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Recoating kite fabric

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foilholio
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Re: Recoating kite fabric

Postby foilholio » Wed Sep 14, 2016 2:55 pm

axel_lotta wrote:As for the spray vs direct application decision, I can only report what I have found myself. That is, to be successful at sealing the gaps between the weave the viscosity has to be such that it just thick enough to 'bridge the gap' whilst still being thin enough to be workable and wet the fabric out before it 'sets up'. In my experience, two coats of a thin solution do not have the same gap filling ability (and therefore measured decrease in porosity) as one coat of a thicker solution, but again I have chosen to go the foam applicator route and can only comment on that. I have not noticed any issue with variable coverage, but yes, theoretically spray application would have a more even coverage depending on your skill although in reality I'd say both options are equal. In my opinion there are many advantages to going a direct application rather than spray even with the time penalty involved. They are:
A thicker mixture will tend not to penetrate and instead form a skin on the surface, which would explain your results. I would be interested in how much goop you used for your 12m? Also note that repeat applications of a thin mixture will combine with existing coatings, set or unset and become thicker but should penetrate better as they won't sit on the surface. I would think a penetrated coating would be more durable, but a skin provides better sealing in the short term but not the long term.
axel_lotta wrote:2. There is no mess to clean up (I actually have a electric HVLP spray-gun but I did not want to potentially damage it, cured Goop sticks REALLY good and my gun has many internal parts that are a pain to clean even with ordinary paint)
Toluene dissolves set goop etc really well. Try acetone for paint cleanup :-) :lol: Everything is different one solvent works well for one paint or thing and not another etc.
axel_lotta wrote:As for Koala Coat's formulation, although I cannot be 100%, it feels, smells, mixes and behaves almost identical to Acetic cure silicon. It does however have one significant advantage and that is its lack of a 'tacky feel' when cured which is a big downside to the silicon option as sand and dust will continue to stick to your kite for the remainder of its life.


Nope I found silicone repels dirt and sand. Sand doesn't stick to the kite at all. There must be something different we did there. All my Pansh kites which are silicone coated behave the same too. Infact not much sticks to silicone at all, I can't use e6000/shoegoo to do repairs on the Pansh fabric because it won't stick :(
Last edited by foilholio on Wed Sep 14, 2016 3:17 pm, edited 1 time in total.

Regis-de-giens
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Re: Recoating kite fabric

Postby Regis-de-giens » Wed Sep 14, 2016 3:07 pm

foilholio wrote:
axel_lotta wrote: its lack of a 'tacky feel' when cured which is a big downside to the silicon option as sand and dust will continue to stick to your kite for the remainder of its life.


Nope I found silicone repels dirt and sand. Sand doesn't stick to the kite at all. There must be something different we did there. All my Pansh kites which are silicone coated behave the same too. Infact not much sticks to silicone at all, I can't use e6000/shoegoo to do repairs on the Pansh fabric because it won't stick :(
I agree with Alex : I also tried silicone diluted in acetone once. hoping to get a kind of 'Lotus effect", but indeed sand was completely adhering to the cloth, much much more than the original dlx cloth: I was embarquing a lot of sand when rolling the kite :cry: ; another friend did silicone as well located on seams only and had the same sand adherence problem, being very happy not to have done it on the complete kite.

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Re: Recoating kite fabric

Postby foilholio » Wed Sep 14, 2016 3:19 pm

Well at a guess, it was because you used acetone. Sand didn't stick to your aurora did it? That had silicone on it. Silicone is one of the hardest things to adhere anything to. There is a possibility we used different silicones, but from that you used acetone to dissolve it and axel used toluene, that would be why it didn't give the same results as mine or Pansh's :- P

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Re: Recoating kite fabric

Postby direnc » Wed Sep 14, 2016 5:43 pm

Guys,

I coated my second hand Speed 3 12 DLX with silicone diluted in turpentine. The kite is still as leaky as it was before coating it, and attracts sand. I guess the cloth was not in very bad shape after all, and the leak is actually from the seams. Spraying the kite does seal the cloth, but not sure if it's enough to seal seams/needle holes. Is there an easy way of sealing the seams?

