Baseboard - Coping inside corners vs measuring angle and cutting to fit

[branimal]

I'm about to start installing 300 linear feet of 5" baseboard. In the past I'd measure each corner with an angle finder and just cut to the best fit possible. Which never is a great fit b/c of various out a square & level issues. Even on new construction.

The formula I use for any angle (inside or outside) is (180 - angle ) /2. So if it's a 88 degree angle, I'm cutting a 46 miter on each leg of the baseboard. If its a 96 degree angle i'm cutting at 43 degrees.

After watching a few video's on coping, it seems you can get a better fit for inside corners by coping. I have a coping saw somewhere (tried it once and wasn't successful). I see the young guys now are using a Collins coping foot attachment on their jigsaws. And then removing the excess with a Dremel or file.

Any tips on getting good fits on inside corners?

Here's a video on the Collins coping foot. It fits my Bosch corded JS365 jigsaw, but the pros are using barrel grip jigsaws.

 

[cmandp]

First off I'm not a finish carpenter. But I've gotten better at installing molding after doing half a dozen rooms.

Absolutely cope any inside corners it really hides a lot of issues that you run into because walls are never square/plumb/straight. I wouldn't bother with buying a coping foot and learning to use it unless you think you will be doing a lot trim in the future. I've just been using a coping saw and some small hand files for clean up/fine tuning.

Outside corners you still have to miter and splitting the measured angle is still best.

Oh and a brad nailer or finish nailer makes trim go so quick if you don't have one already.

I also draw out a quick diagram of the room to show each piece of baseboard, what cuts are on each end and their lengths. I usually measure and cut each piece to fit but I'm finicky about it.

I also do a 45° scarf joint that I super glue anywhere a piece is not long enough.

 

[Jayman17]

I agree that coping inside miters is the way to go. You will get much tighter joints imo.
Coping saw with a sharp blade and some files/rasps is all you need.

Jay

 

[stonesfan68]

Cope the inside corners using a grinder and a flap wheel. It works great and doesn't take very long to do once you get the hang of it (practice with some scrap pieces).

 

[jar944]

I use a Colin's foot and a rasp mostly. I'll also use a 4" makita with 2 sanding disc's.

 

[The Cobbler]

coping is the best fit you will get.
cut a 45° miter, trace the profile with a pencil, lean the coping saw back to create a void and follow the line . . a rasp, sandpaper etc to clean up high spots . with practice & patience you will get nice joints

 

[Viper98912]

Coping blew my mind the first time I pulled off a baseboard that was like that. I use the traditional method of miter both sides all the way through and caulking finishes the rest

 

[The Cobbler]

Coping blew my mind the first time I pulled off a baseboard that was like that. I use the traditional method of miter both sides all the way through and caulking finishes the rest

traditional method? maybe now adays, but pre paint grade trim, cope was traditional! LOL

 

[K'ledgeBldr]

Coming from a background of production and semi-custom homebuilding- 30+ yrs; I've seen everything. It really boils down to time, and money. There are the few that actually have a mental block- I call it "****"- where pride in finishwork is first. Don't get me wrong, I love to see tight-*** joints that could go w/o caulk. But, I also need the job done in 3-5 days.

So, I tend to take the approach that if it's going to be painted-just get it close! It's going to be caulked anyway. If it's going to be stained- make them gnat's *** tight!

Scarf joints, when needed are a strange "devil in the details". Over the years I've seen a lot of different approaches- and the explanations are arguably true and false at the same time. It's really about finding the happy medium between glue strength, surface area, and moisture content (understanding the amount of shrinkage). Using a 45* scarf joint seems like the best joint due to the amount of surface area created to "glue-up". Unfortunately I've seen more of them fail than others. The best joints I've seen are either just good clean **** joints or joints cut in the 15* area. Of course this was the standard with carpenter's glue. Now there are stronger glues/adhesives that are far superior to carpenter's glue. Cyanoacrylate glue- "super glue" is seeing more and more use in carpentry projects- and it's mainly a time factor choice. Carpenter's glue will take several hours to set. "Super glue" can set in mere seconds with a misting of water.

The bottomline- "Time is Money!" Beautiful finish carpentry/joinery is an art form now. When it comes to a house, nobody's getting down on their hands&knees to look at baseboards or climbing a ladder to look at crown- If it looks good from 6', it's called done!

