Shielding FAQs More answers to Magnetic Shielding questions
Breakthrough In Magnetic Shielding Flexibility
GIRON Magnetic Shielding Film, which does not contain Nickel, is unlike any other magnetic shielding material available on the market today. Suitable for applications requiring high saturation and good permeability, it is both thin and strong, and unlike Mu-metal™ it is very tolerant to bending or shaping without losing is shielding properties.
GIRON is a woven, laminated material. Cuts neatly with snips or sheet metal tools, and can be used either flat or molded into shapes for best performance.
Suitable for small shields on magnets, motors, speakers and appliances such as refrigerators, vacuum cleaners etc. Also great for lining car floor or firewall. Perfect for full or partial wall / floor shielding in rooms too! Can be glued, taped, nailed, screwed or riveted into place. Could even be used to make a (heavy weight) vest to shield a person's torso! Works with AC or DC magnetic fields (0-1000 Hz), and will tolerate temperatures from 32░ to 122░F. Coating is UV sensitive, cover if installation is exposed to direct sunlight.
25.5 inch wide, 1 mm thick. Weighs 3.5 Kg/m▓ (about 15 pounds per 10 foot length). Edges are sharp!
MAGNETIC SHIELDING FOIL
"The Best Material Available for Shielding DC, ELF & VLF Magnetic Fields"
Used for years in industry to shield delicate
electronic components from EMFs, this 80% nickel alloy magnetic
shielding foil is now available at affordable prices for home and
office use. The thinner (0.004" thick) material is easy to trim with
scissors and shape by hand. Thicker material offers better shielding
performance but requires snips to cut. Can be formed into magnetic
barriers on cellular phones, microwave ovens, doorbell transformers,
VDTs, buried wiring, and more. With snug fitting shapes, get as much as
75% attenuation of the magnetic field with one thickness. Use multiple
layers for even greater reduction. Foil is available in two thicknesses
and can be ordered in any length. (We recommend the use of a gaussmeter to determine
the proper shape and positioning of the magnetic shield, and to confirm
that the fields have been adequately reduced.) 15
Magnetic Shielding Foil:
Now achieve excellent and affordable magnetic shielding in difficult situations! Mag- Stop Plates are extra thick high-efficiency magnetic alloy (Mumetal«) plates, specially designed to provide superior shielding for electric circuit boxes, side by side computer users, and any situation where you need a flat shielding material on a wall, floor, or ceiling. Can be mounted with ordinary nails or screws, or sandwiched between the studs and dry-wall. Use zinc chromate primer before painting. In one application, we were able to achieve almost 95% attenuation of a 200 mG field!
The 24" wide "stress annealed" plates offer good magnetic shielding and are also well-suited for forming into complicated shapes. The 30" wide "fully hydrogen annealed" plates offer the best shielding available (up to 10 times the shielding effectiveness of stress-annealed alloy) and should not be soldered, welded, or heated in any way. Hydrogen annealed plates have 2 small holes pre-drilled near one end which may be used for mounting. Because of size and weight, additional shipping charges apply.
All Products And Prices
Application Note: How Much Area Do I need to Cover?
The amount of shielding that you will achieve depends on many factors, including the size and shape of the shield. When using a flat shield on a wall, floor, or ceiling to shield a source of field that is close to the shield (within 8 inches), plan to cover an area that extends at least to the 2 mG line.
1- Using your gaussmeter, slide along the
surface of the wall to locate the hot spot to be shielded.
Click here for a short instructional video on doing a magnetic field survery for shield design.
Another format of MuMetal«, great for Magnetic Shield Prototyping and for Joining Mag-Stop™ Plates
When you need more than one Mag-Stop Plate to cover an area, how do you handle the joints? Joint-Shield is the perfect solution! This is a generous .010" thick, fully hydrogen annealed magnetic shielding alloy with adhesive backing (rated 0 - 200░F) on one side. Simply butt the Mag-Stop plates tightly together, and "tape" over the seam with Joint-Shield high permeabilty alloy. This method offers much less bulk and better appearance than the old overlap technique and provides excellent shielding integrity. Simple to use: just cut to desired length with a heavy scissors, peel the protective backing and press into place!
