Is your intention to install a refrigeration
unit or just add more insulation
to make the ice box better?
Also, can you live with a much smaller box or do you need all the interior
space for food
I did a complete overhaul
on my '84 Pearson
422 and the fridge was the most time consuming project
by far. I pulled the entire cabinet apart and pulled out the old fiberglass
box and started over from scratch. Even in the '84 I found the insulation terrible. To call it inadequate would be an understatement. Most areas it was a very thin layer of spray on foam. At most 2-3" max and in many areas there was no insulation at all, just a layer of plywood
. I would bet the older Pearsons are no better.
I was able to pull the front and top off the cabinet to build the new box and then put them back on like original but it was a job. If you really don't want to invest major time in doing insulation I only see two options.
1. Spray foam around the box as it sits in the cabinets.
This has two major concerns. The foam you can buy at Home Depot or similar, usually Dow Great Stuff, expands a LOT and can easily create enough pressure to break apart the box and cabinet walls. Also, over time it tends to absorb moisture and lose it's insulating properties. But it's quick, easy and cheap
and will probably work for years and be a lot better than what's in there now. I think there are commercial
foams and two part mixes you can buy that may be better for long term but still have the concern with over expansion. Maybe someone else can chime in on other options besides the Dow stuff.
2. Add layers of insulation to the inside of the box.
You will lose room but a smaller box will be easier to cool. If you do it this way you can buy sheets
of foam insulation (poly styrene like Dow Blue board or the pink sheets from Honeywell I think), cut them to fit and line the inside of the box. Then cover with fiberglass
. I like the 4x8 sheets of fiberglass you can buy also at Home Depot. Cut sheets to cover the foam and seal all the seams with epoxy