Originally Posted by Colm
The best thing you can do is trash the box, start over, and do it right. If you do, don't feel bad. Just about everyone who starts doing woodworking has been there.
If the gap is where two panels come together at right angles, you can glue or screw a cleat on the inside to provide the strength, then fill the gap with Bondo or another filler.
When you get done, it is still going to look like crap unless you are really, really skillful in hiding what you did, or you veneer it.
I really hope you are bleeping joking. He didn't say there was a gap the entire length of every panel and even if that was the case he could still trim the cuts to straighten them out.
Glue is stronger than wood and using the plpremium on the inside will fix the cutting errors while making an airtight bond. Don't skimp on glue on all of your seams as it is cheap and redoing it will be a major headache if end up with leaks.
Use a wood filler for exterior cosmetic flaws if that is a concern while leaving the glue to handle the structural ones. Using wood filler if staining the enclosure will be fine and you'll be the only one that notices it unless someone really wants to examine your work.
Bottom line, don't let the small stuff ruin your first experience. I've used plpremium and other similar glues on enclosures for the past 15-20 years in areas that need to be sealed and haven't ever had a "blow out" of sorts. The wood would rip before the glue fails.
Keep trucking and learn from your mistakes for future builds.