So, I've designed a frame built of 3mm thick 5 x 5mm steel box tube, which will have inset wooden panels. This will eventually become a unit for an aquarium.

All good in practice but the front wooden panels inset in the frame are going to be doors.

Problem I have is how would I go about adding the hinges for the doors to the frame?

Suggestions I've had so far are:

1 - Weld the hinges to the frame...might be an issue when powder coated

2 - Add the hinge afterwards with self tapping screws...possible chipping of powder coat

Any other recommendations or come across similar scenarios?

Images attached of original design and the almost completed fabricated frame.

Frame Frame Frame

  • Won't any damage to the coating be concealed by the hinge?
    – isherwood
    Jan 23, 2019 at 20:48
  • Hello, and welcome to Home Improvement. Unfortunately, "arts and crafts" questions are off-topic here. Jan 23, 2019 at 21:16
  • 2
    @Daniel Do this really look like an 'Arts and Crafts' question? I can't tell if you're being sarcastic. As you can see it is a professionally fabricated steel frame so don't see this as 'off topic'.
    – Scott
    Jan 23, 2019 at 21:34
  • You need to take our tour, and specifically look at the "off-topic" list, which includes "hobby projects". Jan 23, 2019 at 22:04
  • 1
    Self-tapping can snap off while driving them. Drill and tap instead.
    – Mazura
    Jan 26, 2019 at 0:22

1 Answer 1


Why not pre-drill the holes, put the screw in with tape before powdercoat. Then after complete, remove the screw and hopefully it won't crack around the tape. Or, get a removable pin hinge and weld one side to the frame and cover the pin holes. Or, weld a nut inside and cover to powdercoat. Or, use an anchor system, predrill the holes slightly over size. and leave the bottom open so you can relace the hinge, if need be, in the future.

  • Thanks for the advice. 'weld a nut inside and cover to powdercoat' this sounds like a pretty good option...was thinking how I could somehow add a nut inside the frame but with it being box tube can't get inside...but now you say it makes sense to create the hole and weld the nut in place from the outside. I'd vote up but my reps not high enough yet
    – Scott
    Jan 23, 2019 at 21:40
  • Drill the hole large enough for the nut to fit. Weld it to the "inside" and fill the hex sides. Then grind of course, and your nut will be "inside" flush with the outside of the frame.
    – Jeff Cates
    Jan 23, 2019 at 21:43
  • An alternative to welding a nut to the inside of the frame - which could be tricky for the size nuts you're likely working with here - would be to use a rivnut. But really, I think the easiest would be to drill the holes before powdercoating, then use self tapping sheet metal screws to attach the hinges. Jan 23, 2019 at 22:17
  • Thanks everyone for your advice...the solution I've decided to go with is pre-dilling the holes and then self tapping screws as it should be pretty straight forward
    – Scott
    Jan 24, 2019 at 10:10

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