Envirovent 2 issues / white rust?

[Anna Pepper]

Hi! I’ve had my envirovent installed for about 2 years. I just noticed some weird white rust looking issues along the metal tube. Does anyone know if this is normal? Could it be a buildup of sucking out chemicals? It’s very strange and has caused small holes where there’s a lot of buildup.

[Hulk]

Hi Anna,

Welcome to the Forum!

Looks like the Skutt Envirovent uses "... flexible heavy gauge aluminum ducting..."* - hence, the white rust is likely aluminum oxide, and the holes would confirm.
The oxidation could be accelerated by moisture and corrosive gases that the unit draws from the kiln.

If the ducting were galvanized steel, the white buildup could be the zinc coating oxidizing, however, the steel underneath would eventually be exposed...

*per Skutt's website

[Bill Kielb]

Post a picture If you can. I am compelled to mention if this is operating at fairly high temperatures then any corrosion is usually accelerated. This is actually a common issue as properly installed mostly room air is mixed with just a little bit of kiln air to keep the temperature, moisture and corrosive nature of the exhaust to a reasonable minimum. If the ductwork for the vent is greater than 130 - 140 when the kiln is at top temperature, then this is probably starved for room air.

To get a sense of hot - 140 is very hot and scalds within approximately 3 seconds. If it is currently operating this hot, then very likely it has insufficient room air. Worth checking I think as you have observed excessive wear on the sidewall of the ductwork.

[neilestrick]

Post a picture. White stuff on aluminum vent ducts is normal. They corrode over time and need to be replaced. The heat, moisture, and fumes from the kiln combine to make a fairly corrosive mix.