[tyb525]

How do you guys do eyebrow arches? We have to do two, one 13' and one 19'. How do you lay them out so they are nice and smooth? I'm talking about ellipse arches not standard arches, my boss calls them eyebrows.

 

[Madmak]

I have done a few and always use this method to lay them out on plywood:

http://m.wikihow.com/Draw-an-Oval-Shape

I then frame with the plywood and 2X and skin with drywall. I like to lay out the sheets of plywood in a big area and play around with the nail locations and string length. For the sizes you mentioned you will need some space for sure. You can also google more info on the math behind the oval method such as oval height vs oval width = x distance between nails and x string length.

The half oval seems to be smooth "eyebrow" curve that looks the best. I've seen some terrible free hand attempts.

Good luck.

 

[kiteman]

All numbers either feet or inches, no mix and match.

(W/2)² + H² / (HX2) = Radius

 

[greg24k]

Easy Arch :thumbsup:

 

[KennMacMoragh]

You can also google more info on the math behind the oval method such as oval height vs oval width = x distance between nails and x string length.

Where? Google isn't as smart as you think. For a 19' span you would probably place the nails a couple inches in from each side to get a foot or two rise. I can see how you would do it by guessing, but I don't see anything that gives you the math.

I haven't done this but instead of playing around with the nail locations and string length can't you do it in one shot? If you want a 19' span, snap a line on your plywood and make two marks 19' apart, then make a center mark at 9'6". Say you want a 2' height, measure 90 degrees with your framing square at your center point, make a mark at 2'. Put a nail on that mark, hook your tape to it then measure 9'6" from the nail until you hit your center line that you snapped. Put a nail right there then do the same thing to the other side. Then you have your nail locations for drawing your ellipse, right?

 

[Okiecontractor]

Last time I made arches like that I put some nails at both ends of the boards and take a long piece of pvc or pex tubing and bend it to the angle desired and trace it.

Cut and wrap with sheetrock.

I'm not too good with directions. Hopefully you understand what I mean.

 

[Okiecontractor]

And dont use a jig saw. Set your skill saw to the depth of the board and cut it that way. It won't be as rough.

As long as the arch isn't that sharp anyway.

 

[tyb525]

Got the shorter one done yesterday, the 19 footer is on the right, got it done today, forgot to take pics. Both were load bearing walls.

 

[Okiecontractor]

Looks like it turned out great.

 

[KennMacMoragh]

It looks good but I don't see any ellipse, just looks like an arch.

 

[tyb525]

It started as an ellipse, then I "cut off" the bottoms by several inches to get that shape. Originally I thought the HO wanted the ends to curve into the drywall posts like a true ellipse, but they wanted a defined corner like shown. It is not a standard arch but it does look like it at first, the radius gets sharper at the ends where an arch doesn't.


The biggest hassle was getting the flexible bead to form a smooth curve without waves or flat spots.

 

[KennMacMoragh]

It started as an ellipse, then I "cut off" the bottoms by several inches to get that shape. Originally I thought the HO wanted the ends to curve into the drywall posts like a true ellipse, but they wanted a defined corner like shown. It is not a standard arch but it does look like it at first, the radius gets sharper at the ends where an arch doesn't.

The biggest hassle was getting the flexible bead to form a smooth curve without waves or flat spots.

I see, miscommunication. If someone told me to build an "eyebrow" I would admit I have no idea what you're talking about.

 

[tyb525]

It's a term I hadn't heard till my boss used it. I haven't really heard it anywhere else either...didn't know if it was common or not. Then again he tends to call things by uncommon names....