What 's a Good Size Magnet for holding lightweight stuff down?

[shop]

i have a big pile of hard drive magnets and some of them are tagged for GF duty when mine arrives.

[davidgal2]

You will find that the backing plate on those magnets work well for holding warped wood to the crumb tray. The magnet is placed flat on the crumb tray and the lip of the backing plate goes over the edge of the material to be lasered.

[RookieWookiee]

I was thinking they could be used to consistently place a small piece of material somewhere on the bed - so there’s something to push the edge of the material up against.

[scampa123]

@Jules what did you wind up using to hold things down?

What about tape?

Does wood move around allot?

My unit should be shipping soon and I want to gear-up to ensure I’m ready to do stuff when it arrives!!

Thank you!!

[Jules]

Actually I wound up going a totally different route after pinching the **** out of myself and filling the room with shrapnel a couple of times.

For the lightweight materials, I created a cheap “sticky” mat to hold the little bits and pieces in place while they are being lasered. Just a sheet of scrap plywood with a couple of coats of Krylon #7020 Repositionable Adhesive spray. Works like a dream. (Or you can buy a Seklema mat for about $80).

For the heavier stuff like wood - it generally doesn’t shift unless it’s a smaller piece, but the Honeycomb Pins shared here are fantastic, and I like them better than taping down or using magnets. You can cut a few once you get the machine.

Honeycomb bed holdown pins

the best laser results are achieved with flat (non warping materials) in order to maintain consistent focus. Also, when cutting light materials like paper, the exhaust turbulence can kick up the material and ruin your job or at worst… catch fire. (speaking of which, I hope you all keep a small fire extinguisher in easy reach, near your machine - safety FIRST) I hope you find these useful. I used to 3d print them for my other laser cutter but occasionally , they would see the wrath of the laser …

Some of the other guys use magnets exclusively though. They can tell you what works best.

[scampa123]

Thanks @Jules, this helps!

Thank you for organizing and providing allot of the tutorials too! I’m ramping up now that my GF is nearing its shipping date!

[jbv]

Depending on the material, if I’m going to be jig-flip-registering the piece, and what’s within reach at any given moment, I either use plain ceramic rectangle magnets wrapped in blue painters tape, JJ’s Original Honeycomb Hold-Down Pins, or 2" blue painter’s tape to the plastic edges of the honeycomb tray on the left and right (only for thicker stock that doesn’t leave clearance for anything above the engraving surface).

[kimberly.hammaker]

Hi, I’m new to the Glowforge world, so I have a beginner question … If you’re using magnets to hold down some material, such as cardboard or paper, what happens if the laser hits one? I’m trying to make Banksy-style portrait stencils for spray painting in a school project but I’m worried about the fan blowing it around.

[Xabbess]

Hi…and welcome! Just use low profile magnets and you should be fine. You could try testing the height before you turn the GF on by sliding the gantry with the laser head on it, forward…while bending down and looking underneath to make sure it clears the magnets. There is an assist fan back behind the head as well, and if anything were to come close to bumping into something on the crumb tray, it would be that fan.

When you have time also, do a search for Seklema mat and also for other adhesive things you can use for stuff like paper to keep them in place.

Best of luck! Post your projects so we can all see what you’re making.

[caribis2]

If the laser hits your magnet and it is not covered in tape, you’ll see a really bright light. If the magnet is covered in tape your tape will have a line burned in it. I have several of these. The most annoying part is what is under the magnet will not be cut.

If you’re cutting corrugated cardboard it should be heavy enough and thick enough to not blow the cut out pieces around. Still use a couple of magnets, but they can all be outside the design. If you’re cutting tag board (think the cardboard around a twelve-pack of aluminum cans) use a couple magnets on the outside and one on each cut out piece. If you’re cutting a light-weight paper you should use plenty of magnets inside and outside the design. How many will depend on the size and complexity of your design. The cut out parts of your design can blow around if not secured. Even if they are secured sometimes they’ll be sucked up and around and the laser may “re-cut” the flapping bits. The flying and or flapping parts will go through the laser beam at its most defocused part, which in my experience, makes it much more likely to burst into flames. Nothing that can’t be extinguished with your hand, but still more excitement than one really needs.

Now that I have scared you, don’t be afraid, and don’t place a magnet every half-inch. You’ll get the hang of how to place them soon enough.

If you’re going to be doing delicate work, or have lots of pieces (like maybe a stencil) consider using a sticky mat. The Seklema mat used by a lot of crafters can be pricey, but I am told works quite well. Another option favored by @Jules is to take a piece of plywood and spray it with a repositionable adhesive. Press your paper onto your homemade sticky mat and laser away. When it stops being tacky spray on some more adhesive. A search of the forums will bring up the brand and name of the spray adhesive.

[Jules]

I’m going to echo what @caribis2 said, and strongly suggest that you use a sticky mat for paper or lightweight fabric.

What can happen if you don’t…the little cutout bits can get blown around, into the path of the beam, where they will catch fire and send teeny tiny little flaming missiles towards the exhaust, where they will stick to your fan blades and can cause some real problems that are a bear to fix. (AMHIK)

Use a mat. It saves so many tears and curse words.

[kimberly.hammaker]

Thank you all for the advice! I would never have thought to use a sticky mat … I’ll start there. I read in another thread that the ‘cereal box’ type cardboard works well for stencils so that is what we will be working with to start. Thank you!

[dan]

Since this thread deals with using materials from other vendors in your Glowforge, I’m going to move it to Beyond the Manual.

[marshakt]

I used to work for Sonicare. I have a big stash of their rare earth magnets… they are awesome! I use them on GF all the time.

[marks]

I had some of the magnetic strip from inside a refrigerator door seal. I cut into 8 and 10ish inch long pieces and use it for holding down paper. I found that one side is more magnetic that the other and being so weak of a magnet, i don’t have to worry about my fingers getting smashed or shrapnel.

It’s easy to get, just keep a razor knife in your car and when you see an old refrigerator on the side of the road, slit the plastic seal a bit and pull the magnet (Iv’e never found one to be glued in.)