foilholio
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Re: Recoating kite fabric

Postby foilholio » Wed Sep 14, 2016 10:25 pm

Well I don't think silicone seals that well against air. Unfortunately once you coat with silicone that may be it, i.e. no more recoating. I don't know of any solvent that dissolves silicone rubber. http://www.eng-tips.com/viewthread.cfm?qid=150173 the only suggestion involves using acids :-/ http://cool.conservation-us.org/coolaic ... 2-007.html. The fabric will be destroyed by acid, so I think it is impossible. Maybe you can find something that will adhere to it? Though I strongly doubt you will.

I am really surprised you all have sand sticking to silicone, my experience is completely opposite.

I sealed my seams on the silicone kite by just spraying them more. I think the fabric causes much more leaking than the seams. I think axel came to a similar conclusion.

Maybe buy a pansh ?

axel_lotta
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Re: Recoating kite fabric

Postby axel_lotta » Wed Sep 14, 2016 11:19 pm

Hi Regis, also very nice to hear from you again.

You will be happy to hear that the coating I chose to go with has none of the problems that plague PU (well at least PU expanding filler dissolved in acetone).

On my 12m Speed 3 (deluxe) I applied one coat of a solution combining 1 part Eclectic Products Marine Goop (Canadian formulation) with 2 parts Xylene by weight. As you have probably gathered by my posts above, I hung the kite by its trailing edge, inflated it with a vacuum cleaner and applied the coating to both upper and lower surfaces with a sponge in one session. I originally intended to apply 2 coats but after testing the kite's porosity before and after the first coat I decided to stop at one coat as the result was very satisfactory as you will see from the data below. Test flights also showed that the leading edge is now back to being round rather than flat which indicates better internal pressure.

As for weight, I took the kite to my local post office and had it weighed (without bridle) before and after the treatment and it gained a measly 100grams which is pretty damn good being that I coated some 24sqm! I have a 8 and 10m Psycho 4 that I may recoat in the future and go for two coats but I did not want to restrict the 12m S3s light wind ability by adding too much more weight.

Sand stickiness is absolutely not an issue, the cured finish is exceptionally similar to that of the original FS coating (in that it feels somewhat crinkly, but also a little rubbery) and sand just brushes off. Water resistance is exceptional at this stage, although this has only been tested with a backyard hose as I have not dropped the kite in the ocean as yet. It does however have quite a pronounced smell that still persists some many months later. My advice is if you use this product, ensure you have a space like a garage or shed away from people or animals where you can let the kite 'off-gas' without being rolled up in its bag.

Regis, in my opinion Marine Goop is an exceptional product, it is extremely tough and wear resistant whilst being ridiculously stretchy (it can stretch to 900% without breaking) which is a significant advantage over either Koala Coat or Silicon. I would hazard a guess that my kite's fabric is most likely stronger (tear strength) than when new. The only issue you will have is finding the damn stuff outside the USA or Canada. Here in Australia it is unavailable and I had to illegally import a few tubes in the checked baggage of a friend of mine who was flying from Canada. I have been successful in getting two shipments (5 tubes at a time) without them being confiscated by customs but hey, take your chances you may lose them all or worse still cop a fine if caught. That said, if you do go for this approach, the Canadian formulation which uses Xylene rather than Toluene is far more stable and non-explosive (the cured product is however identical apparently). Another advantage of using the Canadian formulation is that Xylene is a slower evaporating solvent than Toluene which gives a better working time, it is also less of a health hazard than Toluene which is banned in many countries in consumer products.

Please see below for all the test results. All test times are stated in minutes and seconds and should be reasonably similar to what you would find using a commercially available porosity tester as the vacuum pressure and fabric cross section are very close to standard.

