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Punching above his weight
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Discussion Starter · #1 ·
Well that was a waste of my time. Never doing that again.

Is there any way to nicely cope this crap? I got average results with a fine blade on a coping saw and a file, but was really bummed about constant chipping when I tried to fine tune with a knife.
Very frustrating day.
 

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Angle Grinder and file to fine tune
 
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Just try not to breathe the dust, the stuff sucks!
 

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I have done it sucsesfally with a jig saw and a good lenox blade though it does take some practice.Not near as easy as wood of any kind.It's cheaper and eai\seir to just buy chaeap\\\\\\\\\\\\\\\\\\\





I have done it with cheaper mdf and a good Lenox blade on crown but in the long run it's quicker and easier to just buy some poplar crown.
 

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Punching above his weight
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Discussion Starter · #7 ·
The MDF purchase wasn't my choice. hah

I was working alone yesterday and I find coping easier than mitering when by myself, especially on longer runs.
 

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Want to play a game?
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I like to use the coping saw to get the majority of it out. I don't go right to the line with the saw. Leave like a 1/16" or even an 1/8" . Then like others suggested finish it off with a grinder and sanding wheel. This is where that cordless Makita really comes in handy.

I put a couple fingers with my left hand on the trim ( out of harms way of course) while the rest of the fingers to help the right hand steady the grinder.
 

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I sugjseted using a Bosch jigsaw with a good Lenox blade and that does work well for the initial cope but does take some practice and fine tuning.The bosch I have is probably 20 or so years old and very smooth cutting.With the right blade you can get very close.I use some self adhesive sandpaper on a dowel after that to fine tune.Or maybe a drum on a Dremel but it does not take much.I usually don't have to go that far.
 

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topsail's trimcat
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dont cope mdf, its more stable just mitre it.. i used to cope it but its far too brittle and makes for a ugly joint. the only time i cope mdf is on remodels where existing trim wasnt removed so ill cope into it
 

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I ran into the same thing on a whole house paint and remodel job I did last year. The homeowner chose the crown from a local millwork company and ordered 250 ft of 5 1/2" MDF crown without me knowing what they were getting until it was delivered. I learned pretty fast in the first room how to deal with the stuff. I dont really like the way it cuts and installs, but one thing I have to say .........its really nice and smooth after its painted. I ended up coping the inside corners after trying miters. It was more time consuming to keep adjusting the corners to get the miters tight than to cut the copes. I made my initial cuts with a fine toothed coping saw. The fine tuned with smooth files(flat, rat tail, and half round) then back cut with a Makita die grinder with Kutzall carbide grit bit. After the first room I got the hang of doing the corners. My only problem was putting up 16 footers alone. The stuff is really flexible. I ended up putting in a few 8 penny finish nails along the chalk line to hold the piece up while I nailed it in. Not sure if i want to ever use MDF again>:rolleyes: I have to say also that it is pretty stable stuff too. I was back to do some more work last week and I could only see 2 or 3 inside corners that opened up a tiny bit from the dry winter air in the whole house.
 

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diplomat
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dont cope mdf, its more stable just mitre it.. i used to cope it but its far too brittle and makes for a ugly joint. the only time i cope mdf is on remodels where existing trim wasnt removed so ill cope into it
I find MDF LESS stable. Unlike wood, it will shrink along its length because the fibers aren't all parallel to the length. Now maybe this is my own ineptitude, but I find it much more difficult to miter vs cope a tight corner without having to cut twice or more to dial in the length.
 

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I don't like it at all but some customers insist on it for paint grade and budgets.I don't paint but it does look nice after a good painter is finished with it.
 

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Finishing Carpenter
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I always cope MDF, or anything. It makes a big difference in the finished product.

I use the easy coper jigs, and a bosch jig saw with a very small blade. You can get exactly up to the line, even me and I have the shakes. (essential tremors)

Ya it takes a little longer, but the results are amazing. you do have to be careful not to bump into stuff with the coped end(s) but other than that I guess it's like anything else you get good at it after a short while.

As for holding up the 16' lengths I use the Lee Valley crown hangers.

You put a screw up near the ceiling about 1" down, then this hanger "hangs" on that screw. It's sorta like a large fish hook with a movable barb.

Hang your crown on that, then adjust the "barb" part up a little bit so the crown is up against the ceiling, then nail off. When you get to the hanger, just lift it up a bit and slide it down out of the way. The screw will not interfere with the crown.

Lee Valley coping jig: 03J75.80

Lee Valley Crown hangers: 03K18.05
 

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I always cope too. As a remodeler, I'm doing the finish so it always looks good when I'm done.
As a mater of fact, crown is the only place I will use MDF. Once it's installed, there is no chance for abuse. I go into homes that are 2-3 years old with MDF base and casings beat to he!! from the vacuum, pets, movers, whatever.

I just put my glasses on and use a simple coping saw. cuts way easier than solid wood. Just don't bump the cope end when handling..
 

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Finishing Carpenter
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I keep swearing that I'm going to get a copemaster, but on those rare times that I see one on CL, I don't have the money or it's hundreds of miles away. or both.
 

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I always cope too. As a remodeler, I'm doing the finish so it always looks good when I'm done.
As a mater of fact, crown is the only place I will use MDF. Once it's installed, there is no chance for abuse. I go into homes that are 2-3 years old with MDF base and casings beat to he!! from the vacuum, pets, movers, whatever.

I just put my glasses on and use a simple coping saw. cuts way easier than solid wood. Just don't bump the cope end when handling..
I agree it does cut alot easier than most finger jointed pine moldings. And I found out the hard way several times about bumping into door frames when trying to flip a 16 footer around in a 12' x 16' room:no: Sometimes I had some trouble with the nails mushrooming the MDF. Usually after I fill the nail holes and sand the filler the mushrooms go away. I tried plastic crown hangers from Woodcraft and didnt like them, so I usually just put a few 8 penny finish nails in the wall along my chalk line. The resulting holes are filled with the caulking at the bottom of the crown. Works well for me.
 
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