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All of paints and pastes listed on this page have been designed for specific microscopy laboratory applications, but we also know that all of them can be used to make any surface conductive. We offer the following comments to help those trying to decide which of these various products would be the most appropriate for their own particular application. Remember that the ultimate characteristics of the paints and pastes spring from the inherent properties of the respective metals, those being either silver or platinum.
The SPI Supplies Brand of silver paints are used widely throughout the world in the leading laboratories where scanning electron microscopy (SEM) and scanning probe microscopy (SPM) is performed. The high purity of the silver solids and suspending medium make the SPI Supplies Brand the preferred brand wherever these kinds of microscopy are performed.
All of these paint products are electrically conductive. The carbon paint, however, while it is sufficiently conductive for its intended use for the grounding specimens for scanning electron microscopy, may not be sufficiently conductive for other applications, such as plating. One would have to try it in order to find out if it would work in their own specific plating application. The silver and platinum paint products are much more conductive than the carbon paint products, but also more expensive.
The silver and platinum paints, especially the platinum product, are expensive, and their cost may be prohibitive for certain applications.
For SEM and most other applications, surface texture of the dried paint layer is not important. But for plating applications, it can be very important. All of the paint products are designed for brush application, using the brush applicator in the bottle cap. Any reasonable thickness of plating may "see" the texture of the brush strokes in the underlying paint. With "brush plating", we simply do not know what will happen in terms of the final surface texture. For all non-SEM applications, the buyer will have to do their own testing to be sure of suitability of use and only they will be able to determine whether a particular paint will or will not work in their particular case.
With the exception of our new SPI SafeShip™ Nonflammable Silver Paint, all of our paint products are solvent-thinned systems and when the application is the surface of a plastic, there is always the possibility that the thinner could attack, swell, or partially dissolve the surface. Since the SafeShip™ Nonflammable Silver Paint contains some water in its diluent system, we would expect that this product would be less aggressive on many plastic surfaces.
In general, the adhesion of the paint to a surface is dependent on a variety of factors including surface preparation before the application of the paint. For the typical SEM application, one does not do any substrate preparation. But for a plating application, and if the substrate is plastic, there are some tradeoffs. If the solvent attacks the surface sufficiently to get really good adhesion, the substrate will be damaged (roughened) and this damage will be visible through a final plating. If the solvent does not "wet" the surface, and if it is a non-solvent for the plastic, then the adhesion is likely to be poor, and so will be the plated layer. For the attachment of fine wire electrodes, any of the paints should work acceptably.
All of the products on this page were designed to be air drying at room temperature. For the silver paint products, the SPI Supplies Flash-Dry™ Silver Paint has a liquid carrier system with the highest vapor pressure and therefore evaporates (dries) the fastest. On the contrary, because of the aqueous fraction in the diluent, the SPI SafeShip™ Nonflammable Silver Paint will have the longest drying time.
We are frequently asked about the use of SPI Conductive Silver Paint to make electrical connections at cryogenic temperatures. A better choice would be SPI Silver Paste Plus™. We know that some customers have used either product in cryogenic applications, but we do not have detailed information on what they were doing. Typically, in the typical use, the paint or paste may be used to attach a conductor to a pad, but the actual contact is between the conductor and the pad, so the conductivity of the paint or paste is less important than its mechanical properties, which are not the best. A better result may be obtained by using the firing procedure, the bond is converted to metallic silver, which should provide a high level of conductivity even at cryogenic temperatures. However, in more cases than not, the greater concern seems to be more about the effect of thermal stresses on the quality of the bond (as opposed to questions of conductivity).
Where shipping rates for small quantities of flammable materials become prohibitive, the SPI SafeShip™ Nonflammable Silver Paint can probably be used because of its inherently higher viscosity.
At temperatures about 500°C, silver starts to sublime, and this is undesirable since silver contamination is hard to clean out of a vacuum system. This is then the kind of situation where one must turn to the SPI Supplies Platinum Paint.
The smallest silver "spots" or "dots" can be made with SPI Silver Kwik-Stik™ while larger dots can be made with the SPI Supplies brand Silver Streaker™.
Not everyone wants a paint that is conductive. Some would prefer an insulating tape, and for that reason, we have formulated the SPI-Tac™ Liquid Adhesive.
This paragraph is meant only for those placing orders from countries where
one can not ship 
designated flammable products.
It does not apply to shipments to domestic USA destinations, Canada, most western European
countries, and certain countries in Asia like Japan, Taiwan, and Singapore. It is meant to
those destinations where anything flammable, even in the smallest of quantity, must be
shipped either by sea freight or by air freight, and at far higher shipping costs than
if the shipment was made via one of our preferred courier services, UPS or FedEx. It is
for these countries that we have specifically formulated the innovative and so far as
we know, unique product, SPI SafeShip™ Nonflammable Silver Paint,
which has been formulated with enough water to ensure that its flash point is sufficiently high that it is
not considered to be a flammable material.
