Bushing installation with sealant.

[PAPAMAO]

Hi,
I would like to install bushing with sealant per BAC 5435 which requires sealant having a continuous line (squeeze-out). Fairing-out of the squeeze-out is optional.I would like to know what is the definition of “Fairing-out”. Does it means to make to make squeeze-out more smoothly by tool.
Thanks.

 

[Sparweb]

If I had a copy of it I could be certain, but I think it means that you should remove any sealant that will interfere with the fasteners you are going to install through the bushing later. Sealants often "squeeze out" of the joint when assembled, and one must always consider how that last step will be dealt with - either to wipe it off, or let the blob protrude. Some manuals go so far as to specify the shape of fillet that is acceptable. In your case, the sealant that squeezes out may cover he face of the bushing or fitting, preventing the fastener (or mating part) to rest flat.

STF

 

[tbuelna]

The most common reason for installing bushings with sealant is to prevent moisture from getting between the bushing and mating bore/face surfaces, where it can cause corrosion. If there are any tiny gaps between the mating surfaces left unsealed, any moisture present will readily be drawn into these voids. Checking that there is a continuous line of "squeeze-out" at the joint ends is an easy way to visually confirm it is properly sealed. Personally, I prefer fairing-out of any excess sealant wherever possible. It is usually quick and easy to do by hand, and looks way more professional. Also, for situations that are sensitive to debris, globs of excess sealant squeeze-out can eventually break loose.

 

[WKTaylor]

To add to tbuelna's comments...

The ring of sealant between the ends of the bushing and the surfaces surrounding the hole not-only verifies the integrity of the wet-seal installation [100% moisture resistant], it also minimizes the effect of electrolyte [moisture] bridging across the metal surfaces [which are usually dissimilar]... by tiny droplets or thin-films that may form.

Regards, Wil Taylor

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[PAPAMAO]

Thanks for the suggestions!

So the point is that I have to make sure there are no any gaps between bushing and housing to avoid corrosion.