One Thing Audio
Quad
Instructions, Elvamide
Several people have asked advice on applying Elvamide (nylon) to diaphragm material, so we here offer the instructions from our ‘Elvamide kit’.
DIAPHRAGM PREPARATION (Treble panel only). The diaphragm should be washed, both sides, in warm soapy water (two tablespoons full of concentrated washing-up liquid to half a pint of warm water will suffice). Apply the soapy mixture to both sides of the diaphragm (do NOT rinse!) and allow to dry naturally in a warm atmosphere. OMIT THIS SOAP TREATMENT FOR BASS DIAPHRAGMS.
For best results, Elvamide should be applied from a single dilution – in other words, don’t attempt to store the mixture. If there is some left over from the job in hand, dispose of it and make a ‘fresh’ mixture for the next job you tackle. The mixture you make will, however, be good for a day in normal room temperatures.
Many people (thinking they are producing a more effective coating) apply Alvamide in too high a concentration. Elvamide must be applied to BOTH sides of the diaphragm of treble and bass panels, and it should dry in random whitish streaks (don’t worry if apparently ‘uncoated’ areas appear between the whitish streaks – this is desirable and will assist charge absorbtion) . Although initial charge time will be 2-3 minutes, the optimum charge will only be achieved after 5 - 10 minutes. (For this reason, panels with nylon-coated diaphragms should be permanently left on charge – do NOT keep disconnecting the speakers from the mains supply.).
MIXTURE: ONE HEAPED TEASPOONFUL OF ELVAMIDE TO 300ml OF METHANOL OR METHYLATED SPIRIT.
With the mixture in a clean glass (jam jar etc) stand in a small saucepan containing about 2” of water. Gently heat the water up whilst continually stirring the mixture. WARNING: methanol is inflammable, so try not to splash the mixture around. The boiling point of methanol is considerably lower than that of water, so the mixture will begin to boil first (rapid bubbles, slight frothing). When this occurs, turn off the heat, but continue stirring the mixture for another 5 minutes. NOTE: all the granules will not have been dissolved – some will remain floating in the solution and others will stick to the bottom of the jar. Ignore these: just filter (tea strainer, etc) into another clean jar. This is the solution (mixture) you will apply.
A fine, camel hair brush is ideal, but any soft clean paint brush will do.
With your diaphragm prepared and tensioned, dip your brush into the mixture, loading it well, and brush across the width of the diaphragm, back and forth, until you are about one-third of the way down; then load your brush again, and continue the coating down another third. Finally, load your brush for the third time and coat to the bottom of the diaphragm. Allow a minimum of 15 minutes to dry (during this time, don’t ‘tilt’ the diaphragm – allow it to lie flat while the drying process is taking place). Turn over, and coat the other side of the diaphragm in an identical manner.
Your coated diaphragm should be ready to glue onto the stator after 2 hours’ drying time in normal room tempertures.
*Elvamide: TM Dupont
