Cross Check DYKEM - Gray Tamperproof/Torque Seal, 1oz | 83321 (1 Pack)

It's Perfect to use when 2 fittings are tight in and you can use, it to make sure nobody mess around with them.

I saw something like this used at Disneyland to seal the nuts on bolts used for rides and rollercoasters. It allows for a quick visual verification that nuts/bolts have not loosened, been tampered with, and since it should be applied immediately after torquing to specification, it visually confirms that tightening the fastener was not neglected (on Disney's Thunder Mountain Railroad, this proved to have fatal consequences).In aircraft and race vehicles, it has long been a traditional practice to use safety wire. Nuts and bolts are drilled and a stainless steel wire is inserted through both and then twisted, typically around a paired fastener, and the wire visually confirms the fastener has been torqued, has not loosened since it was torqued, and has not been tampered with. To some degree, safety wire can even keep a fastener tightened. This Cross Check seal probably has much less resistance to torque than wire.A big advantage that attracted me to Cross Check is that it can work on assemblies than cannot be drilled for safety wire, particularly assemblies that are too small or that aren't materials that are suitable for drilling like electronic components and small parts.In practice, this Cross Check proved to be a bit frustrating. When I first opened the tube, it came out as a thin liquid. It was runny and part of it was clear. I closed the tube and kneaded it to try to mix the paste better. I had to waste some to get the nozzle clear of runny liquid. Then I got some paste out, but it was difficult to work with a small bead. I will try to get better at applying this, but it seems only practical for large nuts/bolts (like 1/2" or bigger) because it has such inconsistent working qualities in small quantities. I don't intend to use it for large assemblies, but I can only imagine that laying down big long beads of it would get expensive real quick.