New and looking for advice

[Iron Fangs]

It's the same sand I used when I fired up today, worked fine but the hole kept collapsing in on itself and then my anvil stand rebelled and I decided to reevaluate my equipment

[Frosty]

15 minutes ago, Iron Fangs said:

would paving sand work?

Just fine but I'd pick out pebbles say pencil eraser sized and up.

Frosty The Lucky

[George N. M.]

Bentonite is different than many other clays in that it expands considerably when wet.  That is why it is used in drilling mud to seal leaks in the drill hole.  So, using bentonite will probably mean you will have larger cracks when it dries.

"By hammer and hand all arts do stand."

[Irondragon Forge ClayWorks]

What Frosty calls tempering the clay, potters call it wedging (like kneading bread dough) then letting it sit overnight to distribute the moisture throughout.

[Frosty]

No Randy, if you put so much bentonite in the mix wedging worked George's observation would be true in spades. Tempering in this sense is sealing the mix in a container and letting it rest so the moisture content equalizes throughout the mass. 

It takes very little bentonite to bind molding "green" sand, so little it can't shrink as it dries. However, molding ratio isn't bound well enough to serve in a trench forge, no matter how hard you ram green sand you can carve it with your fingernail.

At a 1:3 ratio there certainly is enough bentonite that shrinkage is an issue and why I emphasize the need to minimize the amount of moisture you add in the first place. I use the same test "squeeze hard" as for green sand because it works. If there is too much moisture in green sand, molds can suffer steam explosions when hot metal is poured. Excess moisture prevents steam from escaping quickly enough and it MUST go somewhere. Happily this type steam explosion is usually pretty tame, it's just the mold opening up and as soon as it does the pressure is released and it stops.

In a JABOD a 1:3 mix is porous serving two purposes: first steam is free to vent through the voids between sand grains. Second the sand can move as it expands and contracts with temp changes. However, a 1:3 ratio is clayey enough to ram hard like a brick and once fired it'll be pretty darned durable.

Bentonite is amazing stuff, heck it's just one in a darned large "family" of clays. Maarten (sorry if I spelled your name wrong) did some really good experiments with Bentone and zirconium silicate for a forge refractory. The vitrifying temps for Bentone is really high and the refractories he was testing at IIRC 2% or perhaps .2% it's been a while since reading his posts. The results were hard glassy and more than proof against anything a propane forge can produce. It also laughed at borax based fluxes.

Frosty The Lucky.

[JHCC]

50 minutes ago, Frosty said:

Tempering in this sense is sealing the mix in a container and letting it rest so the moisture content equalizes throughout the mass. 

Perhaps "hydrating" would be the more accurate term.

[Irondragon Forge ClayWorks]

That is what we call it when a block of clay (50 pounds) dries out. Put it in a large plastic bag with a cup of water, then place the bag in a 5 gallon pail and fill the pail to the top of the clay and let it sit for several days. the water pressure on the outside of the bag will hydrate the clay so the cup of moisture is through and through the block of clay and easy to wedge.

[TWISTEDWILLOW]

That’s good information to know Randy, thanks for the tip, 

I thought about being lazy and ordering some clay to mix my refractories in some more pancake forges so I didn’t have to fool with cleaning out gravel in the local red dirt lol 

[Frosty]

I don't know about more accurate but it's a good enough description. Tempering the green sand was probably half a century or more out of date when I learned the term in the 60s.

I don't know if wedging and bentonite cross paths though. 

Frosty The Lucky.

[BIGGUNDOCTOR]

Thanks for the tip Randy. I have around 300# of various clay bodies that have been sitting under the bench since 2007?  All high fire cone 10-14.  I picked up a wheel, now to get off my butt and actually get back to my hobbies. I have not been in the game mentally for a few years now due to some issues I am dealing with.  Seeing the light at the end of the tunnel, but with my luck lately it may be a freight train headed my way.

