Solder paste: Classification, use, and storage


Solder paste is a new type of soldering material that is gaining attention today. So what exactly is solder paste? How to use and maintain? Follow the article below to find out!

What is solder paste?

Solder paste, also known as solder paste, is a wet mixture consisting of alloy particles mixed with flux in a certain ratio. Because it’s wet, it can be applied to the edge of the board easily.

solder paste

In terms of composition, in the past, this mixture consisted of two metals, tin, and lead. But later, because lead is an extremely toxic substance to human health and some countries have banned the use of lead. So at present, solder paste is only made from lead-free solder paste. And this mixture is also very diverse, can be tin and copper or tin with other metals.

Classification of solder paste

Solder paste is now classified according to the size of the solder paste and solder flux.

Sort by size

As for the size classification, it will not be possible to completely classify the solder paste in which category. That it will be based on the range of particle size values to determine.



Type Particle size  (mm)
Type 1 70 – 150
Type 2 45 – 75
Type 3 25 – 45
Type 4 20 – 38
Type 5 10 – 25
Type 6 5 – 15
Type 7 2 – 11
Type 8 2 – 8

solder paste

Classification by flux

Classification according to solder flux, solder paste is divided into 3 types as follows:

Resin solder paste: flux can be cleaned after soldering by using chlorofluorocarbon solvents

Water-soluble solder paste: with this type, the flux can be dissolved in water with organic materials and Glycol-based substances.

No-clean solder paste: this is made of plastic with varying degrees of residue, using it will not require cleaning, but requires a clean assembly environment.

How to use solder paste

First, you apply solder paste on the printed circuit board and should only apply it where it needs to be soldered. Note, if you apply too little solder paste, it will not be enough to create a weld. But if applied too much, the weld will be too large and may stick together between adjacent pads.

After the solder paste is applied to the printed circuit, the worker will put the circuit board into the machine to put the components in. At this time, the solder paste will have the effect of holding the component in the correct position temporarily. Care should be taken not to collide with the board during this stage because it may cause components to fall out. It is recommended to quickly solder the board after a few hours of placing the components so that the solder paste can promote the best soldering effect.

solder paste

Instructions for storing solder paste properly

To achieve the highest performance, users should store lead-free solder paste in sealed containers with lids to avoid oxidation. Also, remember to store the cream solder at low temperatures, not at freezing temperatures.

At the same time, any material has a shelf life and solder paste is no exception. Therefore, you should not use expired solder paste to avoid causing errors when assembling components.

Address to buy genuine solder paste, preferential price

If customers want to buy solder paste in bulk but don’t know where to buy it to get a good price, you can visit Thetech! We are a supplier of genuine, quality solder paste at the most favorable prices in the market. In particular, we also offer many attractive discounts for customers when buying in large quantities. Support nationwide delivery if required by customers.

Above are the answers related to solder paste. Hope this article has provided useful information to readers. If you have any questions, do not hesitate to contact Thetech for advice and support!

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