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Indium 6.3 Water Soluble Sn/Pb Solder Paste

Indium 6.3 Water Soluble Sn/Pb Solder Paste
Manufacturer: Indium


• Excellent wetting and solder joint appearance
• Exceptional printing and response to pause
• Wide reflow profile window
• Outstanding slump resistance
• Low voiding
• Halogen-Free


Indium Corporation manufactures low oxide spherical powder composed of eutectic Sn/Pb and Sn/Pb/Ag in the industry standard type 3 mesh size (J-STD-006). Other non-standard mesh sizes are available upon request. The weight ratio of the flux/vehicle to the solder powder is referred to as the metal load and is typically in the range of 80-92% for standard alloy compositions.

Standard Product Specifications


Metal Load

Particle Size




89.5% (Type 3)


80-86% (Type 3)

25-45 µm



Standard packaging for stencil printing applications includes wide-mouth 500g jars and 700g car tridges. For dispensing applications, 10cc and 30cc syringes are standard. Other packaging options may be available upon request.

Storage and Handling


Refrigerated storage will prolong the shelf life of solder paste. The shelf life of Indium6.3 is 4 months when stored at <10°C. When storing solder paste contained in syringes and car tridges, the packages should be stored with tip down.
Solder paste should be allowed to reach ambient working temperature prior to use. Generally, paste should be removed from refrigeration at least two hours before use. Actual time to reach thermal equilibrium will var y with container size. Paste temperature should be verified before use. Jars and car tridges should be labeled with date and time of opening.

Material Safety Data


The MSDS for this product can be found online at y/msds.php


The high tack value of Indium6.3 assures consistent component holding power. It allows high speed component placement operation, including use of tall components. Tack remains adequate for over 24 hours over a wide humidity range.


J-STD-004 (IPC-TM-650)

• Flux Type Classification ORH0

• Halide Content (F, Cl, Br) 0.0%

• SIR Pass

• Wetting Test Pass


J-STD-005 (IPC-TM-650)

• Typical Solder Paste Viscosity

(Sn63, 89.5%, Type 3

Malcom (10 rpm), 1700 poise*

• Typical Tackiness 40g*

• Slump Test Pass

• Solder Ball Test Pass

*Pending statistical validation


Stencil Design:

Electroformed and laser cut/electropolished stencils produce the best printing characteristics among stencil types. Stencil aper ture design is a crucial step in optimizing the print process. The following are a few general recommendations:
• Discrete components — A 10-20% reduction of stencil aperture has significantly reduced or eliminated the occurrence of mid-chip solder beads. The “home plate” design is a common method for achieving this reduction.
• Fine pitch components — A sur face area reduction is recommended for apertures of 20 mil pitch and finer. This reduction will help minimize solder balling and bridging
that can lead to electrical shorts. The amount of reduction necessar y is process dependent (5-15% is common).
• For optimum transfer efficiency and release of the solder paste from the stencil apertures, industr y standard aperture and aspect ratios should be adhered to.

Printer Operation:

The following are general recommendations for stencil printer optimization for Indium6.3. Adjustments may be necessar y based on specific process requirements:
• Solder Paste Bead Size: 20-25mm diameter
• Print Speed: 25-150mm/sec
• Squeegee Pressure: 0.018-0.027kg/mm of blade length
• Underside Stencil Wipe: Once ever y 10-25 prints or as necessary (dry wipe recommended)
• Solder Paste Stencil Life: >8 hrs. @ 20 to at least 70% R.H. & 22-28°C


Indium6.3 exhibits excellent wetting on a wide variety of sur face finishes, such as immersion tin, immersion silver, nickel/gold, palladium, alloy 42, HASL, and OSP,
under both air and nitrogen reflow atmosphere. The solder joints yielded are ver y shiny and smooth, including those of ultra-fine-pitch components. Indium6.3 has ultra-low voiding per formance. Minimal voiding can be achieved with optimal process conditions.


Residue Cleaning: Indium6.3 flux residue is cleanable up to at least 72 hours after reflow and is best cleaned using DI water with a spray pressure of at least 60 psi and a
temperature of at least 55°C. These parameters are a function of board complexity and cleaner efficency.
Stencil Cleaning: This is best per formed using an automated stencil cleaning system for both stencil and misprint cleaning to prevent extraneous solder par ticles. Most commercially available stencil cleaners and isopropyl alcohol (IPA) work well.


Recommended Profile:

The profile shown here is designed for Indium6.3 with Sn63/Pb37 and Sn62/Pb36/Ag2 under both air and nitrogen reflow atmosphere. It ser ves as a general guideline in establishing a reflow profile for these alloys.

Heating Stage:

A linear ramp rate of 0.5°- 2.0°C/second allows gradual evaporation of volatile flux constituents and helps minimize defects such as solder balling and/ or beading and bridging resulting from hot slump. It also prevents unnecessar y depletion of fluxing capac- ity when a high peak temperature and extended time above liquidus is used.

Liquidus Stage:

A peak temperature of 25°- 45°C (215°C shown) above the melting point of the solder alloy is needed to form a quality solder joint and achieve acceptable wetting due to the formation of an intermetallic layer. If the peak temperature is excessive, or the time above liquidus greater than the recommended 45-90 seconds, flux charring, excessive intermetallic formation and damage to the board and components can occur.

Cooling Stage:

A rapid cool down is desired to form a fine grain structure. Slow cooling will form a large grain structure, which typically exhibits poor fatigue resistance. The acceptable cooling range is 0.5°C-6.0°C/second (2.0°-6.0°C/second is ideal).

This product data sheet is provided for general information only. It is not intended, and shall not be construed, to warrant or guarantee the performance of the products described which are sold subject exclusively to written warranties and limitations thereon included in product packaging and invoices.



Conro Electronics Ltd
Unit 7, Orbital 25, Dwight Road, Watford, Hertfordshire
WD18 9DA

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