Feb 12, 2013 at 2:14 pm #1299185
@richard295Locale: San Francisco Bay Area
In 2010 I tried to thin GE Silicone II with Kean-Strip Odorless Mineral Spirits (the only brand stocked at the Home Depot in my town). It didn't set completely after a few days (I don’t recall the 2010 test daily high temps) and I started a thread to discuss the problem at:
This week I tried it again with new materials purchased from my local Home Depot. It took 2 days of mid 60F day time high temps to dry. I tried white gasoline for an alternative batch and it was dry in less than 8 hours in the same temps. While searching for an answer, I went to the Klean-Strip Web site and discovered that their "standard version" Klean-Strip Odorless Mineral Spirits cannot be sold in CA.
I assume that all brands of odorless mineral spirits, formulated for CA sale, will have the same issue of very long drying times. This is probably due to CALIFORNIA PROPOSITION 65 liability resulting in the harmful aromatic solvent component being removed which dramatically reduces the drying time.
Does anyone know if there is any other downside to thinning silicone with the odorless mineral spirits formulation for CA other than significantly extended drying time? Is there an alternative silicone thinning agent that will dry quickly and can be legally purchased in CA?Feb 12, 2013 at 2:23 pm #1953652
@rayestrellaLocale: Northern Minnesota
I switched to white gas a couple years ago. It is cheaper since I always have a gallon or two around, and dries faster.Feb 12, 2013 at 4:12 pm #1953688
I agree. Tarptents need to be seam sealed and they recommend thinning GE Silicone II with white gas. Worked great.Feb 12, 2013 at 4:16 pm #1953690
We have noticed this problem too. We had a bunch of tents using similar new formulation CA solvents that just refused to dry. Finally fixed the problem by wiping the areas down with Atsko Silicone Water Guard. That seemed to "open the pores" and allow it to dry normally/quickly. Never tried applying white gas over the problem areas but I would be curious if that works too.
-HFeb 12, 2013 at 4:25 pm #1953696
I have stopped bothering with diluting the silicone. I apply it with a hypodermic syringe in a thin bead. I push it into the seam with the nose of the syringe, and then smooth it over with my finger. It always dries at a reasonable rate for me.
Pushing with the syringe: angle the syringe to the fabric/seam and push in the same direction it is pointing. The pressure forces th sealant into the seam. The bead should be quite small as the only sealant which matters is the stuff right at/in the seam. Stuff pushed out to the sides is simply an eyesore.
CheersFeb 12, 2013 at 5:50 pm #1953730
For the Aussie guys here..
just use Mineral Turpentine.(Diggers from Bunnings)
Being doing them like that for 10 years, no problem.
BTW, I too use a syringe but still dilute the silicone.
I used to do the Bibler/Black Diamond with seam grip undiluted but the TT shelters have panel stitching that requires (in my view…) dilution to penetrate.
The same for products from other "cottage" manufacturers that I have sealed.
This is what I am talking about :
"Bibler" type :
TT type :
Feb 12, 2013 at 5:57 pm #1953733
I had the same problem with the same odorless spirits and GE Silicone II…The solution never dried. Of course, I was leaving on a trip the next day. Panic.
I wiped it all off, making quite a mess of my shelter.
I tried again, using a different brand new tube of the same silicone. It dried in a few hours.
I now test a small batch for dry time before anything goes on a shelter.Feb 12, 2013 at 6:04 pm #1953735
Permatex Flowable Windshield Silicone. Unless you really like mixing that goop up yourself. Ready to go in the tube. Inexpensive. Even comes in with an applicator nozzle. Best of all no smell, and it works. Dry to the touch in a couple of hours or less.Feb 12, 2013 at 6:12 pm #1953737
@scfhomeLocale: Chocorua NH, USA
Don't understand why you guys continue to seal with mineral spirits or gasoline mixed with silicone sealers. The NAPA Permatex or the Sea to Summit sil sealer are flowable enough to give a very thin coat using Roger's method, or using a small stiff brush with a thin point.
I think you will get much better adhesion and a longer lasting seal this way, so long as the coat is kept very thin. Can't see how mixing in various volatile liquids, with the various additives they contain, is going to accomplish anything but encourage peeling. Especially if there is any oily content in the solvent. If the silicone actually could be dissolved in something, it would be a different story.
