The surface treatment determines the bond strength. For high-strength structural bonding, the surface oxide film, grease, dust, mold, mold release agent and all other contaminants must be completely removed. The quality of the surface treatment directly determines the bond strength and the degree of resistance to environmental aging.

 

There are three ways to remove contaminants: chemical cleaning, sanding, degreasing

    • Chemical cleaning: A common method of handling metals. The surface including the etching forms an oxide layer having high adhesion or is coated with an organic coating. Chemical cleaning provides the best bonding surface.

    • Sanding: including sand blasting, steaming using abrasives or “Scotch-Brite” cleaning materials. Sandblasting is only suitable for materials that are thick enough (otherwise they will distort when sandblasted). The steam grinding method does not require strict metal thickness.

    • Degreasing: When the bonding strength is high or used outdoors for weather resistance, degreasing can be used for surface treatment. The surface is cleaned with hot alkaline solvent or solvent vapor, but the surface must be free of rust, paint and fine particles. The most effective method for removing residual contaminants when hot alkaline solvents.

 

Recommended surface treatment program

 

There are 3 steps necessary to clean any material:

 

   1) Degreasing;

   2) chemical corrosion or mechanical polishing;

   3) Degreasing

 

For precious metals or jewelry, degreasing can generally meet the requirements. However, silver is an exception. Using a medium amount of emery paper will tarnish the silver. It is recommended to use a trichloroethylene vapor phase degreaser. Most plastic products have a release agent or wax on the surface. They need to be removed with acetone or methyl ethyl ketone solvent before bonding, and then polished and gently sanded with a medium amount of emery paper. The pre-treated parts should be bonded as soon as possible. If the bonding must be delayed, it is recommended that the parts be covered with tissue paper and placed in a dry, non-contaminated area.

 

The following are the recommended chemical treatments (for industrial bonding only):

 

  Aluminum, aluminum alloy or 24ST silicone steel

  Cast iron stainless steel

  Concrete (Polish special cement type) Teflon

  Red copper and its alloy phenolic resin, polyester, polyurethane

  Hexadienyl citrate resin

  Galvanized metal rubber

  Glass tin

  Lead titanium

  Leather goods wood

  Magnesium and its alloys

 

Aluminum, aluminum alloy or 24ST

 

  1) Dry after degreasing with solvent

  2) Soak in a chromic acid solution at 65 - 70 ° C for 5-10 minutes

     Preparation of hydrochloric acid solution:

      10 parts by weight of sodium dichromate

      30 parts by weight of 98% sulfuric acid

      100 parts by weight of distilled water

      First dissolve sodium dichromate in most of the water, then slowly add concentrated sulfuric acid, while stirring, and finally add a small amount of water remaining.

  3) Rinse the metal thoroughly with running water and dry completely.

  4) The surface treatment results are ideal and should be bonded immediately.

 

cast iron

 

  Degreased, emery paper, and degreased again.

 

Concrete (Brande cement type)

 

  1) Concrete stained with grease or grease must first be scrubbed with a strong solvent such as ammonium hydroxide, then rinse thoroughly with water.

  2) Concrete should be surface treated before being bonded. The following methods are available:

     (a) Sandblasting at 1/16" from the surface to be bonded, and clearing the dust with a vacuum cleaner. If the surface is corroded and deteriorated, the surface should be ground or removed for dust removal.

     (b) Remove dust by mechanical erasing.

     (c) Chemical etching (with a steel brush) with a 15% hydrochloric acid solution until no bubbles are formed. Rinse with a high pressure water pipe. It was tested with a wet litmus paper. If the surface was acidic, it was rinsed with a 1% ammonium solution and finally the surface was completely dried.

 

Copper and its alloys (brass)

 

Mixed acid configuration:

   430 parts by volume of sulfuric acid

   72 parts by volume of nitric acid

   490 parts by volume of water

 

Procedure: Soak for 15 seconds in the above solution and rinse the water tube for 5 seconds (25 degrees water). Soak in a 15% (by volume) hydrochloric acid solution and rinse the tube for 2 minutes. (25 degree).

The following solutions may be used:

   8.0 (by weight) ferric chloride solution

   16.3 (by weight) of nitric acid

   75.5 (weight ratio) of water

   Soak in the above solution for 1-2 minutes at room temperature, rinse thoroughly with water and dry with 60-65 degrees air.