Joint-Shield can also be used by itself as an excellent magnetic shielding material when a 4" width and adhesive backing is desirable (wrap it around wiring and conduit, speaker magnets, even small appliances like shavers and hair dryers!). Joint-Shield can be shaped by hand, without the need for special tools, but watch the sharp edges.
METGLAS« MAGNETIC SHIELDING FILM
Paper Thin and Highly Effective
Space-age technology has produced this unique ultra-high permeability (1,000,000+) magnetic shielding alloy. Unlike conventional Mumetal« shielding alloys which are nickel/iron based and depend on bulk for effectiveness, MetGlas is a cobalt based alloy which is only 0.00065" thick (that's 16 microns, a red blood cell is 8 microns across)! Thinner means less material is needed. Less material means less weight and lower cost. Easy to handle, too. Cut it with a scissors, shape it with your fingers, tape it in place. Flexible and tough, with moderate corrosion resistance, it can be used indoors or out. Near-zero magnetostriction means it can be flexed over and over without losing its shielding properties.
Wrap wiring, pipes, switches, or electro-magnets. Make shields for small electronic devices. Even lay it flat (in our experiments, we saw nearly 90% field reduction when a 4" x 4" MetGlas shield was placed flat against an energized lamp cord). Note: This material tends to saturate easily and is not recommended for shielding strong magnetic fields. This is the material often used in Electronic Article Surveillance systems. Best suited for situations where magnetic field is not strong, but high level of attenuation is needed. Formula 2714AZ, supplied annealed. 1 inch wide
SORRY, THIS ITEM IS NOT AVAILABLE FOR EXPORT.
FINEMET« Wide Format Film
Ultra-Light Weight, Wide Format, Flexible Magnetic Shielding
Combining high performance nanocrystalline magnetic shielding alloy sandwiched between layers of clear PET to achieve good performance and easy handling. Very light weight and flexible, easily trimmed with scissors this material will provide good high frequency magnetic shielding for moderate to low fields below 1000 kHz. Tolerates bending very well. Stack multiple layers to improve shielding performance. Maximum permeability: 70,000. Maximum flux density: 1.13T. Only 0.12 mm thick (5 mil) and 470 mm (18.5”) wide. 0.052 lb/ft▓
Specify desired length when ordering.
High Saturation Magnetic Alloy
First line of defense for shielding strong
magnetic fields from magnets, speakers, small transformers and motors.
Strong magnetic fields are harder to shield because they tend to
"saturate" the shielding material. This 4" wide foil is a hefty .010"
thick and has an exceptionally high magnetic saturation of 21400 Gauss
and maximum permeability of 4000. Tin plated for excellent corrosion
resistance and better conductivity, it can be soldered or painted.
MagnetShield typically reduces fields up to a factor of 2 or 3 depending on size/shape of the shield. Can be used in multiple layers, and/or in combination with a higher permeability alloy such as Joint-Shield for higher attenuation. Annealing is not necessary with this material. For increased shielding effectiveness, consider the following strategies:
- The magnets will be attracted to the shield
(this is true of ALL magnetic shielding alloys). If you want to shield
2 adjacent magnets from eachother, each magnet should have its own
Click here for Specs on Magnet Shield
4 inch wide Ribbon:
Light Duty Economy Magnetic Shielding
For small shielding job where you don’t need a high attenuation, this unique material is just the ticket. Only 0.010 inch thick, PaperSHIELD is flexible and can be easily cut with a scissors and shaped by hand into simple or very complex shapes. High saturation and moderate permeability make this ideal for shielding weak magnets, or stronger magnets with many layers of shielding. White paper on one side can be imprinted (by you), peel and stick adhesive on the other side permits easy and semi-permanent mounting almost anywhere. Magnets will stick to it nicely. Really great for experimenting. 36 inches wide. Made in USA.
Unique Shape for Unique Shielding Applications
Do you have an application requiring Mumetal« in un-insulated wire format? We have it in two different diameters! Stress annealed Mumetal« alloy. Wind it, weave it, braid it. Create toroids, coils, chains or simply experiment with its unique properties! Be the first to create a truly magnetic shielded garment! Spool size varies between 1-2 pounds. Click here for Specs on MuMetal« Wire
Breakthrough in Low EMF Wiring!!
