The Audio Circuit Elvamide Owners manual



Directions for Using Elvamide

This set of directions describes the dissolution process of soluble Nylon (n-methoxymethyl nylon),
specifically Elvamide, in anhydrous Methyl Alcohol. A laboratory method is shown and a kitchen
chemistry method is described.

Do read the detailed Elvamide Specifications available on The Audio Circuit (www.audiocircuit.com
and in particular the Safety Section. Nothing to be disturbed about but better safe than sorry.

Laboratory Method

Materials&Equipment:

• 1 x 250 cc beaker

• 1 x 100 cc measuring cylinder

• 1 x 110 °C mercury thermometer

• 1 x large watch glass sufficient to cover beaker

• 1 x heating element with magnetic stirrer

• 100 cc anhydrous methanol or ethanol

• 7.9 grams of Elvamide or other soluble Nylon (when using Methanol solvent)

MethodofStockPreparation:

1. Set up the heating element with built-in magnetic stirrer on a bench. A fume cupboard is not at
all necessary as the alcohols used do not produce particularly toxic vapours, and significant

vapour loss will not occur if this technique is strictly followed. Naked Flame heat sources
should not be used

2. Ensure that the apparatus for measuring and containing the alcohol is clean, and pre-rinse
the beaker with 10 cc of the alcohol in use (e.g. Methanol)

3. Measure 100 cc of the alcohol (e.g. Methanol) and transfer it to the beaker.

4. Place the beaker on the electric heater.

5. Place a magnetic stirring core in the alcohol without splashing, or pre-place it.

6. Start the stirrer on the lowest setting needed to create a steady vortex - very slow speed in
this low viscosity liquid.

7. Set the heater to low heat and heat the alcohol to 40 -:50°C, keeping it covered by the watch
glass until this temperature is reached.

8. Slowly sprinkle the entire 7.9 g into the warm alcohol.

9. Adjust stirrer if necessary.

10. Stir for approximately 40 to 60 minutes until all Nylon "chips" are dissolved.

11. Carefully decant the resulting solution into a 100 cc stock bottle and seal with a tight fitting
stopper, preferably plastic, not rubber.

12. Label the stock bottle -10% w/w Elvamide in Anhydrous Methanol -100 cc Methanol has a

mass of only 79 grams (i.e. ρ

= 0.79 g/ml)

methanol

)

CoatingSolutionPreparationandProcedure

This is the base solution for coating panels with nylon, as per the original Quad coatings. The solution
will become more viscous as it returns to room temperature, achieving a viscosity similar to that of
light oil, or clear sugar syrup

The solution produced above must be further diluted to produce appropriate coating material for the

Quad ESL diaphragm. A good starting point for 6 micron film is to simply dilute a volume of this

solution with an equal volume of anhydrous A.R. or L.R. grade methanol, with about 5cc of each

resultant solution being sufficient to easily coat both sides of a treble panel diaphragm. Proportionally
more for a bass panel -perhaps 10cc of each liquid. This final preparation can be applied using a

paper towel, or tint-free cloth to the polyester diaphragm material. Rapid application is required due to

loss of solvent. If the vaporisation rate is too high and causes application problems (say in a dry, hot
environment) then a further dilution with 5%, by volume, of water may be required. This will produce a
slightly cloudy preparation, and is not recommended since the nylon itself is hydrophilic and will
absorb atmospheric moisture in time.

The diluted solution prepared to this stage should be used within 24 hours to coat a diaphragm. or

discarded. The extra solvent makes the final preparation unsuitable for storage. The higher. stock

concentration will keep in a tightly stoppered bottle for a long time –years in fact – this is the major

re

ason for having the higher concentration in stock in the first place. plus it is less volume to store.

Stability

On prolonged storage at room temperature or below (< 24°C) solutions of Elvamide may show

clouding or gelation, (e.g. a 10% solution will turn the colour of milk –white, opaque). Solution stability

increases as temperature increases. Gelled solutions can be restored by gentle heating in a water

bath (no open flames) with

In alcohol/water solvent systems, or systems where water has been added, the intermolecular nylon

hydrogen

Bonding is reduced and there by decreases the solution time and the tendency for gel formation.

The stability of Elvamide in alcohol/water mixtures can be improved by the addition of small amounts

of benzyl alcohol or other high boiling solvents like m-cresol

The stability of Elvamide in Methylated Spirits and water is higher than in pure alcohol or single

alcohol and water mixtures alone. even at much higher (unnecessarily high) solids concentrations.

stirring prior to use.

.

StaticElectricityHazard

Elvamide like all nylons, will generate static electricity when friction occurs between it and a suitable,
nonearthed, non-conducting surface. This could, in theory generate a spark which could ignite the
solvents used during the preparation phase. In practice, on a laboratory scale, this has not proved a

problem.

The Kitchen Technique

Materials & Equipment:

• Small bottle with a narrow neck, of 100cc or slightly larger volume with stopper to fit.

• Accurate volumetric measuring device (e.g. measuring cylinder, pipette).

• 1 x 100cc Ethanol. Methanol or Methylated Spirits

• Small metal bowl to accommodate the small bottle, preferably deep. rather than wide and

shallow. Tap water for water bath.

• 8 grams of Elvamide (approx.) ± 0.1 gram. The more accurately this is measured, the better.

• Piece of writing paper - A4 or similar.

• Stove - flameless heat source.

Method:

1. Measure 100 cc ofthe chosen solvent and pour it into the small bottle.

2. Place enough water in the small metal bowl to rise about halfway up the sides of the small
bottle being used, or slightly less.

3. Add the Elvamide to the solvent using a paper tube fashioned from the A4 sheet. This is just
to prevent the nylon chips going all over the place.

4. Turn the stove element on to relatively low heat until the water is almost but not quite
"steaming". It is not necessary to boil the water at any time.

5. "Half Stopper" the bottle to prevent unnecessary loss of solvent. DO NOT stopper fully, or the
pressure may build sufficiently to blow the bottle up with volatile solvents like this. This
technique is simply used to reduce solvent loss and consequent alteration of the
concentration of the solution. In the lab. with a watch glass we get a kind of mini-refluxing
effect.

6. Turn the heat off and allow to stand for 10 minutes. This will still be sufficiently hot to keep
Methanol or Ethanol at close to their respective reflux points.

7. After 10 minutes have passed, pick up the bottle with a kitchen towel, stopper firmly, and
shake for ½ minute. The nylon chips may adhere to the sides. This is not a problem, as they
will eventually go into solution. Release the pressure by removing the stopper for a moment,
and then place the stopper back on the bottle top very loosely as before.