Hi, I am wondering if anyone could please help identify the white powder substance that is appearing on the shelves on my shed?
I think it may be some type of acid? It appears to be eating away at the metal of my shelves. I have previously brushed the shelves down to clear this before but it has returned, so I suspect I may need to use some sort of cleaner?
There was a leak in the roof for a few months and some tools became rusty as a result. The leak has been sorted but I wonder if it could be related to the powder substance.
5 Comments
poVoq@slrpnk.net · 3 pts · 1y
Hmm, this kind of stuff is usually a result of water acting as a solvent pulling salts and similar substances from a substrate and later evaporating, leaving the powder behind.
It is probably something that was used to treat the plywood or a combination of that with the zinc coating of the metal (zinc-sulfate?).
Edit: probably sodium-borate, as that seems to be prone to leaching from wood treated with it.
carl_dungeon@lemmy.world · 2 pts · 1y
Just looks like water damage- if you really think it’s acid, scrub it up with a baking soda and water solution. Once it’s dry, you could seal with some paint or leftover stain.
tobylemming@lemmy.world · 1 pts · 1y
Thank you both, great information. I plan to clean the shelves down over winter, I will try some baking soda, then give them a coat of whatever I have lying around to seal the wood.
MysteriousSophon21@lemmy.world · 1 pts · 1y
Definitely seal it with a good moisture-resistant sealant like polyurethane or an outdoor deck sealer rather than just "whatever you have lying around" - this will actally prevent the moisture from causing the same problem again in the future.
tobylemming@lemmy.world · 1 pts · 1y
Thanks, I still haven't sealed the wood yet 😅 But I have, since, been looking into something like this instead https://www.thompsonsweatherproofing.co.uk/waterproofing/one-coat-water-seal/ - I also considered a PVA glue mix but I wasn't sure it was durable enough.