Insulating your 15/15” cooler is expensive:
One sheet foam Home Depot $14
Roll 3M vinyl electrical tape
Utility knife with set blades
One sheet light weight paneling Home Depot
Can 3M 77…check with 3M on this for the foam board surface you have…
One large Walmart cardboard box form.
Bottle isopropyl alcohol
Pointed felt marking pen
Place cooler on Walmart cardboard box section…cut one side box form top to bottom on inside corner so the sheet is flat. Say this: ALWAYS CUT AWAY FROM THE HOLDING MATERIAL HAND
Find a straight edge longer than cooler side heights.
Tape pen to straight edge
Place cooler on box section
Scribe cooler sides onto box cardboard under the cooler.
Add one or 2 thicknesses of foam board to the scribed dimension…depending on use of one or 2 foam board depths.
Measure cardboard box template to scribed dimension and top cooler height or place cooler on side then scribe a side dimension adding one thickness
Scribe or measure the next side as in the preceding diagram adding one thickness
Scribe or measure 4 sides to butt together as in the diagram.
Place on cooler then wrap tape around box adhering tape loop to itself on a beginning second loop.
Is your work forming a cooler enclosure ?
Is YES proceed to use the cardboard template sides for cutting the foam board.
Need to figure how to best use the foam area with your 5 pieces plus a top
There would be enough foam for 2 layers around the cooler.
Cut foam and template by pressing a straight edge along the template side, running the utility knife away from the holding hand and carefully down the straightedge not down the template.
2 foam layers is best as the sheet is there to use.
Cut paneling same way with jigsaw/rotary skilsaw and guide or straightedge and utility knife.
3M 77 was used here glueing paneling to foam and foam to foam for 2 layers with paneling exterior.
Use a flat warm outside surface with flat weight pressing boards together for 24 hours or more.
Wiping foam paper surface with CHOH cleans various manufacturing site and transportation residues from surface. Paper towel wipe and discard wipe and discard……
Dry run thru the procedure before doing it. Tacky means almost dry. Stay upwind of the 77, use a mask
Sides can be 2” higher than top cooler surface for a 2 layer foam top cover insert.
The structure is durable for car camping.
Canoeing may ask for fiberglass and resin over outside and/or inside.
Now, when you read NRS and West cooler prices….
Doahn cut yourself.