Simple Question - Checking for loose nuts

Alright, I'm drawing a blank here.

I'm wanting to add a thread indicator on some of my bolt/nuts. I've seen it done in the past to make visual recognition of loose nuts easy and the color is typically Orange or Yellow.

I know I could use finger nail polish; but I'd rather use the real product (if there is such a thing). I was just unsuccessfully searching Spruce to see if I could find it.

Is there really a true thread indicator product, if so what's the real name?

Phil

Torque Seal

Yup it's called torque seal. I use it to mark bolts that have been torqued. Also it will give an indication if the nut/bolt loosens up.

Aircraft Screw loose has it: http://www.aircraftspruce.com/catalog/cspages/f900.php

Checking for Loose Bolts/Nuts

Torqu-Seal made by Organic Products Co, Irving Texas is better than using nail polish or a paint pen. This is because when you remove the nut the Torque-Seal will flake off and have to be re-applied when the nut is re-installed. Painted marks remain, and yes you will be removing some torqued nuts to add some forgotten item.

Another point to ponder, if you correctly torque a bolt attaching two painted surfaces will the paint compress over time and relax the bolt tension. A couple of local builders suggest that is the case and some attach bolts will be found under torqued after the first 50 - 100 hrs of flight.

George:
In most cases, painted surfaces should be re-torqued periodically. Paint is a relatively soft material and is easily compressed. Under sufficient load, it will migrate out of the joint and thereby reduce clamping force. Think of a (male) fastener as a rubber band. No clamp force unless it is stretched. If the thickness of the paint is greater than the elongation, the paint squeezing out will result in loss of clamp. Good example of this is the heavy truck industry. There is an SAE specification for paint thickness on wheels - this to help prevent loss of clamp during use, particularly on dual rear wheels. In motion loss of wheels from a semi tractor trailer has hugh potential for disaster. Finally, using torque on fasteners is a "dirty" way of generating clamp load. A more precise method is torque angle, which precisely results in a given amount of elongation. For example, a 1/4-20 fastener has 20 threads per inch or .050 inches linear travel per revolution. theoretically, if torque angle was 90 degrees, elongation would be .25 x .050, or .0125 in.