Evaporator Gaskets Made With Noodles

[piscator]

The foam gaskets on the underside of my AC Evaporator housing disintegrated. Since I’m installing an upgraded AC system, I figured I better make some. And this gave me an opportunity to work with one of my favorite high-tech materials… POOL NOODLES!

Unfortunately, I couldn’t find the larger pool noodle size that I needed, but I came across this; made out of the same material.



And guess what? The manufacturer used photos of me on their packaging! :-)



Since the original part has turned to dust, the first thing we need to know are the dimensions. Oooh Fun! We get to break out the metrology toys!









Looks like the outside diameter is approximately 3 3/8” and the depth about 3/4”. We need to add another 3/4” of depth to fill the gap between this pipe and the evaporator housing. That’s a little more than we need, but it will ensure that we get a ‘good squishy seal’ when we reinstall the evaporator box.

So, the overall size for our larger gasket is 3 3/8” x 1 1/2”. Time to cut our ‘work-out’ roller on the bandsaw.







Next...

[piscator]

We probably don’t need a center, yet. But I think it’s easier to draw one now on the larger stock. I applied the tape because I’d planned to use a compass with a pencil to draw the diameter.







Fortuitously, I discovered an object measuring 3 3/8” that I can use as a template – a small hygrometer that I’ve had forever. The mounting holes on the back even make it easy to line up.









Back to the bandsaw to cut out our disk.





Next...

[piscator]

Will it fit?



Seems to!



Time to cut the center hole, so we’ll need the inside diameter of the flange/pipe.







Not quite 2 7/8”. And it checks out with the diameter of the hole in our evaporator box.

The problem is, out of our 3 3/8” disk, that’s going to be hard to cut accurately. Also, we need a little leeway to accommodate the imperfect fit of the box... And.., we don’t have a 2 7/8” hole-saw. Let’s go with 2 1/2” and call it, “good.” EDIT: I'm not sure I'm happy with this and may re-cut the center hole to 2 3/4"







Will it fit? Yes it does!



Next...

[piscator]

Now what’ll we do with this protrusion? We need to make the second gasket to seal the drain hole in the floor of the ‘Smuggler’s Box.”





The outside diameter is somewhere around 1 5/8” but it doesn’t look critical – 1 1/2” will do fine.

Where are we going to find a suitable diameter hunk of pool noodle? How ‘bout the piece we cut out of the larger gasket? That’ll work!







Now we need a center hole. The foam has plenty of give, so a 1/2” drill will do it.









Next...

[piscator]

So how’s it look installed? Not bad. Should keep the drafts out.

EDIT: The second photo shows one side of our gasket standing proud; indicating the imprecision of the alignment between the box and the pipe into the footwell. Cutting the gasket to have a wider shoulder helps compensate for this; but it also reduces the ID, which may restrict airflow. We can't produce the wider shoulder by enlarging the OD of the gasket -- it wouldn't fit into the flange in the pipe. Being somewhat obsessive, I may open up the ID with a utility knife.

[walt]

Awesome set of tools sir!

[Uwon]

Envy your tolols.
Nice job.
What year is your car? I honestly can’t remember if I have one in my ‘78.
What AC upgrades are you doing?
Johan

[Harpo]

Very nicely done!

[piscator]

Thanks very much guys!

My family owned a machine shop that, unfortunately, had to close. Fortunately, I acquired a lot of tools. I have a large closet full of surplus items that should really go on Ebay.

Uwon, my car is a 1979 SC Targa that was also in my family for it's entire life. The car was always used gently, so while it's old, all the pieces are there and in very good condition. I've spent the last four months disassembling the car and replacing or renewing anything that's worn with age.

The upgrades to the AC are really just installing barrier hoses and a new rotary compressor. I took the condensers to a radiator shop for cleaning and pressure testing. I plan to see how well the original system works and upgrade additional components, if necessary.

[piscator]

Addendum: This morning I'm considering re-cutting the 2 1/2" center hole in the larger gasket to 2 7/8". That extra 3/8" of material helps to compensate general inaccuracy of the fit between the box and the pipe, but it's also going to restrict airflow. It may not be significant, but I don't know enough about AC to judge. The ghosts of my very precise German ancestry are bugging me about .

[jpnovak]

This is so awesome. Love the measurement process for a foam annulus.

[piscator]

JP, Thanks for the wonderful new vocabulary word! It sounds related to another Latin term...

I went ahead and custom trimmed my annulus with a utility knife. I now have an asymetrical annulus, that's a little rough; but it corresponds to the 2 3/4" inside diameter of the pipe into the footwell and won't impede airflow. All in all, I suspect it's better to have an enlarged asymetrical annulus than to have a small one that's partially blocked.

Entendre anyone? :-)