Seized Engine Zinc

[sneuman]

Tried WD-40, PBlaster, etc. and cannot get the pencil zinc to turn. Of course, through all my trying, I have managed to wear the corners off the hex top. I assume drilling it out is the only option left, unless someone has a bright idea.

Many thanks in advance!

[psneeld]

Heat is usually the trick...on mine I just filed new sides until I got them out with whatever tool fit my new filed sides.

I have also found the longest leverage arm with slow, medium pressure seems to work better than anything...even if it means a 4 foot pipe and gentle pushing.

[skipmac]

Definitely add heat, plus let the PB Blaster soak for a while.

If you have access to an oxy/acetylene torch with a very fine tip that's your best option. I had a couple of really stuck screws and tried soaking and heating with my hand held propane bottle torch and did not work. Borrowed an oxy/acetylene rig from a friend and it did the job.

The acetylene flame is much hotter and with a fine tip you can focus it on a much smaller spot and get much better effect.

[Blue Stocking]

Heat exchanger fittings to recieve the zinc is soldered in on many versions. Careful with the torch.

[Charlie]

Also after applying the PB blaster give the sides of the offending nut a sharp wrap with a hammer. I don't know why this works but it has worked for me in the past. As far as the rounded nut goes do you have these Bolt Extractors - Screw & Bolt Extractors - Tools - IRWIN TOOLS I don't own Irwin but have used these and find them to be a very good product.

[minaret]

Originally Posted by skipmac

Definitely add heat, plus let the PB Blaster soak for a while.

If you have access to an oxy/acetylene torch with a very fine tip that's your best option. I had a couple of really stuck screws and tried soaking and heating with my hand held propane bottle torch and did not work. Borrowed an oxy/acetylene rig from a friend and it did the job.

The acetylene flame is much hotter and with a fine tip you can focus it on a much smaller spot and get much better effect.

Try the hand held bottle torch with a MAP gas cylinder next time. It burns much hotter. I always keep one aboard. They are cheap too. Look for the yellow cylinder. Heat until spit sizzles off of it and no more. You can over do it with MAP. Plus Aerokroil is better than PB Blaster.

[boden36]

If the rounded stub is still protruding sufficiently, you could try a stillson wrench ( pipe wrench?) on it.
Another way is to get a length of flat bar, drill a hole so it slips over the protruding stub, weld the stub to the bar. After it cools, you should have a good chance of moving it.
Finally, a butchers method is to get a slightly undersized socket and hammer it over the stub so it cuts some grooves and locks on, and then try that.
Regards,
Richard.

[Me-and-Boo]

The concept behind heating is to make the screw in piece expand and break the oxide when it cools.

The best, and this is probably one of the least likely to be found around a boat yard, is to stud weld a copper pulling stud to the head. Works great everytime, and with the zinc already destroyed there is no need to grind the copper off. Like I said probably not around the yard.

[minaret]

Originally Posted by Me-and-Boo

The concept behind heating is to make the screw in piece expand and break the oxide when it cools.

If you heat just the part you are trying to break out, it will expand in the thread and jam up even worse. Heat around the part you are trying to remove to make the substrate expand instead. You are trying to make the hole bigger by a tiny amount, hopefully without doing the same for the fastener to the same degree. Turn it while it's hot, don't wait for it to cool.

[sneuman]

Thanks all for the advice. Heat and a long lever were indeed the key! The surprise was that it was a zinc after all, but a drain plug. I just assumed, since it was not marked in the schematics.