Screwing into thin GRP (without subsequent tear out)

RobF

RobF

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To preserve some dignity to my wife, I've 'invested' in a pleat style blind to go over one portlights in the aft cabin. However, the GRP 'lining' is pretty thin (perhaps 3mm) and the blind is secured by 4 screws, attached to press studs at each corner. I'm a bit concerned that a hard pull on one of the press studs wll simply pull the screw out, potentially damaging the GRP skin that it's been screwed into.

I guess I could fit a thin batten which is glued to the GRP and use this as extra thickness for the screws. . Are there any better ideas, please?
 
I think a press stud particularly if slightly corroded will exert enough force to pull the screw out even if bonded. Velcro could look ugly when the blind isn't in place. Have you looked at bonding anchor nuts in the lining skin, and using set screws instead of self tappers? Or plastic blind fasteners as used on car trims?
 
RobF said:
To preserve some dignity to my wife, I've 'invested' in a pleat style blind to go over one portlights in the aft cabin. However, the GRP 'lining' is pretty thin (perhaps 3mm) and the blind is secured by 4 screws, attached to press studs at each corner. I'm a bit concerned that a hard pull on one of the press studs wll simply pull the screw out, potentially damaging the GRP skin that it's been screwed into.

I guess I could fit a thin batten which is glued to the GRP and use this as extra thickness for the screws. . Are there any better ideas, please?
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Is this an "Oceanair" type of pleated blind? My boat had these fitted as standard, screwed in to the thin(ish) liner, and has been fine for years.
 
pvb said:
Is this an "Oceanair" type of pleated blind? My boat had these fitted as standard, screwed in to the thin(ish) liner, and has been fine for years.
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That was either a very lucky guess, or you really know your boats and equipment. :)
Yup, Oceanair. Really appreciate this info. Thanks.
 
How's about replacing the press studs with neodymium magnets bonded into the GRP., with other halves of the magnet pairs sewn into hem of the blinds. It won't take much force to take down or put up, but there will be more than enough holding power for the blind to stay there when wanted.

Scratch that. Too much faff. If you ever are really concerned about the screw attachment as it is, you can always drill an oversized hole at each press stud location and fill with thickened epoxy befor redrilling the correct size hole. You'll get a much stronger screw assembly that way.
 
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I thought I had posted a reply ...

I have a similar problem. I have to screw rowlock sockets to the double-skinned gunwale of a Bobbin dinghy with no possible access to the back. One rowlock pulled out on the very first stroke because, it turns out, the skin is thin and slightly split. Plan B failed completely, because it turns out that Sikaflex doesn't stick, even slightly, to plastic rowlock sockets.

Plan B is therefore to insert a chewing gum sized piece of epoxy putty down the hole for the socket and squidge it into place behind each screw hole. If it sticks OK to the underside of the GRP I can drill and screw into it when it has set. OP, if you have any access to the back of the linings, would that work for you?
 
HissyFit said:
How's about replacing the press studs with neodymium magnets bonded into the GRP., with other halves of the magnet pairs sewn into hem of the blinds. It won't take much force to take down or put up, but there will be more than enough holding power for the blind to stay there when wanted.
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Seems like a good idea, but these magnets tend to rust. I used some to secure blinds on my companionway doors, and they've rusted quite badly.
 
pvb said:
Seems like a good idea, but these magnets tend to rust. I used some to secure blinds on my companionway doors, and they've rusted quite badly.
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I only have a set for creating a ghost chess board, so have never put them to use in a harsh environment. Are yours exposed or encapsulated?
 
JumbleDuck said:
... Plan B is therefore to insert a chewing gum sized piece of epoxy putty down the hole for the socket and squidge it into place behind each screw hole. If it sticks OK to the underside of the GRP I can drill and screw into it when it has set. OP, if you have any access to the back of the linings, would that work for you?
Click to expand...

I had thought about creating a lumps of thickened epoxy to drill into for the screws (have been watching too much Sail Life). However, I assumed there was no way to access the void behind the inner liner. However, on reflection of your post, I could always take out the entire hatch frame and see if this gives me the access I need between the inner skin and the hull.
 
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