Removing Seized Fitting in Boom

Mark in Portishead

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Hi everyone. Yesterday I was going to post a question on how to remove stubborn fittings from a boom but today I solved the problem so am instead sharing how I succeeded and what I learnt in the process.

The previous owner had fitted stainless steel inserts as stops either side of the vang fitting in the boom T-track. Galvanic corrosion had caused these to be VERY firmly seized in the track. I tried the usual suggested techniques of gentle heat and penetrating fluid but without success. I finally succeeded, with a friend, with the set-up in the photograph. Here, I am showing how I removed the final stop. I used a brass drift with a rounded end, so as not to score the boom, and at as shallow an angle as possible. I placed a claw hammer sideways on against the drift to provide a better, easier-to-hit target. I hit that target with significant energy with a 1.25 kg club hammer. It took about half a dozen blows to move it its own length, after which it was free. My friend kept the brass drift in position with mole grips.

What have I learnt? I applied a lot of various types of penetrating fluid - the last type citric acid based - but I am dubious about whether they were in any way influential. I tried a similar set up with a pneumatic hammer but with no success and think I could get more force with the manual set up below. Many people recommend heat cycles but I doubt this would have been effective. The fitting was not 'bonded in' by the corrosion - the aluminium oxide has minimal strength. Rather it is, in my opinion, just that the volume of aluminium oxide produces pressure and high interference i.e. high friction and heat cycles would have no effect on this. Finally - and this is key - the tendency is to hit too gently, for fear of damaging something, but you really need to put all your might into the hammer strike to get results. You can see in the photograph the measures I took to try and protect the boom and hence have confidence to strike with all my might. In the end, this was successful. And last of all, don't ever put stainless steel in contact with aluminium, even if it's anodised, or corrosion is sure to result.
 

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penberth3

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Well done. The word you didn't mention was patience.

Penetrating oils do help, but I would never use a hammer with "significant energy", as you put it. A lot of people have no feel for the strength of whatever they're hitting, start gently.
 

AntarcticPilot

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before anybody follows this method hitting two hammers one into the other is a big NO NO. because THe steel of the hammer heads is hard and liable to yield shrapnel which can cause injury to eyes and other soft tissues or in the case of a friend mine who did it he put a piece of hammer head through his testicle
All geologists are warned NOT to use the chisel side of a geological hammer to hit rocks for exactly this reason. You use the square end, which is tempered appropriately; the chisel end is for splitting rocks along bedding planes or cleavage planes.

Of course, serious hard rock geologists carry a 10lb sledge!
 

john_morris_uk

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Welcome to the forum to the OP.

There are numerous occasions where it’s impossible to avoid putting stainless steel next to aluminium (anodised or not). The trick is to use Duralac (barium chromate) paste between the fittings to stop the reaction that you’ve described. Duralac is readily available from chandlers (and i note that even Amazon sells it) for exactly this purpose. It’s what they use on aircraft too.

Having extolled its virtues I feel I should mention that i don’t hold any interest in the stuff except as a user.
 

Refueler

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I am now the 'party-pooper' ..... and TBH - I think OP is extremely lucky to have got away with that method.

I've seen tracks distorted / ruined by "striking" force. Its a pain and very difficult to get such a unit moving ... calling for time / easing fluids / pressure with limited shock tactics.
 

Mark in Portishead

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Welcome to the forum to the OP.

There are numerous occasions where it’s impossible to avoid putting stainless steel next to aluminium (anodised or not). The trick is to use Duralac (barium chromate) paste between the fittings to stop the reaction that you’ve described. Duralac is readily available from chandlers (and i note that even Amazon sells it) for exactly this purpose. It’s what they use on aircraft too.

Having extolled its virtues I feel I should mention that i don’t hold any interest in the stuff except as a user.
I see there is the original yellow Duralac and now a more environmentally friendly green Duralac. Accepted that this is an effective barrier. A non-conductive barrier of some sort is needed.
 

Mark in Portishead

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I am now the 'party-pooper' ..... and TBH - I think OP is extremely lucky to have got away with that method.

I've seen tracks distorted / ruined by "striking" force. Its a pain and very difficult to get such a unit moving ... calling for time / easing fluids / pressure with limited shock tactics.

before anybody follows this method hitting two hammers one into the other is a big NO NO. because THe steel of the hammer heads is hard and liable to yield shrapnel which can cause injury to eyes and other soft tissues or in the case of a friend mine who did it he put a piece of hammer head through his testicle
This reply is going to pick up on a few points raised.

Firstly, thank you John Morris for the welcome to the forum.

