3 ways to unsolder

3 ways to unsolder
3 ways to unsolder
Anonim

To recover or replace electronic components, you must unsolder the connections that connect them to the circuit. In general, a pump or desoldering braid should suffice for most of your home projects. In addition, they are not expensive. There are other tools available for finer tasks or for situations where it is worth spending a little more to gain speed or precision.

Steps

Method 1 of 3: Use a desoldering pump

Desolder Step 1

Step 1. Find the tabs of the component to be removed

A desoldering pump sucks the molten tin to separate the component from the plate. Examine both sides to find the one where the component is held in place on the circuit.

  • The desoldering pump works best for connections made through holes. You can also use it for elements mounted on the circuit surface, but it will be less effective. That being said, it is one of the cheapest solutions.
  • You can easily ruin the circuit by accidentally separating the different layers of it as you unsolder the element. Be careful to unsolder only the tabs necessary to remove the item in question.
Desolder Step 2

Step 2. Clean the legs

Take a toothbrush and some isopropanol to gently clean the legs of the component you want to remove. Make sure you clean them on the side where you are going to unsolder, not the side where the element is.

Desolder Step 3

Step 3. Secure the heat sink

The heat produced by the soldering iron can damage sensitive components such as integrated circuits and transistors. To dissipate some of the heat, you need to install the component and the plate on alligator clips to unsolder it.

Desolder Step 4

Step 4. Clean the soldering iron when it is hot

Turn it on and let it heat up for about three minutes. Use a damp sponge to rub the tip of the iron to clean it.

You might see a little smoke coming from the sponge, but it's only the water that evaporates

Desolder Step 5

Step 5. Activate the desoldering pump

Press the button at the top to put it in position. This makes it possible to compress a spring which relaxes to suck up the molten tin.

Desolder Step 6

Step 6. Heat the solder with the iron

Use the tip of the iron and heat the solder until it melts. You can push the tabs with the tip of the device at the same time to release it from the plate when the solder begins to melt.

Use an old soldering iron if you have one, as you could wear it out by pressing on the element

Desolder Step 7

Step 7. Vacuum the molten tin

Apply the tip of the desoldering pump to the molten solder without pressing. Release the spring (usually by pressing a button on the side) and the piston should go up all at once. This creates a vacuum which will suck the molten tin inside the pump.

  • The tip of the pump may melt a bit when in use. Most pumps have a tip you can replace or they're cheap enough to buy a new one, but you can reduce the damage a bit by taking a break after you've melted the solder.
  • The molten tin will harden quickly. Only work on one leg at a time. To make this more efficient, hold the soldering iron with one hand and keep the desoldering pump with the other.
Desolder Step 8

Step 8. Empty it in a trash can

After each use, you have to actuate the plunger again above a trash can to release the solder which has now hardened. If you leave it inside, it might leak onto the next component you want to unsolder.

Desolder Step 9

Step 9. Fix tough weld problems

It usually takes several tries before you can get something out with the soldering iron and pump. If you don't succeed after several tries, try one of the solutions below.

  • Apply a stripper to help the solder melt.
  • Melt some solder to mix it the old-fashioned way.
  • If the element is held in holes, you can use the tip of the soldering iron to gently move the legs back and forth. This breaks the solder that holds it in place.
Desolder Step 10

Step 10. Clean the circuit

You might notice bits of brown resin around the solder point, as it can melt when heated. You can wash it off with a little special cleaning product, or you can gently scrape it off with a flathead screwdriver or steel wool. Finish by cleaning the area with a toothbrush dipped in isopropanol.

  • Sometimes the pressure on the soldering iron or the pump could slightly deflect the circuit around the hole. This is not a problem as long as it is still connected to the rest of the circuit on the plate. If you see that it is broken, you will need to solder a new one.
  • If there are still traces of tin on the circuit, it will be easier to get them off with a desoldering braid, as explained below.

Method 2 of 3: Use a desoldering braid

Desolder Step 11

Step 1. Choose a braid that is slightly thinner than the hole

It consists of copper wires braided together. Choose a braid the same size or slightly thinner than the insert hole on the plate and slightly wider than the tip of the soldering iron. If it is too large, it could burn the plate or take too long to heat up.