The disclaimer: All tests (apart from the final before and after porosity tests at the bottom of the page which were done on my FS S3 deluxe) were done with 3 samples each of identical UNCOATED ripstop nylon. Apart from the fact I could not find a kite or paraglider to cut up and use despite many many months of trying, the advantage of this method was that each test piece was identical and judged for its weight increase and sealing capability on its own merits. That said, a foil kite made of uncoated ripstop would not fly and thus the test was a little unrealistic in that way. This is why the measured results were so much better with one coat on my actual kite (even with its initially terrible porosity readings) than was measured with two coats of the same solution on the test pieces. This is also why the water based 'wash-in' solutions by Nikwax performed very badly, they never had a chance against completely uncoated fabric, and therefore you MAY get some decrease in porosity on an actual kite although I would personally never use them with so many better and more permanent options out there. The only way the foil community is going to get some decent data is to unfortunately coat our own kites and share the results, however in my opinion this MUST be done with before and after treatment porosity tests on multiple sites on the kite to be in any way usefully conclusive. Here is a link to a very easily made and cheap tester that would be great as a standard (I have made mine with some very slight mods to help seal the fabric which I will post later): https://vimeo.com/124682223

Cheers!

Axel
Coating text results.pdf
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Last edited by axel_lotta on Thu Sep 15, 2016 2:11 am, edited 5 times in total.

axel_lotta
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Re: Recoating kite fabric

Postby axel_lotta » Wed Sep 14, 2016 11:36 pm

foilholio wrote:Well at a guess, it was because you used acetone. Sand didn't stick to your aurora did it? That had silicone on it. Silicone is one of the hardest things to adhere anything to. There is a possibility we used different silicones, but from that you used acetone to dissolve it and axel used toluene, that would be why it didn't give the same results as mine or Pansh's :- P
Hey Foilholio, could you post a picture or details on what brand and formulation of Silicon you use? It sounds like you are getting very good results and maybe you have just stumbled on an exceptional brand for our purposes. Apart from the sand stickiness, I am quite a fan of silicon solution as it is very stable and seals quite well when you have the correct thickness. It is also the easiest product to get your hands on worldwide and CHEAP!

I have used silicon / camp gas to seam seal Si/Nyl tents in the past and they are definitely tacky even years later, and even the manufacturer (Tarp Tent) advises that if you don't like your camp mat sliding about on the inside of the tent floor, apply a few lines of this solution to the floor to provide some grip.

As for commercially applied silicon coatings, I agree they are excellent and have absolutely no issues with sand or dust adherence but this is definitely not the case in my experience with 'post applied' silicon coatings. The closest product to a manufacturer applied finish I have come across is Koala Coat#25 which is why I rate it so highly.

As for the choice of solvent, it would be interesting to to some side by side comparisons of the same silicon dissolved in say, acetone and the clean petro solvents such as camp gas, toluene and Xylene, all the way down to the heavier turpentine. My gut tells me that the cured coating will not be that different (apart from turpentine which may have a very slightly oily residue) but I would be very happy to hear otherwise. Unfortunately I am not planning any such test but am happy to loan anyone my porosity tester to get the data (if they pay for the postage).

Cheers

Axel

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Re: Recoating kite fabric

Postby axel_lotta » Wed Sep 14, 2016 11:53 pm

foilholio wrote:
axel_lotta wrote:As for the spray vs direct application decision, I can only report what I have found myself. That is, to be successful at sealing the gaps between the weave the viscosity has to be such that it just thick enough to 'bridge the gap' whilst still being thin enough to be workable and wet the fabric out before it 'sets up'. In my experience, two coats of a thin solution do not have the same gap filling ability (and therefore measured decrease in porosity) as one coat of a thicker solution, but again I have chosen to go the foam applicator route and can only comment on that. I have not noticed any issue with variable coverage, but yes, theoretically spray application would have a more even coverage depending on your skill although in reality I'd say both options are equal. In my opinion there are many advantages to going a direct application rather than spray even with the time penalty involved. They are:
A thicker mixture will tend not to penetrate and instead form a skin on the surface, which would explain your results. I would be interested in how much goop you used for your 12m? Also note that repeat applications of a thin mixture will combine with existing coatings, set or unset and become thicker but should penetrate better as they won't sit on the surface. I would think a penetrated coating would be more durable, but a skin provides better sealing in the short term but not the long term.
With respect Foilholio, having done the testing quite extensively over many months I am aware of how differing viscosities sit and penetrate, and most importantly actually perform when tested for porosity.

