Stubborn Rust

Smoke Stak

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A recent topic on Enginads Smokstak at www. enginads. com/smokstak. cgi

Various individuals started, commented on and concluded this bulletin board thread...

Okay, gentlemen, here we go...Everyone has their own concoction for loosening rusty parts and any help would be welcome! My preference is Kroil brand oil as it has always seemed to be the best. Situation: I have two needle valves rusted in place on a carb and have been soaking them for over a month. No results? I'm afraid of putting too much tension trying to force them to open with fear they might snap off. I would then never be able to reseat the fuel jet portion, if I had to drill them out! I thought about heating to expand the metal, but we're talking about cast iron. Any thoughts? Thanks a heap!

I have had pretty good success boiling parts in water. I use a Coleman stove and an old large sauce pan for small parts. It works amazingly well on some things. I too had a carb with a stuck needle on an Ottawa engine. The boiling did the trick. I have a large hot tank for whole engines that works well to get them free and cleaned, using 3.5 lbs. of lye per gallon. I wouldn't be afraid to heat the casting with a torch, if you take it easy. I have just as good luck using the small propane bottle torches as I do the acetylene torch. Good luck; as you say, it will require lots more work if you have to drill them out. What size are the needles? Are they rusted bad enough to lose some of the dimension? Hope it works for you.

Had the same problem with a couple of Fairbanks Morse duel fuel carbs. I took a weed burner and had the part hanging on a wire, heated part slowly till it just about shimmered, then dunked it in water. After doing this three times, everything came off with no problem. But, I heated slowly and in moderation. Hope this helps.

The electrolysis method of rust removal would be perfect for this situation. Search the old methods for the process; it will not harm anything, and will go inside complicated things and between threads. It works for me, and there is no danger at all!

My preference is GIBBS all by itself for light jobs that have some looseness. Heavier jobs require 'heat'. Sometimes a lot, and other times not so much. Don't melt the brass. Only problem is getting my torch outfit back (with gas left) from my son, who has discovered its wonderful uses.

I've used it so much over the years but it never ceases to amaze me how well electrolysis works. In fact, I have had two buckets going continuously for the last two months with parts rotating in and out of the bath. It is very forgiving, especially on small intricate items such as those needles. I've removed many needles this way. It might, however, require the use of a torch for backup at the moment of truth. By all means you should at least try it out, as it really is an amazing process. And all you need is a battery charger and a handful of baking soda.

Thanks for your support, gentlemen. I had some great help from the boys of the smokestack board. Gonna try three methods. The first one was not too successful with heating. The heat caused the solder on the thumb wheel to come off. The second is tonight with the electrolysis method. Three will be boiling it out. Thanks again guys for your help.

Another idea for you, try an electric skillet full of light oil. My dad uses hydraulic oil, about 10-weight, set the heat control to a low setting. Every time you go into the shop you plug it in and unplug it when you leave. It is surprising the things that will come unstuck this way if you have the patience. But, buy your own skillet at an auction or rummage sale, so you can keep your wife happy! Good luck.

Here is another trick I learned: put the part in the freezer for at least 6-8 hours, bring it out and use a candle flame to heat the stuck areas. This gives a similar effect to applying torch heat, but at lower temps that will not damage things. What you want is the expansion and contraction of the metals due to the temperature change, and this gives it to you at lower temps. An old gunsmith's trick.

If the part has been soaked in oil, that has to be removed first because once the oil has soaked into the rust it is very hard to get it out without heat. For an untouched rusted part, however, put it in the strongest vinegar you can get for a few days and the acetic acid in the vinegar will dissolve the rust completely, right down to the bottom of the pits. If you have access to an ultrasonic cleaner, take the part out of the vinegar and suspend it in the cleaner's tank, turn it on and the rust (now turned to black powder) will just blow off leaving the part in the 'white'--it's quite a sight. Best method for delicate parts, doesn't spoil the heat-treating of steel or hardness of brass as heat can. Also, it cleans brass and other copper alloys well. For degreasing and cleaning intricate or delicate parts, nothing beats a good ultrasonic cleaner either; get a good industrial soap from a janitorial supply store. 'Numero Uno' works beautifully diluted with water 1 to 5.

Smokstak is an engine conversation bulle' tin board which is a part of the Old Engine series of web sites that started in 1985 as 'Harry's Old Engine.' Harry Matthews is a retired electronic engineer and gas engine collector from Oswego, New York, now residing in Sarasota, Florida.