HI -- Just hire someone to do that fine finishing details . Using a lot of caulk to fill or cover up a mistake always shows .

First, practice and be patient. If a 'lot' of caulk is needed, you need more practice and/or patience. Then, if needed, put a small amount of caulk between the coped and uncoped pieces as you assemble them. Excess should squeeze out and be wiped away.

Don't caulk a coped joint? This is the first I've heard of this...

What about caulking a joint where two 45 degree cuts are butted together?

When you cutting 5.25" molding, make the face cut on 45 degree angle, flip the molding and back cut along the flat portion of the molding right along the front edge @ lesser angle... this way you only have to cope the little bit of profile and you have a perfect cope each time with a nice tight joint.

Here is how you do it.

Like any other skill, the only way to get better is to practice. As GN Builder's suggested, using the miter saw to remove material is great way to get nice, straight cuts. You can also use a rat tail file to fine tune any curves.

There are lots of videos on YouTube that will also help.

Thanks, going to experiment with GC Builders method on some scrap pieces.

See Jane Drill has a very good Youtube video on coping. Same method as GN Builder posted.

Make sure that you have the saw blade mounted facing the handle so that you are cutting on the pull stroke.

Clamp the piece down snugly.

After cutting a 45 degree angle on the miter saw and clamping snugly, angle the coping cut so that you are backcutting the joint.

And, the one thing that really, really helped me is: Have Confidence. Approach with a positive 'I can do this' attitude. (I was letting this little chore intimidate me.)

A bit of caulk is perfectly OK on paint grade work but you sure want to avoid 'a lot' of caulk. Make sure you buy a paintable caulk. I like Big Stretch for it's elasticity but you have to be diligent about wiping up the excess. Doesn't want to wipe clean as easily as some other caulks.

Thanks, I love seejanedrill's videos.

Don't forget to glue your joints with Titebond. It eliminates the gap when weather changes.

If your are using MDF don't even bother just use a protractor and get correct angle first.

When coping wood moldings use a coping saw but always have a sharp razor and a sander with some 40 or? grit. They help you get the joint even tighter the the saw can. Also check your angles and don't hesitate to shim with cardboard or? to get your joints tight. Its easier o rough cut with saw and cut in close with a sander.

They sell a simple 10" plastic protractor that when used you can see very few walls have 90 degree corners.