RutlandMike
Well-Known Member
Anyone tried these......?
- Thread starter RutlandMike
- Start date
Loginname
Well-Known Member
That looks like these
http://www.screwfix.com/prods/11923/Fixings/Cavity-Fixings/Metal-RediDrivas-35mm-Pack-of-100
The fixing is described as being "stronger than plasterboard"; hardly a ringing endorsement for marine use.
I don't think that the aluminium/steel mix is a good idea and I suspect that it would be better to just use a bigger screw.
http://www.screwfix.com/prods/11923/Fixings/Cavity-Fixings/Metal-RediDrivas-35mm-Pack-of-100
The fixing is described as being "stronger than plasterboard"; hardly a ringing endorsement for marine use.
I don't think that the aluminium/steel mix is a good idea and I suspect that it would be better to just use a bigger screw.
markdj
Well-Known Member
The very coarse thread would be useless in GRP, BUT...possibly...
...if it was epoxied in place then that would be very strong - the only thing is the holes in the shaft would allow the epoxy into the inner shaft thus removal of the screw would prove difficult and possibly damage the hold to the surrounding material or shear the head off the screw.
Do they come in stainless as I thought it was just galvanised?
...if it was epoxied in place then that would be very strong - the only thing is the holes in the shaft would allow the epoxy into the inner shaft thus removal of the screw would prove difficult and possibly damage the hold to the surrounding material or shear the head off the screw.
Do they come in stainless as I thought it was just galvanised?
Sixpence
Well-Known Member
[ QUOTE ]
Anyone tried these
[/ QUOTE ]
Yes /forums/images/graemlins/blush.gif
No idea about load bearing, but make sure you don't drill the hole too small or you risk craze cracking the GRP /forums/images/graemlins/blush.gif
Also depends on thickness of GRP because they're plasterboard fixings so the threads are set very coarse and in thin GRP they don't grip too well, or didn't for me anyway.
Anyone tried these
[/ QUOTE ]
Yes /forums/images/graemlins/blush.gif
No idea about load bearing, but make sure you don't drill the hole too small or you risk craze cracking the GRP /forums/images/graemlins/blush.gif
Also depends on thickness of GRP because they're plasterboard fixings so the threads are set very coarse and in thin GRP they don't grip too well, or didn't for me anyway.
Adamastor
Well-Known Member
Get some BigHead fastenings or the likes- proper marine-grade stuff. Not from your local swindlery- proper boatbuilding chandlers should be able to point you in the right direction.
RutlandMike
Well-Known Member
Thanks all. I hadn 't heard of the Bigfoot stuff before - looks excellent and painless. Thanks for the tip!
William_H
Well-Known Member
I like to simply drill and tap a hole for standard metal thread screws. I tend to do this even if I put a nut and washer on the other side. The tight thread provides better sealing and doesn't require another person to hold the screw while you put a nut on. olewill
markdj
Well-Known Member
The bigheads require access to the rear of the GRP which was one of the issues here.
http://www.bighead.co.uk/
There is an excellent article about fixing hardware to boats here
http://www.yachtsurvey.com/hardware_attachments.htm
and I think PBO did a comprehensive drawing based article on the various methods of attaching screws etc. to boats. Anyone know the month?
http://www.bighead.co.uk/
There is an excellent article about fixing hardware to boats here
http://www.yachtsurvey.com/hardware_attachments.htm
and I think PBO did a comprehensive drawing based article on the various methods of attaching screws etc. to boats. Anyone know the month?