School me on mirror glass

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Forum topic by CharlesA posted 04-23-2016 01:51 AM 885 views 0 times favorited 8 replies Add to Favorites Watch
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3319 posts in 1793 days

04-23-2016 01:51 AM

I think I’m going to make five mirrors, four for wedding gifts and a big one for our living room.

Any tips on mirror glass? Do you just go to a glass shop, buy old mirrors from garage sales, or somewhere else? I’d love to learn from any wisdom hat you have.

-- "Man is the only animal which devours his own, for I can apply no milder term to the general prey of the rich on the poor." ~Thomas Jefferson

8 replies so far

View conifur's profile


955 posts in 1147 days

#1 posted 04-23-2016 03:22 AM

I have gotten mine from a glass shop, cut to my size, they can even antique the finish to look like an old mirror, bevel the edges, et.

-- Knowledge and experience equals Wisdom, Michael Frankowski

View JBrow's profile


1354 posts in 915 days

#2 posted 04-23-2016 04:02 AM


I am not much of a mirror expert, but have done several glass projects. I have done one a project that incorporated a mirror. It was a bathroom vanity mirror, probably 3’ high and 5’ wide. I am now buying glass for a china hutch, my next project. It will also incorporate a pair of large mirrors. The mirrors on these two projects are ¼” thick glass with reasonably thick silver overlaid with what I think is a protective coating. They appear to be high quality mirrors and had to cost a small fortunate. All three of these mirrors were left by the prior homeowners so I was lucky. I highly recommend this scrounging approach because it is the cheapest way to go, but you have to have some luck.

If I had not been lucky and therefore had to buy these large format mirrors, I would have first shopped the internet for mirrors. It is a great place to learn what options and properties are available with mirrors. Then, knowing what options I wanted and with the internet price in mind, visiting a couple of mirror and glass stores looking for ¼” mirror glass and then buy locally. I like to buy glass and mirrors locally just in case the mirror people cut the mirror to the wrong size. Buying glass or mirrors on the internet would be too much of a hassle to return.

I believe thicker glass on large projects is best. ¼” thick mirrors are stronger glass and hence more durable. I like tempered glass because of its added strength and should it break, there will millions of small pieces rather a few lethal pieces. However tempered glass is either extremely difficult or impossible to cut. Therefore, if tempered, it must be the right size for the project. It is also more expensive than annealed glass.

If you are going for nice details on the mirror edges and at the corners, and there are several choices. Buying from a glass shop is probably the only place to get exactly want you want. If the mirror’s edges will be visible on the completed project, a flat polished edge at a minimum is the best look. There are several other options. I suspect most mirror and glass shops order custom spec’ed products, so lead time from placing the order and receiving the product is likely.

If it is a small project where a smaller mirror is needed, Walmart, Hobby Lobby, or some other retail store that carries mirrors is a good source. Garage sales are fine so long as the mirror is clean enough to ensure the silver backing is intact and not flaking. Remove the cheap frame, if one, and use the recovered mirror on the project. From what I have seen, this glass is 1/8” thick and probably single strength glass.

If the perfect mirror size is not available and modifying the project is not possible, then buying a larger inexpensive mirror and having it cut to size is an option. However, the glass shop needs a few inches of cut-off to get accurate clean cuts. After the mirror is cut, having the shop ease the edges can prevent injury form otherwise sharp edges. The local glass shop told me today that they charge somewhere in the neighborhood of $15 per cut, depending somewhat on the size (not really sure what this meant, but will find out in the next couple of weeks).

I am not sure whether they can cut glass into round, oval, or curved shapes, but do not see why that would not be possible. Nor do I know whether the local glass shop can introduce a bevel to the edges, probably depends of the shop.

When incorporating a mirror into a project, I like to have the glass on hand. The glass shops generally guarantee size to ± 1/8”. Also, even narrow frames will expand and contract, so ensuring adequate clearance in the rabbeted mirror-receiving recess is critical. I like to protect the silver backing of the mirror. Hardboard is a good choice for smaller project where the mirror is set into a rabbet. Thicker glass with a ½” thick MDF backer would probably be a good material on a larger project. A good grade of ½” plywood may also work so long as it stays flat and does not press against the mirror. Unfortunately these larger projects can get pretty heavy with a 1/4” thick mirror and 1/2” backer.

A good way to inset a mirror into a frame is to cut a double rabbet. The deepest rabbet routed around the inside perimeter of the frame at ½” wide would be a depth equal to the thickness of the mirror and the backer, assuming the backer is to be flush with the back side of the frame. The second shallow rabbet is a depth equal to the thickness of the backer. It too has a width at least ½” from the edge of the deep mirror-receiving rabbet. The mirror sets on the deep rabbet and the back sets on and is fastened to the shallow rabbet, keeping the mirror in place.

If the mirror is surface mounted to a frame, the inexpensive plastic mirror clips sometimes work, but are generally the smaller ones are pretty flimsy and the larger one are ugly to my eye. Shop made clips attached with painted screws are my preference. I have made clips from project scrap, but contrasting wood clips could be nice.

View jkid's profile


38 posts in 1073 days

#3 posted 04-23-2016 04:18 AM

As mirrors age they become brittle, recutting may produce a “d**n it ” cut !

View Texcaster's profile


1281 posts in 1669 days

#4 posted 04-23-2016 04:40 AM

Ditto the advice to cut double rebates and stain the glass rebate black for a black reflected rebate.

-- Mama calls me Texcaster but my real name is Mr. Earl.

View vind's profile


27 posts in 1306 days

#5 posted 04-23-2016 05:29 AM

I used those fiqure 8 clips for fastening table tops for holding the mirror/backer to the frame. They’re slim so will not hold the frame out from the wall

-- a dull chisel is just a fancy screwdriver

View DanG61270's profile


5 posts in 1025 days

#6 posted 04-23-2016 04:02 PM

1/4” or 6mm glass makes the best quality mirror. That thickness generally contains the least amount of distortion, and will make a nicer, deeper looking mirror. A glass shop should be able to cut about any size, shape you want. Thinner glass like 3mm, is prone to distortion from the glass manufacturing process, it is difficult to see, more pronounced when looking at an angle. Once you see it though, it is all you will ever see when you look at it. Look for copper free backings, as this will hold up to cleaning better over time, much less likely to blacken around the edges. A lot of chemistry to explain why this is the case, but it is.

View CharlesA's profile


3319 posts in 1793 days

#7 posted 04-23-2016 04:44 PM

Lots of good info here. Thanks so much.

-- "Man is the only animal which devours his own, for I can apply no milder term to the general prey of the rich on the poor." ~Thomas Jefferson

View pintodeluxe's profile


5654 posts in 2809 days

#8 posted 04-23-2016 10:37 PM

I have had great luck with 3/16” mirrors from my local glass shop. They are much thicker than what you’ll find at a home center (1/16” thick or perhaps a little more). The extra thickness gives a truer reflection and a flatter mirror surface.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

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