To Freebee's point about chipping the hammer, contrary to the illustrative photograph, what we actually did was use a 1 kg copper faced mallet to the strike the club hammer, which was resting on the brass drift. I couldn't show this in the photograph because my friend had taken his mallet home by then. This is undoubtedly safer. You do need a reasonably heavy striking hammer as a heavier hammer can be swung more slowly for the same strike energy and slow is more controllable.

If I gave the impression of a lunatic madly beating sh*t out of it, this is not correct. Each strike was undertaken singly and very carefully, with progressively increasing energy.

I am unsure about Antarctic's experience on hammers. The hammer face is temper hardened and hence more brittle. The rest of the hammer is generally softer and less likely to fracture. In fact, the only time I have ever chipped a hammer it was from the edge of the face. Your friend, Freebee, was I think unfortunate to be injured in that way but his post would be one I would definitely have liked to read. Still, fragments are clearly possible and eye protection is sensible. As are ear defenders.

The alternatives were few: Strike with more energy, spend a week making a bespoke screw jack tool (but react from what?), or sell the boat. I chose option 1.
 

samfieldhouse

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Ah same vintage then. Lovely boat.
When Kemps measured up for my new main they were quite nostalgic about seeing one of their masts.
 

AntarcticPilot

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I am unsure about Antarctic's experience on hammers. The hammer face is temper hardened and hence more brittle. The rest of the hammer is generally softer and less likely to fracture. In fact, the only time I have ever chipped a hammer it was from the edge of the face. Your friend, Freebee, was I think unfortunate to be injured in that way but his post would be one I would definitely have liked to read. Still, fragments are clearly possible and eye protection is sensible. As are ear defenders.
I was speaking specifically of geological hammers, which are designed for hitting rocks and are tempered accordingly.
 

KevinV

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before anybody follows this method hitting two hammers one into the other is a big NO NO. because THe steel of the hammer heads is hard and liable to yield shrapnel which can cause injury to eyes and other soft tissues or in the case of a friend mine who did it he put a piece of hammer head through his testicle
Without wishing to deny your friend's anguish I have found that striking via a second object (and a hammer has a handy handle) gives you a clean strike - the "hitting" hammer bounces back off the second hammer, which delivers a clean, sharp, perfectly directed blow to the item - most damage to the substrate occurs from the "soft" ends of the blow, when the friction in the joint is in control.

Agree completely re eye protection, but wearing a steel-capped jock strap seems excessive - he must have been smashing something pretty bally hard to penetrate trousers, pants and skin.
 

ean_p

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Without wishing to deny your friend's anguish I have found that striking via a second object (and a hammer has a handy handle) gives you a clean strike - the "hitting" hammer bounces back off the second hammer, which delivers a clean, sharp, perfectly directed blow to the item - most damage to the substrate occurs from the "soft" ends of the blow, when the friction in the joint is in control.

Agree completely re eye protection, but wearing a steel-capped jock strap seems excessive - he must have been smashing something pretty bally hard to penetrate trousers, pants and skin.
I can only agree with Freebee Kevin. One of the first things you are taught as an apprentice is never to strike one hammer with another. I have never seen the consequences as I've never known anyone ( I was going to put 'daft enough' but don't want to be cheeky! :giggle:) do it but my understanding is that the 'middle' hammer effectively is compressed between the striking hammer and the fixed object. The compression then meets at the side walls of the shaft housing which therein 'explodes' the side walls. It's nothing to do with 'chips' coming off the side of the face etc , its much more dramatic! If your hammer is shedding 'chips' when you use it then you need a better quality hammer and the one you have should be used as a paperweight.....and the convenience of the handle is what lures people into using a second hammer as a handy drift which it isn't.
The above for my part relates to so called 'engineers' hammers. I don't know if the same holds true for other types ie Claw hammers etc.
 

Mark in Portishead

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I can only agree with Freebee Kevin. One of the first things you are taught as an apprentice is never to strike one hammer with another. I have never seen the consequences as I've never known anyone ( I was going to put 'daft enough' but don't want to be cheeky! :giggle:) do it but my understanding is that the 'middle' hammer effectively is compressed between the striking hammer and the fixed object. The compression then meets at the side walls of the shaft housing which therein 'explodes' the side walls. It's nothing to do with 'chips' coming off the side of the face etc , its much more dramatic! If your hammer is shedding 'chips' when you use it then you need a better quality hammer and the one you have should be used as a paperweight.....and the convenience of the handle is what lures people into using a second hammer as a handy drift which it isn't.
The above for my part relates to so called 'engineers' hammers. I don't know if the same holds true for other types ie Claw hammers etc.
If there were true, you'd have to forbid the use of steel drifts too.
 
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