Poster Magnet Board




About: Inventing new and unique products for people, robots (if they ask nicely), and a few plants.

We had a need for a magnet board design that was nice to look at, easy to build, and relatively inexpensive. Specifically, we needed it for our Disc Mounts which we created to store and display our CDs around the gaming zone. Learn more on our Disc Mount Project Page. We also used it for our 3D Super Mario Papercraft Magnet Board instructable so we could build, mix, and mash up scenes from the game.

This instructable shows you how to build a magnet board using a 24 x 36 in. plastic poster frame. These frames are inexpensive, fit common poster sizes, and single tin sheet usually can be purchased in this size. You can scale the design up or down for other sizes of frames as desired.

Buy super-strong, adhesive-backed, disc magnets for your poster magnet board projects from Lab 424.


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Step 1: Get Parts and Materials

To build a poster magnet board you will need the following:

Parts and Materials


  • leather work gloves to handle tin
  • hot glue or white glue
  • tin snips (unneeded if tin is correct size)
  • tape measure (unneeded if tin is correct size)
  • straight edge (unneeded if tin is correct size)
  • marking pen (unneeded if tin is correct size)
  • hammer and block of wood (not pictured, unneeded if tin is correct size)

About The Frame: You want an acrylic face, not glass. Glass can break and is too smooth for these magnets to stick reliably. It should have a rigid backing. Hardboard or cardboard are typical. It should have tabs, staples, or a similar mechanism that bends to put pressure on the backing. The hanger should be attached to the backing, not the frame. Wood and metal frames are not necessary. We use inexpensive, plastic frames.

About The Tin Sheet: Magnets will not stick to aluminum, copper, brass, etc. The sheet can be smaller than the frame. 30 gauge sheet can usually be found at building supply stores in sections that carry heat , ventilation, and air conditioning ducting. Otherwise, suppliers of sheet metal in your industrial districts will usually cut you a piece to size. Bring your gloves to handle it.

Be aware that safety is your responsibility. Please read our Safety Warning and Disclaimer before you start.

Step 2: Remove Frame Backing

Let's get the backing off the frame. In my case, I bent all the tabs up to remove the backing from the frame. Set the backing on a work surface, hanger side down.

Step 3: Cut Tin to Size

Let's see if you need to cut the tin? Lay the tin on top of the backing and square it up (use your gloves). If it is larger than the backing then you need to cut it. If you don't need to cut it then skip to the next step. Otherwise, read on.

If I have to cut the tin, I like to make it smaller than the backing by at least 1" on a side. Smaller is fine since we are going to position and tape the tin to the backing in the next step. Let's cut it! (You are wearing gloves, right?)

(1) Prepare tin:
Lay the tin flat on a durable work surface (tin will scratch surfaces). (See picture.)

(2) Measure and Mark:
Use the tape measure and straight edge to mark lines where you need to cut. (See picture.)

(3) Cut it:
Pick up one side of the tin with one hand and start cutting with the other using the tin snips. If you are not familiar cutting with tin snips, there is a nice explanation at eHow: How to Cut With Tin Snips The cut doesn't have to be perfect, just close. (See picture.)

(4) Inspect the Cuts:
Tin snips can make sharp pointy spikes along the edges. Look at your cut. If you find any of these then use a hammer and scrap piece of wood to flatten them down. (See picture.)

Step 4: Attach Tin to Backing

We need to attach the tin to the backing to hold it in place and protect the poster from the sharp edges. Masking tape is good enough since the frame and pressure from the tabs holds everything in place. OK, gloves back on!

Place and center the tin on the backing. Use small pieces of tape to make it easy to handle and place. Note: it is handy to have your lab/shop/studio assistant hand you pieces of tape since you will be wearing gloves. Let's tape:

(1) Side one
Starting with a long side, rip off a 6-8" piece of tape and overlap it evenly on the tin and backing. Continue down the side, overlapping each piece of tape as you go. (See picture.)

(2) Make sure tin is flat
Make sure the tin does not form any ripples by putting light pressure on the tin and run your "gloved" hand across it from the side we taped. (See picture.)

(3) Side two
Tape up the opposite side just as you did with side one. Always check that the tin stays flat. (See picture.)

