This envelope is a bit more complicated to fold than the one I posted yesterday, but it is self-locking and uses no adhesives. Start with a sheet of letter paper placed long way up. Fold in the sides. I began with a sheet of 8.5 x 11″ paper and folded in 1.25″ on each side. My finished envelope will be 6″ wide, big enough to go through the mail.
Mark the middle of the top edge —my folded width was six inches so I marked at 3″— and then mark the same distance down each side, again 3″ in my case. I used a scoring tool so that I didn’t have to go back and erase pencil marks when the envelope was completed.
Fold the top corners in to the middle to form a point, using the marks you made as guides.
Gently fold the top triangle down, but do not press the fold.
Fold the bottom edge up the same distance as as you folded in the sides. In my case this was 1.25″.
Fold the bottom edge up to the point where the sides intersect the edges of the triangular flap at the top. Crease firmly.
Open your paper completely, then fold the bottom up again on the last fold you made. Turn in the bottom corners to match the creases at the sides.
Open your paper flat again, then turn in the sides of the bottom portion.
Re-fold the bottom section. The portion of the triangle you created above (green pointy finger) will now be under the bottom flap as indicated by the green pointy finger in the image below.
You can skip the next step and proceed with completing your envelope, but I find the side flaps a little loose if I do this, so I add an extra step, folding the outer corners of the triangles at the bottom in to butt against the sides of the main bottom flap.
Fold the sides in over the bottom flap, then re-fold the top point.
Tuck the top point into the bottom section. You will need to push it down a little farther than the initial fold as the sides are a bit narrower now. The top should just fit into the bottom flap between the side folds. Crease the top fold firmly.
If I was mailing this I would put a sticker or some tape on it to secure the top flap to the bottom. It would probably go through the sorting machine without, but there is less risk if the envelope is securely sealed.
I used a cut-out variation of this envelope in Greystone Secrets. You can see it on the left in the image below. It is suitable for heavier papers and card stock.
I created a template for the 3D envelope.
You can download the template here. It can be adjusted in width and height. You just need to remember that the side folds need to be deeper than the bottom fold since they fold over the interior space plus the bottom flap, and the top fold needs to be even deeper since it folds over the space plus the bottom flap plus the side flaps.
Tomorrow’s post will show you how to fold a menko.