On 06/06/2021 12:36, T i m wrote:
On Sun, 6 Jun 2021 10:17:44 +0100, newshound
wrote:
snip
I'd cut several 100 mm long strips of CSM about 20mm wide and with the
stub held securely in place, glass the strips round the pipe like 'L
brackets' and flower petals and do the same again, overlapping the
first layer and then a circular collar over that with the middle cut
like a star (out to the 68mm diameter) and then a band round the stub,
to just pin down any lose ends (woven roving / bandage better than CSM
for that last bit. I probably have some here you can have (stick in
the post etc)).
Or, for less effort, you could use a 3 inch bulkhead fitting or tank
connector (same thing, two different names) connected with flexible
hose. You might get away with a 2 inch.
I think Tim was quite specific in his requirements (if not directly
mateable to 68mm stuff). ;-)
Well the short answer to that,
AFAIK, is that the only official fittings
you will get for drain pipe are for gutters, spouts, and tees. And I
agree that the petal approach should work if the penetration has to be
67mm pipe.
Also, if he does line this tank with fibreglass he might need to glass
in a smooth collar of some sort if using a bulkhead / flanged fitting,
or use some additional sealant to ensure it seals against the back of
fibreglass?
There's a choice there, if the tank is good he can seal against the
tank, and then fibreglass over it. Alternatively try to get a smooth
layer of fibreglass that the standard washer will seal against, or
perhaps use a thick washer made from closed cell foam.
I made an interesting discover the other day. I needed to fit some of
this stuff (two inch, actually) over the threads of another fitting that
was just too big. I popped the end of the hose in boiling water for a
minute or two and it became soft enough to push straight on.
Was the 'discover' doing that on that large a profile or in general?
Well, it was on two inch MM pipe that was definitely not going on to the
threaded boss "cold". I've often used the hot water trick on garden
hoses, and on various nylon or PVC "fuel pipe". But I was interested to
find that the reinforcing "spring" in the Machine Mart hose, which is a
very tough thermoplastic, does in fact soften very satisfactorily in
boiling water while still retaining enough strength to grip when pushed
on to the threads. I just thought others might find that information
useful. The pipe looks and feels superficially as though the "spring"
could be metal, in which case of course the approach would not work.
I've done various other sorts of bodge on that type of hose before, on
the previous connection I needed to attach it to something like domestic
sink waste pipe, and I did that by wrapping the pipe with Sylglas/Denso
Tape and twisting that inside the MM hose. Followed up with my favourite
wrapping with PVC electrical tape under tension.
I secured
it in that case with a few layers of PVC tape as it does not see much
pressure, and small leaks wouldn't matter. I suspect if you used a
jubilee clip, especially when it was warm, it would be very effective.
Or a few turns of galvanised garden wire twisted up at the end?
https://www.machinemart.co.uk/p/3in-reinforced-hose/
Yeah, that sort of construction pipe is often used on boats and in
caravans (for waste / bilge pumps, where I have sometime used the
warming trick).
Cheers, T i m