(4) Side three and four
Tape up the last two sides as you did with side one. Always check that the tin stays flat. (See picture.)

Note: If your tin fits perfectly into the frame (24 x 36 in. in this case) you will follow the same procedure except that your tape will overlap around the edge of the backing. (See picture.)

Step 5: Reinforce Hanger

The tin will add quite a bit more weight to the poster frame so let's take a closer look at the hanger. Flip the backing over and inspect the hanger. Strong or wimpy? Chances are it could use a little reinforcement before final assembly. This can be done easily with either hot glue or white glue.

(1) Prep Tools and Materials
Get your hot glue gun ready (or white glue).

(2) Position the hanger
If needed, bend the hanger into position. Allow enough room for a screw to slide under it.

(3) Apply Glue
Apply the glue liberally around the bracket as shown. make sure to get all sides of the hanger covered, but do not fill in the gap where the screw will go.

Let it dry thoroughly to form a strong, hard bond around the hanger.

Step 6: Reassemble Frame

Let's get that poster in there shall we. Remove the paper insert (if there was one) and the acrylic face. If this is a new frame, the acrylic may have 2 layers of protective plastic, remove them and place the acrylic back into the frame. Now place your poster into the frame. Place the backing into the frame (make sure you have the hanger positioned correctly in relation to your poster). Bend the tabs down so they apply pressure on the backing.

Step 7: Hang It Up

If you are going to hang the poster on drywall then use a molly screw (I prefer the metal ones.). This is how we hang all our poster magnet boards and have mounted up to 40 x 27 in. posters without any problems. Otherwise, put a nail or screw into a stud. Hang it, stick stuff to it with magnets, and enjoy your cool poster magnet board.

About Magnets:
Bare magnets (nothing between the magnet and the acrylic face) will scratch the acrylic over time. It is not very noticeable in my opinion. However, if you are concerned about this do one of the following:

  • Glue vinyl to the back of your magnets (usually found at fabric stores)
  • Stick vinyl inkjet stickers to the back of your magnets (usually found at office supply stores)

We use vinyl inkjet stickers with our disc mounts. Check out our Disc Mount Instructable if you are curious.

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35 Discussions


3 years ago

Also, would you suggest using a liquid nails to glue metal sheet to the board as my frame's size is 40" by 28"? I thought it would make structure more rigid. Thanks

3 replies

Reply 3 years ago

The staples probably will not fold between the metal and carton. Most likely they will just stop and stick out from the surface of the carton. Your best bet is probably the 3M Super 77 (or similar) adhesive.

Super 77 is dry and tacky when it sprays onto a surface. We used a cotton fabric and didn’t have issues with it bleeding through the fabric. However, it's possible that a silky/sheer fabric may allow some of the "tackiness" to bleed through. I don’t think it would show spots; rather, the surface would feel a bit sticky to the touch. Undesirable nonetheless.

One thought is to not spray the adhesive onto the front surface and apply the fabric; rather, just use it to attach the fabric to the back. For instance:

(1) Buy fabric that is significantly larger than the sheet metal so you have several inches or more of overlap on the backside of the sheet.

(2) Lay the fabric down on a flat surface.

(3) Lay the sheet metal on top of the fabric.

(4) Spray the adhesive on the back of the metal.

(5) Fold back the fabric edges and apply to the tacky metal surface and apply pressure to lock the fabric in place.

(6) Work around the edges in a similar fashion. Make sure to pull the fabric tight before applying to tacky surface so face is smooth. (You can reposition if needed since 3M stays tacky.)

(7) Lay the backing on top of tacky surface and press to stick.

(8) Mount into frame.

(9) Eat a delicious sandwich to celebrate how awesome you are.

Note: Using this technique, you'll want to round off the corners of your metal sheet so it doesn't cut through your fabric when pulling it tight.


Reply 3 years ago

I will definitely recommend your site to all my friends.
Guess what? Yesterday I gave myself thoughts and came to exactly same procedure you have recommended. Even rounding the metal sheet corners.
And you're correct: there're no any spots on silk from 3M Super 77.