At last, we are proud to offer wiring which actually reduces EMF emissions to extremely low levels. Patented design incorporates both of these EMF emission suppression features: special internal wire configuration to maximize cancellation of magnetic field emissions: 2 hot, 2 neutral, and one ground wire and shielded wrapping to completely eliminate electric field emissions!
The result is a high quality wire with the lowest possible EMF emissions (over 90% reduction compared to standard wire). Replacing existing wire with MÁCord is likely to be much less costly, more effective, and probably more convenient than shielding.
Includes ground wire. Note: MÁCord will not compensate for unbalanced current. Make sure you correct wiring errors when you re-wire with MÁCord. Not UL listed for in-the-wall wiring applications.
MÁCord™ flexible “appliance cord style” for re-wiring lights and appliances, making extension cords, etc. 20AWG stranded wire. Equivalent to 18/3 SVT, rated for 14 Amps, 300 Volts. ╝ inch outer diameter. Black. Specify length
Make Your Own Shielded
|NEMA 5-15P: 3 prong grounded plug (Cat#A224P) … $2.25
NEMA 5-15R: 3 prong grounded socket (Cat#A224R) … $3.25
Need more room at the end of your cords? This
sturdy adapter converts one outlet into three. Uses standard North
American 3-prong outlet. Handles up to 15A safely. Color/style may
|3 Outlet Socket Adapter (Cat. #A804) .............. $1.95||
Designing magnetic shielding is not a hard science, and
sometimes only experience, careful attention
to detail, and some trial and error testing are available to produce the desired outcome.
Many factors affect shield performance. Naturally, the permeability and saturation induction of the
shield material itself must be chosen carefully… as well as the type of anneal. But that is only the
beginning. Remember that magnetic shielding is not really “shielding” in the traditional sense. One
cannot stop or block magnetic field lines. They will travel from the N pole of the source to the S pole.
What we can do is to alter the path that these magnetic fields lines take on their journey. Magnetic
shielding materials “conduct” magnetic field lines better than air (and most other materials). In a sense,
they create a “path of least resistance” in which the magnetic field lines can travel. But the magnetic
field lines will travel in this alternate path if it is a lower energy path. Not just because we want it to.
Following is an incomplete list of other factors which must be considered, along with comments about
Shape of the shield
In general, spherical and cylindrical shaped shields work best. This is
because magnetic field lines resist making sharp turns. When spherical
and cylindrical shapes are not possible it is always best to make bends
with a curve, rather than a sharp crease. Note however, that a cylinder
shield around a straight wire does not prevent the magnetic field from
emitting. It will however, protect the wire inside from fields originating
outside the shield. See diagram at right.
Pay careful attention to bending the material. Because the magnetic properties are highly dependant on
size/shape of the metal crystals, any manipulation such as bending or high heating which alters crystal
size/shape will adversely affect the ability of magnetic field lines to travel through that area. Often
bending is absolutely necessary. One can either accept some decreased performance, or re-anneal the
material after forming to achieve peak performance.
Size of the shield
In general, the larger the shield, the more magnetic field lines it will
“attract”. However, magnetic field lines which travel at a distance
from the shield location will not have an incentive to travel through
the shield. See diagram at right. On the other hand, larger shields will
also “conduct” more of the Earth’s magnetic field. At about 400 mG,
the Earth’s field can saturate high permeability shields, if large
enough, or thin enough.
A general recommendation for a typical application in a home environment where one is shielding a
circuit box with flat shielding is to shield an area which extends about 2-3 feet beyond the dimensions
of the source. So a shield about 6 ft x 6 ft is recommended. If the presence of a side wall, floor, or
ceiling restricts the size of the shield, the shielding material can be continued around the corner, but the
metal must be continuous, or properly joined.
Number of layers (or thickness) of the shield
Shield performance increases with increased thickness of number of layers. The relationship is nonlinear.
Ultimately, the required thickness will depend on how much attenuation is needed, and cost.
A general recommendation for a typical application in a home environment where one is shielding a
circuit box with flat shielding is to use at least 0.020 inch thick high permeability material.
A general recommendation for a typical speaker magnet application is to make 3 concentric cupshaped
shields from high saturation alloy. Use cardboard spacers between layers. Place the stacked
cups over the back of the speaker magnet.
Spacing between layers of shielding
Spacing between layers of shielding increases shield performance. The larger the space, the better the
performance. Almost any material can be used as a spacer: wood, plastic, drywall, glass, air,
cardboard, other metals, etc. Other considerations such as cost, strength, flammability, weight, etc must
be taken into account.
