Jump to content
I Forge Iron

Moisture in my vermiculite


Recommended Posts

I recently made a monkey tool from 1045. After forging and hot filing, I annealed in vermiculite. It came out rusty. I suspect that the vermiculite is holding moisture (that's why it's in potting soil mixtures).

 

So, I bought a lid to seal my vermiculite bucket and keep it dry. How would you dry it? I'm thinking of putting it into cookie sheets and baking it in the oven at maybe 350°F. Thin layers, so the heat penetrates quicker. Ideas on how long it'll need to bake? What about the temperature? Or, should I use an entirely different approach?

 

Here's the monkey tool, since we're all addicted to pictures around here.

 

post-27926-0-13362400-1397247243_thumb.j

Link to comment
Share on other sites

Where did you obtain your vermiculite ?

 

 

Both perlite and vermiculite are great at retaining water, but vermiculite retains much more water and offers a little less aeration than perlite. Vermiculite literally acts as a sponge that will retain water to the point of saturation. Perlite holds water by having a large amount of surface area within the nooks and crevices of its vast pores. But being porous and made of volcanic glass it allows excess water to drain much more readily than vermiculite.

Reverence World seed supply

 

 

 

Vermiculite and other ore bodies can contain a variety of associated minerals such as mica, quartz, feldspar, etc. The associated minerals are unique to a particular deposit and, in some cases, may include minerals which could pose a health risk if present in significant quantities. In most countries, manufacturers are required to publish and make available Material Safety Data Sheets (MSDS). These sheets will typically identify any hazards associated with the material and also provide information on safe handling and proper disposal.

Asbestos fibres are a potential risk to health, and in the past there has been some vermiculites contaminated with trace amounts of asbestiform material. Vermiculite ore bodies currently in use by the major producers, do not pose a health risk when used in accordance with the manufacturer's MSDS. However, there are numerous sources of commercial vermiculite available in the world today and it is important for the end user to understand test data from a particular manufacturer.

Reference Vermiculite.org

 

 

 

Concerns about Asbestos-contaminated Vermiculite Insulation

A mine near Libby, Montana, was the source of over 70 percent of all vermiculite sold in the United States from 1919 to 1990. There was also a deposit of asbestos at that mine, so the vermiculite from Libby was contaminated with asbestos. Vermiculite from Libby was used in the majority of vermiculite insulation in the United States and was often sold under the brand name Zonolite. If you have vermiculite insulation in your home, you should assume this material may be contaminated with asbestos and be aware of steps you can take to protect yourself and your family from exposure to asbestos.

Reference EPA

 

 

 

 

Horticultural Vermiculite
Vermiculite is the geological name given to a group of hydrated laminar minerals which are aluminum-iron magnesium silicates which have the appearance of mica, and is found in various parts of the world. When processed for horticultural use, the mineral is subjected to intense heat, expanding it into accordion-shaped granules with countless layers of thin plates. Horticultural vermiculite has the excellent property of improving soil aeration while retaining moisture and nutrients to feed roots, cuttings and seeds for faster, maximum growth.

Reference vermiculite.org

 

You may want to do some research before you put vermiculite in your family stove, the place where you cook your food.

Link to comment
Share on other sites

In the soils lab the drying ovens ran 230f an overnight stay eliminates hygroscopic moisture from samples, even mud. A gas kitchen oven will take a  while longer than an electric because a byproduct of combustion is water. Regardless an hour or two should completely dry vermiculite, even in a bucket. Vermiculite and perlite have an open pore structure, that's why they're used to hold water in soil. Water goes in easy and can be drawn out easily by plants but doesn't just run out.

 

Thinking about it, I'll bet you could keep it in a closed box with a light bulb and keep it dry. Warmer than ambient will drive off moisture.

 

Frosty The Lucky.

Link to comment
Share on other sites

Glenn: Homedepot or Lowes (as a potting soil supplement), a couple of years ago. Probably doesn't have asbestos.

 

Yeah, family oven is bigger but gas (therefore producing H2O). I am debating that or my thrift store toaster oven that I use for tempering. The problem is 5 gallons will take a long time in tiny bits. OTOH, next hot & sunny (but not windy) day I could spread it all out on some sheet metal in the sun or even just set it on top of a wood fire that has burned down...

Link to comment
Share on other sites

Ok, I haven't seen this come up yet so I'll toss my thought in the ring. Would it work to heat up some big bars of scrap and put them in the bucket and let it bake out from the inside? That way you dint need to involve the oven or ambient humidity etc. Depending on how tight your lid seals you may have continuing issues with moisture absorption in the future, I wonder if a largish sack of silica gel would survive being strapped to the underside of the lid. If it would be melted or damaged in place when hot metal is in the bucket you can always remove and replace when storing after use.

Link to comment
Share on other sites

That'll work fine Chinobi. What's happening here is pretty normal overthink. Drying vermiculite or perlite is really easy, just make it warmer than the outside air and give it a little time. No need to spread it out, bake it or whatever, just a little warmer is all. A bar of hot steel is dandy and just leave the bucket open a crack so moist air can vent easily. Puttig a wrap of something around the bucket will help prevent condensation on the inside walls.

 

Regardless, unless it's actually damp enough you can feel a little moisture in vermiculite or perlite won't have a significant effect.

 

Still, it's normal for folk to look for the "perfect" solution even if they have to discover a problem to solve. We've all done it, those of us with a little imagination anyway. Perfect dry would require one of two pieces of equipment, a drying oven like we used at the soils lab, or better yet a freeze dry vacuum chamber.

 

A light bulb in a cardboard box will dry it beyond the point of diminishing returns but what fun is that?

 

Frosty The Lucky.

Link to comment
Share on other sites

  • 3 weeks later...

Thanks for popping this thread up in the new posts list. I don't do anything special to dry my perlite, so long as it isn't sopping wet I just use it. If it steams a little it doesn't seem to effect an anneal, even when annealing some pretty small pieces. We live in a pretty dry climate but air dry has been plenty good enough for what I need.

 

I think this is one of those things we can get carried away with trying to get perfect and in truth it's a "good enough is good enough" thing. Of course that's just my opinion, I could be wrong. <grin>

 

Frosty The Lucky.

Link to comment
Share on other sites

  • 2 months later...

kayakersteve brings up a good point.  Vermiculite, by it's nature, will suck moisture right out of the air.  We used it extensively as fill material for fire resistant safes.  We bought multiple pallets at a time and storage was a big deal.  

 

Get it dry and make effort to keep it's storage container sealed.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...