PU or silicon coating to waterproof?

[RAPPLEBY2000]

Hi I'm wondering about making a tarp perhaps with either :
Ripstop nylon
polyester
or a tight weave poly cotton

question is how easy is it to PU coat things? i understand I would involve spraying or painting/spreading gluey type substances.

does anyone know a good product that would do as good a job as PU?

 

[wentworth]

You could just buy silnylon or pu coated nylon- already waterproof. Might be easiest. Then just reapply a waterproofing spray every few years.

 

[RAPPLEBY2000]

You could just buy silnylon or pu coated nylon- already waterproof. Might be easiest. Then just reapply a waterproofing spray every few years.

Yeah I know,
I was wondering if i could save a few quid, and also get the right colour etc.

 

[wentworth]

Whoops. Watering down sno-seal with a solvent turns it into a more liquidy substance, you could paint that on with a paintbrush.

But silnylon is only $8 50US per yard. 3 yards to make a tarp= $25.50

 

[johnboy]

A spray on waterproofing agent such as 'Fabsil' might work...

I've had good water resisting sucess in the past with that. DIY PU application sounds tricky...

When I was in the UK Point North had all sorts of outdoor fabrics and associated haberdashery..

Point North

 

[Mastino]

IMO proofing the fabrich will not be the biggest issue; I would worry about seaming the seals & pinholes. Given the angle a tarp is usually set up I think that a proper coating with spray or washing in a DWR in the case of poly-cotton should be sufficient. Looking how the latter performs on my poly-cotton clothing I have a lot of faith in thos materials.

 

[C_Claycomb]

If you factor in time, even at minimum wage, you cannot make a tarp yourself cheaper than you can buy one, even one of the high end premium ones. If you exclude your time, you are still fighting an uphill battle on cost, once you figure in the necessary webbing and grosgrain edging tapes.

As far as I can see, the only realistic reason to make your own is so that you can get a size/shape/design which you cannot purchase for any money from somewhere else. If you want a light, high performance bit of kit with features exactly taylored to your need, then making it yourself starts to make sense. However, if you want light weight and high performance, you need to be looking at commercially prepared fabric. When you are packing your gear you don't want to have any doubts about the performance of your tarp, no internal arguement like "If I take the basha it will be too small, but if I take mine I might get damp if it rains all the time".

Look at the stuff that Point North do, and spend your time on the construction and design, not on trying to save a few pounds re-inventing the wheel with home brew proofing

 

[C_Claycomb]

PU proofing does seem to be more waterproof than silnylon, which in my experience is just water resistant to some degree. As a tarp water should only mist through silnylon if it is hard rain or wind driven, but if the silnylon is sat up against something, say you have wrapped your tarp around your sleeping bag stuff sack to keep things dry, water can seep through. PU coating seems less prone to soak through. It is also easier to sew.