; otherwise, you risk damaging your surface.

What Acid Will Dissolve Solder?

You can use concentrated acid to remove solder. Hydrochloric and nitric acids can dissolve solder completely. However, the application in question shouldn’t be affected by corrosion. Alternatively, you need to be extremely careful.

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