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Removing Sicura Screw Back


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Evenin' all!

Whilst rummaging through boxes in my storage unit today I came across an old friend.

It's a 1970s Sicura automatic divers watch that I had from new. I wore this watch on a daily basis and it suffered from all sorts of abuse including the loss of its bezel.

As you do, I gave it a twirl or two to put some power into it and away it went.

Given the battering that I gave it (I worked as a mechanic in a tyre bay) it's amazing that it works at all but I'm sure that by now it'll badly need servicing. This leads me to my question.

The back has 14 scalloped facets to engage and there's no way my three-pronged opener will tackle the job. Does this need a brand-specific tool?

Is there a DIY method or should I leave it to someone with the right gear?

Answers on a postcard, etc. :-)

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Try using a stick ball, it's amazing how often it has worked for me in the past, and I wouldn't be without it today. If your watch is as old as you say it is, the ball may not cope, but it's still worth a try.

Here's mine!

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Failing that, superglue a 17mm nut to the case back and use a spanner, you can remove the nut by soaking the back in acetone afterwards to dissolve the superglue.

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Thanks guys, I'll give those methods a whirl. Gaffer tape I've got, ball not. Given your sense of humour Geo, I'm not sure whether you're serious about supergluing a nut to the back but then again you like lateral thinking! I've got some acetone somewhere - I used to dose my diesel with a capful now and again.

It's never been opened since new so could be a bit tricky. If your methods don't do the trick immediately I might try ice cubes on the back and a drop of lighter fluid round the edge followed by a bit of boiling water dripped in the middle of the back followed by more ice cubes - you see where I'm going?

I'll let you know how it goes. :-)

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Try using only 2 prongs of your case opener. You need to make sure its tight against the scallops.

Also secure the watch properly , potential for tool to slip and scratch the back is high.

Anip

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Hi Anil,

I've already tried the two prong trick to no avail so sticky ball is next. The back is really on tight.

As for the acetone, that's only for the super glue removal if I use Geo's trick with a nut. I have plenty of gaskets to hand in any case. Thanks for the warning though!

Maybe if I brazed a T-bar on to the back ...

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about acetone and casebacks...

 

My concern is the acetone will turn the existing gasket now in the watch into a gummy paste and this will act as 'glue' causing more problems.

 

cheers!

Anil

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Not pulling your leg. First used this method a few years back after reading about it on other sites. Make sure the caseback is clean of grease & dirt, apply a thin ring of ordinary superglue to the face of a clean, degreased 17mm nut, apply to caseback & leave for 30 mins to set. put watch in suitable clamp (I use the bench vice in my garage, jaws padded with wood). Undo with socket wrench (you will be surprised how easy it comes off). Place caseback & attached nut (minus any gasket) in acetone (or the bosses nail varnish remover) leave for 30 mins ans it will come apart.

 

A word of warning - do not I repeat do not use anything other than ordinary superglue as you will have difficulty getting other glues off. I know superglue is pretty useless in general, but it does work for this. Also as Anil has rightly pointed out acetone will make a right mess of gaskets etc.

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Okay Geo and Blacklab, I'm a believer!

I did try looking for posts on the subject but obviously missed this. I've never been too impressed by superglue as nothing I've ever tried to stick with it actually stuck! I remember the TV ads when it came out - a drop to join the ends of a rubber belt was enough for the presenter to sit suspended on - but I had no luck.

I don't want to resort to Bob's epoxy unless I have to so how should I use the superglue? Would a small circle a mil or two wide be sufficient or should I shoot the works and ladle it on? Maybe I'm being too cautious here and should just go for it!

Thanks for everyone's input.

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I have used superglue many times on car parts with great success.  Superglue works best when there is a large flat area glued to another large flat area.  Only the thinnest layer of glue is neeede as it cures in the absence of air (that why it stays fluid in the bottle!).  Best results are if the pieces are tightly clamped together as Blacklab says and left for an hour or so to fully cure.  Also superglue is very strong in tension but not as string in shear.  If you use a flat piece of metal glued across the back then it may be possible to 'peel' it off before you use the acetone.

