Does anyone actually Rotozip around plastic electrical boxes?
No amount of practice on spare blue-plastic receptacle boxes seems to be making me any better at following their perimeters with a Rotozip to cut a hole in drywall. I’m using a guidepoint bit and angling slightly away from the box surface I’m trying to trace, as recommended in a couple of videos I watched, and I’m trying to push as gently as possible, but I’m still losing contact with the box or cutting right through it far too often to try it on a wired box I’m going to keep.
Sometimes in videos and forum discussions elsewhere, people will pretend something is a lot easier than it actually is. I’ve always found the advice here much more trustworthy. Do you actually use a Rotozip to cut holes for plastic electrical boxes, and if so, is there some trick you can share?
If you don’t use a Rotozip, how do you cut the holes in the right places?
One suggestion I’ve seen is to use lipstick or something similar on the edge of the box to mark its outline when the drywall meets it. How well does that work?
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Replies
etting,
I don't because I don't do enough drywall, but every contractor I have had used a rotozip.
Thank you, Malcolm. Did they use it on plastic boxes? On the limited drywall you have done, what did you do?
etting,
I make an X marking the center of the box (es) and tack the perimeter of the sheet in place. I then use an oscillating tool to cut out the box, and finish screwing down the sheet.
They also sell these attachments, but I've never used them.
Thanks again, Malcolm. At first, I thought this was a metal shield that protects the plastic from the Rotozip, which would be a great idea. You could slide it on, cut the hole, then slide it off, with just the thickness of the steel added to the hole size. Searching by image, though, I see that it's actually a rectangular saw that an oscillating tool makes cut a nice neat hole. The problem, though, for me at least, is to find exactly where the hole goes. I'm looking at the magnetic devices that show you where the box is, and I might use this saw you pointed out along with such a device.
etting,
On a related note: Once you have cut out the boxes, try and keep the screws away for them, as both installing the cover-plates, and plugging things into the receptacle tend to cause drywall pops otherwise.
Great question, etting. This is a science AND an art, and is one of those skills that can ONLY come from practice. What makes it so amazingly fast and accurate is also what mangles plastic boxes and produces phantom cuts where no box exists. If you're a DIYer just doing a few cutouts now and then, it's not worth the frustration. But all those alternate methods make no sense if you've got a house's worth of boxes to cut.
Not sure what hints you've gotten from the videos, but the primary thing is that this is not a blind technique--a pro knows exactly where the box is and what it looks like. One key might be to punch through in the center of the box, and make two cuts up and down, which makes a cross and shows the exact location of the box's inner surfaces. Then you punch through on the outside and guide your way carefully around, having a clearer picture where the corners are. Another major hazard can be the tiny ridges on the edge of some boxes, where the bit hangs up. Anticipate these, and lighten your touch as you bump over them.
The cross is a great idea, Andy; thank you.
Yeah, you can use a rotozip, but you have to be careful since you can chew up the box pretty easily. The white fiberglass “hard boxes” are somewhat better here, but the rotozip bit can damage them too. If you find it hard to do with a rotozip, you can use a drywall saw to do the job by hand, it’s just a little slower.
Bill
Thank you, Bill. Would you use a drywall saw with the drywall in place, as with a Rotozip, or would you try to measure or mark with lipstick, etc. first?
I usually measure to the center of the box, then punch the saw in there. I hand saw over to an edge to locate the box, then punch the saw outside the box and cut around it. The key is to know where the edge of the box is so that you don’t cut in the wrong place. Remember that you can’t really fix drywall edges with mud, since the mud just falls off, so you need the drywall edge cut tight to the box so that it will be hidden behind the plate.
I have found that the fatter bit for the rotozip is better than the thinner bit for making sure the bit doesn’t cut into the box.
BTW, they make oversized “goof plates” that cover more area around the perimeter of the box, so there is a way to cover up mistakes as long as they aren’t too bad. The only downside is that if all of your plates are regular size and you have one goof plate (especially if on a light switch), everyone will know that is where you messed up :-)
Bill
Thank you, Bill. It makes sense that a fatter bit's guidepoint wouldn't be as prone to cutting, because a 1/4" diameter, for example, would have to go through twice as much plastic as an 1/8" diameter. Cutting from the inside to find the edge also makes good sense.
Our plastic boxes are a bit different, the ones I use are the air tight ones which have a smooth lip. These are much easier to cut as there is nothing to snag on. I guess I'm old skule but I use metal boxes on interior walls.
The key to doing these is not to fight the tool. Cut clockwise direction and have the tool carry itself around the perimeter. Don't push too hard, this is a sure fire way to burn through the plastic. Also you can't be too slow, the more you linger in one spot the higher the chances of melting through.
I haven't tried this but maybe a couple of layers of painters tape around the lip of the box might help.
Thank you, Akos. True about going too slow; I did some melting during my practice cuts. My understanding is that you should go counterclockwise on the outside of a box, clockwise on the inside.
You are correct, counterclockwise on the outside.
If you are having a hard time not cutting through the box, you can try the other direction as this way the bit does not push into the device box as it cuts. You would have to push on the tool to follow the box so you get a bit more control over pressure but it is also very easy to wonder away from the box.
It takes a light touch and practice, and even then sometimes the bit chews through the plastic or goes astray, but yes, I use a Rotozip. You can buy heavy-duty fiberglass boxes if you want to practice, or just to use them; they are harder than the typical plastic boxes. As are metal boxes, of course.
Thank you, Michael. Good (in a way) to know that even with experience it goes astray. This is the first skill I've run into in building a house all by myself that has me somewhat stumped. I've been incredibly slow at lots of tasks, but I've eventually gotten them done reasonably well.
Getting good at flat-taping around boxes is a right of passage, and for those of us who don't build often, one that's always useful!
I am not a pro, but I recently cut over 75 boxes on my house. I've never used a Rotozip. I use Rotozip cutters in a Dremel tool. I had little trouble guiding it. Perhaps it's pencil-like shape and lower power make it easier to handle. The most common mistake was to move the tool in the wrong direction. Once you have found the outside edge of the box, you must go COUNTER clockwise.
I did use Airfoil boxes in my exterior walls, and their smooth edges did make things easier. However, the majority were standard blue plastic boxes. It's important to anticipate the anomalies of each box type. The standard nail-in boxes have two little nubs to help in setting the box depth, and the adjustable type have V grooves where the metal slide meets the box. These can mess with your cut if you are not expecting them.
Still, mistakes happen. To fix errors, prefill with quickset drywall mud, then tape. I use Fiba-fuse tape. It is thinner than paper tape and the mud seeps through it. This makes for less build up so you don't have to feather out as far.
Thank you for the tips, thrifttrust. I'm more worried about ruining the boxes than having drywall gaps to fill. I can see how a slower-spinning bit may help prevent cutting through and especially melting through a box. I did know to go counterclockwise on the outsides of the boxes.
Are you using a bit like the one in this photo note it has no cutting edges near the tip?
Do you have the depth set so that no cutting edge can reach the plastic box?
Are you following the inside or the outside of the box?
Is the bit getting so hot that it melts the plastic?
Walta
Thank you, Walter. Yes, yes, outside, and sometimes yes! I tried having just the non-cutting part of the bit extend past the drywall, but it still cut through the plastic, even when it didn't melt it, at least not obviously.
Have you tried a diferen brand of bits?
It is staring to sound like too much sideways preshure.
Walta
Thank you, Walter. Other bits could help, but I think I may just be bad at it, despite trying to be gentle.