Are You Really Protecting Your Mold From Rust?

Ben Franklin is correct. An ounce of prevention is worth a pound of cure. But Ben needs to add a bit of clarification. You need an ounce of the RIGHT prevention.

Nowhere is this more valid than protecting molds and tooling. The fastest way for a molder to go broke is to use improper methods to prevent his mold or tooling from rusting. Repairs are expensive and quite unnecessary with proper maintenance. It is not uncommon to spend several thousand dollars in repairing a rusted mold.

Using a material that is not designed for industrial applications, such as WD-40, may be the beginning of the end for your molds and tooling.  Typically these products are designed for water displacement and not for neutralization of fingerprints or acid residues.  In addition, a good anti-rust product should be “self-healing” It will provide a film that gels over and flows back in place if nicked or scratched.  A good rust preventive will not have wax or other material that builds up on the mold surface requiring extra cleaning.  It should also have the capability of displacing micro droplets of waer that may have condensed on the mold surface, leaving a barrier to prevent direct water/steel contact. All of the SLIDE rust preventive products listed below meet these basic criteria, so your tooling is well protected.

Spray your mold when it’s warm

The most reliable way to protect injection molds is to spray the proper anti-rust product on the mold immediately after the molding run is over and the mold is still warm.  This will protect it until the mold gets to the tool room where it is cleanded and then immediately coated again with the proper rust preventive.  Often it is hard to tell whether the mold is properly coated.  When in doubt add extra coating.  You are gambling a few cents of extra product against big bucks in repairs if the job isn’t done right.

Protect sprue bushings

Although the interior of the mold surface is the most critical for protection, don’t forget to protect the sprue bushings.  If this area rusts, it will be difficult to get a seal with the barrel nozzle.  The entire exterior of the mold should also be coated to ensure protection.  Rusting of the bases where they clamp against the platens may cause problems with keeping the mold halves parallel.  This can result in flash or excessive clamp pressure being required.

Watch for bleed-out

Anti-rust compounds that penetrate and seal off ejector pins can be a source of oils and solvents that can cause bleed out.  Using a mold protectant that goes on dry, such as SLIDE Mold Shield #42914, can help prevent bleed out.  Mold Shield offers your molds protection for up to two years.  The duration of protection combined with the unique “dry” feature of Mold Shield makes it the ideal rust preventive option for many molding operations.

Test Slide Before you Buy

Using an affective processing aid like those offered by Slide will help to increase your manufacturing efficiency and decrease your overall costs.  Here at Plastixs, we fully encourage you to test out the Slide Products.  The best way for you to know that the products are as good as we say they are is to get them in your operations.  Trial Samples of all Slide products are available by contacting Plastixs at 1-888-792-2223 or