Thanks a lot. I will add a drink to my sandwich to celebrate how awesome YOU are. Till next project - Arkady


Reply 3 years ago

We never glued the metal to the backing since the frame + backing + acrylic face kept it in place and flat. However, if you want to glue it I’d consult This to That for the magical answer (I've never tried liquid nails). Metal to wood comes up with several options. You can choose other materials using their tool if desired.


3 years ago

Thanks for very detailed instructions and illustrations. I'm planning to use a board for "fridge magnets" bought while travelling. I will use red silk fabric on face of metal sheet instead of acrylic face: don't want an exposed metal. What's your opinion? I will staple silk to the carton.

2 replies

Reply 3 years ago

Fabric works nicely (we tried it). We used 3M Super 77 to make the fabric stick to the metal sheet to give a nice, uniform, flat surface. When applying the fabric to the metal with the adhesive:

(1) Cut the fabric so it is much larger than the metal sheet.

(2) Apply adhesive.

(3) Start at a corner and slowly roll fabric onto the surface while smoothing out wrinkles along the way.

(4) Trim the fabric about 1-2 inches from the edges of the metal sheet and stick it to the back of the metal sheet with more adhesive.


Reply 3 years ago

Thanks for quick and, as usual, very instructive reply.
I've never used glue on the fabric before. Is there any chance of making spots on face of the fabric because of adhesive?

What about applying a stapler on the edge of carton's back using an extra 1" of fabric trim. Am I right to think that staples will fold between metal sheet and carton?

Thanks again for your help.


11 years ago on Introduction

Incredibly well illustrated project, I may have to try this. I wonder, would the paint that makes a chalkboard surface stick to the tin? Or maybe even a thin layer of plexiglas to turn it into a white boar. . . .

4 replies

Excellent idea firehazard07! According to Rustoleum, yes it will stick to metal. Check it out here. Unfortunately, plexiglass doesn't make a good whiteboard surface. Glass will make a good surface though, but you should cover your magnets with vinyl or other rubbery/fabric/etc covering to protect against the glass breaking.


Reply 6 years ago on Introduction

Just jumping in a few years late on this...there are two problems with glass. One is the thickness reduces the magnetic force on an average magnet. Second is that glass is slippery - if you try to hold anything with any weight to it, the combination of slippery and weak magnet will allow the object to slide down the front of the board.  You can fix that with a lot more magnets holding up the object.  Putting vinyl on the magnet will not help if the problem is between the object and the glass.  The friction needs to be on the board. 

On Kiteman's niggling point, I vote both ways.  In 28 years as an aerospace engineer that material was always referred to as sheet steel.  When we went to buy it we had to specify 'galvanized.'  Yet in old style hardware stores it was referred to as tinplate.  Now in the big box hardware stores I believe it is referred to as simply, 'galvanized.'  Apparently local custom prevails. 

In the instructable you said that glass should be avoided because it is too smooth for the magnets to be reliable, is there any way to have this wonderful idea be a whiteboard and a magnet board that doesn't have magnets falling off? Thanks for this great instructable!

If you are planning to just stick paper, cardstock, etc to your board then it will work with neodymium magnets that have 2 lbs. of pull (any stronger and you may break the glass from the force). Some recommendations:

  • Get glass at or under 3/32 in. thick so 2 lb pull magnets can be used.
  • Cover your magnets with a thin layer of vinyl (or similar material). This helps grip the paper and adds a little cushion between the magnet and glass. You can get thin vinyl at fabric stores, or vinyl stickers for printers at office supply stores.
  • Be careful when you place the works together, and mount it securely to the wall so it doesn't move.

I steered away from glass primarily because of the breakage issue. In my case, I wanted to be able to hold the weight of a CD on the board, which (after testing) required a large magnet that was more expensive and broke the glass in a couple cases. But the 2 lb pull magnets seem to work fine for paper stuff on glass. If you can find safety glass that would be better since if fractured, large piece would not fall out.

11 years ago on Step 1

You may also be able to get tin sheets wherever there's a printing press. The offset process often uses tin plates to run their printing on. We used to get these all the time for crafts and stuff.

first off, great job on the instructable, mate. Second, where did you get that poster, or does anyone know any cheap poster websites or stores?

1 reply