Ferric Chloride; Dilute or Not?

[ThruTraffic]

I want to do some pit firing and include ferric chloride. I've read a bunch of threads and Google search results but none of them mention the concentration.

100% FC is pretty expensive; like $40 for 16 oz. Amazon had it in 43% dilution, gallon units for ~$25.

Is 53% satisfactory for pit firing?

 

[Babs]

Look out for fumes, eh.

Downwind, no neighbours

@Marcia Selsor is the queen of all this.

Sounds like folk dilute FeCl3 before spraying.

V toxic.

 

[Kellykopp]

What Babs said, exercise extreme caution Ferric Chloride fumes are very toxic.

[Babs]

Try dm a forum member 

@Marc McMillan

He has great album on Ferric Chloride pots .

Do a search Ferric Chloride in this Forum.

[ThruTraffic]

3 hours ago, Babs said:

Do a search Ferric Chloride in this Forum.

Oh! I didn't think of that. ;-)

============

If you're new to the thread I've asked:

• Ferric Chloride; Dilute or Not?
• Is 53% satisfactory for pit firing?

[oldlady]

i saw a firing using this in england.   the 2 men were dressed like astronauts and had lots of experience.    be  VERY careful  if you decide to do this.

[ThruTraffic]

4 minutes ago, oldlady said:

i saw a firing using this in england.   the 2 men were dressed like astronauts and had lots of experience.    be  VERY careful  if you decide to do this.

FLOL :-)

[ThruTraffic]

I got my question answered by Mikkel deMib Svendsen on YouTube. He uses an ~40% solution and gets some nice results.

[Babs]

Take care. 

What about the person who uses Ferrous Oxide? Gets nice results

[Crooked Lawyer Potter]

Does anyone know the ratio of water to dry powdered ferric chloride to get a 40% solution?

[Chilly]

Just now, Crooked Lawyer Potter said:

Does anyone know the ratio of water to dry powdered ferric chloride to get a 40% solution?

40gms powder to 60gms water ?

[Callie Beller Diesel]

A 40% solution would be 40g of dry material to 100g (or ml) of water.

[Bob Coyle]

Make your own  if you  have a little experience playing with chemicals.

All of the safety things you have seen about handling and cleaning up after ferric chloride and Muriatic acid  (hydrochloric acid) apply.  Especially rubber gloves and Eye protection If you have no experience working with toxic chemicals DON'T DO IT!  or get help from someone with  some experience.

 Get some muriatic acid at the hardware store,  In a well ventilated  area, fill a  glass jar 1/4 full of water then add the acid (slowly) till it is half full. Put in a bunch of rusty iron things that  fit inside. DON'T PUT IN GALVANIZED PIPE !!   Let it sit with a piece of plastic screen wired around the top.  DO NOT SEAL THE LID!  ( it gives off fumes that probably wont kill you but are not very nice to  breath. they will also corrode metal things in their vicinity). Store it preferably outside somewhere where it won't be in the way or get filled with rain or snow.  If all of the rusty iron has dissolved,  add more  till it doesn't. Let this evaporate down  till the solution looks dark brown-red.  now you have impure ferric chloride.  You can filter this through a  pant filter and plastic funnel. don't let it touch metal.  All of the safety things you have seen about ferric chloride apply. 

If all the warnings have not scared you 0ff, There are YouTube  vids al over the place that show you how to do this.

I never spray ware for a pit fire.  I get some not too fine saw dust (not sander dust) and use it to absorb a solution of  the unfiltered ferric chloride, until it is damp but but dripping.  I sprinkle this over the pot as it is placed in the pit.  It's not quite like spaying but it gives interesting effects.

 

Edited October 5, 2022 by Bob Coyle
better lead in

[Hulk]

Thanks Bob!
Any concerns being around and/or downwind of the pit fire with ferric chloride involved?

[Crooked Lawyer Potter]

18 hours ago, Bob Coyle said:

I never spray ware for a pit fire.  I get some not too fine saw dust (not sander dust) and use it to absorb a solution of  the unfiltered ferric chloride, until it is damp but but dripping.  I sprinkle this over the pot as it is placed in the pit.  It's not quite like spaying but it gives interesting effects.

Dont think I'm gonna try to make any FC, but this idea about the sawdust sure sounds interesting!  Thanks.

[Bill Kielb]

You can just buy it, a common circuit board etching solution. Chlorine gas release (mustard gas would be primary concern) If you make it, it does not need to evaporate but does require oxidation with peroxide or bubbling air as a final step. Etched a lot of circuit boards as a kid, use all reasonable care.

[Crooked Lawyer Potter]

On 10/5/2022 at 1:07 PM, Callie Beller Diesel said:

A 40% solution would be 40g of dry material to 100g (or ml) of water.

I may be misreading your answer, but wouldnt that result in a solution that is 140 grams, of which only 40 grams are ferric chloride?  Is that a 40% solution or a 35% solution? (140/40=35).

Perhaps this as simple as Chilly suggests above -- 40 grams of FC and 60 grams of water.

[Bob Coyle]

It will probably vary. Depends on how much iron gets dissolved. It doesn't have to be quantitative to work.

[Callie Beller Diesel]

@Crooked Lawyer Potter you’re not misreading it.

 If you want to get technical, I’ve described a w/v solution (weight/volume) instead of the w/w solution that Chilly has. Usually a w/v solution is used when the solute is unknown, variable or irrelevant. The water isn’t part of the chemical reaction on the pot, so it maybe falls into that last category, but most likely the variable part applies. It’s only really kind of important in terms of concentration of the solution. You need to measure it so you’re not winding up with either an entirely too weak or too strong solution,  but you’re not needing to titrate it exactly. 

For repeatability of results, as long as you pick either w/w or w/v and stick to it, you’ll be fine.