 

[ThomasPowers]

Try to look at it positively-----Lots of good scrap metal in a freight train!

[Iron Fangs]

Researching flux today and I had several questions:

1) Borax or Fine sand? I know Borax is widely used but it's also dangerous right?

2) is it only for forge welding or should I always be using it?

Ok. Maybe not several questions, maybe 2.

[TWISTEDWILLOW]

It’s my understanding a lot of commercially available  fluxes contain borax, I wouldn’t be worried to use it, 

heck I wash my clothes with a scoop of it in every load, so I don’t think it can’t be anymore dangerous than driving in traffic lol, 

On your second question,

Other than forge welding and washing your clothes im not sure what else you would need to use it for all the time? 

if you mean do you need it to forge with it all the time on your projects then the answer is no,

Now if you got a bug problem, I’ve known people here locally that have used it successfully to rid rental properties of roaches, bed bugs and fleas, in that case then ya you’ll wanna use it all the time washing, forge welding and pest control, lol 

 

[Iron Fangs]

I was thinking to prevent scale while forging, but it does seem very tedious and polishing with sand paper could probably do the same thing now that I think about it

[TWISTEDWILLOW]

I just use a wire brush in between heats to knock the scale off, I wouldn’t worry about using borax for preventing scale while forging regular projects 

[JHCC]

The point of flux is to minimize oxides (scale) forming on the surfaces of the weld. Sanding beforehand won’t help, as scale forms as the metal heats. Fine sand blocks oxygen getting to the surfaces, while borax both melts over the surface to block oxygen and actually dissolves any oxides that may form. 

There’s a good discussion of this over at:

 

[Iron Fangs]

Oh I didn't mean sanding before, I meant sanding after the project is complete in order to remove any scale that formed on already cooled metal

[JHCC]

Sanding after is an option, but wirebrushing while still hot is better, if you want to preserve a forged surface. 

[Frosty]

No, sand as a welding flux is more an urban legend than reality. There are times and materials where sand works but not so much since borax based fluxes became cheap and easily available.

You can flux your work while forging and prevent scale but reserve that for special cases. Molten flux WILL spray out from between the hammer and project and get on everyDARNEDthing. 

Wire brush visible scale from the piece when before you put it on the anvil to prevent scale from being driven into the surface.

Borax isn't particularly toxic, I add it to the dishwasher and laundry. Breathing the fumes isn't healthy but what kind of smoke is healthy? Good ventilation and don't take nose hits over the weld. 

Borax can be hard to get off weld joints but it's water soluble, soak it in clean water with a little Jet Dry added as a surfacant and it'll go away. Keep the piece completely under water, dry and oil as soon as you remove it to prevent rust.

Frosty The Lucky.

[Iron Fangs]

Awesome, thanks for the tips!

[ThomasPowers]

Yes borax is toxic; last time I checked the LD50 was something like eating an entire box.  We add it to baby diaper washing loads.  Boric acid is used for eyedrops.  Water is toxic in sufficient quantities as is Oxygen.  You note the California warning on children's play sand, sand can kill you too!

What you need to do is to check out HOW toxic something is and make a decision on if it will be a problem.  I generally don't start worrying until something is more dangerous than driving to work.

[Frosty]

1 hour ago, ThomasPowers said:

I generally don't start worrying until something is more dangerous than driving to work.

If you lived here toxins would be more so in summer. Driving in winter is significantly more dangerous. How worrysome will they be when you retire?

Now I'm wondering about my properly seasoned coffee cup!

Frosty The Lucky.

[Iron Fangs]

That's true, I was worried over nothing, if I fan handle driving in PA's winter with its notoriously terrible road systems I can handle a little borax

[JHCC]

As the pharmacists say, the poison is in the dosage. A little aspirin will cure your headache; too much will eliminate the possibility of your ever having a headache again. 

[SLAG]

Mr. JHCC,

High dose aspirin can do a number on the kidneys.

So moderation is recommended.

SLAG