Caleffi 553 fill valve paper gasket - alternative / reuse?

I talked with just about every local supply house and supplyhouse.com without success. A local one had some 3/4" caleffi gaskets, and I thought it would be 1/2", but I measure that tail piece OD at 0.95" and the ID about 0.56", so maybe the 3/4" would have worked… they're closed now. supplyhouse.com had R0001458 "3/4" Union AutoFill Washer", but there's no dimensions on it. and that would take a day or two to get here, at best.

I'm thinking I probably need to make my own gasket. I have some sheet EPDM roofing material and pvc roofing material (both probably about 1/16" thick), the auto parts store has a thinner make your own fiber gasket, and the hardware store says they have a poly, cork, and neoprene gasket material.

I feel the EPDM might be a little squishy, but maybe it's OK.

Any opinions on the best option of these materials for make-your own, and the best way to prep/clean the caleffi smooth surfaces?

Edit to add: AI is recommending red rubber packing instead of the above roofing EPDM and auto parts store products, due to strength and being attached to potable water.

@mattmia2 the gasket you listed is for the backflow preventer. The new backflow preventer has the O-rings. It is the tail piece from the auto valve I need the fiber gasket. Razor blade can work for part of it, but there is a detent groove on the backflow preventer side of the tailpiece with gasket stuff down inside that groove appears to with the new O-ring.

I was wrong about there being a groove in the mating face. It was just part of the gasket that had been depressed, and once I got my reading glasses on, I could see that more clearly initially it looked like there was some brass material showing, but there was still more gasket on there than I thought.

@Jamie Hall yeah, I didn’t put much stock of that fiber gasket, just didn’t know if someone would say they would smear a sealant or something on there. Not what I would typically move towards.

@hot_rod - oops, sorry dude! I thought I attached pics above… clearly not. They're attached below, now, along with pics of the inside of my discal… I've always has issues with large volumes of air in the system - so I'm not sure it has worked. I was replacing the float to see if it would address the issue. Do you know if this machined ridge on the inside is normal? I can call tech support tomorrow to find out, as well.

@mattmia2 - yeah, the issue is there is no part number to be found, and sizes for the various ones are not listed ;)

It's the gasket on the nut side of this with the arrow. The other 533 fill valve mating surface shown in the next pic.

This is the other mating surface of the tailpiece:

Here is that discal that doesn't seem to remove air. Is the ridge normal? Seems odd.

Hi All, crazy last day… apologies for the slow response - just coming up for air now.

First off, want to extend my gratitude to everyone here who has offered great in put and ideas. I always learn so much from you all. It's such an awesome forum.

I was able to get it back together, and because I had to do it the next day, I went to the one shop in the metro area that had some caleffi washers, and confirmed one of them was the right size, so I grabbed it. For posterity, the washer they had was R50058, and it matched the dimensions of the R0001458 tech support suggested with an OD of 15/16" and ID of 9/16".

@hot_rod - thank you for taking the time to put together and share all those photos. genuinely appreciated. Before you mentioned it, I would not have ever thought of rubbing it across smooth concrete. That's a great tip, and hopefully others will stumble across this thread and make use of that. I actually did get the gasket removed shortly before you posted this up. For posterity, I'll mention an alternative approach that worked well, below.

As to the discal, I do think the needle might have been stuck, but am not fully sure. What I can say is that I moved the float down and felt it pop a little. Now, this said, I did ask tech support if the different diameters in the bore were expected, and they weren't sure it would lead to an issue, but did say it shouldn't be like that. Given it hasn't functioned since it was installed 7 years ago, I asked if that part was warranty-able, and they said, no problem, we'll send you one. I figure no downside to that, given the history.

Unfortunately, after the issue I have a new issue, by which it seems I have to really crank up the psi on the fill valve to get it to fill to a lower pressure. I think something is sticking… even adjusting the PSI seemed a bit rough by comparison to normal. I'll call tech support to see if they can provide the rebuild kit number for it. I think I read there is one. I'm not sure if 7 years would be typical on a rebuild.

That bench has had some history, eh?

@mattmia2 - when I put the float in that bore (dry, because the system had been drained down), the float repeatedly caught on that lip caused by the two different diameters. The float has a fair bit of clearance, so maybe it's a not issue when floating. The cap had been loosened previously, but never had any moisture or sounds of air escaping. When I ordered the replacement float, I also ordered the cap that has the check valve in it, as they suggested it is a possible source of air getting into my system (and there was a lot). After I put the old hardware back in (and the needle seemed it might have been stuck), it did vent quite a bit of air out.

Now, how did I remove my gasket goop? Keeping in mind some of the faces with gasket material were attached in-place, so the concrete trick wouldn't work:

Step 1: Razor blade off material (as suggested here - thanks!)

Step 2: Dip maroon scotchbrite in acetone, and rub off the remaining residue. Not as fast as Hot Rod's approach, but for parts that don't detach, it worked rather well.

Now, had I not found that washer, the red packing rubber (from Lowes plumbing aisle) homemade washer was the direction I was going, but alas wasn't needed: