Adam F Posted March 8, 2006 Report Share Posted March 8, 2006 I now have my 5mtr length of 50mmx5mm nylon courtesy of my frindly local trout farmer ....and intend to stick it to the bottom of BW as a sacrifical keel band. As it is lighweight and nylon, I intend only to Sikaflex it into position. 1.) Is this OK, or would a few (4ish) screws along the length be better? and 2.) Where can I get some Sikaflex - how much would I need, where is the best (cheapest!) place to buy or do any of you have a bit knocking around... Ta Adam Quote Link to comment Share on other sites More sharing options...
jack Posted March 8, 2006 Report Share Posted March 8, 2006 Sikaflex comes in a saltwater suitable grade I think its 291 but there are others so make sure.Also it has a short life once opened so no peaking before you are ready to use it.I got mine on the cheap from e-bay,but it was still pricey,But you gotta have the right thing for the job !! cheers jack Quote Link to comment Share on other sites More sharing options...
TomBettle Posted March 8, 2006 Report Share Posted March 8, 2006 Hi Adam Sikaflex 291 is tough stuff. Each year at Southampton Boat Show they build a little boat out of marine ply and sikaflex only! It should be more than tough enough so why screw into the bottom of your boat needlessly. One standard sized tube (310ml) and a caulking gun should be loads. In one of the most expensive chandleries you can find (Salterns) it is Quote Link to comment Share on other sites More sharing options...
crazy fred Posted March 8, 2006 Report Share Posted March 8, 2006 cobbs is about Quote Link to comment Share on other sites More sharing options...
Adam F Posted March 8, 2006 Author Report Share Posted March 8, 2006 Cheers guys - just ebayed a tube for Quote Link to comment Share on other sites More sharing options...
Afishionado Posted March 8, 2006 Report Share Posted March 8, 2006 Nylon due to the high silicone part of its make up is not too good at maintaining an adhesive bond, therefore although Sikaflex is an extremely good sealand and bonding agent IMO you would certainly need some mechanical fixings as well, but the spacings could be further apart than if you were useing a normal silicone sealant. Mad Mike Quote Link to comment Share on other sites More sharing options...
blueboatdriver Posted March 8, 2006 Report Share Posted March 8, 2006 Also the screws will hold the band in place while the sikoflex goes off. Quote Link to comment Share on other sites More sharing options...
TomBettle Posted March 8, 2006 Report Share Posted March 8, 2006 Good point. Would it help to key the surfaces first? Quote Link to comment Share on other sites More sharing options...
Afishionado Posted March 8, 2006 Report Share Posted March 8, 2006 Good point. Would it help to key the surfaces first? Not really, as the nylon has such a tight molecular structure there is no surface penetration by the adhesive. Roughing the Nylon up will only destroy the flat contact adhesive force of air pressure at 15lb per/sq.in. Mad Mike Quote Link to comment Share on other sites More sharing options...
Wedger Posted March 8, 2006 Report Share Posted March 8, 2006 Has anyone used 'Versatape' for the initial bond on a small boat keel band ? Mike, You might know of this stuff from the motor trade. It'll stick a wet breeze block to the ceiling............. Quote Link to comment Share on other sites More sharing options...
TomBettle Posted March 8, 2006 Report Share Posted March 8, 2006 Good point. Would it help to key the surfaces first? Not really, as the nylon has such a tight molecular structure there is no surface penetration by the adhesive. Roughing the Nylon up will only destroy the flat contact adhesive force of air pressure at 15lb per/sq.in. Mad Mike Blimey Mike You really need to be let out of that hospital more often! Quote Link to comment Share on other sites More sharing options...
Afishionado Posted March 8, 2006 Report Share Posted March 8, 2006 Good point. Would it help to key the surfaces first? Not really, as the nylon has such a tight molecular structure there is no surface penetration by the adhesive. Roughing the Nylon up will only destroy the flat contact adhesive force of air pressure at 15lb per/sq.in. Mad Mike Blimey Mike You really need to be let out of that hospital more often! As my good friend Scotty would say about me in Star Trek 1.............. He's life Tom but not as we know it! Mad Mike Quote Link to comment Share on other sites More sharing options...
Brian Posted March 8, 2006 Report Share Posted March 8, 2006 I would certainly screw it near the leading edge, because if it started to come away whilst you're motoring the water pressure would probably peal it off. Quote Link to comment Share on other sites More sharing options...
Coddy Posted March 8, 2006 Report Share Posted March 8, 2006 Hi all Came across this product Keelshield Looks interesting but seems exspensive. Coddy Quote Link to comment Share on other sites More sharing options...
britboard Posted March 8, 2006 Report Share Posted March 8, 2006 Good point. Would it help to key the surfaces first? Yes it would, Sikaflex is top stuff, but if there is any residue of the mould release agents or wax polishs on the gel it will not properly adhere. You will need to rub down the gel where you want the Sikaflex to bond with a light wet & dry enough to remove any glaze and then wipe clean with a rag soaked in acetone (nail varnish remover without perfume) this will ensure a clean suface. Then stick on your keel guard using Sikaflex, make sure you dont leave any gaps or dry bits otherwise the water will capillary straight behind it the first time you put it in the water, dont worry if you get too much on and it ends up being sqeezed out all over the place as it easy to wipe off with an acetone damp cloth before it sets. Try to a colour match for your hull then the overspills wont show to badly. good luck!! I used to make my living designing and building grp so if anyone needs advice please ask?? simon Quote Link to comment Share on other sites More sharing options...
