When thinking of envelope closure seals you’ll probably vision the traditional gummed style closure that you lick and press to close. There are however many types of envelope seal to choose from, with adhesive options that no longer require any nasty licking and specialist closure styles like string & washer that don’t require any adhesive at all!
Common Envelope Closure Seals
Peel & Seal
Peel & seal envelopes have an adhesive strip along the flap with a strip of paper covering. Peel off the strip to reveal the adhesive and press the flap to seal. This style of closure is usually found on straight flap envelopes, rather than ‘V flap’ types.
A self-seal envelope has two strips of latex glue – one on the flap of the envelope and one on the body of the envelope. The latex glue on the flap will only stick to the latex glue on the body of the envelope, so when they are pressed together it forms a seal. You’ll usually find this style of closure on budget business envelopes. It's worth noting that the gum on self-seal envelopes usually has a 6-12 month shelf life, after which it can lose it's adhesive properties.
Gummed envelopes have a water soluble gum adhesive along the flap what you lick to seal the envelope. This traditional style of closure is usually found on ‘V flap’ greeting style envelopes.
Specialist Envelope Closure Seals
String & Washer
String & washer envelopes have two buttons attached to the envelope – one to the flap and one to the main body. A piece of string is wound around both buttons to seal the envelope closed. They are sometimes known as ‘string & button envelopes’.
An old fashioned way of sealing envelopes, a small amount of hot wax is placed on the envelope at a point that will hold the flap shut. Traditionally a metal seal will be pressed into the wax to mould a symbol. Historically the symbol on the seal would be the family crest of the sender.