Assembling an aluminium Fortress anchor - should I use Tefgel or similar on the bolts

[blueazimuth]

Tufgel yes. Delrin washers no.
6 ft of chain? Yep, it’s sweet.
Sorry, but sweet is sweet, nothing more.
All secondary anchors should have at least a full boat length of chain. If you’re a serious cruiser, and want some to sleep well, use 2 boat lengths, or more. It depends on a number of bottom unknown factors, but it’s not overkill. Ask me how I know. Yes, I know you’ll have to stow the chain off the anchor and that’s a pain. But it’s all part of good seamanship.
If you must use stainless shackles, mouse them carefully with soft stainless steel wire, or risk the pin dropping out. Ask me how I know. If you don’t have any soft s/s wire, get some. Or use galvanised wire or even whipping twine, in a pinch.
Galvanised shackles - my preference - will, in time, lock with corrosion. So Tufnel is a must use. And mouse them down.

[a64pilot]

The plastic washers won’t allow enough torque, without enough torque it’s possible but unlikely that a bolt could shear because there is less clamping force on what it’s holding together.

[hellosailor]

Check with Permatex(?) but I think Loctite Red or other permanent thread locker will be a perfectly good corrosion preventive, and help ensure the nuts are locked in place. Killing two birds with each stone.