Divided light interior door question

Hi all

I'm starting on a pair of French doors. They will be around 1 3/8 thickness, VG Fir. The stiles will be laminated and veneered, like the other doors I've looked at.

I have a pair of interior door cope and stick shaper cutters with the full profile. These leave about a 1/4" slot for panels. My question is how best to insert the glass panels. I can't find much good info on the web about French doors. The only solid suggestion I've seen was MCLS's, which said to build the entire door, mullions and all, then use a rabbeting bit to remove one side of the profile around where the glass will be. Then you make up more trim secure the glass panels.

I've also seen French doors which look like they were assembled with the glass being integral to the door. That's to say that the glass panels fit like they were wood panels, and aren't removable.

I'm OK doing it either way, but would love some advice about 1) any other options or 2)which aforementioned method would be better.

I'm already learning a bunch about door construction, door tooling, etc. Totally different arena of woodworking. Good fun!

I personally haven't ever done a French style interior door, frankly it's just so much cheaper to buy one I could never justify it. As for building it there are several ways you could go. I hope your ready for a challenge!!!

First is the traditional way which is a true divided lite door. Your muntin and mullions will have the full molding profile on the face side and a tongue (not sure of the proper term here) on the back side. If you look at the profile it would resemble a T shape. All your pieces would be tenoned to fit into mortises cut into your door stiles and rails. Not to mention the joinery where they intersect. After assembly your (safety) glass gets fit into the back side and glass stops with a matching profile get tacked in to hold the glass in place.
FWIW I build a lot of interior doors and I would never have the time to do this method.

Method 2 is "faking it" by eliminating the mortises and just face gluing a profiled muntin to the door. The back would not have the tongue so you could use a single piece of glass. Then just fill in the back by again face gluing the muntins to the door. I use this method for cabinet doors....not sure I'd want to try it for an interior door though?

I have not heard of the other method you describe but seems like it could be even more difficult? Depends on the type of cutters you have for the shaper I guess, and how exactly you route out the profiles?

Anyway good luck whichever path you choose, you certainly have your work cut out for you.
JeffD

I would not put glass panels in grooves as you would for wood panels; removable strips or molding to hold the glass in place is the best plan. If a glass pane breaks and it's in a groove, you're screwed, or, rather, your door is.

Thanks Jeff. I'm trying to imagine of the least likely way to mess up, and I think the traditional method is the way to go. I plan to use loose tenons on all the joints. What I'm hoping is that I don't have to buy another $300 worth of "glass panel" cutters in order to remove the inside profile for the glass. That's why I thought I thought of building the doors and rabbeting afterward with a router on some sort of support.

I don't have much into materials so far, although I haven't bought the glass. I just dropped by the cull bin at my local HD to get a pile of practice wood in order to try out some joints. You're right, it is a daunting project. If anyone is interested, I could keep a photo record.

Thanks Frank. Upon reflection, I'm sure you're right.

I did that on a smaller scale - a few dozen true divided lite doors for a kitchen. My approach:

Use a stick that is wider than 2 of your muntin profiles. Profile both outer edges. Run it across the TS blade to create a groove down the center. Flip end-for end, and do it again [creating a groove/dado exactly in the center]. Bump the fence a bit and repeat. Continue until you get the finished rabbet dimensions, as measured from the profiled edge.

Raise the TS blade a bit, flip the piece over, and split it down the middle - I'd use a feather board on the side, and a sacrificial push stick - kinda like resawing spaghetti, but you can do it very safely if you just think it through first, and you are using shorter [v. 6'] strips. Now you have your muntin material.

Last - get another stick that is however wide. Profile the two outer edges. Run the stick through the TS twice to rip off a pair of closure strips for the "put the glass in this side" side of the door. Profile that stick again. Repeat. Now you have your closure strip material.

Set the glass. Miter/whatever the closure strips to size, and use a pin nailer to attach them. You don't need a lot of pins - I'd think one near each end and a third in the middle would handle it. You'll need one extra pane of glass for when your aim is wide and you try to pin the glass itself. This only happens the one time. DAMHIKT.

Make extra closure strips for inventory/repairs. With a thin flat-blade screwdriver, or a card scraper, you can pry out the closure strip off of the pins to replace a pane of glass. Sometimes it can be reused, sometimes not, in my experience.

you want to bed the glass in either glazing putty (better) or clear window/door caulk (second best). reason being the wood will move, the glass won't. if the glass is too snug the wood movement can break it. if the glass is too loose it will rattle without anything else to hold it in place, so bedding the glass in something flexible eliminates those issues. any squeeze out of your putty or caulk on to the glass, just let it dry that way, you can cut it away later with a razor scraper. after one or two panes if you use caulk you'll start to get a feel for how much is required for it not to squeeze out. if you're staining, the caulk will hide better. if you're painting, the glazing putty will seal better and leave a cleaner line. preference depends on the finish really. if you opt for glazing putty, dap33 will work fine.

