SILICA GEL SACHETS
Silica gel sachets or bags are simply flexible ‘containers ‘ of silica gel.
The sachet material has to be robust and capable of withstanding normal handling whilst, most importantly, being able to breathe. This means that water molecules can pass through the material and be adsorbed by the silica gel.
Standard sachet materials include Tyvek™, non-woven fabrics or cotton.
Most sachets have heat-sealed seams. The larger bags are sewn.
We produce a range of silica gel sachets using non-indicating (white) or self-indicating (orange to green) silica gels.
In the latter case, the colour of the silica gel is visible
through the non-woven sachet outer.
Self-indicating silica gel sachets are often useful in test situations,
to confirm the suitability of the sachet size chosen or in cases
where an item is frequently inspected and the sachet
can be replaced if it has become exhausted.
Non-indicating (white) silica gel sachets
½ gram (32 x 20 mm)
1 gram (39 x 20 mm)
3 gram (55 x 25 mm)
5 gram (65 x 30 mm)
10 gram (75 x 40 mm)
These sachets are made as standard in a
heat-sealed Tyvek™ material.
Tyvek™ is a very strong dust and lint free material which is ideal for sensitive applications.
Small silica gel sachets can prevent moisture damage to electrical goods and electronic components (internally and externally), scientific and optical instruments, communication equipment, metallic parts, leather goods, tools and many other small to medium sized items in use, store or transit.
For situations where the physical space for a sachet is very restricted, consider silica gel in capsules: 0.3 gram, 0.6 gram and 1 gram.
Self-indicating
(orange to green)
silica gel sachets
1 gram (40 x 20 mm)
5 gram (65 x 45 mm)
10 gram (80 x 55 mm)
25 gram (100 x 80 mm)
50 gram (130 x 80 mm)
100 gram (170 x 80 mm)
250 gram (185 x 125 mm)
500 gram (270 x 125 mm)
1 kg (320 x 160 mm)
These sachets are made in a heat-sealed paper and non-woven fabrics.
They are ideal for applications where visual inspection is made to see if the silica gel is active or now (orange = active, changes to dark green = near exhausted).
These can be times when it is unknown how much moisture is present or when new air and moisture is being regularly introduced.
Non-indicating (white) silica gel sachets
25 gram (115 x 50 mm)
50 gram (130 x 80 mm)
100 gram (170 x 80 mm)
250 gram (185 x 125 mm)
500 gram (270 x 125 mm)
1 kg (320 x 160 mm)
Medium and large sized heat-sealed non-indicating sachets are made as standard in both non-woven fabric and Tyvek™
These sachets can prevent moisture damage to larger electrical/electronic items, metallic components and fabrications, contents of export packing cartons or crates and hygroscopic powders.
Non-indicating (white) silica gel cotton bags
250 gram (18 x 14 cm)
500 gram (20 x 18 cm)
1 kg (30 x 18 cm)
2½ kg (38 x 25 cm)
5 kg (55 x 35 cm)
10 kg (70 x 45 cm)
These largest silica gel bags are sewn in cotton to give them extra strength and robustness.
The 2½ kg bag has two 30 cm tapes sewn into its’ seams as standard, so can be hung from a suitable fixing point. The smaller cans can also have tapes attached, if this is desirable.
The largest silica gel bags can prevent moisture damage to items in transit in packing crates and shipping containers or protect large machinery and engines and enclosed vessels such as tanks or pipes.
FDA grade silica gel sachets, non-indicating
½ gram (35 x 16 mm)
1 gram (42 x 19 mm)
5 gram (65 x 34 mm)
10 gram (90 x 34 mm)
These sachets are suitable for medical and pharmaceutical applications and are FDA approved for use in food contact packaging. All of the sachets are made in Tyvek™ and printed Moisture & Odour Adsorbent Do Not Eat (in six languages).
Silica gel sachets
non-indicating
to Def Stan 81-68/4
5 gram (108 x 50 mm)
10 gram (120 x 50 mm)
25 gram (144 x 80 mm)
50 gram (160 x 80 mm)
100 gram (180 x 80 mm)
250 gram (250 x 125 mm)
500 gram (300 x 150 mm)
This range of sachets are made to meet
Def-Stan 81-68/4 (then 5 and 6).
They are made to order.
They are filled with silica gel that conforms
to BS 7554:1992 (beaded silica gel) and are printed with our (or our customer’s) details and also the date of manufacture, to meet
the requirements of the Standard
Silica gel sachets
to MIL-D-3464E
Types I and II
½ unit (95 x 50 mm)
1 unit (115 x 50 mm)
2 unit (130 x 80 mm)
4 unit (170 x 80 mm)
8 unit (175 x 125 mm)
250 gram (185 x 125 mm)
16 unit (255 x 125 mm)
500 gram (270 x 125 mm)
1 kg (320 x 160 mm)
These sachets are made to the military specification MIL-D-3464E in either Type I and II (non-dusting) or Type I (general purpose) formats.
A ‘unit’ refers to the weight of desiccant required to meet adsorption capacities laid down by the Standard.
Typically, 25 grams of silica gel = 1 unit.
So, for example, a 16 unit sachet is filled with 400 grams of silica gel (and a 500 gram sachet = 20 units)
The sachets, as standard,
offer a two year shelf-life.
Bandoliers
Bandoliers are ‘connected’ groups of silica gel sachets. In their simplest form, they are machine made sachets that have not been individually cut as they are produced, but just left as a ‘string’ of sachets.
This form is mostly only suitable for smaller sachets.
Our standard bandoliers are seven connected ‘pockets’ made using a cotton fabric and where each pocket contains a 500 gram silica gel sachet. The 500 gram sachets can be filled with either non-indicating or self-indicating silica gels to commercial or defence standards.
The bandoliers are made such that the sachets cannot fall out of their pockets during normal use and, as such, are extremely useful when used to protect high value machine parts.
…and more. Variations, non-standard sizes and special packing
In addition to our more standard range of sachets, we can also:
Make sachets (10 gram to 1 kg) filled with blue to pink (BS3523:1991) self-indicating silica gel.
Make sachets filled with orange to colourless self-indicating silica gel.
Make sachets to any other weight or shape that meets customer’s requirements.
Attach loops or lengths of tape to sachets
so they can be hung or tied in use.
Individually over-wrap sachets in foil or poly pouches for extended shelf-life or distributed use ‘in the field’.
Sew all sizes of sachets in non-woven fabric (or cotton) sachets where regeneration and reuse of sachets is desired.
Make sachets using a mixture of materials e.g. silica gel and molecular sieve or silica gel and activated carbon.
Which Size Sachet To Use?
A silica gel sachet is most effective in an enclosed environment. A physical barrier will prevent water molecules from
continually entering such an environment, leaving the finite volume enclosed to be protected by the silica gel.
A general rule of thumb in a ‘hermetically sealed’ environment, is that 5 grams of silica gel are required per cubic foot of enclosed volume
(or 170 grams per cubic meter).
It is often prudent to err on the side of caution and use the nearest standard size sachet over the amount of silica gel that is theoretically required.
For large volumes, using a few well spaced smaller sachets will reduce humidity levels faster than if using a single large sachet.