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How do I remove fire scale


Blake Laperriere

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I have no experience with this specific method, but I would guess that a nice long soak in some vinager would loosen it and revove it.

                                                                                      Littleblacksmith 

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Thank you. I just wasn't wanting to say "this is the way, it WILL work" and end up ruining his work with my advice somehow.

                                                                                         Littleblacksmith 

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Better to use a weak baking soda solution...some Windex is ammonia-free if that is what might be doing the neutralizing with Windex.  I use Windex on the windows ;)

Vinegar is great...kinda like aspirin...seems to be good for just about anything!

 

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What style of rose?

What finish do you want for the finished project?

If your doing a Russian Rose, ie one piece wrapped rose. You can get all your prep work done, and then wirre brush it hard with a wire wheel on a bench grinder, and polish both sides.  Then you can take a torch and apply heat to the bends and wrap it up. Should get very little scaling, then you can wire brush the outside of the base.  If you leave it too open then the little bit of scaling will show inside the flower.

With a Composite Rose, ie one assembled out of several peices.  Some guys cold work all the pieces, and wire brush or sand the sheet first before they even start. If you do hot work the sheet pieces, you can shape them up 60-80% of the way, and then use the wire brush on a bench grinder for the outside, and you can get smaller wire brushes that can be chucked in a drill or a die grinder, and slick up inside the bell of the flower.  Then when you assemble the rose you, tenon/rivet, or solder or braze the components on to the stem.  After it is assembled you can close things up a bit more if your gentle and careful.

Chemical cleaners like vinegar, and OSPHO or some other Phosphoric acid paint prep, work for painting. Like everybody mentioned you need to neutralize the acid in the vinegar, pull it out of the vinegar rinse with water and dip into some water with some baking soda, then rise again, then dry quickly and apply finish, before it can flash rust.  The OSPHO will convert some of the scale to iron phosphate which will be nice and black, but will have a lot of white dust on the surface.  Hit the white powder with a wire brush to smooth all the surfaces you can reach.  I would like to experiment with OSPHO more, haven't been totally satisfied with the results, if I could get the whole surface to covert to iron phosphate that would rock...

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26 minutes ago, SJS said:

Then you can take a torch and apply heat to the bends and wrap it up. Should get very little scaling,

Do this at a LOW heat, and you will get very little scaling. If you do it at a high heat=more scale. But be sure not to do it at too low of a temperature, or else you risk breaking it.

                                                                                                                       Littleblacksmith

 

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Also, try to keep your work out of the bottom of your fire where the oxidizing zone is...contributes to scale.  Get further up in the fire, the neutral zone...less or very little scale.  Glenn has posted a diagram several times here on IFI of the "layers" in the firepot.  See if you can locate it.

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OR, you can just flux the piece before doing hot work to prevent scale forming. Borax dissolves in water so removal is a hot water soak and rinse. Dry and finish immediately.

I'm an OSPHO fan, use it in a dilute solution over a longer time. Keep the pieces completely submerged and rinse IMMEDIATELY on removal from the solution or it WILL turn black. Dilute NAVAL JELLY works well too as a soak.

OSPHO and NAVAL JELLY used according to the label instructions are paint preparations and the black, phosphorous oxide(?) finish holds paint like it's welded. Don't let it oxidize and it'll leave bare clean steel or iron. Just be aware iron that's molecularly CLEAN WILL oxidize instantly on contact with oxygen. You can watch it rust, it happens very fast.

Frosty The Lucky.

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  • 2 weeks later...
On 2/10/2017 at 6:17 PM, SLAG said:

No guessing,

Vinegar will do the job.

Regards, SLAG.

 

I guess you must know how to get the SLAG off!  Thanks so much.

On 2/11/2017 at 5:12 PM, SJS said:

What style of rose?

What finish do you want for the finished project?

If your doing a Russian Rose, ie one piece wrapped rose. You can get all your prep work done, and then wirre brush it hard with a wire wheel on a bench grinder, and polish both sides.  Then you can take a torch and apply heat to the bends and wrap it up. Should get very little scaling, then you can wire brush the outside of the base.  If you leave it too open then the little bit of scaling will show inside the flower.

With a Composite Rose, ie one assembled out of several peices.  Some guys cold work all the pieces, and wire brush or sand the sheet first before they even start. If you do hot work the sheet pieces, you can shape them up 60-80% of the way, and then use the wire brush on a bench grinder for the outside, and you can get smaller wire brushes that can be chucked in a drill or a die grinder, and slick up inside the bell of the flower.  Then when you assemble the rose you, tenon/rivet, or solder or braze the components on to the stem.  After it is assembled you can close things up a bit more if your gentle and careful.

Chemical cleaners like vinegar, and OSPHO or some other Phosphoric acid paint prep, work for painting. Like everybody mentioned you need to neutralize the acid in the vinegar, pull it out of the vinegar rinse with water and dip into some water with some baking soda, then rise again, then dry quickly and apply finish, before it can flash rust.  The OSPHO will convert some of the scale to iron phosphate which will be nice and black, but will have a lot of white dust on the surface.  Hit the white powder with a wire brush to smooth all the surfaces you can reach.  I would like to experiment with OSPHO more, haven't been totally satisfied with the results, if I could get the whole surface to covert to iron phosphate that would rock...

 

I am making coposite roses.  Thanks for the advice!

On 2/13/2017 at 9:15 AM, ThomasPowers said:

Of course if you are using a propane forge you tune the burner to a reducing atmosphere realizing that you do get more CO that way so VENTILATE!

I am using the old fashioned coal forge!

 

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Slag's from a crusty crew alright.

No matter what you burn it needs to be reducing fire or it'll damage your work. ANY reducing fire makes CO as a combustion product and is dangerous. So, unless you're using an induction forge ventilation is a MUST.

I love Sitka, beautiful place heck, South East is all beautiful if you don't mind web growing between your toes. Where in Sitka is your shop? Just generally it's not like I'm going to drop in on ya unannounced.

Frosty The Lucky.

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