In all projects there are things you do not look forward to. Gluing and sewing the partition board to the gusset is one of them. The reason is that it did not went well last time I did it. I had huge problems keeping the edge of the partition board up against the gusset. When I then sewed it I did not penetrate the board having to pull out stitches and forcing the partition board in place. It was a real mess.
Having learned from my mistakes I now have a thought of bullet proof approach... I hope. The ingredients to success are lots of contact cement, two strips of wax paper and four paper clamps.
Last time I think I was a bit stingy with the contact cement. This time around I made sure that there were plenty of surface covered with glue. I marked a line around 7 mm from the edge and sanded it to help the cement get a better grip. The folds of the gusset were also covered with a fair amount of cement. Make sure that you do not go all the way up to the top unless your partition board also does.
To avoid that the sides would get stuck while inserting the partition board I covered them with a strip of wax paper held in place with paper clamps. This worked exactly as I had hoped for. The partition board glided right down the gusset without issues.
After removing the paper clamps in one side you pull the wax paper up a few cm and press and pinch the gusset around the partition board. Make sure that the partition board goes all the way out to the gusset.
I put a small mark to help guide in the board when gluing it to the gusset
The gusset need a mark as well. The right mark was placed wrong so it is the left one that is correct
Scribe a line around 7 mm from the edge along all 3 sides of the gusset (not the top)
And on the back as well.
I tried to scribe inside the gusset but the lines was not very visible
Hold a piece of sandpaper grit 80 like so and use your index finger as a guide sanding all 3 sides.
This helps the contact cement bonding.
Don't forget the back side.
Apply contact cement using a wide applicator
I started with the back side. When doing the front side you need to hold it from the table.
The folds of the gusset needs contact cement as well. Use a brush for this.
Cut a strip of wax paper and fold around the edge.
Hold it in place with paper clamps and trim the top.
Put the partition board down gently making sure the marks line up.
Press it down with a roller.
You can see that the wax paper prevents the cement to bond.
Remove both paper clamps. And pull the wax paper up a few cm.
Press until you feel the edge of the partition board.
And then slide your fingers inwards so that the cement will bond.
Gradually pull up the wax paper and repeat previous steps
Do it on both sides and your are ready for sewing. Don't forget to go over with the roller to ensure that everything is pressed down.