One of the advantages of using a slightly thicker solution but applying it with a sponge is you get good bridging ability whilst still forcing the product between the weave. This is the technique expressly recommended by Koala Products for their #25 coating.

In addition, as long as the product is adequately 'anchored' in the weave, a slightly thicker coating should have better abrasion resistance although without doing further extensive testing this is just my theoretical position and we could argue back and forth forever.

As for how much Goop I used for the 12m, I'd say it was about 10-15oz (300 to 450ml) of product, but the finished coating added about 100g of weight in total (for one coat over both top and bottom surfaces).

Cheers,

Axel

Regis-de-giens
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Re: Recoating kite fabric

Postby Regis-de-giens » Thu Sep 15, 2016 8:13 am

@ Folholio : I used acetone as well for the PU and the behaviour to sand was acceptable (but not wonderful), like original DLX of Flysurfer I would say. I agree that Pansh used Silicon with a good behaviour to sand, I think alos that Lotus is a Silicon base, but maybe the secret is indeed in some addings or silicone formula....

@Axel : thanks for having shared the file, now stored in my computer for decades ; You seem to find a wonderful solution, and I love the idea to find good tips to extend kite lives of our loved kites, instead of throwing all these beautiful large cloth material to trash ...

I do not need to recoat a kite anymore... but I am incorrigible :oops: :oops: ... and think about a potential optimization of my recent and loved Conceptair Pulsion kite, by adding a thin layer of Seal And Glide on some parts of extrados only ...just need to assess if the time and risk on the kite is worth the expected improvement on air glide and water / sand deperlance (no need to improve porosity as it is new). I had loved the impact on SNG on my Speed2 which was not very porous... and I still have the quantity of SNG to slightly over a kite). Lets live a dozen of nights plus your all opinion on the idea ...

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Re: Recoating kite fabric

Postby foilholio » Thu Sep 15, 2016 10:49 am

axel_lotta wrote:Hey Foilholio, could you post a picture or details on what brand and formulation of Silicon you use?
Well it's sounding like my silicone was different than others, I can't remember the brand, but it was the most expensive, clear and acetic. You mentioned roof silicone( I know you said acetic), this is usually neutral cure, the acid from acetic cure can take the protective coatings off things and then they rust. Not the nicest look on something new. There is quite a different feel between neutral and acetic. As I said Pansh use a silicone coating and you only need ask anyone who has had one of them about sand sticking and it doesn't, nor does water. As Regis just said.
axel_lotta wrote:With respect Foilholio
It's ok to disagree with me lol. I ain't going to berate you unless you go on and on like kitexpert,windrider or :roll: ...pullstrings... the trio of terrific fools they are.

I'll take what you have done with respect too. You have a proper porosity meter, I do not. I do know for certain a thicker coating is more likely to sit on the surface and a thinner one will penetrate. I sprayed some of my kite coating on a wetsuit and it just went in and did nothing. I am also certain a skin will seal better, like the rubber skin on a wetsuit. Durability is a bit of a guess, this I am referring to the sealer/porosity lasting not abrasion. You may have a very good technique using a thicker mixture and rubbing/wiping it in with some foam! I will have to give it a try :-)

I can look at your kite numbers and see you used quite a bit. 3to4 tubes? So that is .25 to .33 tube per meter of kite(12m). I used 1 tube on an 8m kite so 0.125tube/m2. Of 1 tube I was able to get 91.8g of shoe goo out of 98grams possible in the tube. This becomes 41.8g when set or dry. Inevitably there is more wastage from spray etc, so at a guess 21g to 38g ended up on the kite, lets say 30g. Now the density and amount of solids in marine goop is slightly less than shoegoo. Marine goop (toluene version I couldn't find a xylene version??) has a specific gravity of 0.886, so 109.4ml has 97g. lets assume you can only get 93.7% out of the tube like me so you have 90.9g per tube. Of that only 45% is solid, so 40.9g. So out of a possible 122.7g(3tubes) and 163.6g (4 tubes) out of tube amount you got 100grams on the kite. That is not much wastage but similar to what can/could be achieved with a spray gun, I think your foam may have had quite a bit left in it?

