What's the best way to cut a circular porthole window into the sheet metal of a van?

I VTC this as off topic as it is clearly a question about automotive body work, and not about home improvement.

I received several arguments in the comments thread.

Of merit, was the question: What if the question was about cutting duct work? Which is an entirely valid argument.

In my opinion, sheet metal work is generally off topic, with minor exceptions when it is clearly part of home improvement and maintenance.

Would this question be ON topic if it didn't mention the van at all?

  • Automobiles are neither here nor there. This is a question about cutting sheet metal.
    – Mazura
    Commented Sep 23, 2021 at 0:20
  • 2
    OP: "this is a van I am building out myself to live in" - could be true, could be a lie. Don't make people lie to get on-topic.
    – Mazura
    Commented Sep 23, 2021 at 0:37

4 Answers 4


I see the result of this sometimes... A user will ask a question on the electronics site that does have merit there because they are asking about component level electronics or theory, but if they hint that its a 120v circuit in a house, they want to immediately migrate it to DIY. If its a 12vdc circuit on a car they immediately want to migrate to Mechanics.SE. Any of the Electronics users could have answered the question.

I think this question is similar. It's about a van and modifying that van, but it's not strictly a "mechanics" question. Vans, RVs, and travel trailers are going to blur the lines between home and vehicle, and in this case I think the question at its core is about cutting sheetmetal and can be separated from the "vehicle" part of the question rather easily.

I'll also point out that I have a high rep on Mechanics and DIY. I think if they asked it on either stack, it would have received good answers and would be on topic. I don't think we need to get that technical on question placement.

  • 1
    I want to note that I included the terms "circular" and "sheet metal" in addition to "porthole window" and "van" because the first two seems to clearly link the question to DIY. If I had not included the latter two, eg "What's the best way to cut a circular hole into sheet metal?" the on-topic-ness of this question would be more clearly DIY. The end result is the same, but would have fewer relevant details. Commented Sep 22, 2021 at 16:43
  • 1
    @ijustlovemath I think thats a good way to look at it. If you remove the non-DIY.SE details from the question, is it still answerable and on-topic? Did you just remove half the question, or just a small part?
    – JPhi1618
    Commented Sep 22, 2021 at 16:50
  • To my mind, and I could be wrong here since I'm an amateur DIYer (hence my asking the question in the first place), the information about it being on a van does not change how I would tackle the problem, but instead just illuminates the techniques that should be used with a given tool in this given environment. It doesn't change the tools needed (I would have had a hard time knowing what to search to find 'pneumatic nibbler'), or the general way you're going to do it. Commented Sep 22, 2021 at 16:55
  • The van aspect adds a couple of things: it's not flat, and it's vertical with no way to change that. The first is relevant as seen in the comments; the second turns out not to be. Retitled to "What's the best way to cut a 12" circular porthole window into sheet metal?" the van aspect would be downplayed and the relevance to this site clearer
    – Chris H
    Commented Oct 5, 2021 at 11:26

The key here on this would be the scope of DIY. There's a couple of clear points I think we can all agree on

  1. Working on making an automobile (or any motor) run (or maintaining it) is off-topic
  2. Using tools are on-topic for DIY, even if the subject would otherwise not be

In this case, the question falls squarely under the second rule: it's a question about using a tool. That there is a car involved is irrelevant.

  • We regularly close tool related questions on hobby projects. Commented Sep 23, 2021 at 14:36
  • 2
    As long as it isn't a crochet needle, it's on topic. Although it's called Home Improvement, it's name is Do It Yourself.
    – Mazura
    Commented Sep 24, 2021 at 16:30
  • @Mazura It's name is what it's called: Home Improvement. DIY only shows up in the URL and is largely irrelevant.
    – TylerH
    Commented Sep 29, 2021 at 14:12
  • @ChrisCudmore the majority of those questions I've seen get closed here have been more about small craft tools that might sometimes be used in DIY (not quite Mazura's crochet needles but close - and now I'm tempted to ask something about hanging a crochet curtain I have in my house). Questions about DIY tools used for hobby projects that aren't attached to dwellings seem to get answered instead
    – Chris H
    Commented Oct 5, 2021 at 11:19

If the question is specifically about cutting a hole in sheet metal and didn't mention a car, it might be on-topic. Personally, I'm on the fence there.

Questions about cars or car repair in general are explicitly off-topic per the Help Center's On-Topic page:

Note, the following are considered off-topic:

So if it mentions a car, chances are I'm CVing it (well, I'm flagging it since I'm below 3,000 reputation). Take it to a mechanic or body shop, or ask on https://mechanics.stackexchange.com, where questions about body work, welding, etc. (e.g. working on the frame of the car) are on-topic (see the tags for [body-work], [body], and [welding] there).


RVs count as dwellings and are under NEC

#VanLife is a thing. And VanLife means using a van, pickup, schoolie, box truck, RV, etc. as a house. And most "van-improvement" work is done with 2x4s and deck screws and other kit from Home Depot. The exact same stuff we do.

"House on rubber tires" electrical code is written by NFPA/NEC not SAE, whether it's a manufactured home, a purpose built RV or a schoolie.

The question at hand was hardly hammers and bondo, so calling it "body work" is disingenuous. It was metalwork for the purpose of fitting a window.

It seems like a silly exercise to punt people over to mechanics.se for the insulation and framing and drywalling... and then have them punt people back here for 120V electrical wiring questions.

  • I agree. My van conversion used mainly parts, tools and techniques from our equivalent to Home Depot and next to nothing from automotive suppliers (though we paid someone to cut out/fit the windows). I'm not sure about 2x4s though unless you've suddenly gone metric - they wouldn't leave a lot of living space in a Transit (and it's usually ply rather than drywall)
    – Chris H
    Commented Oct 5, 2021 at 11:14
  • The question here isn't about electrical work though, it's about body work. What the NEC says or doesn't say is irrelevant, just like when someone asks about framing out a wall or repairing a hole in their roof. I don't see what's disingenuous about calling this body work, either; the question's about working on the body of the car; whether it's metal or fiberglass or plastic, that's what the term "body work" refers to.
    – TylerH
    Commented Oct 5, 2021 at 13:33

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