CORROSION TESTING

Salt Spray (Corrosion) Testing




Salt Spray Testing – What is it?

Salt Spray Testing, also known as corrosion testing, is a lab testing method that is used to determine if metal parts of the product will rust and/or corrode when exposed to water and inclement weather. This test is generally included in the lab testing protocol of any product which has exposed metal parts.


Why should I care about it?

If the products you are importing from China include exposed metal surfaces, no matter what the product is, you should definitely be testing for salt spray exposure as part of your regular lab testing. One reason for this is that Chinese factories are notorious for substituting inferior quality metals and electroplated parts for the ones that they used in your approval sample. In-line testing of corrosion resistance can therefore easily protect you from a product nightmare, such as parts that rust or corrode with just a tiny exposure to rain or moisture…

What kind of products is it applicable to?

Generally, this type of testing is applicable to any product with an exposed metal surface. It’s especially applicable to products that are meant to be used outdoors and will likely be exposed to the elements. For items that may not be used outdoors, it is still a good test to perform to determine the quality level of the metal that the factory is using, and how likely the product is to corrode should it accidently come in contact with water, etc. Some items on which you should definitely perform this test are: keychains, bicycle parts and outdoor furniture. Some items for which this test may be applied if you are looking for higher quality products include: electronic items, bag accessories and hardware (zippers), and indoor use toys.

What standards are available for salt spray testing?

The most common standard for salt spray testing of consumer products is ASTM B117. This standard dictates the item to be exposed to a moist environment which is composed of 5% sodium chloride (salt), for a period of 24 hours, and then given a grade of 1 to 10. See the below scale for grading the results of salt spray testing based on ASTM B117. The % of salt that is used in this testing is often modified depending on the likelihood that the item will be exposed to the elements. For example, when testing a keychain or other simple consumer item, the % may be modified to 1-2% salt. Another common standard for this testing is ISO 9227.

Polybag Quality - check points

A. Ways to Check Polybags for Quality through physical inspection:

1. Hold bags up to direct sunlight and check for areas of non-conformity in texture and color, other areas of weakness.

2. Seam Quality – Fill bags with sand and drop onto a hard floor from 0.5, 1.0 and 2.0 meters.

3. Seam Quality – Cut the bag open at all but one of the seams, pull on the sides of the “opened” bag to determine the seam quality.
4. Fill with water/sand and hang for a prolonged period of time.
5. Take just one face of the bag, and rub/pull on the plastic to determine overall strength.

B. Polybag Lab Testing:


1. Analytic testing to determine if the material used matches the approved material composition.
2. CONEG testing to ensure bag complies with CONEG heavy metal requirements.

Other Security Issues to Consider with Polybags:


C. SECURITY


- Warning on the polybag
Depending on the product and the export market, it can be a must. This printed warning prevents children for playing with such polybag.


- Holes in the polybag
It is also convenient to have holes, 2 or 4 depending on the size of the polybag, in order to avoid suffocation if kids paly with the bag.


- Dessicant inside the polybag
A small pack of dessicant inside prevents humidity inside the polybag. The proper warning DO NOT EAT in several langages must be printed on it.


D. GENERAL INFORMATION ABOUT POLYBAGS


In examining and communicating about polybags, it is important that you know the product. Here are the types of polybags, including an excellent Polybag Glossary provided by: http://www.source1packaging.net/


1. KINDS

2. CLOSING


- Piece of adhesive tape
The simplest way, a piece of tape joins the 2 edges of the polybag to close it. It may damage the polybag when removing though.


- Self Adhesive closed
The edge of the polybag includes a band of adhesive tape, the polybag can be easily opened and closed, several times if needed. It is usually used with small items.


- Heat seal
Both edges of the polybag are pressed and heated in a machine in order to get them melt. It is a one time use only, once opened it cannot close again.


- Shrink wrap
The p[package or product is inserted in a machine that envelops it with a polybag, then the machine heat the polybag to perfectly fit to the product or package, like a new skin.


- Zipper
2 small parts on top of the polybag fit into each other to hermeticly seal the polybag. Frequently used in the kitchen to prevent air from coming inside the polybag to fridge or freeze food.


- Zip Fly
For big items like mattresses or blankets, the polybag may have a zip fly.