 

[jar944]

Coming from a background of production and semi-custom homebuilding- 30+ yrs; I've seen everything. It really boils down to time, and money. There are the few that actually have a mental block- I call it "****"- where pride in finishwork is first. Don't get me wrong, I love to see tight-*** joints that could go w/o caulk. But, I also need the job done in 3-5 days.

So, I tend to take the approach that if it's going to be painted-just get it close! It's going to be caulked anyway. If it's going to be stained- make them gnat's *** tight!

Scarf joints, when needed are a strange "devil in the details". Over the years I've seen a lot of different approaches- and the explanations are arguably true and false at the same time. It's really about finding the happy medium between glue strength, surface area, and moisture content (understanding the amount of shrinkage). Using a 45* scarf joint seems like the best joint due to the amount of surface area created to "glue-up". Unfortunately I've seen more of them fail than others. The best joints I've seen are either just good clean **** joints or joints cut in the 15* area. Of course this was the standard with carpenter's glue. Now there are stronger glues/adhesives that are far superior to carpenter's glue. Cyanoacrylate glue- "super glue" is seeing more and more use in carpentry projects- and it's mainly a time factor choice. Carpenter's glue will take several hours to set. "Super glue" can set in mere seconds with a misting of water.

The bottomline- "Time is Money!" Beautiful finish carpentry/joinery is an art form now. When it comes to a house, nobody's getting down on their hands&knees to look at baseboards or climbing a ladder to look at crown- If it looks good from 6', it's called done!

Scarf alternative. Works every time and won't move.




I'll also disagree about a inside miter vs a cope. You can be off on the length and angle with a cope. It basically guarantees first time right unlike a inside miter.

 

[LeonardY]

I personally cope all the inside joints. I've been doing it for years and it's second nature for me.

I'll also disagree about a inside miter vs a cope. You can be off on the length and angle with a cope. It basically guarantees first time right unlike a inside miter.

Me too.

 

[shoot summ]

I'm a coper....

I've tried a number of the different tools, best is still a coping saw, rasp, and an angle grinder with a flap wheel.

For base with a large flat I will make the first cut on the miter saw, then finish it out with the coping saw.

 

[Bruce 993 SEA]

If you are going to miter, cut a degree or so on both pieces so that the visible part of the joint comes in tight.

 

[Jazz1]

Wood filler is your friend.

 

[Git]

I am in the coping camp, for both crown molding and base boards - Bosch jig saw with Collins coping foot

Gary Katz has some good videos if your just starting out

https://www.youtube.com/c/THISisCarpentry/search?query=base%20board

 

[The Cobbler]

some years back I was installing about thousand feet of 4" colonial base per month under contract. we butted the inside corners & caulked the profile. very little caulk to fill the profile. and less than if we 45'd the inside corners . Customer was totally fine with it . I had another contractor tell me we were butchers, that we didn't know how to do trim because we weren't mitering the inside corners.I said, well, 45 is butchering too, that a proper job was cope , but they didn't want to pay for the time. He said, WTF is cope? I've never heard of that ! LOL

 

[Viper98912]

some years back I was installing about thousand feet of 4" colonial base per month under contract. we butted the inside corners & caulked the profile. very little caulk to fill the profile. and less than if we 45'd the inside corners . Customer was totally fine with it . I had another contractor tell me we were butchers, that we didn't know how to do trim because we weren't mitering the inside corners.I said, well, 45 is butchering too, that a proper job was cope , but they didn't want to pay for the time. He said, WTF is cope? I've never heard of that ! LOL

Wait, are you saying that you cut the pieces at square 90 and just caulked the entire rest of the profile? Not even at a 45? If so, wow, that's pretty gutsy.

 

[The Cobbler]

yup. the profile is not very deep , we were using 5/16" thick baseboard and approx 75% of the base was flat. a small swipe of caulk along that and a bit more to fill the profile . as I said, used less caulking that if we mitered, and the customer wanted fast & cheap

 

[PossumDog]

I’ve been coping this week. Website ‘thisiscarpentry’ has a good tutorial. I cut 45, use handsaw on straight portion and coping saw on curved portion. Not tight enough for stain grade but good enough to paint after caulk.

Around here Lowes sells 8 or 12 ft pieces. Home Depot sells up to 16 ft by the foot. Since I discovered that I don’t scarf since none of my lengths are over 16ft.

