rubber to steel - high temp adhesive
September 16, 2009 12:06 PM   Subscribe

I need a recommendation for a particular adhesive. The application is to secure a synthetic rubber(not sure of exact composition) seal or gasket to smooth stainless steel that will remain at temperatures of at least 100C (212F) for 5+ hours at a time.

I am trying to re-affix the double wiper seal in the lid of my water distiller's boiling kettle. I have a small Kenmore branded water distiller and after several years use, whatever adhesive was used to secure the gasket in the lid has failed and the gasket just falls out. The gasket itself seems to be in fine shape so I'd like to try just re-affix the gasket. This image shows the seal as it will be mounted to the steel lid.

At minimum the steel is reaching 100C to boil water but the temps may in fact be higher so I would like something that could take high temps for the 5 hour distilling cycle. In addition, I would imagine the adhesive would need to be somewhat elastic to withstand small horizontal and vertical forces as the kettle lid is twisted then lifted to remove and replace for filling. Given that this is for use in water purification it seems wise to avoid anything too toxic.
posted by well_balanced to Home & Garden (12 answers total) 1 user marked this as a favorite
The groove that the seal sits inside of looks pretty clean. Did you find residue of old adhesive inside that groove? I'm wondering whether the glue that failed was just on the end of the seal itself, gluing 2 ends of the seal to each other...
posted by jon1270 at 12:09 PM on September 16, 2009

I checked on and 3M 80 was the best match I could find. It's close to your specs, but it only rated to 200F which is just shy of boiling temp.

Have you tried calling/mailing Kenmore and inquiring about replacement parts? They might have an idea for you.
posted by reptile at 12:12 PM on September 16, 2009

MIL A-46146B Spec RTV Silicone Adhesive is good up to 300c if you can get your hands on some.
posted by I_am_jesus at 12:29 PM on September 16, 2009

Response by poster: Did you find residue of old adhesive inside that groove?

No but neither was there any residue on the end of the seal and when the unit was new the seal's ends were not sealed together. They joined flush but not perfectly so. This is the second unit I've had and the seal was like that on both units. The first one failed in the same way but did so within one year so Sears just gave me a new one. This one lasted for three years and Sears no longer sells this product. Looking around on the net I find this is a common failure in the unit and Sears has been of no help.

The back side of the seal that mates to the steel has micro ridges on it and seems at least very slightly tacky. I wondering if some sort of light spray adhesive was used.
posted by well_balanced at 1:14 PM on September 16, 2009

I'd suggest an epoxy
To apply: clean thoroughly, lightly abrade the surface with emery cloth or the like and clean it again, mix up a little epoxy, mix it up a little more (don't stop mixing just when the colours merge). Apply a thin layer to the metal (you want as thin a layer as you can manage for a strong bond) and then fit the rubber in place. I'd suggest using something to apply light pressure to hold in place. With most modern epoxies it'd be useable inside half an hour, but leave it overnight to be sure.
Check to make sure that it's cured properly (some people make two bonds with the same mix: do the job with one portion, but bond two pieces of scrap together with the rest - that way you can check that the main mix cured properly without tearing it to pieces) and away you go.

I haven't read the MSDS on 3M 80, but I'd advise caution - if it says that it contains stuff that can cause birth defects and isn't rated to boiling temperature and doesn't mention that it can bond to metal substrates, it might not be ideal.

It's difficult to find what I want on the net for some reason, and I left my adhesive catalogues at an old job, but a brief look suggested 3M 125 or 3M 190 could do what needs to be done.
posted by YAMWAK at 2:10 PM on September 16, 2009

Best answer: My pressure cooker (not a distiller but has a gasket of a similar nature that I had to place in the lid of the canister before first use.

After the first use the gasket, which was a bit sticky before (I assume because it was young rubber), was well affixed to the lid... I believe the manual said something about ordering a new gasket when it inevitably lost it's stickiness/pliability.

Presumably because after a qualitative amount of use it had been completely vulcanized to brittleness and could no longer be trusted at pressure.

Naturally you may be in a different place with this different equipment, but I would not be surprised if the manufacturer advised you to replace the gasket since naturally the steam vessel of a distiller will be under some pressure and will be filled with scalding hot steam.
posted by Matt Oneiros at 3:26 PM on September 16, 2009

I can't really think of an adhesive that would be safe to use with water you'll be drinking.

Could you try McMaster-Carr's website for a suitable silicone o-ring replacement? They have a surprisingly wide selection.
posted by orme at 3:31 PM on September 16, 2009

I would suggest using super glue to butt weld the seal, preferably loctite 404. I would avoid seating this seal solid to the lid but if you must then the adhesive I would use is Elmer's stix-all.
posted by hortense at 3:36 PM on September 16, 2009

Best answer: Use an RTV silicone adhesive, for example SU5005 which is food grade USDA approved and good to 400F.

You could also just get any tube of clear silicone adhesive from the local hardware store. It may not be marked specifically as food grade but is probably the same stuff.
posted by JackFlash at 4:11 PM on September 16, 2009

Response by poster: Although Sears was unhelpful with replacement parts I was finally able to track down the original manufacturer/supplier for this Kenmore 34480 distiller. It is identical to the Waterwise 8500 & 8800 models and Waterwise continues to stock complete replacement parts, including the gaskets. Curiously, Waterwise seems to use a solid one-piece o-ring gasket so hopefully it will be more durable. In case anybody else comes looking with this same issue you can find the replacement parts list here.
posted by well_balanced at 4:25 PM on September 16, 2009

Cool - I'm glad you found a decent replacement part. An 'o' ring gasket sounds like a good solution.

Just wanted to mention that superglue is not the solution when hot water is involved - it's good for most other applications, but superglue degrades rapidly in hot, humid environments. If you stick your fingers together with superglue, warm and soapy water is best for getting them unstuck.
posted by YAMWAK at 10:55 PM on September 16, 2009

Loctite 404 (super glue) is used industrially to make large O ring type seals, most likely used by the OEM to make your seal. It's performance is based on the width of the gap between parts joined. Moisture actually initiates the cure for this adhesive.
I've use it to patch bike tire tubes and assorted rubber items for years.
posted by hortense at 7:26 AM on September 17, 2009

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