Shelf brackets for acrylic?

[wkearney99]

Anyone have experience with using clear acrylic for shelving?  The wife wants some clear plant shelves in front of a window. It'd require a 32" width to get to the point on the trim where I'd like to mount them.  It's flat there and there's plenty of stud width behind it to make a secure connection to framing (I have pix done during construction). 

I have zero experience gauging what thickness material and the bracket necessary to make it work.  I'd like something more attractive than angle-iron (or stamped equivalents).  An 8" depth would be desirable.  A 36" x 8" piece would need to be how thick to handle three pots (for kitchen herbs). 

I'm thinking 36" wide, with the brackets at 32" (16" from center of window).

Any suggestions on brackets and acrylic thickness?  Because thickness will then lead to questions about cutting it.

 

[rvieceli]

[member=25351]rst[/member] any help?

 

[squall_line]

My initial reaction was a flashback to the scene Star Trek IV where Scotty shares the formula for Transparent Aluminum.

My second reaction is: sun + acrylic = lensing effects and possible burns, depending on the thickness.

There was plenty of furniture made of clear acrylic in the 70s and 80s, so I'm sure it's an already-solved problem, but definitely keep in mind the dangers of direct sunlight and lensing indoors.

 

[wkearney99]

Good point about solar lensing issues.  The window does have full southern exposure, but does have motorized blinds that have been mostly closed until now.  Light-passing material, not black out.  So I've never had an issue there, if only because of the shade.

The shelving will stand in front of the shades, which will probably get adjusted to open above them during the day and close at night.

I'd probably thus want to avoid polished edges on the shelves, eh?

 

[Bob D.]

this might get you close.
https://www.acrylite.co/resources/calculators

 

[Cheese]

FWIW...I built something similar for my wife's plants. It was an area situated under a skylight so I thought the clear acrylic was going to be the charm.

Once erected all the plants needed felt coasters placed underneath and any movement of the plants had to be a lift up-move-lower sequence because if they were slid at all, the acrylic was scratched even on the felt coasters.

Another big issue was watering the plants because if the spilled water was not immediately wiped up there were water spots and mineral staining and the sunlight from above on the acrylic just made matters worse.

If you really want the look of glass shelves, I'd stick with using glass along with the felt coasters.

 

[Packard]

Acrylic is probably not the best choice.  I don't have load figures for acrylic, but in a window with radiant heat from the sun, it is likely to sag quite a bit. 

This is a situation that calls for glass.  If you have the standards on 28" centers and it is 8" deep by 32" wide, 1/2" thick glass will hold 40 - 50 pounds and 3/8" will hold 18 - 22 pounds. 

It won't sag, but it can fracture.  It is highly scratch-resistant.  You can order these online or get them from the local glass shop. 

If you can add a support at the rear of the glass shelf, it can hold a lot more weight.  A 1/2" x 1/2" angle iron at the rear of the shelf will probably double or triple the strength of the shelf. 

Plants mean watering, which means wiping up the shelves, which means the acrylic will quickly get badly scratched.  So I would definitely consider glass.  All the retailers use glass shelves for a reason.  None that I am aware of use acrylic.

 

[Steve1]

I agree with Packard.
Glass would be a better choice than acrylic.
Your home cut edge on the acrylic will look poor.  And the acrylic is possible to sag over time.

3/8" thick glass would likely be sufficient.  But I am of the opinion that going 1/2" thick would look better.    Also, keep in mind that you can get tinted glass --- perhaps a smoked bronze ?

If you are really concerned about breakage, you can get tempered glass.

Just tell the glass shop its for a shelf, and you would like the edges polished smooth.

A few soft self-adhesive clear pads will keep it from moving.

Maybe check out Lee Valley Tools -- they have a fair selection of decorative shelf brackets.

 

[Packard]

I am not proposing that acrylic be used, but I will describe "flame polishing". 

You can achieve a polished edge on acrylic fairly easily.  Here are the steps:

1.  Cut to size.
2.  Sand edges with 100 grit sandpaper until smooth and there are no saw marks.
3.  Use a propane torch to play gently over the edges only.

The propane will melt the plastic, but will melt the smaller profiles first.  So all the rough edges from sanding will fuse smoothly.  Also the sharp edges of the sawn edges will melt first slightly rounding over the edges.

This video show a variation on that.  The aluminum is protecting the corners and they are not rounding over.  If you use my method, you will have to peel back some of the protective film or it will burn.


This video shows the technique I use:

 

[mino]

Go with glass.

As you expect to place "scratchy" things on it, bes is to visit your local place where they make safety glass doors/windows etc. and have them make the shelving for you along below (or similar):

GLASS GLASS

Then use the "film" version on the top side of the shelving. You can even put a secondary self-install "protective" film above that which you will replace when scratched too much.

You can use single-layer safety glass too, but then would need to put a film on top anyway so it kinda defeats the point.
Having the composite shelf made, including any edges, holes etc. in a pro shop will result in a much better setup and it may go even cheaper than a plastic panel with the same strength would.

 

[Packard]

Here is a useful article on using glass for shelving.  It pretty much covers all aspects.
https://www.artistry-in-glass.com/what-is-the-best-thickness-for-glass-shelves/

These images might give inspiration: https://www.google.com/search?q=glass+shelves+for+window+plants&tbm=isch&ved=2ahUKEwisjdbUyoT2AhUzLFkFHd53DA8Q2-cCegQIABAA&oq=glass+shelves+for+window+plants&gs_lcp=CgNpbWcQAzIFCAAQgAQ6BAgAEEM6CwgAEIAEELEDEIMBOggIABCABBCxAzoICAAQsQMQgwE6BwgAELEDEEM6BggAEAUQHjoGCAAQCBAeOgQIABAYUOwQWO9gYLFiaABwAHgBgAHfAYgBhB6SAQY2NS4wLjGYAQCgAQGqAQtnd3Mtd2l6LWltZ7ABAMABAQ&sclient=img&ei=Ox4NYuyDN7PY5NoP3u-xeA&bih=775&biw=1600&client=firefox-b-1-d

If you google store fixture and display distributors you will find heavy duty shelf brackets designed for glass shelves.  These brackets generally include a thumbscrew to lock it into the slots. 

Here  is one: https://www.americanretailsupply.com/8-left-universal-flange-brackets-6180108l.html

 

[rst]

With 40+ years as glass and plastic fabricator my recommendation would 3/8" glass with polished edges.  You could go with thick acrylic, 3/8" or thicker but glass will be cheaper.  Do not use polycarbonate because while unbreakable it's surface is softer and will scratch much easier.  Keep in mind that while water will stain plastics it will also stain glass.  When an insulated glass window fogs up it is the condensation on the interior surfaces etching the glass. Glass will also scratch from ceramic or clay pots.