Hello I make a lot of boxes and do not have the facilities for mitered edges,
I always have a visible seam when I make a butt join.
I fill it with fine crack filler and it seems to shrink into the seam as it dries, and when I sand it back it is always apparent after painting plus it roughs up the particle boards finish around it.
This is "no shrink filler".
I have been looking for some kind of high build primer or something more thin to fill the scratches and seams, any hints for me?
Best Answer
You might want to pre-treat the gap you are filling with shellac or paint so that the raw/cut particle-board is not "sucking up" the filler.
On the filler front, for painted boxes, you might visit the auto-body supply and pick up some bondo. Possibly just the 1-part "Glazing and spot putty" will do, but the 2-part (and stinky) standard auto body filler will fill larger gaps more effectively.