How To Replace These Screws?

[Sonosailor]

My Fountaine Pajot Tobago 35 has wrap-around acrylic windows on the salon held on with a combination of black foam rubber, glue and some round-head screws. The screws go through some oversized pre-drilled holes and into the sandwich of the salon wall. Please see the pictures. The rubber and glue are continuing to keep the water out and the acrylic in place, but the screws appear to be rusting in the rubber and need to be replaced. I attempted to tighten or loosen one, and the head could have been picked off with my finger. How might I replace these screws?

[rwidman]

Originally Posted by Sonosailor

My Fountaine Pajot Tobago 35 has wrap-around acrylic windows on the salon held on with a combination of black foam rubber, glue and some round-head screws. The screws go through some oversized pre-drilled holes and into the sandwich of the salon wall. Please see the pictures. The rubber and glue are continuing to keep the water out and the acrylic in place, but the screws appear to be rusting in the rubber and need to be replaced. I attempted to tighten or loosen one, and the head could have been picked off with my finger. How might I replace these screws?

You would drill a hole in them them and then remove them with an "easy out" (which usually isn't actually that easy). Directions should come with the easy out set. You might find examples on youtube.com.

[minaret]

Vice grips.

[leftbrainstuff]

Several options. I'll go through the pros and cons. Using some kroil oil, mouse milk or other penetrating oil will help things along. Except for 4.

1) impact driver. Requires a very solid non flexing structure. Not much use on anything composite.

2) Use a very long blade screwdriver with a properly sized phillips head. The twist you can generate provides good preload. Light taps with a dead blow hammer often help to break the fastener free.

3) drill out one size under the thread inside diameter. I typically use a center drill to get my hole started. I sharpen my drill bits by hand. Blunt bits are no use here. A normal drill bit has no stability for hole starting. If the head is mangled then you can use a dremel or die grinder to prepare your start point.

Sometimes you can use an ezi out or simply retap the original thread. You can try the short tapered ezi out. If they dont work you can use the longer parallel version. I usually just drill them out. Over the years I've done thousands so I can drill or cut straight and true.

4) use a stick or tig welder to either tack the rod or tack a rod. You then have something to crank on. I usually fashion a thin stainless backing plate to protect from sparks.

5) Cut away the plexiglass and use vice grips on the exposed head. I personally tend to prefer 3.

6) butcher it. I dont ever use this method. I have a motorsport background. Butchers we dont let anywhere near the tools. But for some it works.

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[atoll]

a big hammer,and just bang them through then replace with a bolt would be the quickest method!

however looks like you need to do some major surgery,using an" easy- out" will be very difficult .

if you can get behind the inner window frame I would suggest using small diameter hole cutter to cut away the fiberglass around the screw then remove the rested screw,fill hole with epoxy and redrill with new self tappers

[bstreep]

Before you do anything...

There are 2 ways to secure windows:

1) With an adhesive, such as Dow 795. In this case, the screws are primarily used to hold the windows in place while the adhesive sets.

2) With butyl tape and fasteners. This requires the fasteners to keep the window in place.

The difference between these is pretty obvious. Those with butyl tape have dozens of screws, the other has just a handful.

If your windows don't leak, I'd just leave them for now.

[gonesail]

wow those most be some really high quality screws used by fountaine pajot

[bsurvey]

switch to 316 stainless steel as your replacement fastening

[a64pilot]

Originally Posted by bstreep

If your windows don't leak, I'd just leave them for now.

Or pop the heads off if they are really that bad, and fill the holes with black silicone so your hiding the screws.
To replace the screws right would I believe require removal of the windows, and if I understand what is going on, that may break one and I assume you don't want this to turn into a major expense

[Privilege]

Also...when you replace the screws, keep them the same size. Polycarbonate windows expand and contract as they heat up and cool down. If the screws are a snug fit the window will crack as it expands.

[dfloeter]

No one has mentioned starting with a left handed drill bit. That way if the drill bit catches the screw enough to put some torque on it it is at least turning the right direction. Good luck.

[skipmac]

With the screw heads twisting off it will be almost impossible to drill a hole in the remaining screw shank to use an EZ-Out or reverse twist drill. An impact driver will just knock the screw heads off faster so that's out as well.