 

[Dan in Pasadena]

I’ve always done coping with a coping saw but I do it so infrequently that I almost have to learn it over each time. This flap disc method looks waay easier and more exact. I'd like to know more about the "super glue" used? Why an "activator"? I probably don’t NEED the Starrett gauge hell, my garage is full of things Garage Journal taught me I needed, ha ha. Where would someone find the Starrett miter gauge and the little corner marker chingus? (Like the technical terminology?!)

EDIT: Found the Starrett Protractor.

Miter Saw Protractor replace the model #505P-7 for carpenters, Ruler (Inch) on Carpentry, Renovation Work, Home Improvement and More Building Trades - Silver - - Amazon.com

Miter Saw Protractor replace the model #505P-7 for carpenters, Ruler (Inch) on Carpentry, Renovation Work, Home Improvement and More Building Trades - Silver - - Amazon.com

www.amazon.com

 

[Slednut]

I love coping, if you do use a hand coping saw the secret is keeping the saw blade moving.

 

[HenryAZ]

Method to get an outside "miter" angle that is not a 90* corner. Lay a 1x2 along one wall, sticking out past the corner. Lay another 1x2 along the other wall, again sticking out and laying on top of the first 1x2. (you could use a support piece of 1x2 under this second piece so you don't have to hold it in mid air). Mark the intersection of the two boards, front and back, on the first (bottom) 1x2. Connect the two marks and there's your angle cut.

This also works for an inside miter cut, but you'll have to precut your 1x2s so they go into the corner enough to overlap each other. But coping the inside corners is definitely easier.

 

[TRWham]

The most important rule in construction regarding trim: what looks right is right.

A wooden building will never be perfectly square or plumb or level so some adjustment is always necessary. Even if by some miracle it were perfect at the start, ten minutes later something will have moved as the woods expands and contracts.

Whether coping or mitering, a slight back bevel helps make the joint tight where it is visible. And caulk is not evil.

 

[captain14]

This is a skill I definitely need to learn. I have 2-3 projects that need this to complete the project.

 

[quickfarms]

The base board in my house is all but joints because that’s how they built the house in the 70’s, 1870 that is.

 

[jar944]

Post from a production trim carpenter I have a lot of respect for regarding this specific topic.

Like him I leave the length a bit long to allow it to snap into place. A sharp cope with a back bevel will slightly cut / deform into the matching moulding provided its wedged into place. This leaves a perfect looking joint that will never open up regardless of seasonal movement.

Justin Huisenga​

Coping accounts for at least 3* out of square on a corner without adjusting the saw settings to anything but a 45* angle. The only corners that need to be read for a custom angle are outsides. Not having to play with the angles make it faster. You're right outside corners will need to be mitered but there are always more inside to inside lengths in a house than outside corners so there are fewer angles to do anything with except dropping the saw into a detent and cut.

If one is mitering inside corners the lengths of the moulding must be perfect but with a cope a slightly long length can be snapped in rather than running back to the saw to change a length. The snap fit also makes for a better long term joint. Not needing everything to be a perfect length makes it easier to install alone. Crown doesn't require 2 carpenters working in tandem to install.

When mitering walls and ceiling need to be pretty perfect for miters to line up quickly and without extra time tweaking. Any hump bow or belly in a wall can throw off the miters. With a cope the corner can be tapped up or down to close anything that's open.

The forgiveness of perfect length makes scarf joints better and easier to fit. I use a **** joint with a biscuit on scarfs and cutting it a little long allows me to put extra pressure on the glued joint to allow the glue to set better.

Seasonal wood movement has less effect on a cope than a miter even if the miter is glued. A glue joint on an inside corner miter is held in place with tension because you can't put enough pressure on the joint to get to full strength. Unlike Ghidrah I usually only cope lefts unless I need to fit back to a pre-assembled corners. I'm right handed so it's faster to cope lefts.

My tracked time numbers show that coping is substantially faster than mitering. Part of that is because it's the way I usually do it but most of it is the above advantages.

There are enough un-copable mouldings out there that a carpenter needs to know how to do both efficiently and well. Done well either method looks good. With something like a simple s-curve crown coping an inside corner takes less than 30 sec. to cope. That time is made up for and then some on the install. For large mouldings I use a jigsaw with a coping foot. For smaller stuff like shoe, cove or picture rail I use a hand saw.

To miter or cope is often a function of how you learned to run trim or a regional thing. In my area even tract houses get coped.

 

[jar944]

The base board in my house is all but joints because that’s how they built the house in the 70’s, 1870 that is.

The only time I've seen that in a Victorian Era house was base with corner blocks.

Is is a flat profile?

