Seized bolt - help needed

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alanporter

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I have a stainless steel bolt seized (galled) into a Zamak alloy davit base. There is no room to get a drill in if I fracture the head of the bolt off with a big wrench. I have tried penetrating oil without any benefit. Can any of the forum gurus advise please ?
 
But don't trash your polyester in the process of heating.

Try soaking in acid, masonery & brick cleaner (hydrochloric) will work. You may need to keep applying while it uses itself up un the corrosion. Any overspill will bring the stains out of your topsides.

Some say Coke Cola will work too, but I bet not as quick as this.
 
Its probably a silly question but have you already got the nut off the bolt? if its machine screwed into "something" then I would go for the brick cleaner suggestion and maybe build a small "coffer dam" around the bolt with say plasticine to give some depth/direction for the acid to work in, gently try moving it both ways at first until it "cracks" and starts to undo if you feel brave enough? or just gently try to undo it till it moves. Take your time, if you can leave the acid over night it might be better.
 
All of the above.

However to heat the bolt only, electrically weld something onto it. This localises the heating.

Cover the flammable bits and don't set the whole thing on fire. See what's going to be heated internally and take suitable precautions - have a bucket of water and a sponge ready.

If corrosion is the problem rather than galling of the stainless attempt to disolve the corrosion products of the aluminium. Water or acid may be more succesful than the oils.

I take it that you have hit it well with a hammer already to loosen things a bit and tried tightening as well as loosening to free it.

Good luck! /forums/images/graemlins/grin.gif
 
Thanks everyone for your helpful replies. The bolt is 3/8 inch diameter going horizontally into a threaded hole in the base of a davit. It sits about three inches above the fibreglass deck, so I will have to exercise care with whatever I try.
 
Is their room for a right angle drill to get in the gap? if so, you could try one of those Screw Extractor things which drill anto clockwise rather than clockwise - such that when they can go no further they try to unscrew the bolt. (not sure if they work with bolts, but worth a try after the loosening exercises).

Richard
 
The bolt extractor is great if the bolt is sheared off level with the alloy. You still have to drill a hole of suitable size to get the extractor in. We call them "easyout". They won't work miracles and you still have to loosen the bolt. The arc welder onto the end of the boilt would be a way to a lot of localised heat onto the bolt. Just a few seconds should do it. But no good if the bolt stump is level. Slower heating with a flame will heat the alloy as well.

good luck olewill
 
ACF 50/corrosion block, dissolves corrosion.I've used it on severely seized alloy to alloy, thats been in salt spray and not moved for 10 years. Its good...no very good. You won't use Plus gas/WD/3in2 again.

It does what it sais on the tin, dissolves corrosion, allows moisture to disperes from the surfaces, seals surface from further moisture whilst activeley converting any remaining corrosion that developes. There are some places on aircraft it can not be used as it can remove the small ammount of alloy corrosion between rivets and skin and thus loosen rivets.

It was being imported by a guy at Hurn Airport, Hampshire, as it started life as an aero product. Made in Canada for use on carrier based Aluminium aircraft.

Ooops just noticed you're in Canada!! you should be telling us about this stuff?
 
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