Bronze/aluminium freeze-up

[Bergalia]

Bit of a problem... Restoring elderly (1950's) one-off sailing dinghy and original builder used a lot of aluminium deck fitting (God knows why) and unfortunately used bronze screws and bolts for fastening. The years - plus salt water - have frozen the bolts/screws in place.
I've tried WD40 (thread unfreezer), heat, and a modest tap with hammer. Still no movement. Other than drilling out and re-threading and retapping can anyone out there suggest another method...Please....

[gonzo]

I have , sometimes, been succesful hitting the screw on the head with an impact screwdriver. It twists as you hit it.

[Thunderhead19]

You'll find that when you get the screws out, that all the threads in the fitting are ruined anyway. You'll have to drill and re-tap them in the end anyway.

[Bergalia]

Thanks Gonzo...I did try it...but still no effect. Looks like I'll have to resort to Thunderhead19's method. He's right - the screw heads are already pretty chewed up...
But once more it shows just what a great place this forum is...And what a great wealth of wisdom there is to draw on...Wish there was the equivalent forum for the world's politicians....

[Bergalia]

Gonzo - Thunderhead 19 - thanks guys. Resorted to drilling and retapping. Replaced bronze screws - bolts, but with a liberal coating of graphite grease, and will give an annual check over. Thanks again.

[Dave Fleming]

To the best of my knowledge AL and Bronze is a big No-No.

Usual practice is to use SS fasteners with AL and coat the fasteners liberally with Aluma-plast or similar compound.

Rigging Shops/Aluminum Mast Makers should have it.

[Bergalia]

Originally Posted by Dave Fleming

To the best of my knowledge AL and Bronze is a big No-No.

Usual practice is to use SS fasteners with AL and coat the fasteners liberally with Aluma-plast or similar compound.

Rigging Shops/Aluminum Mast Makers should have it.

Thanks Dave. Took your advice. Earlier graphite grease made removal easy. Thoroughly cleaned the fasteners are now well coated in Aluma-plast.
Mind you, after the cash outlay, my old granny will have to wait a bit longer for her hip operation...
Must admit I was a bit doubtful about the branze/alum combination, but where possible I try to stick to original materials when rebuilding. On the other hand as she is a 'one-off' only the builder (half a century past) will know if the fittings are no longer 'original'.
But thanks again to all who waded in with their thoughts.

[FAST FRED]

I have had good luck using SS screws in aluminum when wrapped with plumbing tefflon tape,before instalation , they usually WILL come out .

Neverseze and other goops get really messy ,

FAST FRED

[marshmat]

I'll add my thoughts....

To stop stuff from seizing in the first place:
- Make sure metals are compatible!
- Coat bolt/screw threads with Loctite Anti-Seize before installation. (Even after 10years in terrible conditions, nuts with this on the threads come off easily.)

To get seized stuff out:
- Mastercraft makes a very handy gadget that looks a bit like the tip of a drill bit, only backwards and steeper. Placed in a reversible drill, it can easily bite into stripped heads. (Similar product may have different brand name elsewhere.)
- Impact wrenches are your friends. So is WD-40.
- And of course the old drill-out-and tap.....

[yokebutt]

Bergalia,

Aluminium, bronze and graphite together sounds like a frightful idea. Unfortunately, the graphite and aluminium has a .7 volt potential, wich means that with a bit of electrolyte you can actually run a tiny lightbulb off such a cell.

Use something that will isolate the two metals instead, perhaps a good ohm-meter could be of service.

Yoke.

[Bergalia]

Originally Posted by yokebutt

Bergalia,

Aluminium, bronze and graphite together sounds like a frightful idea. Unfortunately, the graphite and aluminium has a .7 volt potential, wich means that with a bit of electrolyte .... Yoke.

Now you tell me.....