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A couple questions for those that have more experience than I:
What is the best way to glue a coped crown joint? I install paint grade poplar mouldings (latex caulked & then usually finished with an oil-base primer/topcoat), and have had an occasional problem with cracked paint (at the joint) a few weeks after installation(s). The very fact that the coped piece is back-cut does not leave much of a contact surface for glue/adhesive???
Also, any tricks for giving the appearance of a miter other than leaving a paper-thin piece of material at the bottom?
Thanks folks.
Cheers, William
Replies
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I'm not aware of any good way to glue a coped inside crown moulding joint. Your observation is correct in that the coped joint offers too little poor quality glue surface for it to be effective. If you have access to a small brad nailer, you can usually angle a shot through the coped piece into the long piece to help hold things in place.You may also be fighting the drying process of the caulk. If the caulk has not finally dryed or cured when it is primed and painted, it will continue to dry and shrink for a period of time. That may explain the cracks in the final paint coat.
P.S. No tricks on the mitre problem. Just keep a sharp coping saw and be careful with the little piece that is left behind. Good luck.
*John makes some good points. I've never glued coped joints for the reasons you both point out. The secret to a tight joint is solid backing to nail into, preferably a continuous, angled backing strip. There should be a slight gap between the face of the strip and the back face of the crown molding, so that nailing along the middle of the molding will pull the edges tight to the wall and ceiling. This makes for a very stable placement along the entire length of the molding, and hence a stable joint.
*Agree with Steven about adequate backing to nail to. Another trick is to establish how far down on the wall the bottom of the crown will be, then cut a small block of wood to that measurement. Using the block as a gauge, hold it to the ceiling and go along the wall and mark it every 2-3 feet. This will give you a much straighter job in relation to the ceiling, and make corners much easier to fit.As to the sliver of wood left on the bottom after the joint is coped - I don't see any need for it. I cut it off while I'm coping, square with the bottom of the cove part of the moulding. Leaving it on does nothing to improve the look of your work.
*Interesting, I have always just nailed into studs and joists, am I wrong? The backing strip sounds interesting, perhaps some further details?Thanks, much appreciated. David S.
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We install a lot finish work and had the same problems that you point out. After doing some flooring work we figured out that the trim wasn't in the house long enought to help "balance out to the conditions" in the house. We try to leave all trim a few days with the heat on before installing crown or stain grade(prefinished) trim. Also we have changed to differant caulk a few years ago (more money but we don't have to recaulk)
We also cut out the little tail to match the cornor. It gives a more finished look to the cornor. If the stud work won't work with the crown we install backing but on most cases we can use the studs or top plates. Next big question is do you butt your middle joints or 45 or 22.5 or bisket joint?????????????
*Hello William,Your right about not having much surface toglue to on those inside corners. I personally havenever seen a need to. If the crown moulding can be put up in one piece, I cut it snug enough that italmost has to be bowed in place, wedging itself and the previous piece in place.As far as the blocking issue goes, I have never used it. I use the wall studs, top plate and ceiling joists. To maintain the the right fit tothe wall, I lay a piece of the crown in a framingsquare to find my distance down from the ceilingto the bottom of the crown. Ithen make light pencil marks every 3 or 4 feet to work to.As far as that little miter at the bottom of thecope goes I cut that off. I don't think it mattersmuch to the appearance of the joint, especiallyif it's caulked and painted.For Bill: I use the settings for cutting crown flat on my Dewalt compound miter saw, so thats the angle I use to cut my joints at mid-span. Inever have to change any angles.Hope this is of some help,Mike Merisko
*Mike when I started in this trade I worked for a guy who butted everthing at a 90. Changed jobs and the new boss screamed at me that any good carpenter used a 45 to join in the middle now I just laught and use a 22.5 or butt depending on trim. Most of the older carp's will get right up tight about that item.
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Thanks gentlemen...I did have a hunch that the cracks were due to painting too soon over uncured caulking, along with the quality of the caulk itself. The timing of my original post was such that I was starting a job that involved crown the next day (nothing like being prepared/confident).
I installed the moulding this past wednesday, caulked with a higher-end DAP product (Formula 230) specifically for corner/butt joints. I won't be priming until monday, in the past I usually primed the very next day. We shall see. ;-)
Thanks again for the help, and I am still interested in what others may have to say (that is, don't let this post end the thread if you have more to offer).
cheers, William
*I do agree that gluing the joint is a futile attempt at best. The way that I have solved this problem is with trim screws. First, I tack the 2 pieces of crown in place with just enough nails to keep it from falling. Then, I take a counter sink bit and drill a pilot hole at a steep enough angle to make a good connection with the square piece behind. I usually place only one screw in center of the crown profile. Be sure to drill the pilot hole far enough back from the joint on the coped piece as to prevent it from splitting out. You will be surprized at how snug the resulting joint will be.As for your question about the bottom of the joint appearing as a miter, I will share a technique with you that I use on shoe molding. As I cope out the joint I leave a 1/4 inch of material uncoped at the desired location (bottom in your case, top in the case of the shoe). I then take my square piece and miter, from the corner, with just enough depth to receive the uncoped section. You then put the pieces together as you normally would. This technique works great on profiles that round over as in the shoe molding.Jeff PalumboRemoldeler Northern Virginia
*Does anybody know how to install crown moldings in a room with cathedral ceilings?
