How to Make Perfect Picture Frames
Picture frames are one of my favorite things to build. They are simple. A frame consists of 4 pieces of wood, a piece of glass, and a backer board. That’s it. But the trick is each rail of the frame needs to be absolutely perfect.
I like to cook and enjoy watching cooking shows. Some of the tutorial based shows where a chef is teaching the audience how to make a recipe and some competition shows. One show in particular I enjoy is Master Chef. I’ve watched it with my wife for years and over the years we’ve picked up on the trends of the show. Generally those who win can do two things, they can cook and plate complex dishes at restaurant quality and they can nail the most simple dishes. You’d think it would be harder to make a complex dish, but the thing that trips up contestants is always the simple dishes, that’s where people get sent home. Minor flaws in a complicated dish can be overlooked by the judges as they can appreciate the ambition and let the contestant try again. If the contestant messes up the most simple dish, there is no where to hide.
For example, the other day I was watching an episode where the contestants had to make egg yolk ravioli. It’s a simple dish, really only 3 ingredients, egg yolks and pasta with a brown butter sauce. If any of those three things isn’t perfect there’s trouble.
Picture frames are the egg yolk raviolis of the wood working world. Every miter has to be tight. The glass and backer have to fit just right, the dados need to be deep enough to hold the glass, backer, and artwork. And the finish has to be flawless. That’s it. There isn’t anything to hide behind. You can’t hide a flaw by putting the bookshelf in a corner hiding the bad side against a wall.
The good news is, picture frames are simple and do not require complex joinery. I see YouTubers adding all sorts of support to a picture frame, but to me it’s unnecessary. Most store bought frames are held together with staples and they do just fine. The weight of the picture is so small that the picture frame really just needs to hold its own weight together. In my opinion there is no reason to complicate picture frames with miter keys or dowels or half blind mitered dovetails. As long as the miter joints are nice and tight that glue bond is all the frame needs. If you like that look and want to spend the time on them, go for it, but I prefer simplicity.
An example of a tight miter on a frame.
Here are my steps for successful picture frames.
Cut the right depth groove
Cut the right length rails
Pre-sand
Even clamping pressure
Cut the glass and backing
Keep the finish simple
One thing you don’t need to worry about with frames is the details. Sure if you want the frame to have a fancy profile using molding or multiple pieces that’s great, but these principles all still apply.
Cut the right depth groove
Cutting a groove for the glass and backing to sit in is the first step. I’m assuming you’ve already milled your lumber down and cut it to the width you want. I generally go with 1 3/8” width for my rails using 3/4” thick stock for my frames. The size doesn’t really matter, I go with that because I think it looks nice. The groove I make is usually 1/8” wide by 9/16” deep. The 1/8” width doesn’t matter too much. I like that size because it is enough to hold the glass in place while not obscuring too much of the picture. The important part is the depth. I specifically use 9/16” because that’s the size I need to hold everything in the groove. This is the acrylic I use is. It comes in different size sheets but I like this stuff because it is thin. It says 0.093” which is somewhere around 1/11” or 2.3mm. Weird I know but it just needs to be thin as it is supported on all four sides and from the back. For the backer I use either 1/8” hardboard or 1/4 plywood, which is actually closer to .23”. Lastly, I use glaziers points to secure everything in the groove, so you have to leave space for that plus whatever is being framed. For the glazier points I like to leave at least 1/8 so they don’t protrude past the back of the frame. The points need to have enough wood to bite into as well, so don’t forget to calculate them in.
2. Cut the right length rails
How to determine the right sized rails. If I’m making a frame for a 5x7 picture I know I want the inside of the groove to be 5x7 so the picture will fit perfectly. But to measure a mitered piece of wood you can’t measure the inside, you have to measure on the outside. So what I do is I’ll start with math. Here’s a simple formula:
Rail length = picture length + (2 x rail width) - (2 x groove width)
If the rails are 1 3/8” wide with a 1/8” groove I know I need to take the rail width and double it to 2 6/8”. In this case it’s easier to stay in 8ths otherwise the conversion can get confusing. Step two, subtract off the groove width for each side which is 2/8 (1/8 on each side) and your left with 2 4/8” to add to the picture size which is 5” x 7”. So one set of rails needs to be 7 1/2” and the other needs to be 9 1/2” to fit a 5x7 picture. It seems complicated, but once you make a few you’ll get the hang of it.
The next step is to cut the miters. I’ve talked about this in my post The Importance of Trust, but here’s the gist. Set your saw at 45 degrees and double check that it is correct. Use a stop block to make sure each parallel side is the exact same length. If that’s not possible and you have a miter saw, cut the pieces at the same time, one stacked on the other. If you want to obsess about perfection, build a shooting board and use a hand plane to ensure everything is perfectly 45 degrees. I personally pull everything off the miter saw and it is good enough for me. I find that the more important variable here is to make sure every piece is exactly the right length. If any one of the rails is slightly smaller or larger off it will pull all of the miters out of whack more so than a 0.1 degree variation.
3. Pre-sand
Sanding the inside corners of anything is a pain and often nearly impossible, so don’t do it. Pre-sand all of the the interior facing parts first, before glue up. That way you don’t have to fight with getting into the corners. I like to hand sand the inside edge with 150 grit to remove any saw marks.
4. Even clamping pressure
Once you have all your rails cut, the next step is to glue them together. Before you smear on the glue and clamp the frame, test fit the frame to make sure everything will go together the way you want. This is your opportunity to lay out each piece in the order you want. I suggest marking each one so you don’t lose track later. I start on the left and mark that with a 1, then the top is 2, the right side is 3, and the bottom is 4. That way I don’t confuse myself with rights and lefts, tops and bottoms, I just put them in order and that’s that. Now for clamping, I like to use a ratchet strap picture frame clamp like this Pony Jorgensen one. I find it the most consistent way to get even pressure and keep everything flat. An alternative to this is to use blue painters tape. Just lay all your boards out, tape each corner, put glue on and fold the pieces into a square.
You can use parallel, bar, or f-style clamps, but I don’t suggest it without using a jig. You will likely tweak the boards out of square which will cause an issue down the road.
5. Cut the glass and backing.
The trick here is to cut it the same size. I setup my table saw and use the same settings to cut both the backer board and the acrylic. Acrylic cuts easily on a table saw and is much more user friendly than real glass. Just make sure you are getting Acrylic and not Polycarbonate. Acrylic won’t yellow with age while polycarbonate will.
6. Keep the finish simple.
I almost exclusively spray water based polyurethane on picture frames. Frames are are low traffic for touching, but collect dust. I’ve found that the water based poly gives a nice smooth finish and doesn’t stink like oil based. Plus it’s clear while oil based will yellow the wood. But this is all personal preference so use whatever you want, I just recommend going with a film finish (polyurethane, varnish, etc.) vs an oil because a film finish will leave a smoother surface making it easier to dust vs an oil which will cause more dust to stick to it and harder to get rid of.
If you want to stain, go right ahead, I just recommend using a water based stain if using a water based polyurethane or oil based stain if you want to go with an oil based poly.
My go to is Minwax Polycrylic. Of course pre-finish I sand, usually for picture frames up to 180 grit is plenty. When using any water based finish I always raise the grain by spraying down all parts of the frame with a little water, letting it dry, then lightly sanding the frames again. Raising and knocking down the grain will ensure the finish doesn’t raise the grain which will cause a bumpy texture.
And that’s it. Beautiful, simple picture frames. I make all my frames with these steps and once you know the basics, adding an extra rabbet or chamfer around the edge are easy detail additions with very little extra effort.
Interested in staying up to date with Keaton’s blog? Subscribe