How Are Ugg Boots Are Made?

By Geoff Sharp

Well we all know about this Ugg Boots fashion craze that's hit the world don't we? Those ugly fluffy looking boots that originate from Australia. But how is the humble Ugg Boot made?

The number one essential factor needed for manufacturing a genuine Australian Ugg Boot is the material (the sheepskin hide).

You may be aware that their are plenty of different ugg boots styles popping up on the internet these days. If you do a few basic searches on the net you will find yourself a cheap pair of non-authentic uggs somewhere, but let me tell you 99% of ugg boots sold on the internet are made in china. China made Australian ugg boots? Hmm how doess that work? Anyway these China boots are maufactured using inferior sheepskin internal material and probably suede external material which doesn't allow the boot to breath and leaves you with a smelly boot you wont want to put back on after 4-5 wears.

These china made copies just dont stand up to the Genuine Australian Made Boot. So one things for sure if your interested in buying a pair of sheepskin ugg boots on the internet or anywhere for that matters, dont try to save a dollor or two when purchasing your boots?

If you want a boot that's warm in winter cool in summer then you must insist on a boot manufactured with Genuine Australian double faced Sheepskin preferbly Australian Merino Sheepskin.

One of the questions often asked about ugg boots is:

Do you have to really kill the poor sheep just to make a pair of sheepskin boots?

The answer is NO. Not one sheep has to be slaughted to obtain their hide and fleece. The sheepskins are shawn of the sheep back and the sheep regrow their fleece just like humans do hair. It's completely painless for the sheep. I've been told by a few old school ugg manufaturers that the sheep actually like the experience of feeling free and would prefer to be shawn rather than have to carry a thick thick woolen coat around with them in the hot Summer.

Once the sheepskin hides are taken from the sheep then the process of preparing the hide for manufacturers and ensuring the hides are up to export standard begins.

Woolskins are usually preserved with salt prior to being processed by tanneries. At the tannery the skins are processed in large vessels called paddles which vary in capacity from 3000 to 15000 litres. In contrast to hide processing, in woolskin processing mechanical action is kept to a minimum in order to minimise felting of the wool. Rotating blades on the paddles move the skins slowly and gently, and processing is performed at much higher float ratios (typically 20-35 litres of water per skin) than are used in hide processing.

Typically it takes about 10 working days for the skins to be tanned and finished ready to be cut into panels for ugg boots.

Step 1. Tanning/ Processing

Soaking (16 hours) - The skins are rinsed in cold water to remove excess salt and dirt from the wool and pelt. Rehydration (soaking) of the pelt takes place in a fresh cold water float overnight.

Fleshing - The skins are fleshed using a fleshing machine which removes excess fat and muscle tissue from the back of the skins. This allows for more rapid and complete penetration of chemicals in the later stages of processing, particularly during pickling and tanning.

Scouring (30-45 minutes) - Surfactants are used at 38oC to remove dirt and grease (lanolin) from the wool.

Pickling (16 hours) - Prior to tanning, the skins are pickled in a solution containing acid and salt. The salt is added to prevent swelling of the skins by the acid. The internal pH of the skins is lowered to approximately 2.8-3.0, thereby preparing the skins for penetration by the tanning agent.

Tanning (16 hours) - Tanning is generally achieved by using chromium salts which form cross-links with the collagen, stabilising the skin structure and preventing putrefaction. The tanning step is conducted at about 25oC and pH 2.5-3.0 to allow for penetration of the chrome. Once penetrated, the chrome is fixed to the collagen by raising the pH to about 3.6 using sodium bicarbonate, and heating to about 35-40oC. This step raises the shrinkage temperature of the skin from about 60oC to around 100oC.

Wool Dyeing / Fatliquoring (3-4 hours) - After tanning, the wool may be dyed a variety of colours. Wool dyeing is performed at about pH 4.5-6 and at 60-65oC, "Pelt reserve agents" being added to prevent the wool dye staining the pelt. After the dye
is exhausted, the pH is lowered to about 4.0 to fix the dyes to the wool, and fatliquor is added to the bath. Fatliquors are emulsified oils which are used in leather manufacture to lubricate the collagen fibres, allowing them to move freely when the skin is dried, thereby imparting softness to the skin.

Drying (4-24 hours) - Once tanned and wool dyed, the skins are then dried in heated forced-air dryers by "toggling" the skins to a frame. Drying is conducted at temperatures of 50-80oC.

Drycleaning (4-24 hours) - The dried skins are "drycleaned" in either white spirit (a high-boiling petroleum fraction) or perchloroethylene. The drycleaning removes the natural fat and grease present within the skins.

Pelt Dyeing / Syntanning - Once the pelt grease is removed, the skins are returned to the paddle for pelt dyeing. This step is performed at low temperature (less than 30oC) in order to minimise staining of the wool by the pelt dye. After pelt dyeing, the skins are "syntanned" using synthetic tanning agents in order to give the pelts added fullness and firmness. The skins are then redried.

Step 2. Finishing

Once all the tanning and processing steps have been completed, the skins are ready for final finishing prior to being used in ugg boot manufacture.

Staking - After "conditioning" the skins to approximately 20% moisture content, the skins are staked in a staking machine. This softens and stretches the skin pelt, and puts a "nap" on the pelt surface.

Combing / Ironing / Clipping - The wool is combed in a combing machine to remove tangles and any burrs or grass seeds present in the wool. An iron (a hot, 150oC revolving cylinder) straightens the wool, removing the natural wool crimp. Finally, a cylinder clipping machine is used to clip the wool pile to the desired length, usually about 12-15 mm.

Step 3. Manufacturing

Panels are cut from the skins using a "clicking press". Once cut, the panels are sewn together using industrial sewing machines, then the sole is glued to the boot. Once this is done, the boots are ready for sale!

About the author:
Hopefully this article has helped you understand a little on the process of sheepskin hide preperation and ugg boot
manfacture.