To repair a dented hat, and you don’t have a steamer, first of all boil a kettle over a gas or electric ring, do not use an electric kettle as you will need a constant supply of steam. Ensure the kettle does not boil dry. When the kettle is steaming freely, turn down the heat just enough to keep steam coming out of the spout with a little force.
Position the affected area over the jet of steam and allow it to penetrate the straw or felt, keep moving the hat around in order that the heat and steam spreads evenly in and around the material. Remove the hat from the steam after about 20-30 seconds and quickly push out the dent or rework the shape with the fingers, blow on the repaired patch to cool it and the material will stiffen. Do not overdo the steaming as you can distort the hat, especially if you are working on a sharp edge or fine detail. Try not to “overwork” any area and work in small stages. It is also possible to stiffen your hat by steaming the felt or straw thoroughly and allowing the hat to cool, this is due to the nature of the stiffening agent used in hat making, the stiffener will soften when hot but re-bonds and hardens when cooled.
Damage to straw hats can be ironed out successfully using an iron set to number 3, do not allow the iron to stay in one area for too long but keep it moving over the damaged area. If it’s a flat brim you are repairing, lay the hat on an ironing board, if the area is curved then hold a thick wad of material on one side of the straw and iron from the reverse side, sometimes the repair will be easy and will only require a few passes with the iron, but with more difficult repairs it will be necessary to use the iron to apply heat and steam, then using the fingers, quickly manipulate the straw into shape, while the material is still hot. Do not use an iron on a high setting as it will burn the straw, and do not iron felt hats, use steam only to effect a repair on felt hats, steam can be used on felt and straw without problems.
To remove dirty marks from straw, gently wipe with a damp cloth, if this does not succeed, then you can use dry cleaning fluid. Use it sparingly and be sure to test it first on a small piece of the hat that will not be seen, apply the fluid with cotton wool and do not over-wet the area as this could remove the varnish or dye.
Bend brim wires back into shape and stitch down loose trims as soon as the damage is noticed. Always store unused hats with crowns supported, preferably placed in a hat box and put in a warm dry place, alternatively stuff the crown with tissue paper, put the hat into a plastic bag and store on the top of a wardrobe.
Never wear a hat in the rain unless it designed specifically for use in wet conditions. The residue from raindrops will often disappear when the hat is steamed. If not you will need to apply a very thin coating of stiffener.