Removing stainless bolts from vang/mast plate. advice, pleas

[Ereiss]

The plate that hold the bottom of the boom vang to the mast has 4 holes on each side containing (or formerly containing) stainless 1/4 screws. Three of them have broken, sheared at the interface of the mast and the stainless vang plate. I assume that was due to corrosion of the screws. I tried backing out the broken pieces but they didn't move. That leaves me the opportunity to drill them out and re-tap. Anyone have anything to share before I undertake this? Am I missing anything?

When replacing the screws I will use an anti-electrolysis material before inserting them (I bought the stuff from the UK but can't remember what it is called at this sec).

All advice would be appreciated.

Thanks

[katorpus]

Sounds like to me you're on the right track. I can't see that trying to back them out with an "EZ-Out" would work very well, but you might give it a try. Either way, a drill and some GOOD bits are going to be needed.

My booms are painted, and applying heat to try to "break the bond" by differential expansion of the dissimilar metals would be "out"...I assume you are in the same shape.

I'd suggest removing the boom and drilling/re-tapping on a drill press with sufficient stabilization of the boom while doing so. I think it would be worth the effort.

Trying to drill out a stainless steel screw that's "welded" into an aluminum boom (with a hand-held drill) could result in a mess and more "oversizing" of the replacement screws than you had contemplated (or want).

[GeoffSchultz]

I would also suggest using 1 or more penetrating oils on the bolts before starting this.

-- Geoff

[THATBOATGUY]

Some thoughts:

1. Kroil works better even than PB Blaster on stainless bolts corroded to aluminum spars.

2. Nothing beats the "heat wrench". If you still have a nub that you can grab with a vise-grip you can try pin-point heat on the bolt itself. I have o2/acet torch but I also have a little o2/map gas torch (available at the hardware store) that makes a great pin point flame for avoiding collateral heat damage and it's very portable.

3. If you go the drill route, first file the threads flush with surrounding surface and use a center punch before drilling. It is very difficult to do so without damaging the original threads. Not to worry. Drill oversize and go back with helicoil thread inserts. The big advantage with this is that from now on you will have stainless on stainless so that next time you have to pull those bolts out they will come out... with a little help from step 4.

4. And last but not least. Be kind to the next guy even if you go with the thread inserts.... use anti-seize. Furuno actually includes a little syringe of some stuff that works great but I've never found it on the open market. I just nurse the little I have from job to job but the Permatex product is great too.

George

[Michel]

I suppose you're talking machine screws here. An EZ-out tool can work if the screws are thick enough to drill holes in the ends of them. If extracting seized screws from carbon, take care not to break a chunk out of the carbon. As suggested, make liberal use of releasing agents. A bit of heat fed into the screw with a soldering iron can have a healthy effect too.

When mounting new screws it does not hurt to use a larger gauge screw to maximize thread length 1/4" (6mm) screws are a bit thin for good holding, I feel. I always use 8mm minimum in my masts to get more thread. When tapping in carbon fibre, take care of the following: the stuff is very brittle, keep your drill and taps very still! And use a smaller drill then the tap-manufacturer suggests for metals. I had a lot of problems with oversized holes. Only use the first and second tap if you use a tap-set of three taps. The third tap makes the threads so deep the tops will break because of the brittleness (is that a word?). I'm now more and more going to use monel riv-nuts when mounting hardware, but in the beefed-up area for the vang collar they are no use, nor are normal rivets. Always use Locktite; moving screws in CF ruin the holes.
Good luck.

EDIT: I just now saw George's post. Helicoils seem like a very good idea that I never thought of before for the mast, although my engine is full of them. In that case the 1/4" screws are fine.

[THATBOATGUY]

Egads Michel!

Glad you posted behind me. Everything I said above concerns stainless screws in aluminum spars. I have absolutely ZERO experience with carbon fiber spars and I yield those with the greater experience here. Mia culpa.

George

[Ereiss]

Thank you, team. I am told that there is a plate inside of the carbon mast which is glassed in to which the vang screws. So I don't think I would be really tapping the carbon fibre but the plate inside the mast. The Vang plate is (from memory) aluminum and the bolts are stainless. shame I can't light the anchor light with the current produced.

Has anyone had constructed (instead of my bolt arrangement) a girdling band that went around the mast? Any success with this arrangement?

Again, thank you for your help.

regards,

[katorpus]

It's my understanding that an external collar arrangement is what Garhauer uses with their rigid vangs, and that they have done many of these on Freedoms and have the templates etc so they can just "make one up"...seems I recall their prices for these collars were remarked on as being "VERY reasonable".

I'll bow to the experience of someone else...maybe we could make this a "New Topic" thread

[markedwards]

The 1/2" curved aluminum plate is set with epoxy to the inside of the spar. The bolts for the external Hall Quick Vang bracket were to be tapped through the mast wall into this plate. Corrsosion of course has been a problem so pretty quickly Freedom stopped using the aluminum plate and went to an external stainless ring that is fit around the mast with flanges bolted that squeeze the mast bracket around the mast with high durometer rubber material between the stainless wall and mast wall. Paul Dennis at Warren River Boatworks in Warren RI makes these up all the time. 401-245-6949. Give him a shout.

Mark Edwards

[Ereiss]

Thanks, Mark. I had actually spoken to Paul Dennis about it (Dwight had also made that suggestion) but Paul thought that reusing the existing set up was preferred. I don't recall his reasoning but I think from the pure engineering of it the wring is a better solution. If my tapping doesn't work I will go with a ring but I do have a mast step at the same height as where the vang connects to the mast. Oh, well, nothing is simple.

Wishing you and yours a wonderful holiday.

Regards