Solder FAQs

Yes. Syringes and cartridges should be stored vertically with tips facing down. If stored on their side, the piston can move, introducing air to the paste. Jars should be stored right side up.

Recommended storage temperature for solder paste is between 40°F and 50°F (4°C to 10°C). Storage at temperatures above refrigeration will reduce shelf life and voids the guarantee.

At a minimum, nine months for SolderPlus dispense paste, twelve months for PrintPlus print paste and twelve months for FluxPlus paste flux when stored as recommended. Warmer conditions will reduce shelf life and/or cause flux separation with solder paste. The end user needs to determine actual shelf life if stored outside recommendations. In this case, the replacement guarantee is void.

Our shelf life values were developed to include expected heat exposure during normal shipping conditions which may exceed refrigeration temperatures. If there was a problem with shipping and the paste was exposed to temperatures over 27°C for an extended time period, paste should be tested before use.

In many cases, nothing happens. However, some pastes are susceptible to damage that impairs performance. As a consequence, we recommend not freezing any of our solder pastes or paste fluxes. If you do “freeze” some paste, test its performance before use on live product.

Nordson EFD guarantees that properly stored paste will perform for at least the shelf life on the product label, or material will be replaced at no charge. Many of our solder pastes and paste fluxes will last beyond the warranty period. Customers wishing to use “expired” paste should re-qualify the material by running test boards or parts through the entire production process to confirm good soldering results. Nordson EFD does not ‘extend the shelf life’ of a product in writing beyond the expiration date indicated on the product label.

Aside from poor performance, the other major sign of mishandled solder paste is separation of the flux and alloy particles. Solder paste should be uniform in color and consistency.

No. Solder paste should be used at “room temperature.” This will assure intended viscosity and prevent potential condensation. Recommended warmup time is four hours. Syringes can come to temperature in less than four hours. This time must be validated by each customer.

We do not recommend it. However, if necessary, faster warm-up may be achieved by placing the sealed container in a water bath or similar equipment at or near ambient temperature. Syringes require approximately fifteen minutes while jars and cartridges can take up to 45 minutes. DO NOT heat paste with an oven or other environment set above “room temperature.” Dry all packing completely prior to use to prevent water coming in contact with the solder paste.

Usually, no. Solder paste should be used as needed. Material should be left at an acceptable room temperature once removed from refrigeration. In the event that a container of solder paste would go unused after removal from refrigeration, and ambient temperature exceeds 75°F (25°C) for an extended time before use, it should be returned to cool storage.

In general, we do not recommend reuse of solder paste remaining on the stencil. However, if paste is relatively fresh, it can be put into a jar and stored for reuse. Never put used paste back into the same container as new paste! This will contaminate the unused paste and degrade its performance.

Solder balls on the sides of chip components are typically referred to as “solder beads” due to their large size. Two process changes may be possible to minimize or eliminate the problem.

1. Aperture reductions designed to decrease the quantity of paste trapped between the part and board solder mask. The most effective shape is a triangular shape removed from the inside edge of each aperture, often called reverse home plate. Two other options in use are a home plate shape and simple aperture reduction on the inside edges. Call Technical Service for specifics.


2. Component placement accuracy relative to paste is critical. Reductions all by themselves do not guarantee elimination of solder balls if pick & place accuracy is inadequate. Tune your equipment to optimize vision recognition and placement accuracy of your chip components.

Four effects are more significant than others.

1. Increased surface tension of molten solder alloy changes fillet shapes, improves part centering, and may increase tombstoning.


2. The low oxygen content retards oxidation, allowing for longer and hotter profiles.


3. Nitrogen transfers heat better than air so set points may be lower.


4. Evaporation of many fluid flux constituents is increased, thereby reducing the quantity of flux residue.

No-clean residues should be colorless or nearly so to facilitate visual inspection. They should be tack free and fairly brittle, allowing for easy penetration of test probes without clogging.