Cycling UK Forum

I have a Robert Saunders Space Packer Plus - 3rd one I have owned (1 stolen, one the UV got to the flysheet).
The last time I used it (last autumn) I noticed the what I suspect is the water proof coating is coming off from the innerside of the flysheet - see photo, the paler spots are where I think the coating has come off.
Question, can this sort of coating be replaced, if so, with what? If it can be recoated, is it a good solution, or a so - so solution?
The reast of the tent is in good order, and the flysheet is its original shade of green so I would say no/minimal UV degredation.
I have not used it in the rain to test the proofing.
If recoating not a good solution, I'll be in the market for a new tent!

Are you looking for DIY solutions (!) or sending it to a specialist?

Thanks

Jonathan

The fly should be coated both sides.

Is it actually leaking?

I'm not sure if it is leaking. In recent years most of my camping has been for 2 with a bigger tent . I'm not sure when I last used it in the rain (lucky me!). Slight leaking of course might look a bit like condensation. There is the odd leak through the seams - I have seam sealed these and it mostly had worked proofing the seams.
I guess I'll have to up it up in the garden on a rainy day to be sure, can't do that for a week or more as we are away for the next week.

PT1029 wrote: ↑1 Jun 2022, 6:52am I'm not sure if it is leaking.

The method Terra Nova recommend (Insist you do before returning a leaking tent under warranty) is to suspend a section over a bucket so it makes a hollow and fill that with water.
The more important aspect IMO is how well water beads and runs off. It's this DWR coating that can wear off and be re-applied. There's several products available and you'll find people have used them all with varying levels of success. It works if it sticks and there's an issue with that, it sticks well to itself, or to new fabric, but it's inconsistent on anything else. I did a fly with the Nikwax product, in a hand spray bottle, It worked fine for a couple of years, maybe 30 nights, a few showers but on serious rain. Then a wet week in Scotland and it was back to how it was before.

PH wrote: ↑1 Jun 2022, 11:20am

PT1029 wrote: ↑1 Jun 2022, 6:52am I'm not sure if it is leaking.

The method Terra Nova recommend (Insist you do before returning a leaking tent under warranty) is to suspend a section over a bucket so it makes a hollow and fill that with water.

Same method was suggested to me by the late Robert Saunders (for a suspected leaky groundsheet, turned out it was just condensation)

PH wrote: ↑1 Jun 2022, 11:20am The more important aspect IMO is how well water beads and runs off.

I'm not convinced this is "more important". Fundamentally, you can have a waterproof fabric that doesn't bead up, and you can have a leaky fabric where it does bead up. It's good if it beads up and is waterproof (because it's easier to shake dry and you end up carrying less water around in your baggage), but I'd suggest that if you want to stay dry then waterproof is more important than beading performance.

PH wrote: ↑1 Jun 2022, 11:20amIt's this DWR coating that can wear off and be re-applied.

Indeed, but if it's leaky you can take things from rubbish to merely bad with a beading coat refresh but fundamentally you need a new fly (not really possible on a Saunders any more, sadly).

Pete.

pjclinch wrote: ↑2 Jun 2022, 1:51pm

PH wrote: ↑1 Jun 2022, 11:20am The more important aspect IMO is how well water beads and runs off.

I'm not convinced this is "more important". Fundamentally, you can have a waterproof fabric that doesn't bead up, and you can have a leaky fabric where it does bead up. It's good if it beads up and is waterproof (because it's easier to shake dry and you end up carrying less water around in your baggage), but I'd suggest that if you want to stay dry then waterproof is more important than beading performance.
Pete.

My understanding is that the waterproofness of the fabric comes from the absorbency of the threads and the weave, neither of these things change much with age. The fabric isn't likely to lose much of it's waterproofness, the chances are without the DWR coating it was never 100% anyway. By the time that's been lost (UV degradation, damage, stretch) it's going to be knackered anyway. The other element of course is that a wetted out fly is an invitation to condensation, which is then often misinterpreted as water having come through (Hence TN insisting you do that test).
I used to be involved in the manufacture of tarpaulins and marquees (Before they all went plastic), though a different scale to camping tents the principals are the same, water is going to take the easiest course, you don't have to worry about it seeping through if you can get it to roll off.

