3-3/8 Wide Flange Round Outlet Install Tips for Clean Downspout Drops

If you’ve ever had an outlet that oil-cans, leaks, or looks sloppy, it usually comes down to three things: hole prep, flange support, and sealing. A wide flange outlet gives you more material to grab and seal, especially when the metal is thin or the drop location is tight.

When a wide flange outlet is the right move

Use a 3-3/8" wide flange round outlet when you need:

• More sealing surface around the cutout
• Better hold on thinner aluminum
• A cleaner install when you’re close to a seam, rib, or end detail
• A safer option when the cut isn’t going to be “perfect machine-shop pretty”

Specs that matter on this outlet

• Size: 3-3/8" round
• Material thickness: .025 aluminum (1100 O temper) 
• Pack size: 100 ct 

The clean install process

1. Layout the centerline
   Pull from the end cap or miter line so every drop is consistent.
2. Drill a pilot
   Just big enough to start your cutter clean.
3. Cut the hole clean
   Hole saw, snips, or your preferred method—just don’t leave burrs.
4. Deburr the edge
   Burrs = guaranteed future leak points and ugly sealant lines.
5. Dry-fit the outlet
   Make sure the flange lays flat and doesn’t rock.
6. Seal the flange
   Continuous bead. No gaps. Don’t “dot” it.
7. Fasten
   Rivets or screws based on your shop standard.
8. Tool the sealant
   Smooth bead = less dirt, better look, fewer callbacks.

Common problems and fixes

• Flange won’t sit flat → you’ve got burrs or a warped cut. Deburr and re-fit.
• Sealant keeps pulling open → metal was dirty or wet. Clean and dry before sealing.
• Outlet leaks on the back side → you didn’t run a continuous bead, or the gutter wasn’t pitched right and water is riding the edge.

Quick comparison table

FAQ

What does wide flange actually help with?
More flange surface gives you more area to seal and fasten, especially on thinner metal.

Is 3-3/8" the same as a 3" round drop?
No. Always match the outlet size to your downspout/drop system. Don’t guess on “close enough.”

Do I rivet or screw outlets?
Either works if the flange is sealed correctly and the cut is clean. The “best” method is the one your crew does consistently without shortcuts.

What’s the biggest cause of outlet leaks?
Bad prep (burrs, wet metal, dirty surface) and broken sealant lines.

Get your supplies

Need outlets that install clean and hold tight?
Shop the 3-3/8" Wide Flange Round Outlet (100 ct) and keep your drops consistent.