This approach works best for insert holes or to clean up any leftover solder on the plate after you've finished unsoldering the component. You can try with components mounted on the surface, but it will be more difficult and take longer to desolder at several points

Desolder Step 12

Step 2. Add some stripper to the braid

Most of them are already coated with this product which weakens the weld. You can also put a little on the end of the braid to make this solution more effective.

Desolder Step 13

Step 3. Melt some solder on the leg

Once you've plugged in the soldering iron and heated it up, it might help to melt some more solder on the tab. This will help more easily melt the old solder in place. Remove the iron once you have completed this step.

Desolder Step 14

Step 4. Lay the braid over the solder

Place the end on the tab you want to unsolder.

Desolder Step 15

Step 5. Place the soldering iron on top

Without pressing too hard, place the device on the braid, avoiding moving the circuit around the hole. Wait a few seconds for the heat to pass through the copper and melt the tin underneath. Once it's melted, the braid is going to be there to absorb it.

  • Hold the braid by the spool to which it is attached. She's going to be too hot to hold her directly.
  • If the solder does not melt, it may be because the braid is dissipating too much heat. Try cutting off one end and using it instead, holding it against the solder.
Desolder Step 16

Step 6. Uncoil more copper if necessary

It will change color as the stripper wears off and the solder is absorbed. Unroll more braid and continue on the other leg. Apply more liquid stripper if necessary.

Even if you are working on an insertion hole, you are going to have to remove the solder that is around the component. If you want to use it again, keep the braid and the soldering iron away from this element so that the heat does not damage it

Desolder Step 17

Step 7. Remove it once it is cool

Once you've removed it, let the baking sheet cool for about 30 seconds before you finish pulling it out by hand.

Method 3 of 3: Use other tools

Desolder Step 18

Step 1. Upgrade your desoldering station

The next time you walk past an electronics store, you might consider purchasing a station that includes a better model of soldering iron and desoldering pump. It will allow you to set the temperature you want for soldering or desoldering. This is very useful for components that you want to remove on the circuit surface (that is, most of them) to avoid damaging sensitive parts.

Desolder Step 19

Step 2. Melt the solder with hot air

You can use brute force with a heat gun to melt the welds, but you're definitely going to fry other components. If you want to find a more precise solution, you are going to need a hot air station. It consists of a small pipe that sends very hot air to melt the solder on a specific point on the plate without running the risk of damaging the rest of the components. It's a cumbersome and expensive tool that is only recommended for people who desolder often and have old plates to get their hands on.

Suck up the molten solder with the desoldering pump or the tip of a vacuum cleaner

Desolder Step 20

Step 3. Remove small bits with tweezers

There are specialized tweezers whose ends are actually small soldering irons. You just need to pinch the tab of the resistor, diode, or other component to melt the solder.

Desolder Step 21

Step 4. Melt on low heat

There are several companies that offer soldering irons that melt solder at low temperatures and that are sold especially for desoldering. When you apply it over an existing weld, it creates an alloy that lowers the melting point of the metal. This will keep the solder liquid longer and easier to remove with the pump or braid.

Desolder Step 22

Step 5. Detach a row of legs with a cable

If there is a component mounted on the surface of the circuit which is connected by multiple legs, you will waste a lot of time unsoldering them one after the other. Instead, you can melt the solder on one side and use a thin wire to lift up all the legs in one go before the solder hardens.

  • Apply paint stripper and a new solder point to all the legs to mix it up the old way.
  • Use a desoldering braid as explained above to remove the solder.
  • Strip the end of a thin copper wire. Remove the rubber layer at the end of the wire.
  • Thread the wire under the line of the legs, then solder the end to the last to hold it to the plate.
  • Pull on it as you heat the nearest leg with a soldering iron until it comes loose.
  • Repeat on each leg. Try not to pull too hard or at too steep an angle.

Advice

  • If the circuit is old and dirty, you should clean the grease and dirt off it by rubbing a little isopropanol before you start.
  • If you're willing to spend a bit of cash, you can buy a desoldering pump with a heated tip to melt the solder and suck it up in one go. If you have one, you need to make sure that the end is not wider than the insertion hole. If the end is too wide, you will burn the circuit.

Warnings

  • The soldering iron is an extremely hot device! Always be very careful when handling it.
  • The smoke from lead-based solders is bad for your health. Desolder in a well ventilated room and wear protective goggles and a mask.
  • The spring mechanism of some desoldering pumps can sometimes break and throw the piston into the air. Avoid pointing the top of the device towards your face.

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