Tech index -> Tech articles -> Thread sealant
Ths page is for information relating to the differences between common thread sealants out there. Whenever you remove or install an air fitting on your marker, you'll have to re-apply a type of sealant so it holds pressure. Only fittings with o-ring seals don't need sealant (such as small low-pressure tube fittings).
Loctite is likely the most common method to seal air fittings. This is available in liquid or "stick" form (similar to a glue stick) and is designed to prevent screw components from vibrating or rattling loose. Loctite has the added benefit of providing a pressure seal in the process, when correctly applied. Loctite is used on many markers and parts as the stock sealant from the factory since it's very easy to apply; simply coat the male-threaded end with the liquid sealant, screw it into the female-threaded hole, and let cure for one day before use. The loctite seal ideally won't break down over time or otherwise need to be replaced, unless you remove the component later (at which point you'll have to re-apply).
Loctite is available in many grades, most of which are colored as blue, red, or green. Blue is the lightest strength and can be used for most air fittings except high pressure ones, meaning everything downwards of your tank can use blue. Parts that will be pressurized above 1000-psi should use red loctite instead. Additionally, non-pressurized mated parts (such as hammers, feednecks, etc) usually suggest using red. Green loctite is the penetrating grade which is technically as strong as blue, however the application of green loctite will seep down into the screw threads and cause them to become entirely coated, making a much stronger seal. Some companies use green loctite on their tank fittings (gauges, fill nipples, etc) however personally I don't suggest it.
Teflon tape is a rolled-up tape seal that you wrap around the male threads prior to insertion into the female threads. The two parts are instantly sealed together if the tape was applied correctly. The main disadvantage to teflon tape is that it can be difficult to correctly apply in some situations, due to the thread types. If the tape doesn't stay in place and rather gets pushed out of the threads as you screw the parts together, chances are you'll have to separate the screw parts and re-apply the tape until you get it to stay relatively in position. The other drawback to teflon tape is that it tends to break down over time, and often requires replacement after at least six months.
Teflon tape is commonly used in the plumbing and utilities industries so it's available from many manufacturers. Different brands are rated to different pressures, but most all can withstand at least 5,000-psi in most situations. Teflon tape is inexpensive and can be purchased at many local hardware stores.
The main alternative to either loctite or teflon tape is plumbers' thread wax compound. This is also commonly used in the plumbing industries so it's available from many manufacturers, however they all provide relatively the same thing. This substance is in a wax/gel form and can be easily applied to the male threads prior to installation in the female threaded hole. Thread wax typically doesn't require any curing time unlike loctite, so you can use it instantly. This substance can be found in many well-stocked hardware stores however it should be noted that some thread wax might not do the job on your marker so if you're unable to create the proper seal using one type, trying an alternate type will likely help.
This table briefly synopsices the differences between the three common sealants above.
|Condition:||Loctite:||Teflon tape:||Sealant wax:|
|Sealing time before use:||Requires minimum 12 hours to fully cure, 24 hours suggested.||Seals instantly, no curing time needed.||Seals instantly (usually).|
|Sealing lifetime:||Ideally won't ever require replacement.||Slowly breaks down over time, often requires replacement within a year.||Ideally won't need replacing.|
|Application form:||Available in liquid or solid "stick" form, applied to the threads.||Dispensed in the form of tape, wrapped around the threads at least once.||Typically comes in a waxy "gel" form, applied to the threads.|
|Removal force:||Will seal mated parts together, force is required to separate.||No added force is needed to separate parts.||Increased force needed, however not as much as would be present with loctite.|
|Downstream issues:||Liquid loctite may seep into nearby internal passages/grooves before it solidifies.||Exposed pieces of tape can break off and flow through the marker, clogging small ports (such as solenoids).||No issues.|
|Relative cost:||$10 maximum per stick or liquid tube.||$1-2 per roll.||$2-5 per tube.|
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