OP says the screws are into the fiberglass sandwich of the cabin sides. Unless there is epoxy or something similar in the holes then the screw shanks might be fairly easy to remove if you can get a grip. I would try a good set of needle nose pliers or if you have a pair of needle nose vise grip pliers try that.

If you can't remove the remaining screws that way then consider bstreeps suggestion. Are the screws there to hold the window in against bedding compound like butyl tape or just to hold the window in place while a permanent caulking/adhesive cured.

1. Is the window leaking or were the screws just used to hold the plexiglass in place while the adhesive dried. If they aren't leaking then I would lean towards putting a dab of sealer over the screw shank and leaving it alone.

2. If the windows are leaking then I think the easiest solution is atoll's that is come in from the back or drive the screws through. If that isn't acceptable (maybe cosmetically it will leave a hole in the interior wall) then you may end up having to enlarge the holes in the window to get to the screws and then may end up having to replace the plexiglass.

[Hawkeye]

What has actually happened to the SS screws that were installed is the three metals that combine to make stainless steel, which I think are iron, chromium, and a third I forget (could be manganese?) anyway, over time the elements making up the molecules migrate back to elements (there are several theories why, all are 'iffy' and boring) and the iron then rusts away, leaving crystallized chromium. It is brittle difficult to get a drill bit started. However, just below that troublesome layer is plain, undamaged stainless, which will drill if you can hold the bit centered in the hole.

Failure to hold the drill perfectly will result in it running off and damaging, maybe ever cracking, the plastic. A bummer. Possible leak, and more problems. Do not go at this without preparing properly. More on that in a moment.

It is common for only a few of the screws to have gone south, while many others are fine. get at least one good screw out and replace it with quality screws and a good caulk, like Boatlife. Avoid straight silicone if you can.

Once you have completed all the ones you can and have only the rotted shanks left, you can prepare for them. Find a way to see if you can get at the screw tips from inside the boat, where a careful bit of work with a small pair of vice grips might simplify get the dead shanks out. If not, or, if only a few can be cured that way, and you still have to get at the others with a drill bit, you need to get clever.

You say the screws are in oversize holes, which is a blessing. Carefully clean out the hole between the dead shank and the plastic with a sharp scribe or dental pick and measure the hole diameter. go to the local auto parts store and see if the have some steel brake line that will fit into the hole. Once you find some, cut off an inch of it, deburr it, and press it into a drilled hole in a small block of wood so that about 1/16 of an inch of the tubing is poking through the bottom and the wooden block can sit flat on the plastic with the tube sticking down into the hole. Now you have a jig to prevent damaging the plastic.

Select the largest drill you can that will fit through the tub without binding and carefully, at slow drill speed, clean up the top of the broken screw. It will feel and sound 'crunchy' at first, then smooth out. Stop there.

You should have a clean divot, dead center in the dead shank, which will guide your smaller drill right where you want it. Complete this action on all the broken screws before going to the next step.

Now, stainless steel is tough to drill and gets hot fast, but with sharp, new buts and a little lube, and care, it drills just fine. Too big a drill will leave nothing in the hole but the threads, and that's no good. Too small a drill will either snap off, or not allow the easy-out (screw extractor) in far enough to get a grip. You have to examine the screws you were able to safely remove and select a drill size of exactly the right size.

When you begin drilling into the screws, go slow and keep pulling the drill back to clear the chips. It is possible during this that any old sealer holding the shank will heat up, break loose, and the screw may start sinking. Stop immediately. Have the easy out ready, and quickly try to withdraw the screw. If it sticks partway out, that may just be the old sealer cooling due to the heatsink effect of the easy out, but the extractor should still overpower it and get the screws out.

This all seems elaborate and tedious. but when you are done, without damage to the plastic or the boat, it will be well worth it, and you'll have a great tale to bore others with during sundown cocktails.

[Cheechako]

I seriously doubt you are going to be able to drill that small a SS screw for an easy out. You are likely in for a window removal and rebedding. The other option being just fill the holes as stated above and let the bedding hold the windows.
316 screws are a tiny bit better but they will likely do the same thing over time.

[rwidman]

What this forum needs is a smiley for making a mountain out of molehill!