So lets compare my 30g vs your 100gram. 3.75g/m2 vs 8.33g/m2. Now if my guess at how much wastage is off it of course will change things but that is still an interesting comparison. I think I could have doubled the amount I applied and got much better results but already the result are very good! Considering my kite is a psycho4 and you want to apply double to your pyscho4 it will also be interesting what results you get with the current amount 8.33g/m2 or double at 16.66g/m2 (the 666 mixture :lol: )

http://eclecticproducts.com/downloads/t ... nglish.pdf
http://eclecticproducts.com/downloads/t ... nglish.pdf
axel_lotta wrote:it is also less of a health hazard than Toluene
I don't know about xylenes being less lethal than toluene. I can find info that they are pretty comparable in oral and inhalation, admittedly toluene needs a 1/3 less for inhalation, but then for skin exposure xylene is 3x more potent than toluene on rabbits. I think they deserve equal caution, and you couldn't say one is much more dangerous than the other.

http://www.labchem.com/tools/msds/msds/VT910.pdf http://www.labchem.com/tools/msds/msds/LC26170.pdf
axel_lotta wrote:in my opinion Marine Goop is an exceptional product, it is extremely tough and wear resistant whilst being ridiculously stretchy (it can stretch to 900% without breaking)
In my opinion it is the same SBR as in all the other Electic product just with some UV additive. But I will see how my shoegoo holds up and I might use the marine stuff in future.

axel_lotta wrote:Please see below for all the test results. All test times are stated in minutes and seconds and should be reasonably similar to what you would find using a commercially available porosity tester as the vacuum pressure and fabric cross section are very close to standard.

The disclaimer: All tests (apart from the final before and after porosity tests at the bottom of the page which were done on my FS S3 deluxe) were done with 3 samples each of identical UNCOATED ripstop nylon. Apart from the fact I could not find a kite or paraglider to cut up and use despite many many months of trying, the advantage of this method was that each test piece was identical and judged for its weight increase and sealing capability on its own merits. That said, a foil kite made of uncoated ripstop would not fly and thus the test was a little unrealistic in that way. This is why the measured results were so much better with one coat on my actual kite (even with its initially terrible porosity readings) than was measured with two coats of the same solution on the test pieces. This is also why the water based 'wash-in' solutions by Nikwax performed very badly, they never had a chance against completely uncoated fabric, and therefore you MAY get some decrease in porosity on an actual kite although I would personally never use them with so many better and more permanent options out there. The only way the foil community is going to get some decent data is to unfortunately coat our own kites and share the results, however in my opinion this MUST be done with before and after treatment porosity tests on multiple sites on the kite to be in any way usefully conclusive. Here is a link to a very easily made and cheap tester that would be great as a standard (I have made mine with some very slight mods to help seal the fabric which I will post later): https://vimeo.com/124682223

WoW that is some truly EPIC work you have done! Thanks heaps :-)

Can you elaborate a little on what "seepage" was? I guess it was the second coat crossing to the other side?

Kites will get different results than to plain fabric, as you say. There is the potential for seals to form by bonding with the existing coating. Possibly a thinner coating could achieve this better on old flysurfers where the coating is on the inside of the fabric. A porosity meter would be a good way to test the results, but many checks would need to be performed to get a more accurate average. It's notable at certain points on flysurfers the coating really comes off quickly and a lot. A simple "Full kite deflation test" is a simple and good way to gauge some sort of results. I think a "full kite pressure test" would be the most accurate way to test changes in the kite. How I am not sure, some way similar I guess how homes are pressure tested.


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