MODUK - DTD-5633
General Purpose Locking, Sealing and Retaining Materials: Anaerobic Polymerisable Compounds Giving Very High Torque Strengths (01.81);
| Organization: | MODUK |
| Publication Date: | 1 January 1981 |
| Status: | active |
| Page Count: | 7 |
scope:
The materials covered by this specification are one part anaerobic polymerisable compounds which polymerise upon the exclusion of oxygen and activation by a metal surface to form bonds which have a very high strength.
By the terms of this specification this bond strength is quantified as being within a certain range when determined according to a test procedure described in DTD 5628.
It must be emphasised that this classification of the strength of the bond is arbitrary, and has been done to provide a simple but effective means of classification.
Attention must also be drawn to the fact that the torque test chosen for this classification normally gives a spread of results, and that the value reported is a straight arithmetic mean. No attempt has been made to define an acceptable coefficient of variation, and the user of this specification should appreciate the simplicity of the test and the classification system.
Further gradation of these compounds is provided by consideration of their viscosities. The viscosity bands specified are considered typical of present commercial material and offering a sufficient spread of values to satisfy most Ministry of Defence purposes. The introduction of further bands will be considered in the light of experience.
General applications of these materials include locking and sealing threaded fasteners and assembling slip-fitted parts. The materials should not normally be used on electrical connections where the assembled connection is required to carry electrical currents.
Some of the compounds are compatible with certain explosives and propellants, but the appropriate Design Authority Approval must be obtained before use in proximity to such materials.
Anaerobic adhesive complying with this specification can cause severe Solvent Stress crazing in some stressed thermoplastic components and aircraft organi transparency, - leading to a catastrophic failure.
NOTE: Similar materials providing different torque strengths are covered by specifications DTD 5629, 5630, 5631 and 5632.
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