then set the glass in place with glazing points. the glass should be 1/16 short of the edge of the rabbets all the way around. there's a gun made by a company named fletcher if you prefer to buy one (it's called a point driver, it's manual like a staple gun doesn't require air), or you can find hand driven points on the web from various window restoration supply places, you just lay a putty knife against the hand driven ones and tap them in with a small hammer against the putty knife.

for your glazing strips, kent's method works fine, just takes some trial and error with scraps, no need to buy special tooling for it. but think about that with your rabbets, you will need to be precise on the depth and width of your rabbets. you need to be deeper than square on the rabbet by the precise thickness of your glass, plus a hair to account for whatever you bed the glass with, so that the profile winds up the same on both sides. hard to explain but when you start cutting a trial piece it'll dawn on you. bonus points if you cope the ends rather than miter them, they look better that way. then you cut a relief in the back of your strips so that they fit over your glazing points flat against the glass and you're done, nail them in place with small finish nails.

if you'll have to cut the glass yourself and haven't cut glass before, recommend a diamond tip glass cutter, they are more forgiving of less-than-optimal technique than the steel wheel cutters are. you can find them from any window frame supply place for about 20-30 bucks.

the above is the 'old school' way for glazing doors/transoms/other inside windows/etc. works fine, lasts a long time ;).

i build windows/transoms all the time with nothing but the profile cutters and a dado blade. that's all you really need. it's alot more doing things in the proper order and making sure your measurements are absolutely correct than having specialized tooling.

if you start by building a transom out of cheapo lumber you'll cover pretty much every technique required for the door.

edit: almost forgot, pick out your lock/knob set and how you want the inside to seal first. if you want an old style mortise lock you can get them in several sizes, which are determined by your stile width. then there's the matter of whether you prefer an astragal between them or whether you want to rabbet the inside edges and use a rabbeted lock. those decisions have to be made first (preferably with the lock/knobs in your hand to measure with) since they affect the dimensions of your parts, and in the case of laminated parts, how thick your veneer needs to be if you opt for the rabbeted lock option.

Excellent pieces of advice, Neal.

On divided light cabinet doors I've used only colored putty for fixing the glass on the inside; more correctly, I had a glass shop do it for me. On passage doors, where both sides are seen equally, I prefer wood fixing.

yeah, coloring your putty to match your stain is also an old school method, that's how they used to glaze windows that were to be stained on the inside in the old days.

that said, i don't bother with it since clear caulk can accomplish pretty close to the same thing these days. i don't like caulk for most of its intended uses but in a protected environment like bonding glass to wood where it's completely covered, it will last indefinintely.

[QUOTE=Neal Clayton;1650586]


if you'll have to cut the glass yourself and haven't cut glass before, recommend a diamond tip glass cutter, they are more forgiving of less-than-optimal technique than the steel wheel cutters are. you can find them from any window frame supply place for about 20-30 bucks.

He won't, (or at least shouldn't), be cutting the glass himself, as anything short of safety glass is illegal in most places in passage doors for obvious reasons. I highly recommend staying with the safety glass.

I use the clear silicone caulking myself, just a couple dabs around the perimeter of the glass is all that's needed.

Not sure how wide your muntins and mullions are going to be, but in a "typical" French door they're pretty narrow. May be tight trying to use loose tenons, but if you make them wider I suppose you could give it a try?

The more I think of it the more I would try to avoid routing the pieces after assembly. Even if you come up with an accurate jig, your going to have some flex in the pieces your routing which could lead to problems. I think your better off coming up with jigs to profile the material beforehand and avoid potential problems.

good luck,
JeffD

You don't need the glass rabbit cutter for your shaper set to make divided lite doors. It sure goes quick that way, but not much quicker than two additional TS cuts. I've made them both ways, and have no preference. Depending on your shaper it can actually be easier to shape the muntins with only half the profile and simply rip off the square side after to create the glass rabbit. You will need a carriage with the cope shaped into it to make the second pass on the vertical bars safely and without snipe if you are using a glass rabbit set up. It is very difficult to shape narrow bars other wise. I usually cope blocks wide enough to make 6-8 verticals, mold both edges, rip these off, etc. Then go back and shape the other side. You CAN shape the second side without a carriage if you are only using only half the stack to profile one edge, but it requires a very careful set up and good feeder wheels.

Only on the lowest quality of door would you find the glass held captive in a groove, this is not an advantage but a way to avoid mitering the many intersections of glass stop for a bulk industrial production shop. Avoid that. For exterior doors I'd agree with Neil, but for interior passage doors all that putty is a waste of time. A drop of clear silicone on each corner will more than suffice to hold the glass and keep it from rattling, the stops will do the rest.

