Which Sikaflex

mlines

Well-Known Member
Joined
31 Aug 2009
Messages
2,038
Location
Finchampstead, Wokingham, Berks
www.sportsboat.org.uk
I have fitted underwater LEDs today. For now they are dry fitted whilst I complete the wiring. The instructions say that when work is complete they should be sealed in place. They are underwater and the led housing will get warm. Which sikaflex number should I use?

Martin
 
Martin -- Are you sure they said Dry-Fit first then use Sikaflex / 3M 4200 ?

Reason for asking is that 'for most lights' the SIKA/3M forms a 'bed' between the underwater light and the hull which shouldn't be totally squeezed out during tightening. Nothing to do with heat -- all to do with making watertight .
 
When I said "dry-fit" I meant cutting the holes and test installing for fitment and wiring. They will be removed and, as you say, bedded in on sealant. The instruction say to install and check everything before sealing.
Martin
Me stupid :roll eyes:

BTW 3M 4200 is better than 281 in our experience -- only in that seems to go off that little bit faster. No big deal one way or another.
 
Yep. Also works nicely as a general thread sealant on the inside fittings that you attach to the skin fittings
(I'd prefer bronze to brass though!)
Thanks John
Sorry to confuse ,its actually a bronze transducer ( Airmar B60) going on to a GRP hull. 3M4200 Still ok?
 
Thanks John
Sorry to confuse ,its actually a bronze transducer ( Airmar B60) going on to a GRP hull. 3M4200 Still ok?
Ah yes. Those "B" airmars are top quality and are in bronze casings. Yes 3M 4200 will be fine for that, as would sika 291. I have one B60 and a pair of B175s installed with 4200 and 291 respectively, into GRP, and they are and have been perfectly fine. Also my underwater lights, made from aluminium-bronze alloy, are all installed into GRP with 4200 and they are fine too

When you have installed the airmar you might think to clean it up on the inside by wiping with acetone on a rag. Perfectly good idea, as it cleans up excess adhesive nicely, but it also rubs off the printed product details from the top of the transducer, which is really annoying. Don't ask me how I know this...
 
Last edited:
Ah yes. Those "B" airmars are top quality and are in bronze casings. Yes 3M 4200 will be fine for that, as would sika 291. I have one B60 and a pair of B175s installed with 4200 and 291 respectively, into GRP, and they are and have been perfectly fine. Also my underwater lights, made from aluminium-bronze alloy, are all installed into GRP with 4200 and they are fine too

When you have installed the airmar you might think to clean it up on the inside by wiping with acetone on a rag. Perfectly good idea, as it cleans up excess adhesive nicely, but it also rubs off the printed product details from the top of the transducer, which is really annoying. Don't ask me how I know this...

thanks very much for your response John, most helpful.
 
CT1 (Colloquially known as Jimkin) is amazing stuff. Stick 2 elephants by the tail with it and they wont pull apart. I use it for all sorts. For marine use it is incredible. Best stuff I have ever used......................................................... No I am not a rep

Dennis
 
Top