Bronze/aluminium freeze-up

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....

 

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

 

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.

 

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....

 

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.

 

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.

 

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

 

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.....

 

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.

 

Now you tell me.....