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I've never seen it done. Actually, I'm not sure it can be done, since the molding coming down the from the highest corner to the lowest corner would have to be cut at an angle, which would expose a different profile (and different exposure) than the molding running parallel to the floor that it would meet at the lowest corner. Not sure that made sense, but you can visualize it as trying to match long edge of a 2x4 with another 2x4 cut at 45 degrees; the width of the two edges will be different, so they can't be joined exactly.
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Having recently installed new kitchen cabinets I now intend to trim out the upper cabinets with 2 1/4 crown molding.(AS there is no soffit) A couple of questions fro those experienced at this. #1 If I sit the molding in the chop saw as it will fit the cabinet top will a 45 degree + or - miter cut work? If not what will work? Should I provide a nailer behind it or just nail on the bottom where it will meet the top of the cabinet. P.S There are no inside angles.
*Chuckyou can stand the molding up in the chop saw to cut your miters but remember it must be "upside down and backwards", meaning the cieling edge will be on the table, the wall edge on the fence. use your framing square to measure the size of the crown and scribe an appropriate line on the table as a reference to position the molding. usually there isn't much nailing surface left above the cabinet doors so I add a strip of wood to top of cabinets BEFORE hanging them.if the crown doesn't reach the cieling and the span isn't too long then a single block angled to 38 or 45 degrees along with the corner miters will usually be enough to keep the crown straight.RWD2sure you can crown a cathedral cieling. the sloped piece will have to be a wider molding than the level piece though. 3.5" and 4.25" usually work ok together, you can change the pitch of the sloped piece in or out to line up top and bottoms if nescessary.also you must use the same plumb cut as on the rafters. cope the joint, fit it and scribe as required, then recope or rasp and file for a good fit. due to the different profiles, a bit of fudging is unavoidable unless you have the two different pieces custom milled to match.The top miter will simply be a pair of plumb cuts.this is all easiest to do with the crown standing up on the saw rather than flat.good luck.carp
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Carp & RWD2
Yes, I suppose it is possible if you use different size molding. I was working on the presumption that you would trim a room with the same molding. I suspect the "fudging" would involve a reasonable amount of caulk/filler and paint. Good luck though, if you decide to try it.
*Bill, I understand what you're taliking about. If you don't put some type of degree, they go nuts!I started with a gut who put a 10 degree cut on everything. It took me a decade to shake that habit. I now use a special angle, thats guaranteed to make a nice tight fit. It won't let the two members slide by like a 45 will. I'll let you guys in on my secret, but don't tell anyone else. The magical angle is ...90 degrees!It works every time if both members are exactly 90! On crown, it requires a backing piece that efectively ties the two together.Blue
*Like the 90* angle. On base we have taked to using a bisket and the 90*. Set to the face side this allows you to get a perfit fit. We use this a lot on stain grade trim. Oh annd those old guy's would go nut's if the 45* was cut the wrong way. The right way was subject to change all the time but some how I managed not to kill anyone.
*Cathedrally speaking...one could also turn the angle of the cathedral ceiling upon reaching the lower end of the end wall so as to meet eve end wall run at a standard 90 degrees...It might look strange but all molding would be the same size and no fudge would be served,Jack : )
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As a trim carpenter for 15 years I am happy to hear that homeowners actualy know how to cope or even what coping is!!!!!. I feel that if you cope the crown properly by filling it with a file and taking your time, by the way with the new primed molding I find it even easier to cope because the line is defined even better, you will never need anY glue to adhere to asjacent piece of moulding. There is nothing really too glue too. If you were to glue I think it could cause a problem. Wood moves with the condition of the humity of the room if you were too glue I think it would crack the cope. I feel that if a crown is properly coped and installed properly you will never have any problems with paint cracking ever!!!!!
*try cutting a decorative block from 2x lumber wide enough for the crown to butt into at the peak of the cathedral and where it meets the lower wall...we have trimmed stair ways having sloped ceilings like this...i was not the one who cut the blocks so i cant tell you all the details but i know they were wide enough to accept the crown on its angle and were stained to match .....hope this helps
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Old Loeffler proverb: "Perfection is the enemy of good." Another old Loeffler proverb: Never use "never" and never use "aways" . I have always found these sayings to have some truth and I have never found it otherwise.
Dennis
*you might try building a small soffit at the bottom along the eave wall, this would allow for butting the gable molding to end into the soffit and the lower crowns could be installed along the soffit.Geoff
*P.S.- all trim should be allowed to acclimate to the inside moisture levels for at least a few days, also I believe that a coped joint is intended NOT to be glued, hence the reason for coping and fitting so precisely.Geoff
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A couple questions for those that have more experience than I:
What is the best way to glue a coped crown joint? I install paint grade poplar mouldings (latex caulked & then usually finished with an oil-base primer/topcoat), and have had an occasional problem with cracked paint (at the joint) a few weeks after installation(s). The very fact that the coped piece is back-cut does not leave much of a contact surface for glue/adhesive???
Also, any tricks for giving the appearance of a miter other than leaving a paper-thin piece of material at the bottom?
Thanks folks.
Cheers, William
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hey swede
by fudging, I mean to work the joint 'till it fits! no amount of caulk or filler is "reasonable" in a coped joint. maybe just a tad in a painted moulding on production work.
Carp