Need advice on how to cope this crown profile

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Old 04-16-11, 04:21 PM
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Need advice on how to cope this crown profile

I am hanging this crown molding (photo below) in our entrance way. I was planning on coping inside corners. I have tried every angle that I can think of to cut and cope the corner but none work out. Is it possible to have a profile that cannot be coped?

Thanks for any advice.

Martin
 
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Old 04-16-11, 04:47 PM
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Are you using a miter saw? It is really easy without coping, but all angles can be coped. One piece will run into the corner. The piece you will cope will be short bottom/long top, cut at a 45 or 38 degree angle, depending on the size of your molding and how it sits on the wall/ceiling. Then with the miter cut, just cut out the bare mdf profile.
If you are using a compound miter saw, there are bevel and miter settings for crown on the saw and you can lay your molding flat and cut it that way. Otherwise, upside down and backwards.
 
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Old 04-16-11, 05:48 PM
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If you are going to cope the crown, place it flat on the table of the mitre saw and cut a 45 degree bevel. Then use your coping saw and cut along the line where the white prime meets the bare MDF. You saw should be at a 90 degree angle to your bevel cut except at the ends. Maybe a picture of your failed attempts would help as well.
 
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Old 04-17-11, 07:05 AM
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It could be that the piece on the wall is positioned too high or too low, which would make even a perfect coped joint seem to want to "open up". Check that the bottom your crown is just as far down from the ceiling as the top edge is out from the wall on top.

I cut crown "upside down and backwards", like Chandler mentioned, using crown stops on my miter saw. Since your profile is symetrical, there really is no upside down, but for a cope on the left hand side, you'd cut the right end of the piece of trim.

If it's in position on the saw, the top of the piece will be down against the saw table, while the bottom of the piece will be standing up against the fence. (you can obviously only do this on miter saws with tall fences, like the Dewalt). You'd cut a 45 degree L (left) miter, and cope the resulting line. The flip the piece end for end and upside down and put it on.

But cutting it flat is simpler for others. I just don't like all the angle charts that you need to consult. Never learned it that way and I'm pretty stuck in my ways. LOL
 
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Old 04-17-11, 07:23 AM
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First, why cope it? I would miter the corners.

The Dewalt website (and I'm sure many others) has good instructions on how to do that without a compound miter saw.

Upsidedown and backwards -- the top of the crown moulding on the table, the bottom against the fence (you'll need a tall enough fence to support the work), and you'll keep the piece on the right to install on the left of the wall.

Be aware that there are a couple of assumptions being made which aren't necessarily true. First is that the corners are absolutely square. Don't count on it!! Second is that your saw is cutting perfect 45's, and that there no 'slop' in the stops. Only in a perfect world!!
 
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Old 04-17-11, 07:29 AM
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I stunk at cutting crown until I bought these two tools.
Bench Dog Crown-Cut - Rockler Woodworking Tools

Starrett Catalog 32
Look at the #505A-6

No inside corner is a true 90 deg. so I use the protractor to find the exact angle to set the saw and cut it on the Mitre attachment. Perfect cuts every time now.
 

Last edited by joecaption; 04-17-11 at 08:26 AM.
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Old 04-17-11, 11:44 AM
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Having that bottom stop on the miter saw makes it so much easier. I found that store bought crown isn't always a total of 90 degrees with there angles. So if the bevel against the table is flat, the bevel against the fence is not. Having the bevel against the fence flat is the most important. The Dewalt saws (at least old models) had threaded holes in the table so you could attach something for that reason. They may have actually sold an accessory as well.

Coping makes it easier to get a tight corner without the hassle of figuring what the angle is. It's also good if you don't have a miter saw and have a small job to do. Not that I have done much coping in my life. I've always mitered.
 
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Old 04-20-11, 02:57 PM
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The one thing I did not see in any of the posts is that when coping by hand you need to back cut (take more out of the back side of the crown by holding your coping saw at an angle from the line you are cutting). Cut upside down and backwards and at a 45% angle, where the primed edge and the raw wood meet is where to cope, but make sure to take more out of the backside of the piece to give more "swing" to the fit. Is there a better way to explain this you pro's??
 
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Old 04-20-11, 03:07 PM
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I agree a well fitted joint is best but since this is painted crown molding, I don't know that I'd spend a lot of time trying to get it perfect - caulk and another coat of paint should make it look good
 
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Old 04-20-11, 04:55 PM
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you are right about back cutting, m1951mm, but if you cope MDF to a sharp point like that it will usually crush the tip of the coped joint when you spring it into place. It helps to use a grinder and a flap sander to bevel the back side of the crown after you cope, to make sure nothing in back will be pushing the coped joint apart.
 
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Old 04-21-11, 07:50 PM
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I have coped and mitered crown over the years. One builder used a 7" crown that you couldnt cope cause of the thin edge it left would always break as someone mentioned before. We mitered usually and glued the inside corners with latex liquid nails, We never had a joint open up. Cutting crown flat gives you a lot more adjustment for out of square corners. I did notice that the crown settings on the dewalt saws are for 52/38 degree crown and most of the crown ive seen is more 42/48-43/47 so a list of the settings for different degree crown is helpful for the miter and bevel settings. And like drooplug said the angle of the edges is rarely 90 degrees. In the old days it was more then 90 to allow for out of square corners at the ceiling to make sure the front edge would hit first. I have put crown in 3 rooms in the house we bought last year and over the winter they opened up a little so when i do the rest of the crown in the house im mitering and gluing.
 
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Old 04-25-11, 09:41 PM
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I cut my crown at 45 degrees and then blacken the edge, that will be coped with the edge of a pencil.

Then I get out the Dremel tool, using a 60 grit sanding 'drum', and cut away. This gives great coped joints, but you need a little patients.
 
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