Heat resistant, food grade silicone?

Hey folks,

Just constructing my MLT. I need suggestions for some silicone that will seal the hole drilled through the cooler. Does anyone know of a heat resistant, food grade silicone that I can use?

Thanks!

I have used 7545A471 from McMaster-Carr. I had a .75 inch hole in my MLT from where a temp probe went through and it has help up great so far for 9 months.

102, 103, 108, & 109) Multipurpose— Use for sealing, bonding, and gasketing. Won't run on overhead and vertical surfaces. Adhere to metal, glass, wood, silicone resin, vulcanized silicone rubber, ceramics, natural and synthetic fiber, and plastics. Begin to harden in 20 minutes. Temp. range is -75° to +400° F. Meet MIL-A-46106B, Group I, Type I. FDA compliant and USDA approved. NSF-51 certified for use with food equipment materials. UL recognized.

Mike

Your bulkhead setup should include a gasket or Oring so you shouldn't really need any kind of goop.

Thanks Mike. I'll look into getting that.

Bobby - I built the FlyGuy version of the bulkhead. I'm nervous that if the o-ring fails I'll get the innards of the cooler ruined. Seems like an inexpensive fix, even if probably not necessary.

Cugel said:

Bobby - I built the FlyGuy version of the bulkhead. I'm nervous that if the o-ring fails I'll get the innards of the cooler ruined. Seems like an inexpensive fix, even if probably not necessary.

Click to expand...

You are still using the original rubber seal from the spigot, right? If you use that, there is no way that the cooler should leak into the 'innards' of the cooler, unless you really overtighten everything.

No, I have to drill my own hole... no pre-existing spigot in the cooler I'm converting.

Ah -- I understand your need now.

Yes, you might need to reinforce the area between the walls of the cooler where you drilled. The gap can be substantial (as you already found out), and the bulkhead will seal better if you fill that gap somehow.

As Bobby mentions, however, as long as you have a high-temp, food-grade o-ring on the inside of the cooler, nothing should leak past it. Therefore, you won't need a food-grade product to fill the gap between the walls of the cooler where you drilled your hole.

Flyguy - thanks for your response. You know what - I'll try the heat resistant o-ring and look for leaks afterward.

Thanks also for your work in getting all this info to us all!!!! I'm sure it'll work great once installed and sealed.

The trick I've suggested to a few folks doing cooler conversions as a means to reinforcing the cooler wall is as follows:

Drill a small pilot hole through both walls from the outside (about 1/8"). That establishes centerline. Now drill the outer wall out to 1/4" larger diameter than the finished inside hole needs to be. You can continue through the insulation, but do NOT drill the inside wall with this large hole saw. Now switch the bit to be the "tight" inner wall hole and go ahead and drill that.

The larger outer wall hole is to allow for a piece of PVC pipe to be inserted to push on the inside part of the inner wall. You'll use a large enough washer on the outside to provide support on the other side of the PVC. If you can't find pvc that fits over your pipe nipple snuggly, you can slot a piece, compress it to fit into the hole, and then let go.

I'm horrible at describing things that could so easily be done with a picture.

Makes perfect sense, Bobby. Great idea.

Essentially all pure silicon is food grade once cured.

But any aquarium silicon will meet potable water standards and is much cheaper than the special stuff.

AS has been said the double wall is a challenge and should be kept in mind when tightening it all up.