Technical Information
Procedure for Butt-Type Coated Abrasive Splices with Liquid Adhesive on Tape
  1. Generally recognized industry definitions are short belts (3 x 24), narrow/long belts (12 x 132), and wide belts (50 x 103).

  2. Cut belts at 55, for narrow or long belts, and 67 or 75 for short and wide belts.

  3. Backrub (abrade) non-abrasive side of belt ends using either sandblast, wire brush or abrasive belt (sandblast is preferred).

  4. Adhesive formula:
    ADK 75A, Bostik 7070 or ADK 7514A: 100 parts
    Desmodur RE:9-14 parts (ADK 75A or Bostik 7070)
    7-9 parts (ADK7514A Spray Adhesive)
    Use higher amounts of curing agent when experiencing low humidity. Mix Bostik 7070 with Desmodur RE (or ADK 75A parts A and B which are proportionately mixed). A liberal amount of adhesive should be applied to both belt ends and to the proper side of the tape, apply adhesive to tape side opposite mylar splices. A dry deposit of 1.0-1.5 mil per surface is adequate. An 18-20 mil gap setting for adhesive coater with tape in unit is recommended.

  5. Dwell time after application and prior to joining should be a minimum of ten minutes and a maximum of 30 minutes. This can vary depending upon the amount of adhesive, curing agent and relative humidity.

  6. The belt ends should be assembled on the tape by hand or by using automatic equipment. The adhesive has sufficient building tack for hand assembly. For more accurate joining, a fixture for positioning belt ends on tape is suggested.

  7. Joining cycle
    Time: 8-15 seconds*
    Temp: 150F +/- 20 ** (66C +/- 11C)
    Pressure: 2,000-4,000 psi (140 kg/cm2 280 kg/cm2)
    (24 Ton on a 12 wide belt)
  8. Cover cloth: To prevent crushing of abrasive side of belt, a cover cloth is recommended over joint area during pressing.

* Bottom press bar should be covered with Teflon tape.
** Higher joining temperatures (60-90C) can be used. The dwell time should be increased to 30-60 minutes.

DIRECTIONS FOR ADHESIVE KIT MIX AND APPLICATION:
Mix one full container of part a with one full container of part b, thoroughly. if a portion is unused, it may be stored, refrigerated, and sealed, for use within 24 hours.

Apply a liberal deposit of adhesive mixture to belt ends and to tape, allow to dwell, as noted above, and join according to the directions outlined above. two liberal applications of adhesive are suggested for coarse grit belts.

Procedures for Processing Butt-Type Coated Abrasives Splices with Film Coated Adhesive Tape

Storage Conditions: It is crucial to store tape at -20F to 0F. The product has a shelf life of at least three months at -20F to 0F. Shelf life at ambient temperature is four hours. All material is shipped in insulated containers with dry ice and should immediately be stored at -20F to 0F upon receipt.

Instructions for Processing Belts
  1. Cut belts to desired angle.

  2. Backrub (abrade) belt ends using either sandblast, wire brush or abrasive belt (sandblasting is preferred.

  3. Adhesive formula:
    ADK 75A, Bostik 7070 or ADK 7514A: 100 parts
    Desmodur RE:9-14 parts (ADK 75A or Bostik 7070)
    7-9 parts (ADK7514A Spray Adhesive)
    Apply liberal coat of the above adhesive to the back of each belt end.
    • Allow treated belt ends to dwell at 10 to 30 minutes. This could vary depending upon the amount of adhesive, curing agent and relative humidity.

  4. Alignment of film coated tape and belt
    • Position film coated tape, adhesive side up, on alignment press platen (temperature: 180F +/- 20)
    • Remove poly-liner from adhesive side of tape
    • Position adhesive-treated belt ends on tape
    • Pre-press for three (3) seconds, using pressure of 300 to 500 psi, and a bottom platen temperature of 180F +/- 20


  5. Remove assembled belt from alignment press, and place under hydraulic press for final operations according to the following sequence
    • Place cover cloth over joint area on the abrasive side
    • Joining cycle
      Time: 8-15 seconds
      Temp: 180F +/- 20 (82C +/- 11C)
      Pressure: 2,000-4,000 psi (140 kg/cm2 280 kg/cm2)
      (24 Ton on a 12 wide belt)
    Note: Cover bottom press bar with release material to prevent sticking to press platens. Belts should dwell a minimum of eight (8) hours before further processing and at least 24 hours before use.

    Modified procedure for manual assembly
    • Apply a light coat of adhesive to back of abraded belt end
    • Drying time 10-30 minutes
    • Assemble belt manually
    • Place belt under hydraulic press for final assembly


    Press Cycle
    Time: 8-15 seconds*
    Temp: 140-194F (60-90C)