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I opened up a hole in my concrete wall to pass a threaded PVC 2 inch male adapter. On the other side there is an aluminum metal sheet. The problem is that I hit rebar and can not change the position of the hole. I just need about a quarter or a bit less of an inch on each side of the remaining rebar to fit the adapter.

I tried drilling into the rebar with increasing bits but started going nowhere. A grinding wheel does not fit in the hole, since all I have is a 4 and a half inch disc. I don't want to cut the aluminum sheet on the other side anymore than I have already. I even tried using a hacksaw blade and tried cutting, but it's very uncomfortable and didn't do much. Even tried filling, but it's too thick.

The adapter fits in the hole, but the wider side catches on the rebar, so it over extends on the wall. I'm tempted to just grind the excess PVC.

Hole hole

Hole with threaded 2 inch PVC male adapter in place hole with threaded 2 inch PVC male adapter in place

Other side with lock nut other side with lock nut

Any recommendations that don't involve a heat torch to cut a piece.

Edit: Bought a Dremel 3000 and was able to cut the rebar. Took a while but worked out great. The Dremel cost me about $61 on sale at Wal-Mart and bought some discs that were also on sale. Always wanted to get a Dremel. No time like the present I guess. Here are some pics.

Thanks to all!

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  • Grinding the pvc and leaving the rebar seems like it could “rub”.
    – Lee Sam
    Aug 19, 2018 at 15:32
  • Answer to the title is a grinder. But you'd need to remove some more concrete, which is what you had to do anyway for a dremel tool.
    – Mazura
    Aug 26, 2018 at 20:42

6 Answers 6

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A Dremel Tool with a cut off wheel is going to be your tool of choice here. Here is a picture of what that looks like:

enter image description here

When approaching a job like this I make sure I have plenty of the cutoff wheels. I also have a half dozen of the mandrels so that I can have all of them with cutoff wheels premounted so it is quick change in the tool when one wears down or breaks.

The cutoff wheels come in thin normal thickness and thicker heavy duty style as shown above. The heavy duty ones have to grind away more to perform a cutoff bit are less prone to breakage.

You will have to cut the re-bar at an angle as shown on the below picture. It may even be necessary to break a small amount of the concrete on either side to permit the tool to have a better angle of attack on the re-bar.

enter image description here

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  • Seems like the best way, but don't have a Dremel tool. Also, not sure if will reach or grind on the remaining cement.
    – Rick
    Aug 19, 2018 at 17:00
  • @Rick - The suggestion is being made as to the tool for the job that in my experience should work. Many times I have to purchase an appropriate tool to get a job done. I would widen the two sides of the hole to allow the tool to get in place. They do sell a flexible shaft assembly for the Dremel line that allows the business end of the tool to extend out from the wider body of the tool. It looks like you will be filling in the area around the PVC adapter anyway so a little bit more widening of the hole will not be problematic.
    – Michael Karas ♦
    Aug 19, 2018 at 17:09
  • Ended up shelling out $100 on a Dremel 3000 and extra discs and did the job. Had to cut out more concrete. Pictures here.
    – Rick
    Aug 26, 2018 at 13:05
  • @Rick "Had to cut out more concrete" - that would've been my goto so I could get my grinder in there. Big hole; little hole. (makes no difference)
    – Mazura
    Aug 26, 2018 at 20:38
  • @Rick - Glad to read and see photos that it all worked out. In a year or so you may find yourself asking how you ever got along without a Dremel rotary tool.
    – Michael Karas ♦
    Aug 26, 2018 at 21:31
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What you need is an oscillating saw, also called a "multitool" and maybe some other trademarked names. They vibrate back and forth very fast but don't move a lot and are perfect for narrow spaces like that. In the linked article below, look at photo #5 to give you an idea.

https://www.popularmechanics.com/home/interior-projects/how-to/g830/10-jobs-you-can-do-with-a-multitool/

Most good home center type stores sell these now. Just make sure you get the best metal cutting blade you can find for it and plan on going through several blades if the re-bar is hardened, as it often is in vertical walls.

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  • In my experience you will pay for the equivalent of at least one Dremel type tool by the time you have used enough expensive metal cut off blades to cut those rebar nubs.
    – Michael Karas ♦
    Aug 22, 2018 at 11:36
  • Maybe, but the oscillating saw makes it so that you don't have to enlarge the hole in order to get enough access to angle in the rotary tool.
    – JRaef
    Aug 22, 2018 at 23:59
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You'll be the judge of whether it's appropriate to grind the pvc (it's bound to be easier), but if you have to cut the rebar, my mind goes to a die grinder/ (small d) dremel type tool with a small cut off wheel. For a very small job like this, you might even just chuck a cutoff wheel+arbor in a drill. (Just know that drills aren't really designed for sideways loads, so it's not a good idea for heavy use.)

If you don't already have a dremel, it's an excellent excuse to get a new toy.

One other idea, and this depends on the rebar being really well set. (ie, not going to move around at all.) Get a metal-cutting holesaw, cut through plywood for a guide, attach the ply to the wall, and cut through the rebar. Repeat for the other side.

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  • Wish I had a Dremel. Although not sure if it would reach or grind on the concrete. Thought about using my smaller 1 1/4 inch hole saw drill attachment, but not sure how to place the wood to stabilize and guide. The rebar is about 2 inches deep. Also thought about putting a metal mending plate on the other side with a bolt in the center and put the wood thorough there without having to drill the wall for a temporary piece.
    – Rick
    Aug 19, 2018 at 17:07
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A bare hack saw blade will do it, with work. Hold the blade with vice-grips; I have had to resort to this technique for automotive work. Rebar tends to harder than ordinary cold rolled, possibly up to twice the strength but a hack saw will still cut it.

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I think a hole saw will do what you need, the problem is you don't have material to drill the pilot bit into to keep the hole saw on center.

There is a trick that should work here. You put two hole saws on the same arbor at the same time. The inner hole saw is the diameter of the hole in the sheet aluminum. The outer hole saw is half an inch larger. That will trim a quarter inch off each side of the rebar.

You might have to put some washers between the hole saws to get the inner to stick out far enough. You might have to mix or match brands / arbors to get the right setup.

If you can't get a combination of hole saws and arbors that works, just use the bigger hole saw to cut a hole in a piece of plywood, and use that plywood as a jig. Mount the plywood to the wall temporarily to guide the saw.

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Use an oscillating tool with a blade for metal. https://www.youtube.com/watch?v=6VJzEF0j0VA

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