When Kathy posted the fantastic cardinal stamp for download, one of the commentors asked about how to best glue it to their mail. This was an excellent question and one I get a lot since I post pictures of my collaged mail art on Instagram. So, instead of typing a lengthy reply to the comment which you all might not get to see, I decided to do a post. Viola!
From left to right, that is glue tape, a glue stick, and a glue pen. I use the glue tape 85% of the time, the glue stick 13% of the time and the glue pen 2% of the time. I get my glue tape and glue sticks from the regular old office supply store. The glue pen came from that wonderland known as Jet Pens.
If I have to pick just one, it's the glue tape. It works like a white-out runner and is sticky on both sides. It works like double-stick tape, but is thinner and easier to apply. It isn't liquidy; so it doesn't smear ink or buckle paper. I can do nearly anything with the glue tape. It is my go-to for constructing envelopes. It has a strong bond almost instantly. If I'm ever gluing down anything thick like cardboard or cardstock, I'm using the glue tape. You can find them in refillable and repositionable form as well.
I use the glue stick instead of glue tape for anything that's really fragile, such as vintage paper. The glue tape is so strong that it can rip up more delicate pieces. I'll also use the glue stick for uneven edges. The tape isn't so easily worked around a bunch of noodley-bits. The glue pen I only use if I have to affix something that is so weirdly shaped and so delicate to handle that I need minute control over where the glue is going. I like having it as part of my tool kit, but rarely use it.
I hope that answers everyone's sticky questions regarding glue and mail art! Thanks for reading and for asking. I'm always happy to share. Oh, and if you have favorite glues or glue techniques, please share in the comments.
P.S. I get asked a lot about perforating stamps too. Here's a link to the post I did on making your own perforations.