 

[K'ledgeBldr]

Scarf alternative. Works every time and won't move.

Nice Work!
Tenons AND pocket screws! Yep; wouldn't expect that to move at all. On the other hand- having a HVAC vent made "into" the base will probably wreak havoc with that area if the humidity fluctuates a lot.

 

[PCMusicGuy]

I lived my later teenage years watching my older brother work as a finish carpenter. He was a pro with the coping saw. All of the houses he took me to where he showed his work had coped base boards and crown molding and it looked great. It wasn't until many years later that I discovered modern homes have sloppy baseboard and crown molding and use caulk or silicone to cover it up. I'm in the coping camp for sure.

 

[wrenchguy]

Coping is your friend iffen you got the patience. Measure long points and cut to long points. I use sanderwith thick grit all the time. Come back when doing crown, my suggestion will be the same, but with tips. Good luck.

 

[Bert_]

The base board in my house is all but joints because that’s how they built the house in the 70’s, 1870 that is.

Mine is a very simple cope. It's flat other than the rounded corner. The joint is still tight 100 years after they put it in.

 

[like2wheel]

I've been known to stick a piece of thin 80ish grit psa sandpaper on a scrap piece to tune a cope to fit tighter.

 

[jmdirk]

The most important rule in construction regarding trim: what looks right is right.

A wooden building will never be perfectly square or plumb or level so some adjustment is always necessary. Even if by some miracle it were perfect at the start, ten minutes later something will have moved as the woods expands and contracts.

Whether coping or mitering, a slight back bevel helps make the joint tight where it is visible. And caulk is not evil.

No, but it can definitely be overused. There is definitely a time vs money trade off. Only issue with too much caulk is that over time it will dry out and shrink opening up the joint.

 

[TRWham]

No, but it can definitely be overused. There is definitely a time vs money trade off. Only issue with too much caulk is that over time it will dry out and shrink opening up the joint.

Did not mean to say caulk should be used to excess, but to use it at all is not a crime.

 

[firebirdparts]

I actually coped an outside one just a few weeks ago. On outside corners the miters look "right," I guess, but they're so fragile. You'll knock splinters off over time as a result of just life. Caulk looks like hell on them. So I decided to try to cope one and see if it looked okay.

 

[Tman]

Been doing trim for over 30 years. As mentioned above, it just has to LOOK right. What we are doing is building facades, like a livable stage set. This is even more evident in Commercial construction

When I was getting paid for it I developed a fast method to cope. You use your miter saw to chop the corner at 45 degrees. Some corners take a couple degrees more, some less. You get a feel for it. Once its chopped that is your guide. I then take a mini handheld belt sander and quickly rough in the cope. Depending on profile you can sometimes end it here but some more intricate profiles I touch up with a sharp utility knife on the backside. The trick is the belt sander, the small front drum matches the top part of the cope on many ranch style casings.

 

[GirchyGirchy]

If I coped my joints, they'd stick out like a sore thumb in our 1930 house.

 

[Pntyrmvr]

There is art in every trade’s work when well executed, but it’s almost invisible to most.

We let the painters prep, prime, and first coat the trim first even at the cost of reduced blade life. Sometimes to their surprise.

And we cope.

 

[Viper98912]

I gotta say, I'm blown away by the amount of coping in this thread. I would've sworn that a majority of everyone would say 45 it and call it good.

 

[pizza]

I'd like to know more about the "super glue" used? Why an "activator"?

cyanoacrylate (CA) glue, aka super glue, comes in various viscosities. i actually haven't looked into the chemistry, but ime, the thin glues cure faster than the thick ones. i'm not sure if if cure rate and viscosity are directly linked somehow or if companies just decided to make thicker glues cure slower because they figure you probably need more working time since it will be a sloppier assembly (thicker glue for gap filling ability for pieces that fit together poorly, more adjustment time needed).

anyway, especially for the thicker glues, it doesn't cure instantly. maybe you want to fill gaps with a heavy application of viscous CA but still get a fast cure. that's what that accelerator spray was for.

countertop guys use it, too. after an install, maybe the countertop still has a small void here or there that someone missed. you just drip some of that thick gap filler CA glue in the hole, spray the accelerator, wait a few seconds, and then scrape it flush with a razor.

if you don't have commercial accelerator, you can experiment with diy. sodium bicarbonate (baking soda) seems to work.

don't get confused though. it's not like epoxy. it's a one-part adhesive, and accelerator isn't actually needed.