Those poor dusty, greasy, dirty cooktop burner valves. All of them needed a bit of TLC; a bit of cleaning and some new parts. Alltrol valves have steel and brass components. I treated each metal type a little differently.
After complete disassembly, I soaked all the pieces in Goof Off, then rinsed, then soaked them in a strong cleaner/degreaser and scrubbed them with a medium stiff nylon toothbrush. Then I sorted the valve pieces into two piles; the brass parts and the steel parts.
The steel pieces had been damaged by rust (iron oxide). Even after washing and brushing, there was still some rust. While rust is a lovely color, it’s also a sign of slow destruction of iron and steel. Due to their small size I soaked all the little steel pieces in a cat food tin full of phosphoric acid (Prep & Etch), a derusting solution. I chose full strength phosphoric acid to quickly remove the iron oxide (more precisely to convert the red iron oxide into black iron phosphate), that provides moderate corrosion resistance. I saw some foaming while those pieces soaked. That indicated the acid was working.
There are a wide variety of solutions to remove rust, depending on the condition of the metal. the size of the piece, the speed to remove the rust.
- sandpaper, steel wool, wire brush
- Bar Keeper’s Friend (it’s the oxalic acid that does the job)
- rhubarb leaves, wood sorrel (aka Oxalis, sourgrass) (it’s the oxalic acid that does the job)
- vinegar (it’s the acetic acid that does the job)
- lemon juice or unsweetened lemonade Koolaid powder mixed with water (it’s the citric acid that does the job)
- molasses or Coca Cola (it’s the phosphoric acid that does the job)
- phosphoric or hydrochloric acid
- oxalic acid( changes iron oxide into a stable, water soluble salt)
- WARNING: I learned the hard way to be careful about derusting parts that also have an enamel coating. Phosphoric acid, at least, does a fine job of etching (dulling) a nice shiny smooth enamel surface. 🙁
The brass pieces got a soaking in diluted muriatic acid to remove the tarnish. There was really no need to remove the tarnish. It doesn’t represent serious damage, it just looks dingy. Without protection, the tarnish reappears in short order.
Tarnish is self-limiting, unlike rust. Only the top few layers of the metal react, and the layer of tarnish seals and protects the underlying layers from reacting.
All metal cleaning removes some surface metal. What is very important is to proceed very carefully when cleaning the brass plug or plug hole. Those mated parts are precision sized. Aggressive cleaning of those surfaces could remove too much brass and distort that precision sizing.
Following that – a good rinsing of all the brass pieces in water with a bit of dissolved baking soda to neutralize any residual acid. Then I let the pieces completely dry. I used pipe cleaners to snake through the valve channels between the conical plug hole valve space and the main and simmer orifices. There was a lot of gunk in those small channels, junk that could have impeded the flow of gas.
Then it was time to lube – gas valve grease on the brass plug, a light smear of high temp grease on everything else. After reassembling the valve, I buffed the valve exteriors with a Dremel abrasive buff and/or rubber bonded abrasive wheels.
Time to put things back together. I assume the factory had specialized tools to make assembly easy and quick. The trickiest part is setting parts on top of the spring. Without a way to keep the spring compressed reassembly can be a little challenging. But not impossible.
Screw the main and simmer burner orifices back on to the back of the valve. Now it’s time to address the front of the valve.
Ain’t she purty?
After reinstalling the valves I turned on the gas to that burner. The noise of rushing gas indicated too much gas was flowing through. So I tightened the two orifices to restrict the flow a bit more.
The cleaning worked! The burner lit up quickly.
I’ve a sneaky suspicion all the pipes/tubes that carry gas throughout this stove need the same cleaning, attention or replacing. #427 on my growing list of things to do.
Note: these are precision sized holes. They’re sized only for natural gas. If converting to propane, these holes would be way too large.