Did RS not use "Silnylon" i.e. Silicon coated Nylon.

There are spray on silicon solutions either in aerosol or for use through an applicator such as a garden type (aphid) sprayer.
As above, the silicon layer causes water to bead and run off before it has a chance to soak into the fabric of the fly.

jimlews wrote: ↑2 Jun 2022, 7:03pm Did RS not use "Silnylon" i.e. Silicon coated Nylon.

There are spray on silicon solutions either in aerosol or for use through an applicator such as a garden type (aphid) sprayer.
As above, the silicon layer causes water to bead and run off before it has a chance to soak into the fabric of the fly.

RS used both. IIRC the Spacepacker 1 used silnylon, the 2 used a PU coated polyester.

Pete.

PH wrote: ↑2 Jun 2022, 3:22pm
My understanding is that the waterproofness of the fabric comes from the absorbency of the threads and the weave, neither of these things change much with age.

That's a thing for canvas, but synthetics are kept waterproof through the coating, typically on both sides but you only need one.

PH wrote: ↑2 Jun 2022, 3:22pmThe other element of course is that a wetted out fly is an invitation to condensation, which is then often misinterpreted as water having come through (Hence TN insisting you do that test).

They're all condensation traps because of the impermeable coating: that's why coats stopped using them in favour of "breathable" fabrics, but synthetic tent flys (and groundsheets) aren't, for the most part, breathable. A wet out fly will be worse still, but in any case you will have a large, relatively cool, impermeable surface.

PH wrote: ↑2 Jun 2022, 3:22pmI used to be involved in the manufacture of tarpaulins and marquees (Before they all went plastic), though a different scale to camping tents the principals are the same, water is going to take the easiest course, you don't have to worry about it seeping through if you can get it to roll off.

That's the point of a DWR on a coat (and on a cotton canvas fly), but it's not enough to keep something waterproof, hence the layer of Goretex etc., or some coating. But it's the impermeable barrier that stops the water, while the DWR keeps things lighter by stopping water soaking in, quicker drying and, where applicable, breathable. Those are all useful, but it's the inner layer of PU or silicone that will keep it waterproof whether or not water's rolling off.

But aside from specialist one-layer designs with breathable flys, synthetic tents are almost all made from impermeable fabrics where it's the coating on the fabric that keeps the water out. The fabric is there in large part to anchor the coating!

Pete.

On older Egyptian cotton tents such as Itsa etc. the 'waterproofness' derived from the wetting. Water filled the interstices between the threads effectively (or not) preventing water passing through into the tent because of surface tension. The higher the dernier the more water resistant. Hence, Ventile. I remember being warned to never touch the interior of the flysheet as that would break the surface tension and cause a drip.

jimlews wrote: ↑10 Jun 2022, 8:53am On older Egyptian cotton tents such as Itsa etc. the 'waterproofness' derived from the wetting. Water filled the interstices between the threads effectively (or not) preventing water passing through into the tent because of surface tension. The higher the dernier the more water resistant. Hence, Ventile. I remember being warned to never touch the interior of the flysheet as that would break the surface tension and cause a drip.

That's my understanding too. (though I think that might be lower denier, not higher). A crucial point with cotton is when it gets wet it swells up, so a fine woven cotton tends to fill the holes in its own weave when it gets wet to the point that surface tension will be enough. Nylon actually sags when it gets wet.

Pete.

Re testing for impermeability. Rather than use a bucket, my method - which I've never used on tent fabric - is to line a colander with the fabric - in my case generally a garment - with the outer side forming the inside of the resulting bowl. Then, fill it up with water. That allows quite a weight of water to be used while the fabric is supported. Any leaking would come through the colander. FWIW, this has always confirmed to me that the wet on the inside of a Goretex garment is condensation, but that's a different story.

Thanks for the replies. Been a bit busy recently, so not done anything yet. Camping next week, if I don't get rained upon and obtain conclusive results, I'll try Thirdcrank's bucket test afterwards.