The Metal Guard product line has been around 20 plus years now and has different variations to meet varying needs. Here are a few questions that should be answered to determine which Metal Guard our experts would recommend.
- Is the rust preventative being applied to the part during an in-process step or is this the final step in the production process?
- Will the part be stored indoors or outdoors?
- How much corrosion protection is required?
- Are there specific customer or military specifications that need to be met?
- What type of finish is desired on a part after treatment (oily, dry-to-touch)?
- How is the rust preventative being applied (immersion, spray, brush, etc.)?
Customers that need short-term temporary in-process rust protection between manufacturing steps, a Metal Guard 800 series water based rust preventative is typically preferred. For example, parts that need rust protection prior to painting, plating, or powder-coating would benefit from this type of rust preventative. Water based rust preventatives do not contain oil, therefore the parts are easily cleaned and do not contaminate the pretreatment processes on the paint or plating lines. However, water based rust preventatives only provide a few days of rust protection.
For the cost-conscious customer wanting more rust protection than what is provided by a water-based product, a water-soluble or water emulsifiable oil such as Metal Guard 320 would be recommended. These products are very versatile and are used heated, typically around 140o F. They are diluted 5%-25% by volume in water, depending on the amount of rust protection desired, and the level of oiliness the customer prefers on the part surface. These products typically provide 48-96 hours (about 4 days) of ASTM B-117 salt spray protection over a black oxide finish.
The best protection is provided by a water displacing rust preventative such as our Metal Guard 400 and 500 series of products. These products are considered long term indoor rust preventatives and differ based on the type of final oil film left on the surface. If the customer desires a drier final finish, they will use Metal Guard 450, however they would be accepting a reduction in corrosion protection in order to get that drier finish. Conversely, if the customer desires up to 200 hours (about 1 week) rust protection, they will use Metal Guard 560, but the final finish will be oilier.
Customers that need outdoor rust protection will use Metal Guard 900, which is a viscous thixotropic liquid that forms a soft easily removed barrier to protect bare steel from corrosion in outdoor environments. A customer using Metal Guard 900 would apply this material via spray, immersion, or brush, and they can expect up to two months of outdoor rust protection.
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