Is it possible to cut only on top of the pipe?

Is it possible to cut only on top of the pipe?. Or the laser will cut through all, like other side of the pipe as well. Then do I need to insert something in pipe, so laser does not cut the other side.


what is diameter of the pipe (cardboard tube)?

If it fits in the Glowforge, I think you should be able to cut only the top, without having to put anything inside.

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How big is it? I don’t think it will fit in the gf.

The short answer is yes. But it might char the far side.

Presuming it is 1 and 1/2 " or less, it seems that it would fit. That’s a good question. What is happens to the beam on the other side of the cut? How much power in a through cut? You can make the power just enough to cut. Will it scorch the other side?

my random guess is in the 2"+neighborhood on the tube on the basis the tiles are in the fairly typical 12" range each side.

To be safe you would want to put something inside to keep the laser off the far side of the tube. The laser coming out of the cut wouldn’t be in focus but could cause some burning or discoloration depending on the power setting.

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Putting some scrap acrylic or wood might be all you need. Also, i think you could expect the beam wouldn’t be so focused to cut through the top AND the bottom in one pass, so probably safe.

Or just put in a bit of aluminum foil.


Yes, foil line the inside of the tube if your plan is to CUT on one side.

If you want to just engrave/mark one side of it… easy. No worry about the other side at all.

If you want to cut holes in one side… the other side will get cut, and you will likely start up a nice little fire.

In theory, you could find the precise power level to just barely get through the thickness of that type of cardboard, but since you are working on a curve “that thickness” changes at every position, since you are changing your angle of approach.

So… you could find the precise power gradient you need, and still get the “I just perfectly cut it with nothing inside, so there!” settings. But figuring that out would take a couple decades of experimentation, or a whole new field of study.

Meanwhile, if you line the inside with aluminum foil, then you can blast the tube at high power and cut only the side you want to, with (nearly) no worry about flames.


Good advice above - in this example, it’s best to shield anything below the cut area.

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Thank you everyone for sharing your expertise. All of my doubts are cleared. Amazing.

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Get used to being amazed by the helpfulness of the folks here - it happens all the time!


Is aluminum foil a good idea for something like that, or do you want a definite beam absorber? (I had a vision of a piece of foil, roughly curved to fit the inside bottom of the tube, acting as a focusing mirror…)

Foil should be fine. It is a pretty lousy reflector (otherwise people would just use foil for their main mirrors), and if your power is dialed in properly you are talking about pretty low energy anyway.