Fresh latex must be strained through a fine mesh to remove bark and debris, kept in clean closed containers out of sun and heat, and either coagulated within 4-6 hours of collection or stabilised with ammonia at about 0.6% by volume if it must stay liquid for dipping. Latex spoils within hours because it is a food for bacteria, which sour it and clot it into a foul mass. Containers and cups must be washed between uses, since any old latex left in them seeds the next batch.
Part of Rubber Processing
Keeping tapped latex usable between the cup on the tree and the coagulation tank or dipping tank.
Latex Spoils On A Clock, And The Clock Starts At The Cut
The corpus’s Latex Processing article puts the limit at 4-6 hours before coagulation with acid; Coagulation says latex spoils into a foul mass within hours. Nothing in the corpus gives a longer safe time for unpreserved latex. Planning a workday around the collection time is more reliable than hoping.
What You Need
- A fine mesh strainer and clean buckets with lids; keep one bucket per tapping round.
- A shaded, cool spot for the buckets while the round finishes.
- Water for washing cups and buckets after every round.
- Ammonia, if latex must stay liquid. The carrier gives the dose, 0.6% by volume of the latex, but does not say what strength of ammonia solution that refers to. Treat the dose as unverified for any solution you hold, and test on a small sample to see whether it keeps the latex liquid.
Method: From Cup To Tank
Step 1: Pour the cups into a bucket through the strainer, taking out bark and debris.
Step 2: Keep the bucket covered and in shade. The carrier says rubber degrades in sunlight and melts in heat.
Step 3: Decide the destination now. Coagulate within 4-6 hours (see Acid Coagulation) or stabilise for dipping (see Dip Molding).
Step 4: To stabilise, measure out 0.6% ammonia by volume and stir it in slowly.
Step 5: Wash everything. Cups, spouts and buckets, every round.
Worked Example
A round of 20 trees gives 20 × 30 mL = 600 mL to 20 × 80 mL = 1,600 mL of latex (the carrier’s 30-80 mL per tapping), so one 2-litre bucket is enough, and a day’s coagulating tank can be small. The dry rubber is 20 × 15 g = 300 g to 20 × 30 g = 600 g, using the tapping article’s per-tapping yield.
Ammonia dose for a full 2-litre bucket at 0.6% by volume: 2,000 mL × 0.006 = 12 mL. For 1,600 mL: 1,600 × 0.006 = 9.6 mL. Again, this is a volume of whatever ammonia solution the carrier assumes, and its strength is not stated.
Common Mistakes
- Leaving the bucket in the sun. Heat speeds spoiling and degrades the rubber.
- Not washing cups. Residues start the next batch clotting early.
- Adding ammonia in one lump. Stir slowly so the latex does not shock-clot locally.
Safety
Ammonia vapour
Strong ammonia vapour burns the eyes, nose and lungs, and a closed shed or a bucket opened under the face can overcome a worker (recalled general fact, not from the corpus). Add ammonia outdoors or in moving air, never put the face over the bucket, wear eye protection, and never mix ammonia with bleach or acids.
What’s Next
- Learn next: Acid Coagulation — turning latex into rubber
- Combine with: Tree Tapping Technique — the round that feeds the bucket