How to Hang a Porthole Mirror

Quick Reference Steps – Watch Video for Full Explanation!

Step 1: Decide which wall you want to hang the mirror on and locate the center of the wall, where you want the porthole to hang. Mark the center with a pencil.

Step 2: On your porthole, measure the distance between the two mounting spots. We will call this measurement Y and use it in Step 4.

Step 3: Locate the stud closest to the center of the wall using a stud finder. Mark it with a pencil.

Step 4: Now that we have the center, measure 1/2 of measurement Y above your center mark, and mark that with a pencil. Now, measure a full measurement of Y downwards, to mark the second mounting spot with a pencil.

Step 5: Use a level to ensure that both of your pencil marks are exactly level.

Step 6: Now that we’ve found the studs and marked the center of the wall, use a very small drill bit to make a pilot hole and ensure there is a stud behind the wall.

Step 7: In this video, we’re using a 1/2 inch round lag bolt to hold our porthole up. When creating the larger pilot hole for this lag bolt, we used a 1/4 inch round drill bit. You want to stay smaller but enough to give it a bite, so that it will hold.

Step 8: Now it’s time to put the porthole up with the lag bolt. You can do this by yourself, but if you have another set of hands, it would be very helpful. Hold the porthole in position and use a drill to put the lag bolt through the porthole, into the wall. Don’t over-tighten.

Step 9: Line up the second lag bolt position and install the second lag bolt. Use a hand wrench to tighten once both bolts are in position.

Step 10: Once the porthole is in place, you can add decorative lag bolts/washers all the way around to give the porthole a completed look if you want. You can buy these lag bolts in stainless steel if you are installing an aluminium porthole and you can buy them in brass or bronze if you are installing a brass porthole.

If you have any questions about this or anything else at Big Ship Salvage, you can visit us at and fill out an inquiry form. We also have a phone number listed there that you can call at any time.