Best way to plug a 1.25" hole on inside of hardtop?

LaRea

Can anybody suggest a good, clean way to plug a 1.25" hole drilled into the inside surface of a fiberglass hardtop?  It's a cosmetic plug (not water-tight) that needs to be removable.  

The surface might be slightly curved.

The reason is that I need to install additional safety rails on the outside of my hardtop.  That means I need to drill some holes:  1/4" bolt holes through the outer layer, and 1.25" through the inner layer so I can insert a backing washer and nut.  

Or, if somebody has a better idea for how to install grab rails, I'd love to hear it.

Michael T

Would a self tapping screw with 5200 handle the "pull". The loading should not be that much? Pre drill smaller holes first. I installed two 8" cleats for fenders just below the hard top in the fiberglass and screws with 5200 worked great and the fenders get a lot of pull on then in locks and at docks.

LaRea

The rails I bought have 1/4" bolts like this:

Maybe I should look for different ones.  It sure would be easier without thru-bolting. But I wonder if it would be strong enough to hold the weight of a person in rough seas.   

frenchship

Hi,
those type of plug are available In most hardware store or any woodwork shop.
Paul

LaRea

Merci!  If I can find locations where the inside surface is flat, this will be the way to go.

Michael T

I'd make sure to seal the edges of the holes I drilled in the underside of the hard top as aluminum tends to corrode very quickly when exposed to salt moisture. Easy enough to do but I'd do it right away before it got started.

rasbury

with a 1.25 plug? Did I win?

aero3113

Maybe you can find some weather resistant vinyl tape. Cut to size and stick it on!

rasbury

sorry, I could not resist....I sure would think that you can run some screws in the hard top and have plenty of holding power no problem- don't under estimate the power of a good screw. Maybe you can use the same rail with a different fastener .

frenchship

LaRea,
if you used rubber (flexible)one even if the surface is not flat it would look good. The are 1/12" and available on eBay.com and they are white

Michael T

Ras I would never underestimate the power of a good screw! :-)

frenchship

Should have read 1 1/2 inches

MarkB

Frenchship that's exactly what I was thinking about.

frenchship

For a grab bar I really think that you need a backing plate. If you use a screw there has to be enough material thickness so it would hold securely, I don't think it is the case with the hard top wich probably as a void between inner and outer skin.

Michael T

On the EC 360 there are two aluminum sides about 2 inches apart. Each side is about1/8" or more thick. I think a screw or threaded nut would hold but if the handle were pulled sideways hard I could see it bending the aluminum. I guess better safe than sorry.

LaRea

Mine is fiberglass, and from memory the outer skin is about 1/2".  My thinking if I'm holding the rail and my feet slip out from under me, the rail had better hold my weight.  So I don't think a screw mount is a good choice.  Also, I looked last night and all the rails I saw are stud mount like the ones I bought.

So I guess I'm stuck with having holes and plugs on the inside.