Mill Scale

[RouletteRun]

Most all of the steel aside from the 275-gallon tank is new steel and coated with mill scale, I've noticed where I have welded the mill scale wants to flake on the opposite side of the piece of steel being welded and comes off pretty easy with a wire brush on an angle grinder. My question is, do I need to try to remove the mill scale from my firebox prior to painting, or should I run an unpainted burn through the smoker and will that cause the mill scale to flake to strip before painting? How have you guys dealt with or not dealt with mill scale in the past?

[Big T]

I normally have mine sand blasted before I paint them but at the very least I clean them with a wire wheel on a grinder.

[RouletteRun]

I normally have mine sand blasted before I paint them but at the very least I clean them with a wire wheel on a grinder.

Wow! How much does it cost you to have something the size of a 275-gallon fuel oil smoker sand blasted?

[Rodcrafter]

I haven't done it but there's another option too called soda blasting.


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[Big T]

It really varies depending on how many blasters are in your area. The first one that I ever had blasted charged me $225 for a 24''x48'' smoker and a small trailer. I found another guy and he charges $65 per hour for sand blasting and you have to take it to him.

[Dirtytires]

I just got a quote for about $100 an hour for soda blasting if I take the smoker to him. He estimated it would take about an hour to do my pit.

I feel money well spent to protect a huge investment in time and material. I hope to give this thing to my kid someday and a good first paint will help ensure that it lasts.

[RouletteRun]

I've been watching some YouTube videos and reading some other forums on welding and metal work and it seems the easiest and cheapest way is to use muriatic acid to remove the scale, you've got to keep it wet down for 15-30 minutes then wash it off and dry immediately and paint as soon as possible. I also read where a guy used 1 lb. baking soda in a gallon of water to neutralize the acid and he says he could leave the metal exposed for an extended period of time with no oxidation (rusting).

[Dirtytires]

Ever spray muratic acid?

Not something I want to play with.

Besides, the acid will chemically etch the metal leaving all sorts of extra crevices for rust to start in. I hate rust.

[RouletteRun]

Ever spray muratic acid?

Not something I want to play with.

Besides, the acid will chemically etch the metal leaving all sorts of extra crevices for rust to start in. I hate rust.

Muriatic acid specifically? No, I haven't, I do have, however, 17 years as a heating, air conditioning, and ventilation (HVAC) service technician and am very familiar with acidic coil cleaners. When you spray this stuff on a dirty air conditioner's condenser coil it foams up and smokes. Air conditioning coils are made out of aluminum and copper and far more delicate than steel. In fact, they're so delicate that a condensing unit (the outdoor unit) if left where a male dog can continually urinate on it will over time eat the aluminum fins from the condenser coil because the urine is acidic. With immediate water washings to neutralize the acid very little damage is done using fairly strong acid to clean them. http://www.ebay.com/itm/Nu-Calgon-4133- ... Sw-CpX~sRN

Oh! The same sites also say vinegar (5% acetic acid) will work if you can soak the metal for 24 hrs.

[Dirtytires]

I gave a quick answer cause I was crunched for time but did not mean to slam the door on you....sorry. I'm not saying it won't work or that you don't have a ton of experience.

However, my college chemistry degree tells me that there are better alternatives....at least for me.