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I use an old case back opener . Glue it with superglue and let it harden over night . Usually work for that hard to open case backs . And to remove superglue i use aceton .And i remove the o-ring before  if there is such . 

Edited by rogart63
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Hi ClockWatcher,

I've worked on quite a few Sicuras and have had some super tough casebacks that simply would not budge. Super-glue doesn't always work and forget about duct tape or rubber balls--these work when the caseback is only moderately stuck. This is what has worked for me with an identical problem. You will, however, need a PENCIL TORCH to remove the epoxy, but I assure you the caseback will come off with no scratches. You'll have to clean the burned epoxy off with some brasso, but it'll be fine. I've done this at least three times. 

1) get a fast curing epoxy:

post-328-0-72107400-1429497173_thumb.jpg

 

2) Mix the two components and immediately smear some on a lug nut, but not too much that it gets into the middle of the lug--This will make heating the epoxy difficult, and the only way to break the chemical bond is to heat it.

post-328-0-28586100-1429498299_thumb.jpg

 

Wait at least 1 hour before attempting to remove the caseback--if possible let it cure overnight. Then grab an adjustable wrench...should open with no problem.

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To remove the lug nut from the caseback you will need to heat with with a pencil torch--these are cheap and easily found on ebay for $5.00 to $7.00

post-328-0-87031600-1429498409_thumb.jpg

 

Heat the lug evenly all the way around. The epoxy will smell bad as it burns. when it begins to turn black (kinda like charcoal) cover it with something (a paper towel or a dry rag) and scrape it against an edge or use a paint scraper.

post-328-0-94598800-1429498599_thumb.jpg

 

Thecaseback will have burned epoxy on it, but will not be scratched. The burned epoxy can be removed with Brasso and a Scoth-Brite pad. The epoxy will also come off by scraping with a fingernail!

 

Hope this helps

Edited by noirrac1j
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Hi Joe,

I've not attempted any of the methods suggested since I originally posted this but when so many forum members, like your good self, have gone to the trouble of posting on the matter I think I owe it to you all to 'damned well try' one or more of them.

I've resolved to start with the simplest and work my way up to jackhammer and beyond. Therefore please anticipate a photo account of my efforts in short order.

Thanks for the detailed breakdown of the epoxy method - that'll be the one I try just before jackhammer. The one after will be to lay it on a railway track!

Cheers

John

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Right, here we go! And before anyone says so, yes, I should be ashamed of mistreating a watch this way. All I can say is I was young and careless!

post-742-0-20694000-1429562245_thumb.jpg

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Well, it worked!

I stuck the nut to the watch back and left the watch on a sunny window sill where it warmed up nicely.

After an hour I put it, nut side down, on some frozen sausages that were defrosting in the kitchen. Yes, I forgot to photograph the sausages! :rolleyes:

Anyhoo, with a slight temperature differential case to back, I applied the spanner (wrench for our colonial brethren) and good ol' Bob was my uncle! Thanks Bob!

 

The innards turned out to be a Brevets SIC39 movement and were remarkably clean given that the stem was bent, see the photos, and rusted internally and the seal in the crown was just black goo. (Anil, I swear I haven't had acetone anywhere near the watch!)

 

The main gasket was split into three or four sections through shrinkage but not too gooey so cleaning won't be too much of a problem.

 

There it is! Another watch for me to play with when I get a proper bench set up.

 

Thanks to all who contributed and encouraged.  huge-thumbs-up-smiley-emoticon.gif

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NICE!! Congratulations on a job well done!! John that movement looks like a BFG 158 31/7 of which I have many many spare parts of every sort (including balances). You've already mentioned it was a SIC 39? I've never heard of that particular movement in a Sicura, but who knows? It sure does look like a Baumgartner 158 31/7 with 25 jewels which means they've included some jewel caps for the pivots and probably a jeweled rotor bearing for the auto-winder. If I could see the balance I could tell for sure--Does it have a KIF shock system? It is shaped like a little triangle. In any case, If you need any parts, just send me a picture of it and you can have it for free--just pay the shipping. I have entire movements so every little screw, spring, and lever is available!

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