Dura®, Durachrome®, are trade names of Plating Resources, Inc. Copyright and all other World Rights Reserved, 1990, 1995, 2014.

 

 

 

FS Fume Supprssants

Introduction:
FS is a group of concentrated fume suppressants for use in chromic acid solutions. The FS products are fluoropolymer suppressants that are permanent and do not break down to contaminate the bath. Two types are offered depending upon the application. These perform by lowering the surface tension of the bath; they differ only in the amount of foam generated. In many cases the use of this product is all that is needed for regulatory compliance.

FS-600 High Foam
FS-750 Low Foam

Compliance:
The FS Fume Suppressants are capable of reducing the chrome mist by over 99%. When properly used they can exceed the OSHA PEL Action Level of 2.5 ug of Cr(VI) and the EPA air quality discharge standards of 0.015 mg/dscm.

Advantages:
The lowest cost permanent fume suppressants available.
Compliance possible without modifications to the ventilation system.
Less mesh pad plugging, cleaner hoods, tank rims, bussing & fixtures.
Lower surface tension for reduced drag-out and better rinsing - recovery.
Does not break down to cause pitting or form coatings on the anodes.
Very effective in controlling Cr(VI) misting, over 99% effective.
Does not contain any PFOS chemicals.

Product Selection and Use:
Two types of FS Fume Suppressants are available; both are very effective in lowering surface tension. The difference is the amount of foam desired; selection is based on the shop conditions. We can provide assistance in choosing the ideal product for your operation.

FS-600 High Foam:
Works best for decorative chrome and for relatively thin deposits of hard chrome. FS-600 forms a dense blanket of small bubbles, typically up to 4-6” thick. This provides the best chrome mist reduction, but is not ideal for all applications. This product can be controlled by either the foam height or by surface tension.

FS-750 Low Foam:
FS-750 is the most commonly used version; it is very effective in both decorative and hard chrome applications. FS-750 forms a relatively thin foam blanket, typically 2-3” high that may dissipate in 1-2 days without affecting the surface tension. This is generally the best selection if some foam is acceptable.

Foam Blanket Height:
A dense foam blanket along with low surface tension provides the best control of chrome misting. Thick foam blankets, however, should not be used in operations with high solution levels where the mist can overflow the tank or be drawn into the hood, where hydrogen explosions are possible (due to low buss bar height), where bath cooling is a problem, if trivalent & metallic impurities are high, or for thick hard chrome deposits. In these cases the use of a lower foam product such as FS-750 is best.

Additions & Maintenance:
The initial addition shown is for baths without any fume suppressant present. This amount will be lower if converting a bath.

FS-600 FS-750
High Foam Low Foam
Initial Addition (% vol.): 1.0% for 45 dynes
1.3% for 35 dynes
0.65% for 45 dynes 0.85% for 35 dynes
Maintenance Additions, (10,000 amp. hours): 75 mls. (2.5 fl. ozs) 150 mls. (5.0 fl. ozs)

Note: Use the above amounts as a starting point. Some baths with a lower initial dynes will require more than what is indicated. It’s best to go slow and make multiple additions.

Bath Additions:
Always agitate the FS Fume Suppressant before measuring as some settling may occur. It is best to dilute the product (4-5 times) with water before adding to the bath. Spread the addition evenly across the baths surface. Regular testing and small but frequent maintenance additions are recommended to maintain the desired surface tension or foam thickness, as per the regulations.

Surface Tension:
Most chrome baths have a surface tension between 75 and 90 dynes/cm., depending on the chromic acid level and the amount of trivalent, iron and copper present. The FS Suppressants can effectively lower this to below 20 dynes/cm, but most operations will want to maintain a surface tension of around 35 dynes/cm. Surface tension can be controlled by either a stalagmometer or a tensiometer, with additions per the chart. Irrespective of a foam blanket, a low surface tension reduces the chrome misting significantly by preventing large gas bubble formation.

Conversions:
The conversion addition is based on the desired surface tension, as per the chart. It is best to make these additions in small equal steps until the desired surface tension or foam thickness is obtained. The FS Fume Suppressants are compatible with all other types.

Other Applications:
The FS Fume Suppressants can also be used in plastic etch baths, and in chrome or sulfuric anodizing tanks to effectively control emissions.

Deposit Pitting:
Base metal pitting does not occur simply because a fume suppressant is being used. Fume suppressants can increase a pitting tendency caused by substrate imperfections, particularly with thicker deposits and bath impurities. Pitting is always related to improper cleaning or imperfections in the base material. Abusive preplate grinding or polishing can leave non visual surface debris that must be removed to avoid pitting whenever a fume suppressant is used. If pitting is a problem and the surface was prepared correctly, then it is likely due to minute base metal pinholes, microscopic substrate cracks, surface oxides or non-metallic inclusions in the base metal. Pitting can also be caused by stop-off residue, degradation of plastic material, as well as debris from wire brushes and grit blasting, or oils - organic materials in the bath. In some cases, this can be overcome by using an increased catalyst level and/or changing the reverse etch time. The use Dura Prep scrubbing, glass beading or vapor blasting can remove surface debris while also providing better adhesion.

Disclaimer & Non-Warranty:
This information is, to the best of our knowledge, true and accurate. All recommendations are, however, made without guarantee or warranty and Plating Resources, Inc. specifically disclaims any and all liability arising from the use of these products or the information contained herein. All factors relating to compliance with OSHA worker safety and EPA environmental regulations are strictly the responsibility of the user of these products.

Caution:
This process uses industrial strength chemicals which must be handled carefully and in accordance with the directives provided in the individual MSDS forms. Read and understand the MSDS on all of these chemicals before handling or using. Ensure that all regulatory standards are followed and limit personal exposure as required for Cr(VI) and other chemicals by OSHA.

Avoid personal contact with these chemicals, avoid splashing and avoid breathing any fumes released during operation. Do not inhale any dust, mist or vapors from these chemicals. Do not allow these products to contact the skin or eyes. In case of contact, flush immediately with large amounts of fresh water and seek immediate medical attention. Wear protective clothing such as aprons, gloves, face masks and respirators. Be sure that adequate eyewashes and emergency showers are available nearby before handling or using any of these chemicals. Designated work clothing should be worn while using these chemicals and the worker(s) should thoroughly shower and change into fresh-clean street clothing before going home. Decontaminate all work clothing before reuse. The user is responsible for providing adequate work clothing, personal protection, limiting personal exposure and providing any required clean-up, decontamination as well as any needed medical attention.