Making a polymer flange

[Neeves]

I'm taking my turn to ask questions

We have a sump under the removable sole of our shower. The sump is simply a square box with a submersible pump with float switch. I have made a filter that fits, almost neatly into the open top of the box. I would like to make a flexible flange, gasket to seal the edge of the filter (which is close to the exact same dimensions as the box) to the top of the box. I want to be able to remove the filter to clean it.

So - my thought it silicone or sika (or something similar, or anything else) how do I ensure when I 'male' the flange from a conventional sealant gun that the chosen material does not stick to the box - what can I stick to the box, that will be removable, that silicone or ska will not adhere to.

For sika I can possibly use neat Fairy liquid? I've obviously never done this previously.

Jonathan

 

[VicS]

I'm taking my turn to ask questions

We have a sump under the removable sole of our shower. The sump is simply a square box with a submersible pump with float switch. I have made a filter that fits, almost neatly into the open top of the box. I would like to make a flexible flange, gasket to seal the edge of the filter (which is close to the exact same dimensions as the box) to the top of the box. I want to be able to remove the filter to clean it.

So - my thought it silicone or sika (or something similar, or anything else) how do I ensure when I 'male' the flange from a conventional sealant gun that the chosen material does not stick to the box - what can I stick to the box, that will be removable, that silicone or ska will not adhere to.

For sika I can possibly use neat Fairy liquid? I've obviously never done this previously.

Jonathan

I suppose is the mould release solution they use when making fibre glass things is one possibility

A light spray with silicone oil or polish would work ( but many will frown on the use of silicone)

Probably anything oily, waxy or a light grease will do. Or furniture polish

See Buy Release Agents - Wax, semi-permanent, PVA - East Coast Fibreglass Supplies

( but note that PVA release agent is not the same as PVA wood glue)

 

[lw395]

Ordinary polythene?
You might find sticking a gasket made from neoprene sheet using sikaflex to be less 'variable' than a thick wodge of sika?
For dinghy hatch covers I buy foam neoprene cord and stick it with superglue.

 

[bluerm166]

If its a small perimeter then I have used both parcel tape and electrical insulation tape .A sheet of polythene ( find a carrier bag or rubbish sack) works if the situation allows fixing flat.

 

[vyv_cox]

Avoid any silicone wax, grease or similar material. It inhibits the cure of many paints and resin systems. I always used wax furniture polish as a mould release for grp as a cheap alternative to buying the 'proper' wax polish release agent.

 

[differentroads]

I've used clingfilm to ensure release when 'moulding' a sikaflex bead as a hatch seal. Cetainly prevented sticking but left a few creases cos I used too much sealant and didn't take enough care getting the clingfilm straight. Bit of a rush job before setting off across Biscay.
The sikaflex also didn't fully cure before I had to dog down the hatches, so they were a bit difficult when it came to opening them 6 weeks later.
My other tip would be to use a sealant with adhesion qualities considerably less than sikaflex 292 e.g. sikaflex 291, though much cheaper sealants gor car windscreens might be a better choice.
Just don't use a silicone sealant. The adhesion to the surface that you want it to stick to will fail sooner or later. And the residual silicone prevents anytjing else sticking without a lot of sanding or grinding off. Previous owners of my boat were big fans of silicone and its a real pain fixing leaky deck fittings and beads of it pulling off sinks and worktops.

 

[thinwater]

I've done this before, just using 2 coats of a traditional paste wax (Colonite in my case). Waxed paper also works.

Yes, I've made filters that way before, coating the edge of the media with either PU or silicone and then clamping it in place very loosely. In fact, 100% silicone may work better in this application (yes, it has some uses on boats!); it will better resist hot water with soap, but this depends on whether it bonds well to the filter media.

 

[Neeves]

Thanks for the answers.

I confess - wax polish never occurred to me - a common problem, cannot see the wood for the trees. The power of having access to people not closely involved with the specific problem

This not one of those critical applications, safety is not involved - it would be just 'nice' to get it clean and neat. As its winter and no chance of going north to follow the sun there is plenty of time to explore these little tasks. Our State borders are still closed - though restrictions are easing and the population largely accepting.

The frame I cut as one piece from marine ply, a bit like a one piece picture frame, about A4 size (in fact it might be A4 size). It has then been well varnished. The sieve is attached with Sika and all smoothed off. The sump narrow, slightly, as it deepens so the sieve fits neatly into the top of the sump, except there are very slight gaps, maybe 1-2mm all round, primarily as I did not get the 'round' of the corners perfect. The sump is set into the shower floor with a removable base on top, simply a big slap of foam, glassed and with a non slip surface. The actually base of the shower 'falls' to the central sump - the false base is flat. I access the sump by simply lifting the fall base. I thought the easiest way was to close the gap with a flange or gasket, or all the crud (or some of it) will run through the gap into the sump and clog both pump and float switch. . I further thought if the flange 'ran up, 2 or 3mm,' the sides of the box at the top and narrowed to a thinnish film, that I could trim off with scissors to allow it to be strong enough, that would be the 'perfect' answer.

I was thinking if it were epoxy I was using I could just attach packing tape and run thickened epoxy into the gap - but I'm not using epoxy so wondered what the alternatives were. when making a flexible but removable seal. I though something flexible would be better than epoxy.

I have used cling film in the past, unsatisfactorily, I had the same problem getting it flat and if its overlapped on itself the Sika or silicone then sticks and adheres and you are also left with any wrinkles from the 'unflat' clingfilm. I think if you get it flat, say laid on a piece of glass, and stretched, it would be adequate but going round corners is difficult. I've never made a gasket or flange - so this is new to me. Usually I want the 'grout' to stick - not release!

Its small enough that I can try various options outlined in your recommendations - and see what works best. The answer appears to be wax - in some form or other. Furniture polish looks to be the easiest answer - and maybe the cheapest. I need to find a non silicone 'wax' - real wax. I agree with the problems of silicone - once used then getting anything else to stick is a nightmare (you need to abrade to get a clean surface) - like others I use silicone sparingly. I'll start with something like Sika and if that is not satisfactory move onto silicones.

If Sika works but fails later due to hot water, the water is pretty cool by the time it gets to the sump - but still soapy, then its not life threatening and I simply make a new frame, or a new flange.

Thank you, all, for taking the trouble to post.

Jonathan