Frequently Asked Questions

Table of Contents

Bonding polypropylene or polyethylene

Avoiding thermal expansion mismatch problems?

Achieving faster production

How to make waterproof bonds

FDA approved adhesives

Bonding nameplates


Bonding Polypropylene or Polyethylene

Q. We are looking for an adhesive that will cure clear and bond PE, PP to make small containers.


A. There are a number of clear hot melt adhesives designed to bond polypropylene and polyethylene.  These products are economical and a variety of application equipment is available.  If small quantities of parts are to be assembled, cyanoacrylate adhesive, used with a polyolefin primer, may be appropriate.  This option can be implemented without purchase of equipment.



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Avoiding thermal expansion mismatch problems

Q. We need to bond pieces of ferrite (100 x 240mm total area) to a sheet of aluminum.  The thermal coefficient of expansion of the ferrite is around 7e-6 / K and aluminum is 25e-6 / K.  The minimum shipping temperature is -20c max working is about 120c.


A. This is a difficult design issue that can't be solved by the adhesive selection alone. Some suggestions are:

1. Complete a careful analysis of the stresses resulting from the different expansion rates.
2. Determination of the physical thickness of adhesive layer needed to absorb the mismatch. Generally this will be thicker than an ordinary joint.
3. Consideration of a surface treatment for the aluminum.  This will improve the durability to the aluminum side of the joint.
4. If possible, select a ferrite that has at least some small amount of porosity to allow penetration of adhesive during the bonding process. The resulting interlock between cured adhesive and the ferrite may be helpful in getting the desired durability.
5. A rigorous thermal cycling program should be part of the qualification test.



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Achieving faster production

Q. We manufacture galvanized and aluminum roof vents made up of 4 pieces, leaving 4 overlapping seams to seal weather   We have been using a latex glue in a trigger type oil can to dispense glue on the product. The glue takes too long to dry (8 - 12 hours.)


A. I would suggest testing a 2-component urethane adhesive for this application. These materials cure quickly have good adhesion, flexibility and weathering resistance. Cost will be higher than latex - especially for small packages. Larger sizes could bring the economics into line.


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How to make waterproof bonds

Q. I am looking for a fast curing adhesive that will bond wood to wood, to make a solid part. The part must also be waterproof, easy to use, it can be a catalyzed product, but it must have rapid set up time.


A. Marine grade polyurethane adhesives are often a good choice for waterproof bonds.  Both single component and fast curing two component versions are available.


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FDA Approved Adhesives

Q. I am looking for an FDA approved adhesive for neoprene. I will also need the adhesive to stay flexible after adhesion. I will be connecting neoprene to itself. Any suggestions would be greatly appreciated.


A. The US Food and Drug Administration covers a wide regulatory area including food, drugs, medical devices, cosmetics, biologics, veterinary products, and radiation emitting devices.  The FDA has differing requirements for adhesives depending on the regulatory area and the specific bonding application.  As an example, an adhesive used for attaching a label to a food product would have entirely different requirements from one used in a medical device.  While there are many good adhesives available that have received FDA approval, it is important to note that approval only covers a specific application.


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Bonding Nameplates

Q. I need to bond an aluminum name plate (2.5"X4") to a powder coated metal computer server enclosure. The powder coat paint is a textured finish. Please advise.


A. Transfer tapes should do the job.  Transfer tapes are a pressure sensitive film supplied on a release paper roll.  They can be die cut to the right size and easily applied to the back of the nameplate.  The release film is then removed allowing mess free installation of the nameplate.



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Last revised: 05/24/05