Distance from the shield to the source of the field
As the distance from the source increase, the concentration of magnetic field lines decreases.
Saturation may be less of an issue, unless shield size must also be increased.
Orientation of the magnetic field as it encounters the shield
Aligning the shield surface parallel or nearly parallel to the orientation of the magnetic field lines will
yield the best shielding. Magnetic field lines perpendicular the shield will not change their course as
they travel through the material. See diagrams below.
This can be used to advantage. For example, orienting a flat shield perpendicular to the Earth’ s
magnetic field can minimize saturation problems due to Earth’ s field.
Note also how the magnetic field is concentrated at the edges of the shield pictured on the right.
Gaussmeter readings at these edges will be higher than if no shield was present. Shield design should
take into account the positioning of these edges.
Strength of the magnetic field where it encounters the shield
The strength of the magnetic field at the source is not relevant to shield design. The strength of the
field at the proposed location of the shield is relevant. The stronger the field at the location of the
shield, the thicker the shield should be.
Frequency of the magnetic field
Magnetic shielding performance decreases as frequency of the field
increases. Attenuation is proportional to permeability, all other factors
being equal. Note that permeability drops dramatically over 1kHz
The effect of the Earth’s magnetic field (and other ambient magnetic fields).
The omnipresence of the Earth’ s magnetic becomes an important factor in shield design when shields
are large. Saturation is the instantaneous and reversible process whereby the shielding material is
“ conducting” all the magnetic field that it can. Additional magnetic field will not be affected by the
presence of the shield. The higher the permeability of the material, the lower the saturation point.
There are several strategies for overcoming saturation:
1] increase material thickness/layers. This will be useful if the magnetic field is only slightly more than
saturating the initial shield design.
2] use a multi-material approach: Use a high saturation material on the side closest to the source of the
field, and high saturation material on the other side.
3] orient the shield to avoid the saturating field, if possible (as discussed above in the section on
Handling joints and seams
When using multiple pieces of shielding material to make a larger shield, care should be taken at the
seams/joints. Magnetic field lines will “ jump” an air gap between two adjoining pieces of shield, but
since introducing such an air gap increases the overall “ resistance” of the shield design, it will
compromise shield performance. Good metal to metal contact at the seams/joints is important. One can
achieve this in several ways:
1] Overlap. Two edges of shield can overlap, 1-2 inches typically.
Compression, such as between layers of drywall or plywood will
help to make good metal to metal contact.
2] Tape. Two edges can be butt joined, then use a high permeability tape
(such as Joint-Shield™) to tape the joint. Naturally, the shield pieces should
be adequately fixed in place by mechanical means to avoid separation of
Magnetic shielding plates and foil can be fixed in place with nails, staples, screws, glue, rivets or any
other suitable mechanical means that will support the weight and prevent annoying vibration or
shifting. Small perforations due to a few nail or screw holes will not significantly affect shield
performance (unlike radiofrequency shielding). Exposure of sharp edges should be avoided to prevent
injury from contact.
Other factors to consider, such as:
Temperature of the shield location, vibration, sharp edges, corrosion resistance, structural strength,
support for the weight of the shield, method of fixation, venting, perforations, ability to clean,
durability with respect to scratches/dents/handling/etc., available space, and of course: cost. Finally,
magnets will always be attracted to magnetic shielding alloys.
PRINT THIS PAGE AND
SEND PAYMENTS WITH THIS FORM TO
SILESIA GROUP INC., USA TO ADDRESS CONTACT
To order with
order by mail, please print this form and choose your products.
Please add Shipping and Handling
|ITEM NO AND DESCRIPTION||PRICE||QUANTITY||TOTAL|
|SHIPPING AND HANDLING||.||.||.|
ALL ORDERS ARE SHIPPED AFTER ALL FUNDS WILL BE
AT OUR FINANCIAL INSTITUTION. SOME ORDERS ARE NOT REFUNDABLE.
ALL SHIPPING OUTSIDE USA NEEDS TO ADD ADDITIONAL SHIPPING FEE.
WORLD WIDE SALES NEW DISTRIBUTORS WELCOME
All Products Come With 30 Day Money Back Guarantee!