Can you cut holes on one face of 1-1/4 tube and not burn through the other side?
Several ways:
If you can submerse part of it in water, you would be fine.
Or put a piece of sacrificial metal strip inside.
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I will see if I can make that work, Thanks
The lower the amps the better chance you will have.
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I have been cutting 14 ga sheet at 30 A I will take some scrap tube and see how it works.
Also like to get advice from you guys first!
Thanks George
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Here is someone cutting 2 inch square tube and he is not using either suggestion I gave.
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wonder why he has it sitting on that sheet
He has the tube running parallel with the slats. Probably just set it on the sheet to hold it above the slats.
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I’ve cut box tubing. Low amps for sure on the 1.25". The 2 inch I did got hot, stupid hot, so be careful when you grab it.
If you can take a pond pump and run coolant down the tube while you are cutting that will help, unless both ends are hanging of fthe table, then it will make a mess.
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I’ve done it when making slots in the legs for my welding table. They were 1-1/2" 14 gauge tube and the only thing on the other side of the tube was slag that wiped off.
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I did not even notice that. Maybe he did that so he could video it. Thanks for pointing that out
I think I’d tack a 1" long section of tubing to each end and sit it in the water between the slats. The tube would partially fill with water, but the cutting surface would still be above the water line. That would limit splashing.
Another thing that might help the guy in the video is he could have spread out his cuts using the “Preserve Order” in CAM. That would help with heat dissipation.
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Tried it on scrap and it went better than planed.
Not bad for the ole RW45 w/Hypertherm torch. 
1.25 x 14ga sq tube 30 amps 120ipm
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I think you may have just solved my extra Cross Beam with no upright problem on some metal shelves.
Now I just have to learn to index accurately
Pshaw! The cutouts are already cut on a fixed pitch. You could index that in your sleep! 
one of the first projects i did on my table was cut slots in a piece of 3" 304L tubing fit perfectly between the slats, made up the code for a row of slots, cut it, rotated the tube cut, rinse, repeat.
was for my fire pit in my back yard. it lays acros the bottom and i have a small 12v fan (120mm from an air hockey table) i run it it. keeps the smoke down and it doubles as a wood fired forge 
you’d be surprised how much heat cardboard makes with forced air…
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