Loose tenons are fine for the outer frame assembly, but not really for the muntins. There is simply not enough material to get a loose tenon in there. So a true "stub" tenon is your only real option short of just cope and stick. Just cope and stick will work for the bars, and the whole thing is generally strong enough with the glass and stops in, but that is simply not the best quality of work. To keep all your bars going in a straight line make two "punch sticks" from 1/4" MDF, one to locate the horizontal bars and another for the verticals. These will keep all your lines straight and your spacing consistent. I actually screw these to my stiles, rails, and all bars to locate the mortises on these parts and guide the mortising chisel. Do not rely on a mechanical layout over that many pieces for accuracy. It is critical that all your parts are very accurate on length, and that the sum of your horizontal bars' widths and your vertical bars lengths fits into the space in your frame. Small errors multiply quickly causing nightmares on glue up or bowed muntin grilles. DAMHIK. I like to shape and fit all the horizontal bars then cut the verticals to length using test pieces to verify the lengths are correct.

You only need a 1/4" stub tenon on your horizontal bars and half that on your verticals, and by that I mean a tenon that is 1/4" deeper than the depth of the glass rabbit. To do this you can run a single cope cutter with the fence backed in 1/4" deeper than your regular cope set up, then cut the rest of the cope to meet the glass rabbit in a separate operation, like a mini haunch. Remember to add the additional length of your tenons to your muntins lengths. Seriously, I always forget that and wind up making new bars at least once, which just sucks when you don't realize it until dry fit, so don't do that!

All that said, for VGF 1 3/8" doors, I wouldn't bother making them, I'd just buy them. I can buy a factory made french pair of reasonable quality in Doug fir with tempered glass for less than it costs me for materials and glass. Thats prehung, ready to instal. Unless a special wood, unique molding profile, or very custom size is required, or you are just really itching to make your own doors, which IMO always has its own merits, there is no practical reason to compete with a factory made commodity when they do it so well and so cheap. Desire to do the work would for your own enjoyment would fall outside of the realm of practical, and if that is the case bravo and proceed with gusto!

Thank you for the excellent advice my friends. It's much harder to imagine everything that goes into a door than it is with a table! I have half of the day planned to practice coping and sticking cuts tomorrow and figure out how to cut the stub tenons per Peter's suggestion. I've already made a decent router jig (don't have a slot mortiser) for the loose tenons on the rails and stiles. I also made a functional coping jig for the shaper and got some of those really thin arbor spacers.

Quote:

---

Desire to do the work would for your own enjoyment would fall outside of the realm of practical, and if that is the case bravo and proceed with gusto!

---

Thanks for the encouragement Peter. I'm sure I'm not saving money, but I'm having a great time.

Quote:

---

He won't, (or at least shouldn't), be cutting the glass himself, as anything short of safety glass is illegal in most places in passage doors for obvious reasons. I highly recommend staying with the safety glass.

I use the clear silicone caulking myself, just a couple dabs around the perimeter of the glass is all that's needed.

Not sure how wide your muntins and mullions are going to be, but in a "typical" French door they're pretty narrow. May be tight trying to use loose tenons, but if you make them wider I suppose you could give it a try?

The more I think of it the more I would try to avoid routing the pieces after assembly. Even if you come up with an accurate jig, your going to have some flex in the pieces your routing which could lead to problems. I think your better off coming up with jigs to profile the material beforehand and avoid potential problems.

good luck,
JeffD

---

i think that's subjective based on the size of the glass, tbh. with fake muntins laid over a solid pane i don't disagree that safety glass is required, but with true divided lights, you have much smaller panes which are much stronger. and yeah, wider muntins makes for stronger glass too, because there's more of a base for the glass to rest on.

in addition to not trying to route the profiles after assembly, you'll probably find that the loose tenons are an extra wasteful step too. you can just as easily cut integrated tenons as you cope the ends. cutting those tenons off just to make another loose tenon is an added step with no real benefit.

i completely missed that this was an inside door and not an outside door, in that case peter is correct, bedding the glass with a little caulk here and there is fine in that case, since there's no condensate to worry with.

Quote:

---

Originally Posted by david brum

Thank you for the excellent advice my friends. It's much harder to imagine everything that goes into a door than it is with a table! I have half of the day planned to practice coping and sticking cuts tomorrow and figure out how to cut the stub tenons per Peter's suggestion. I've already made a decent router jig (don't have a slot mortiser) for the loose tenons on the rails and stiles. I also made a functional coping jig for the shaper and got some of those really thin arbor spacers.


Thanks for the encouragement Peter. I'm sure I'm not saving money, but I'm having a great time.

---

Those stub tenons add a lot of strength and greatly aid in alignment of the various parts when you start gluing. Your wood will almost be kissing the spindle on a 3/4" machine, an 1 1/4" has a bit more reach, but either size works. Have fun with it and let me know if you need any help or perhaps am picture or two. Once you play with a fee test pieces the geometry becomes more obvious.