Condensation in upright cavities?

[Martin Luber]

I had stored / left two moulds on my desk upstairs at home. I had not oiled them. In each case, l noticed flash rusting at the noses only. House is at 55% humidity for guitars. I suspect the moulds stayed cooler uan the room and moist air in the cavities consensed vausing the rust. Thoughts? Moulds on their sides didn't rust. Those in a tool box on the floor also didn't rust. None are oiled

[poppy42]

I always oil my steel molds when not in use. That would solve the problem.

[jsizemore]

Or put them in a ammo can with a good seal and a few desiccant packs.

You got to keep the guitars hydrated.

[Martin Luber]

Was trying to understand the physics, it appears that upright moulds rusted, sideways or upside down didn't . Was looking to hear from others experience as the rust was only in the tip area.

[country gent]

Upright moulds hold the condensation longer. On the side or upside down they drain out faster. If storing upright leave the blocks open a little bit this breaks the blocks seal allows condensate to run out and allows airflow to dry much faster. Even better is if you can store with sprue plates opened. 1 and 2 cavity blocks the plate can be swung open over the handles. A light coat of oil or sealed with desiccant is also a very good idea.

[Petrol & Powder]

When you get done with that experiment, oil or grease those molds.

Seriously, short of placing them in some very dry container (and even then you're taking a chance) clean iron molds are going to rust eventually. The ones standing up simply rusted before the ones laying down did.

For short term storage I will use a Kroil and for long term storage I use RIG. After using the mold I will place the oil or grease on the mold while it is still warm and dry. After it cools, the mold goes in its box. That practice requires that the mold be de-greased before use but that's the price you pay when dealing with tools made of ferrous metals.

[lightman]

I always oil my steel molds when not in use. That would solve the problem.

I never thought about mold cavities forming or holding condensation. But, around here anything made of steel will rust if not oiled. I spray my molds with whatever flavor of oil that I use on my guns and clean it off with brake cleaner before using them. Its another step in the process but not a very time consuming one.

I've even had rust form when I left lead in the cavities, a trick once used by older casters.

[gwpercle]

Upright moulds should have let any damp air out the sprue hole ...like a chimney but...
maybe the open sprue hole let the damp air in ?
Don't have that problem in Louisiana rust and mold covers everything if it stands still more than 15 minutes . Louisiana...the home of rust, mold and mosquitoes !