Reply
 
Thread Tools Search this Thread
 
Old 17 May 2005, 08:38   #1
DGR
Member
 
Country: UK - Wales
Town: Barmouth
Boat name: Blue Marlin
Make: Ribcraft
Length: 7m +
Engine: Yanmar 315/Bravo 2X
MMSI: 235020218
Join Date: Jun 2003
Posts: 827
Mounting stuff on GRP

I've done a search on screwing things into GRP to secure them, but I'm unclear on a couple of things - so before I stick a drill into my console...

I'm only attaching small things which won't need to take huge loads, i.e. extinguisher ports on the engine box, air vent on the console etc. From looking at the threads there seems to be different ways of doing it:

1) drilling the pilot hole and self tapping into the GRP, or

2) over drilling the hole, filling with sikaflex, and then drilling/self tapping into the sikaflex.

Is there a 'best' way of doing it to give the best finish?!?

Dylan...
__________________

__________________
DGR is offline   Reply With Quote
Old 17 May 2005, 09:13   #2
RIBnet supporter
 
Erin's Avatar
 
Country: UK - Channel Islands
Town: A large rock
Boat name: La Frette
Make: Osprey Vipermax
Length: 6m +
Engine: 200 Suzzy
Join Date: May 2004
Posts: 2,830
I always just pilot drill a hole through the gel coat with a drill larger than the screw thread, and then let the screw self tap into the fibreglass beneath. I find that if you don't break through the gel coat then it fractures when the screw gets driven through and can look unsightly.

Worth putting a bit of Sikkaflex behind whatever it is your'e mounting to add a bit of waterproofing.

Keith
__________________
Erin is offline   Reply With Quote
Old 17 May 2005, 09:28   #3
DGR
Member
 
Country: UK - Wales
Town: Barmouth
Boat name: Blue Marlin
Make: Ribcraft
Length: 7m +
Engine: Yanmar 315/Bravo 2X
MMSI: 235020218
Join Date: Jun 2003
Posts: 827
OK - so just to get this straight...

(1) You drill an oversized hole just through the gel-coat laywer to stop it cracking and looking messy

(2) and then let the screw self-tap through the GRP (i.e. you don't drill a pilot hole all the way through the GRP first?)

(3) and once finished, just put a bit of sikaflex on the back where the self-tapper has penetrated the console on the inside to keep waterproof?

Is that right?

D...
__________________
DGR is offline   Reply With Quote
Old 17 May 2005, 09:32   #4
Member
 
Country: UK - England
Town: I.O.W/Bristol
Boat name: HotShot
Make: shakey
Length: 5m +
Engine: 70hp Tohatsu
Join Date: Jul 2003
Posts: 1,543
The way I have always done it is to drill a pilot hole smaller than the thread all the way through (I guess it could be half way...doesn't really matter), then cover the thread and underside of the screw head with silicon sealer (less of a glue than skiaflex which means it'll be easier to take out), then screw it in nice and tight. The sealant will squish out around the screw as its tightened up but it can then be wiped off with a rag to make it look neat. This way it minimises the risk of water getting into the hole and soaking into the laminate.

Tim
__________________
slimtim is offline   Reply With Quote
Old 17 May 2005, 11:24   #5
RIBnet supporter
 
Erin's Avatar
 
Country: UK - Channel Islands
Town: A large rock
Boat name: La Frette
Make: Osprey Vipermax
Length: 6m +
Engine: 200 Suzzy
Join Date: May 2004
Posts: 2,830
Yeah pretty much right but depending on the size of screw you may need to pilot drill a hole right through the GRP. Also best to put the sikkaflex or sealant on the outside face of the console before tightening up the screw as mentioned above.
__________________
Erin is offline   Reply With Quote
Old 17 May 2005, 11:29   #6
DGR
Member
 
Country: UK - Wales
Town: Barmouth
Boat name: Blue Marlin
Make: Ribcraft
Length: 7m +
Engine: Yanmar 315/Bravo 2X
MMSI: 235020218
Join Date: Jun 2003
Posts: 827
Thanks guys - much happier now.........

__________________
DGR is offline   Reply With Quote
Old 17 May 2005, 12:22   #7
RIBnet supporter
 
nugent's Avatar
 
Country: UK - England
Town: Bromsgrove
Boat name: Kick-Ass !
Make: PAC/Artic 22
Length: 6m +
Engine: 250hp Yamaha
Join Date: Nov 2003
Posts: 3,385
i actually prefer s/steel nut and bolt on every thing if you can get behind it + silkaflex or every day silicoln will stop any water absorbing into glassfibre.

i have large bag of M4-m6+ machine screws and nyloc nuts awaiting my rib to arrive..friday i ope in case i need to change any self tappers that are present, as they allways work loose in the end
__________________

MY BIGGEST WORRY IS THAT MY WIFE(WHEN I"M DEAD)WILL SELL MY TOY'S FOR WHAT I SAID I PAID FOR THEM.
nugent is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 23:54.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.