Cope or miter? What says you?

[Scott Hildenbrand]

So, I've got two 4' sections of cove molding cut... Planning out exactly how I want to lay out the joints.. I'm debating just coping this corner against a full run of molding in the center.

I've got plenty if I screw up, but not if I change plans and screw up that center section of molding.

So.. What do you think? Should I just cope it? Image is of the outline of the fireplace top.. Profile is based off the simple cove molding I made. Not to scale.. ;)

http://pics.fuzzywolf.com/molding.gif

I find myself saying this alot... Thank goodness it's paint grade.. :D

[lowell holmes]

I always cope moldings. I know people that miter their moldings, but if the molding dries withtime, there will be cracks showing.

[John Keeton]

Should I just cope it?:DI think most folks would say "Should I just miter it?" I think coping is the superior method of running trim, and I always cope everything that is going into a corner - baseboard, and wall trim alike.

[Scott Hildenbrand]

Should have noted.. I made it our of a double of 3/4" MDF.

LOL John.. I think I've got a fair shot of ruining it either way I go.. :D ;)

My thought is I have a far better chance of getting a good, tight fitting joint if I cope it and just keep adjusting until it fits well.

[Rob Woodman]

Mdf that will be painted may just as well be mitred as the amount of movement from drying out is virtually zero.
And I am, though, with John Keeton and Lowell Holmes that coping is the better method, more professional one might say.:D

Don't forget that if you make a mitre cut on the cope end of a moulding, the subsequent edge will show the cope's cut line. ( Just for those who may not know)

"Cope well or you mitre's well not bothered!" as we say in our 'shop.:D:D

Rob.

[Mike Henderson]

I miter because my copes look worse than my miters.

Mike

[Scott Hildenbrand]

Think I'm going to go with a cope cut.. Yes, MDF won't move.. But it's good practice none the less and for some odd reason I feel safer doing it that way.

[Jerome Hanby]

Anyone got any helpful hints about coping? My one attempt at it didn't go well and I ended up mitering all the trim.

[David DeCristoforo]

Mitering outside corners is a "piece of cake". Inside corners can be a PITA or worse if the surfaces are not all flat and plumb and true and square, etc. Coping inside corners gets you around ninety percent of the hassle of fitting inside corners. And the level of "PITAness" increases logarithmically as the size of the moulding increases.

Miter the end of the moulding. The line formed by the intersection of the face and the bevel is the cut line for coping. BUT... if you cut "square" you will have a time of it trying to get the joint to close. So it's best to cut a "back bevel" of a few degrees. Most "field" carpenters will cut just shy of the line at a pretty strong back bevel and then file, sand, chisel or otherwise get down to the final line. It is also common practice to cut an "inside" piece a bit long so that the moulding can be "sprung" between the two ends, forcing the joints tight when the material is pressed against the wall or whatever surface you are applying it to.

[keith micinski]

Here's how I cope. Take your trim and put up the longest piece possible straight. Then take your shorter piece and cut an inside 45 on it. Then lay your piece down flat and parallel with the blade. Nibble away all of the wood in the mitre and when you are done if you are careful you only have to hand sand or file a little bit.

[Joe Scharle]

I lay the molding down flat and using a coping saw, cut just under the face profile. !0-15 degree undercut leaves a strong edge and clears the mating piece. What you're trying to accomplish is a 'false' miter. But instead of butting the mitered ends together, you're going to lay a coped edge over a molding profile. Done right, the joint will appeared butt mitered.
If you've never coped, you may want to practice on some short pieces first.
It's easy....even I can do it!

[Peter Quinn]

I doubt I would go through the trouble of coping an MDF cove in that situation. Its a short run, you can dry fit and blind nail with glue, MDF doesn't move much, I have never found it that much fun to cope MDF ANYTHING to begin with. Stain grade or a trickier paint grade installation? Sure, I'd cope away. But for that one, not worth the time IMO.

[Von Bickley]

A professional trim carpenter explained it to me.

A bad cope is better than a good miter.......... Go for the cope.

[sean m. titmas]

Cope, cope, cope. I cope everything with a Collins foot and have had excellent results. for your particular layout i would cut the short pieces straight into the wall and double cope the long piece and spring it into place. it takes a good bit of skill to cope the MDF with a jigsaw from the back side but that method yields excellent results.

I try to avoid using MDF for trim because it is a face material and not an edge material. one caution with coping MDF, the coped edges of the cut are very fragile and tend to crush easily when being coped and especially when being sprung into place. However since its MDF i can assume that its going to get painted so a nice bead of caulk will cover up any discrepancy in the cut edge.

[Scott Hildenbrand]

However since its MDF i can assume that its going to get painted

Now that is a pretty safe assumption, there.. :D :D

MDF isn't bad at all to work with and does well enough in this application.. It's very forgiving and has done well for this, being a first project on this scale. That said, I'm not sure that I'll be using it again for a while though.

What ever is left will make up my new router table top extension for my table saw, edge banded in red oak for strength and durability.

After this is done I've got a bathroom to gut and build cabinets for... Then a second bathroom to redo with a new vanity... Then a kitchen... With maybe a nice 14' built-in tossed in between for further practice on cabinet carcasses.

Wish I could do this for a living... Or at the very least had more time to put into it.. I'm having fun.. :D

[Larry Edgerton]

Finish tip for MDF:

Paint it first with West System. The epoxy will soak all the way in and the next day you can sand it. The surface will be far less prone to damage as the epoxy will soak in quite a ways making the surface essentually a piece of plastic, it will sand to a shine, and it will not suck paint like raw MDF tends to.

[lowell holmes]

A sharp utility knife works quite well for final trimming.

[David DeCristoforo]

I had a friend who specialized in trim carpentry. We worked together on a number of jobs. He was a big advocate of coping inside miters. He only used three tools, a power miter box, a coping saw and one of those small, hand held angle grinders fitted with a sanding disk. He would miter the trim, cut close to the line with the coping saw and finish it up with the grinder. While the rest of us fussed around with our chisels and knives and files and rasps and spent half the time keeping them all sharp enough, he would buzz through his coped joints in no time and his joints always looked better than anyone else s. It's all about what works for you.

[Scott Hildenbrand]

David, that's going to be my plan.. Miter it.. Cope it.. Sand smooth with a small sanding drum attached to a die grinder.. Should be a fairly painless process.

Not sure about using epoxy on it.. I've got a gallon of fiberglass resin laying around I could try. I might mix up a little and brush it on a test part cut at 45deg to see how it works on the.. hmm.. end grain?

My only worry about that is making it more difficult to sand, but then, it's just paint grade.

[Larry Edgerton]

Scott

You want the MDF sanded to its finished quality "before" you paint on the epoxy. You will be amazed at the finish you get with just a light sanding after, like a car body. It will be far less prone to chipping as well. I make my router patterns in this manner and I can run many parts with the patterns without any wear.

I am not sure about fiberglass resin, try it on a small piece first. It may not sink in as well. The West System using normal hardener just disappears, sinking in about an eigth of an inch average, especially on the cut surfaces. Again, have it sanded to perfection before you epoxy.

[Jim Summers]

I just did some baseboard with an inside corner. It was in a bathroom and the inside corner is behind the door so it would not be seen most of the time, so I decided to miter it to see how it would come out. The corner was relatively square but not plumb. I ended up having to do some shimming behind the bottom of the trim. In the end it came out nice. But if I had coped it, I would have got it done easier, probably quicker and just as nice. In the future I will cope the insides.

HTH