Fernox 603022 Ls-X Leak Sealer External, 50 g

This is just like aquarium sealant, which works out cheaper, but requires a caulk gun, and I didn't want to have to use one every time I want to seal a joint. Brilliant for screw-in or push-in irrigation or hose fittings instead of PTFE tape - works a lot better. You can undo the connections, although might require a bit more strength than PTFE sealed joints. It also sticks to most surfaces, including to PP (polypropylene plastic) - tried other solutions, but none worked as well as this. I sand down the plastic, make sure surface is clean & dry and use quite a lot. For example, sealing the outflow on a water barrel.. my application was not that, but it's a comparable job. For screw-in connections or surfaces with better adhesion, you don't need a lot.You can put it on wet surfaces but it's a lot easier if they're dry - if it's still leaking, I find it much harder to get a good seal, and it definitely won't work if the system is under pressure, but other than that, it's worked every time for me.I've not yet tried to seal fittings in LDPE/HDPE (normally nothing will stick to it) pipes, but think it would work if connections/fittings are PP or that black rubbery stuff (it defo sticks to those).It sets quite quickly - in low pressure systems, provides a good seal within an hour to few hours, depending how thick. It starts setting within 10 mins, so you have to work quite quickly.You can't sand and paint it like plumber's epoxy, as it's still flexible when dry, but personally, I found plumber's epoxy horrible - nowhere near as good as this.I didn’t find it that easy to work with, but that's inherent in the material - it's not quite as sticky as most glues, but same consistency, and tends to stick to tools or hands. I tried various tools to apply or smooth it (a washing-up liquid wetted knife is recommended, I think), but found fingers work best for me - I also can't ever get filler smooth, so maybe it's just me (as you can see, it’s not smooth!).It can be hard to remove from skin - I found baby wipes best, for both skin and cleaning tools. It’s keeping well so far (3 months), a dry layer forms on the opening, but it's easy to remove.I will definitely buy this again when I run out, and would recommend this for all sorts of jobs...

I first used this sealer way back in the early nineties to fix a leak in a hot water boiler tank in a mobile home, it worked superbly, and over the years it’s continued to serve me well on every application I’ve put it to. This time round I needed it to seal a puncture in the inflatable ring of an inter self riser swimming pool, and again it gave excellent results, what I like most about this stuff, is the fact that you can use it under water to seal leaks, cracks and punctures whilst tanks, radiators, pools, and the like are still in use. Fernox is without doubt the best leak sealer on the market, I reach for it every time, and after 27 years of use, it’s never let me down, it’s the same formula today as it was then, and that’s because you can’t improve upon perfection.

Great product which has helped me out a lot over the years. Very effective on leaks and will ensure a good seal on old plastic pipework especially those that run under the sink and flooring. Equally easy to undo joints that have been sealed with LS-X for years. My only bugbear is that it tends to cure itself in the tube and I have to resort to clipping the bottom of the tube off to get the stuff out.

Was really struggling to stop a slight leak on new radiator valves. In the end ptfe tape wasn't working. I bought this and put some on with some ptfe tape as well and I've had no problems since. Worked wonders and it's been 3months with not a single drop of water. I honestly think this might of done the job itself, it's think and easy to use and you will still be able to remove the valve after using this with just a little extra force so don't worry about doing things wrong. Highly recommend

Perfect joint sealer for plumbing jobs

Tried to stop a leak with this and it initially worked. Can't fault the product but as the leak got worse this did not hold and needed plumber to replace and resolder joint. Expect this would work for minor drip or as a stop gap.

worked perfectly. To use. Check how far piece screws in without sealent. Then ptfe tape, coat inside of rad with sealent also put some on outside of pipe then. Screw in to full depth. Job done

If you're doing any kind of work this is the compound to use - yes 'Boss White' has had its day.Having had some valves / tails on rads replaced with leaks by 'professionals' - I decided to DIY, replacing the old olives - that again 'professionals' left and using this not Boss White - and hey presto 20 valves+lock-shields replaced and not 1 leak (so far!). Maybe there is better stuff but this is more than enough - sticks like glue but you can still unscrew and replace valve just fine.I cannot think of a time I've been more impressed by a product - from leaks almost everywhere other people touched - this stuff + my rubbish DIY stills have come up golden 22 times - yes went back and re-done their work too with no issues. What else can I say?