 

Hexadienyl citrate

 

Wipe the surface with a rag, acetone or methyl ethyl ketone solution, and then sand with a medium mesh of emery paper. The lipid was again rubbed with acetone or methyl ethyl ketone solution.

 

Galvanized metal

 

After degreasing, sand with medium mesh of emery paper, degrease again or chemically etch using the solutions listed below.

 

Solution: 20 parts by weight of concentrated hydrochloric acid

     80 parts by weight of distilled water

step:

   1 degreased

   2 Soak the metal in the configured hydrochloric acid solution for 2-4 minutes at room temperature.

   3 rinse with deionized water with cold distilled water

   4 Dry in a 60-70 degree oven for 20-30 minutes

   5 Bonding with adhesive as soon as possible

 

glass

 

For general bonding applications, only surface degreasing is sufficient. If the best bond strength is required, the glass surface should be sanded with fine sandpaper until the surface "frosts"

 

lead

 

Degrease, sand with medium mesh of emery paper and degrease again.

 

Leather

 

The rag is wetted with acetone or methyl ethyl ketone solution, then ground and then degreased.

 

 

Magnesium and its alloys

 

   1 Degrease with stable trichloroethylene vapor

   2 Soak in 10% sodium hydroxide at 76-87 degrees for 10 minutes.

   3 Spray in cold water for 5 minutes.

   4 Soak at room temperature for 8 minutes in a solution consisting of 1.5 pounds of chromic acid and 0.25 pounds of sodium nitrate and 1 gallon of water.

   5 rinse for about 3 minutes

   6 Soak in hydrofluoric acid solution for 5 minutes at room temperature

   7 rinse for half a minute to one minute

   8 71 to 98 degrees of hot air drying for 10 minutes

   9 Immediately bond or protect with a zinc primer.

 

  

stainless steel

 

   1 degreased

   2 Corrosion for 10 minutes at 65-68 degrees in the following solution

     Solution: 90 parts by weight of water

             37 parts by weight of sulfuric acid

             0.2 part by weight of Nacconol series surfactant.

 

   3 water pipe or distilled water rinse

   4 Soak in the solution clock for 10 minutes at room temperature.

     Solution: 88 parts by weight of water

              15 parts by weight of concentrated nitric acid

              2 parts by weight of hydrofluoric acid.

 

   5 Rinse with distilled water and dry in a 95 degree oven

 

Teflon

 

The preparation of chemically corrosive solutions and the materials used are hazardous and are recommended to be purchased from the companies listed below:

  W.L Gore Associate, Newark Delaware-(Tetraetch)

   Acton Associate, Newark New Jersey-(Fluoroetch)

   Joclin Manufacturing Co. Wallingford, Conn.-(Fluorobond)

 

Phenolic resin, polyester, polyurethane

 

The rag is wetted with acetone or methyl ethyl ketone solution, then ground and then degreased.

 

rubber

 

If maximum bond strength is required, chemical corrosion is recommended. A satisfactory bonding surface can be obtained using the following cyclization technique. Soak the rubber in concentrated sulfuric acid, soak the natural rubber for 5-10 minutes, and soak the synthetic rubber for 10-15 minutes. Many rubbers are acid resistant and therefore require a longer cyclization time until there are small cracks when the rubber is bent. It can also be immersed in the concentrated sulfuric acid of the complaint. When the paste is added, the barite is added to the concentrated sulfuric acid to obtain a uniform, non-flowing paste-like concentrated sulfuric acid. The soaked rubber is rinsed with water and dried. Sometimes it may be necessary to neutralize the residual acid with a dilute alkaline solution, and if there is an acid residue, the opportunity to consume a portion of the curing agent, weak bond strength. The surface at this time can be used for bonding.

 

believe

 

Degrease, sand with medium mesh of emery paper and degrease again.

 

titanium

 

In general, the most effective bonding surface can be obtained by etching the metal titanium with an acid. The titanium is cationized with a 15% sulfuric acid solution or with hot sulfuric acid. It is then washed with a detergent of sodium alkyl sulfonate. A good bonding surface can also be obtained by previously aluminizing or nickel plating on the surface of the titanium.

 

wood

 

Use a sander, axe, and planer to remove oil stains, rots, and other contaminants from the surface. Make sure the wood is dry. Smooth with sandpaper