Seamouse Posted March 9, 2006 Report Share Posted March 9, 2006 Adam, When I did my keel band, I found I could get access to the full length of the keel whilst on the trailer simply by removing the central keel rollers as required. Drilling and screwing holes was trickier as the boat had to be moved back several feet to get drill access for some holes. Make sure you hitch it to the car first, helps keep the nose down A useful tip when using sikaflex inboard for securing wiring channel or hardwood fixings - glue gun. Dollop the Sikaflex over the item to be glued down but leave two small patches clear. Fill these with a dab of hot melt from a glue gun, position the item and press firmly for a minute or so until the hot melt hardens. It'll then hold the whole plot in place overnight while the Sikaflex cures. Much easier than trying to hold items in place with props, or cobwebs of duct tape. Steve Quote Link to comment Share on other sites More sharing options...
Afishionado Posted March 9, 2006 Report Share Posted March 9, 2006 Quote........ Fill these with a dab of hot melt from a glue gun, position the item and press firmly for a minute or so until the hot melt hardens. It'll then hold the whole plot in place overnight while the Sikaflex cures What a bloody good idea Steve, thank you. Previous to seeing this I had made all sorts of Heath Robinson devices to enable me to jamb what I wanted fixing in place overnight. Brilliant, and so obviuous now you have pointed it out Mad Mike Quote Link to comment Share on other sites More sharing options...
great white Posted March 9, 2006 Report Share Posted March 9, 2006 Mike The hot melt glue gun has been a great purchase for my small project at home its great for holding all sorts of thing in place while tacking in with grp matting. then knock the blocks off, peal off the glue or clean off with a chisel and mat that side. Its going to save hours and loads of swearing Charlie Quote Link to comment Share on other sites More sharing options...
Afishionado Posted March 9, 2006 Report Share Posted March 9, 2006 I can see that now Charlie, it's so bloody obvious now, and I feel duly ashamed for not thinking of it my self. It's one of those wonderful ideas that come along every now and again. The club has proved it's worth once again. Mad Mike Got my builder mate round for a coffee at the moment and I passed this tip on to him, he too thinks it's a great idea. Naturaly I have claimed it as my own original thinking Quote Link to comment Share on other sites More sharing options...
jack Posted March 9, 2006 Report Share Posted March 9, 2006 QUOTE From Trevor {Wedger} Has anyone used 'Versatape' for the initial bond on a small boat keel band ? You might know of this stuff from the motor trade. [[ It'll stick a wet breeze block to tthe ceiling..}} C'MON TREVOR !! How do you know it will,and who the hell thought to try it..?Although I believe you !! jack Quote Link to comment Share on other sites More sharing options...
Wedger Posted March 9, 2006 Report Share Posted March 9, 2006 'course I've tried it Jack.................. I don't make idle statements of such a serious nature. Quote Link to comment Share on other sites More sharing options...
toerag Posted March 14, 2006 Report Share Posted March 14, 2006 PMSL!! Nice one wedger! I must also warn you that sikaflex sticks to everything you don't want it to, it's much more 'grabby' than silicone sealant. It doesn't peel off like silicone does once dry either, you have been warned!! Best to mask off either side of the area you're applying it to just in case. Quote Link to comment Share on other sites More sharing options...
Mike Fox Posted March 14, 2006 Report Share Posted March 14, 2006 Sikaflex also has the unusual property of making an incredible mess.... You get a bit on your finger, and dab it by accident elswehere on the boat. Both blobs somehow spookily remain exactly the same size. You then touch something else, and a further black blob appears - again the same size. It goes on and on like that until you notice...scientists say it can't happen, but I've seen the evidence. For some unusual reason, it NEVER does this when you're watching. It has a mind of it's own. That's why you have to watch really really carefully when using the stuff...and never try to pretend for one minute that it ISN'T watching you.... Mike PS....never, ever, check to see if it is dry. It won't be. Quote Link to comment Share on other sites More sharing options...
Mike Fox Posted March 15, 2006 Report Share Posted March 15, 2006 Also meant to say.... You throw away more than you use, mainly on masking tape, and acetone-soaked cloths; The tube goes "off" in a couple of days after opening, and is then useless; There's never a tube available in a small enough size. By the way, it's brilliant stuff! Mike Quote Link to comment Share on other sites More sharing options...
jack Posted March 15, 2006 Report Share Posted March 15, 2006 Nice one Trevor,I should have known you would be ready for me.. NOW THEN can anyone say how thick/thin Sikaflex is ? I have my unopened tube ready to fix the needlehole [caused by a BASS spine ] in the inflatable floor of my Zodiac.I hope to be able to inject some into the hole,so that it will be virtualy "an invisable mend " I plan to use the needle kit that comes with printer ink refill bottles [heavy duty job ].Does this seem feasable ? will it be thinner if warmed in water prior to use ? or can it be thinned slightly without affecting its efficiency ? .The answer to any or all of these questions would be much appreciated..jack Quote Link to comment Share on other sites More sharing options...
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