EXPERIMENTS WITH HISTORICAL GLUE AND PAINT
Peter Beatson - NVG Miklagard
Glues based on casein (the protein of milk and cheese) are attested in classical and medieval texts . Exceptionally strong, permanent  and waterproof, they were used in carpentry up until the invention of synthetic adhesives in the early twentieth century. Casein can also be used as a binder for pigments, to make paints.
 C. M. Helm-Clark (2007). Medieval Glues Up to 1600 CE.
Ingredients: Skim milk , white vinegar .
Yield: a rubbery squeezed curd 'cake' about the size of a squash ball (~50g), which can be kept in the refrigerator until needed.
 Powdered skim milk is more economical (make up as directed) but liquid skim milk can also be used for convenience.
WARNING - Lime causes severe eye damage, use gloves and safety glasses.
Prepare glue immediately before use. For big jobs, prepare and combine several small batches to make one big batch.
Ingredients: Milk curd (see above), hydrated lime (calcium hydroxide) .
To use - Casein glue is wet bond, it works best on porous surfaces (wood, leather) and for close joins only. Use freshly prepared glue, it can't be kept . Coat both surfaces liberally, and press together while wet. Use clamps or weights to press the joint together while curing (12 - 24 hours). Clean up with water.
 Known as slaked lime or hydrated lime, as it is produced by burning crushed limestone to create calcium oxide = 'quicklime', then adding water. Get the purest and finest-ground lime you can, food grade (pickling lime) is the best - it can be bought at Indian food shops as a pure white powder or paste called chuna or chunam (it is normally used in paan, a southern Asian chewing drug). Builder's lime, lime plaster powder, and garden lime are mixtures with limestone and/or contain impurities and grit, I found them unsatisfactory. Quicklime itself should also work and was historically used, but is a much more reactive and hazardous chemical - I haven't tried it and wouldn't recommend it - if you do, wear protective gear and add slowly while mixing well to prevent explosive heating.
Casein paint is brittle and thus not suitable for flexible surfaces. Paint can be applied directly to smooth absorbent surfaces such as wood or leather. Fabric could be pretreated by sealing with coat of thinned glue, or could be coated with gesso  if a smooth ground is required.
Ingredients: Strained casein glue (see above), powdered natural pigments.
Colour should not rub off once dry, but may become tacky and smear if wetted. For an additional waterproofing seal, rub a 2:1 mix of beeswax and raw linseed oil (or olive oil) over the thoroughly dried paint with a soft cloth, then rub off excess.
 A medium used to prepare artist's canvas, such as equal parts chalk and powdered hide glue.
Product name ('Brand') 
Red ochre (haematite, iron oxide)
Jeweller's rouge powder
Yellow ochre (limonite, iron oxide)
Italian yellow earth ('Rublev')
Umber (iron & manganese oxides)
Cyprus burnt umber ('Rublev')
Kaolin ('Art Spectrum')
Carbon (bone char) 
Bone black ('Rublev')
 'Rublev Colours Dry Powder pigments' ($10 for 100g) and kaolin both available from Kadmium Art + Design Supplies (80b Bay Street, Broadway, NSW 2007). 'Rublev' brand by Natural Pigments L.L.C. (USA).
Kite shield with leather facing, using historical glue and paints
Curved ply blank supplied by MFC.
|Experiments with Historical Glue and Paint,|
written and webbed by Peter Beatson.
(c) Birka Traders 2014. Not to be copied without permission.
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