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Hi,
I wouldn't say it would not work as it really depends on the cross laid network of fibers that paper is made of.
The tar can be considered as a binder to hold the fibers in alignment during handling. The tar could eventually be broken down my the fluids detergents of which is not a great concern as long as the it cannot travel out of the internal network or allow spaces within the fibers themselves to become channels.
I was once in a bind for gasket material to contain a leak of R12 refrigerant coming from an canister that held a replaceable desiccant filter on a 25 ton 3 stage compressor unit. It kept several refrigerated walk-in rooms cold. It always has to work or else a lot of food, going be served in three days could make people sick, very shortly.
In this particular case I had plenty of filters but was short on the cover gaskets. Warehouse numbers were off to generate a reorder request.
So I still knew what they looked like from previous replacements, so I was desperate, as the leak was not going away no matter how much the bolts were tightened.
As it turned out that I ended up staring at my solution hanging on a clip board near my desk of the shop.
It was a paper cover that laid on top of the papers it held.
It was dark brown and thin but with a cardboard like toughness and with a sheen on its surface.
It had a raised portion in the center that was an embossed impression for a tag to be placed in it for identifying the clipboard.
I studied the lay of the surface below the sheen and could see lots of crossed fiber that look like a strand board panel used in the home housing industry in the sheeting of homes.
That fit the bill of gasket material in my mind but would it contain a gas?
It's all about holding back molecules!
I had seen file folders made out of the same material elsewhere in the plant. Mostly used to transport papers as the interoffice secretaries used them. I had to go grovel a tiny bit!
I took a cheap chance and made about a eight inch circular gasket from it.
I put it in under the cover and crossed my fingers when I opened the bypass valves. Nothing went whoosh or anything.
My leak detector made no sounds for the many times that I checked it later.
The gasket stayed on the unit for at least six years until I retired at 56.
I'm sure it got changed out after the last 12 years as the whole unit did get replaced. Even though I'm retired now, when I heard they got rid of it, I felt happy, for it was a PITA on cold morning trips to a roof!
That change from a multi zone monster, to individual room compressors on the roof was a BIG capital outlay but the bigger deal that it was due to the R12 refrigerant was now banned for more than twenty years.
Our own stockpile was not going to last forever.
Also, If you had a leak, you wouldn't know it right away until the cooling faltered on the farthest or largest rooms being starved or icing up with frost.
That big unit had other design issues for the climate it was in. Too cold at night because of a head pressure issue, that caused flowing issues.
Especially, when pressures staged the system on and the smallest 5 ton compressor had it shut down. Not enough drop long enough to keep it on!
It acted like low on refrigerant symptoms cycling or maybe not?
We are talking 200 lbs was a normal charge up with up to a possible 50 lb. loss before you got a hint! That is if you kept it truly full, or is it just a cold morning question. The systems condenser was to big at times. Seldom ran all four fans on hottest days.
I finally dialed the charge in balance to where I could tell if I lost a little bit or just needed to push it into an override on those cold mornings.
Sometimes that was easier done with a pencil pushed in on a contactor until a lonely toggle switch found a home in the controller box.
Doesn't hurt to have a little bit of "Scotty" lurking around somewhere to out wit a half baked electronic controller. (:-)
Tar paper, hmmm I'll remember it.
Thanks for the thread!
Phil
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