Material Fasteners (Hold Downs) - Sick of Using Duct-tape

[ryandewitt]

This is really good advice. My cardboard almost caught on fire. Go faster and put card board in fridge prior??

[evansd2]

Cardboard is flamey. Go fast, don’t cut super complicated jaggy lines with lots of fiddly details. That’s what’ll set you on fire faster than anything.

BTW, that thread I just posted has pics of the magnet tabs:

Hold downs

Right, so I find that with proper magnets I have yet to find 1/8" I can’t unwarp. I stack 2 magnets on each other, and they just yank it down. Hang on, I’ll go get a picture of my magnet rigs, I already stack 2 magnets in each unit. Here we go: [image] I tape my magnets up to protect them and make them easier to pick up, and find that the discs are ridiculously strong. The bars are nice and narrow for laying right along the edge. The discs, being really thin, can be stacked with another p…

I doublestack my bars, they hold down all but the most stubborn 1/8" wood.

[ryandewitt]

Magnets work thru 3/16" warped cardboard?

[evansd2]

Cardboard? Easily, it bends like a punk. Just be careful about total stack height. The air assist fan is about 0.5" above the tray. 3/16" only leaves you with 5/16" at most. You’ll probably be ok with a doublestack of thinner magnets, but just keep the total height in mind as you consider all this.

[evansd2]

Also this might be of interest:

Magnet organization

So up until today my magnet organizational system was “put them somewhere that isn’t too close to the others” so they wouldn’t ball up into a finger-pinchy mess. Today I went to Home Depot and spent 3$ on a nice big steel bar: [image] Devised a 2 layer mounting bracket and screwed it onto the workbench. No more magnet mess.

[jamesdhatch]

@evansd2

it’s easier than trying to wrangle them bare

If you have a prying tool or dental pick type thing then you can dip the tip into a hole in the honeycomb and slide the magnet up the shank a bit until it’s easy to grab.

[evansd2]

Not a bad idea but the duct tape method works so well and requires no tools… I’ll probably stick with it.

[jamesdhatch]

@evansd2

the duct tape method works so well and requires no tools…

I use the pick to see if the parts have all cut out the whole way so it’s no extra effort to use it to slide a magnet for pickup.

[caribis2]

When stacking magnets, or using them on thicker materials, be careful that the head of the glowforge doesn’t “drag” your magnet. I bought some very powerful magnets, 25lb of pull iirc, and they work great. But if I stack them and the laser head goes over them they sometimes pull the laserhead and cause its alignment to go all to heck and I wind up with a very interesting cut, or it can drag a single magnet with it leaving it somewhere it is not supposed to be. Later it goes over the magnet doing a cut or score and I now have a big uncut area in my design. I’ve learned to use these larger magnets unstacked and don’t place them on thick material where their attraction to the laser head will be greater than their attraction to the steel crumb tray.

But as evansd2 said, magnets will easily flatten cardboard.

[evansd2]

That magnet dragging thing has been kicking around for a while. I personally haven’t had it happen, and just judging by the physics of the thing I have always been a bit skeptical. While I don’t doubt that your alignment got screwy, I wonder: have you verified that the magnetic field was the issue and not the air assist scoop? It hangs really low, it could catch a magnet pretty easily.

In any case, so far so good on my end.

[Jules]

@evansd2

That magnet dragging thing has been kicking around for a while. I personally haven’t had it happen, and just judging by the physics of the thing I have always been a bit skeptical.

One of the PRU users caught a video of it happening once…the little magnets were just jumping up and catching the head for a ride as the head passed over. (It was totally cute/funny/scary simultaneously.)

[rpegg]

Not only had a magnet move but had one jump off of the material and attach itself to the air assist port behind the head.

[shop]

i have to wonder how tall the stack of magnets is or how close to the head thicker materials with thick magnets are. i’m using pretty strong magnets, so they’re never stacked or that tall.

[Jules]

I’m not sure…I won’t use them. (Not just for that reason, but because I tend to hurt myself with them too.)

[rpegg]

Magnet movement will only be a problem when the distance between the magnet and the head, or port, approaches the distance between the magnet and the honeycomb. A thin magnet and material less than 1/4" or so will never be an issue.

[evansd2]

Maybe that’s why I’ve been in the clear. I don’t screw with anything over 1/8" really. Like I sad, the physics just never seemed right to move the head without the magnet straight up jumping to the head.

[caribis2]

My problems came with 3/16" material and a double stack or a single magnet with 3/16" and enough warp that it was still off the honeycomb.

At first I couldn’t figure out what was happening and thought I had placed my magnets over a cut line. Then it happened when I knew nothing was close to a cut line. The odd thing was I would watch the head go right over a double-stack with no issue, so not a catching on the head thing. The very last time I watched the magnet being towed, so to speak, across the material. It was towed right under a cut on a pretty simple design - just my luck.

There have been one or two times when I have placed a magnet under a cut or score and didn’t notice until it was too late. I have one magnet with a partial snapmark scored in the gorilla tape. That one was my bad.