Also discovered that with some sil-coated fabrics, like balloon cloth, the silicone sealer can be rubbed into the coat, reinforcing it with a very thin layer. For coating more than just seams, suggest trying that first before going to diluted mixes.Feb 12, 2013 at 6:20 pm #1953739
@ngatelLocale: Southern California
I use the same Klean-Strip product, but with Silnet. Works fine and dries in a few hours. Never had anything leak.
So perhaps the properties of the silicone sealant are different?
Perhaps it is temperature — when it gets to 60F in Palm Springs we declare an emergency and call in the National Guard :)Feb 12, 2013 at 7:22 pm #1953759
@jamesdmarcoLocale: Finger Lakes
Yeah, CA could be the problem with drying. All sorts of regulations around VOC's that will cause slower drying, and, may interfeer with drying, period. WG works as a good alternative.
There are two basic forms of sealing fabrics. One is used for sealing the seams. The other is used for resealing streatched or damaged fabrics. A third form for attaching reinforcments/patches probably should also be included.
For seam sealing I agree that a thicker mix is needed. But, I do not agree that full strength silcone sealers are needed. 2:1 up to about 5:1 is real good for sealing seams. The sealer should flow into the seam and threads, not just coat over it. Thinner coats are better for adhesion, anyway. There is less chance of peeling loose later.
For resealing damaged fabrics, a thinner mix is wanted. I have used two coats of 50:1 successfully on my tarps. This leaves enough build up on damaged coatings (from stretching, mostly)to close up any open pores and bind any loose fibers/loose coatings back onto the fabric. Damaged cloth, abraded areas may need 20-30:1. Both will add some weight to a tarp or tent, so go easy. But I have a tarp that I use fairly regularly, over ten years old, that has been treated twice and is still in use. Fresh fabric (untreated) may require 10:1 both sides. I made a mistake about 20 years ago with some white ripstop nylon that I used to make a tarp out of. Turns out it was not treated.
For small patches, about 3" diameter, I often coat one side with 100% caulk. Stick it in place and smooth it out with 20:1-30:1 brushing over it. This works for anything up to 1" pokes and gashes.
I usually use Mineral spirits and GE silicone caulk for sealing and coating all my tents, tarps, and spraydecks on my canoes. Nothing has peeled loose so far…Feb 13, 2013 at 12:29 am #1953829
"Don't understand why you guys continue to seal with mineral spirits or gasoline mixed with silicone sealers.."
In my case it is very simple. I may not do a tent for a week or so then have 4 to do in a day.
That day can be at 60f, 40% humidity or 90f and 85% humidity, so I need to dilute the mix to suit that range.
like everything else with me, no I don't use a chart , I just mix it and see what happens.
If you only do one item and can pick the time to do it, then there are other choices.Feb 13, 2013 at 5:29 am #1953849
You miss the point Franco. The Permatex is ready to go in all conditions. Put the cap on the tube when you are done.Feb 13, 2013 at 6:09 am #1953859
@kenlarsonLocale: Western Michigan
NOTE: Discussions with the technical folks at Duco (the glue and sealant people) produced the following information:
1. Thinning silicone resin with mineral spirits or anything else weakens the cured resin because the slurry structure interferes with the resin forming long polimer strings as it cures.
2. If you want thinner silicone sealant, buy a thinner silicone sealant. It will be a unitary formulation containing no thinners, just a thinner formula of resin.
3. I just cut the end of the applicator as small as possible, squeezed out a bead onto the seam and smoothed it out with the index finger of my other hand. No problem….it even looks half decent. Cost runs three to five dollars and one tube should be adequate for most tent or fly sealing aplications.
"Permatex #81730 Flowable 100% Silicone Windshield Sealant", available at any auto parts store, is such a thin, unitary resin.
I have used Permatex for both sealing and glueing seams for years. Compared to Silnet, it is tougher, less sticky, more liquid with better penetration, and perhaps more UV resistant. It cures to the touch in 30 minutes, sets as a glue in 20 minutes, fully cures in 24 hours. It's also cheap – half the cost of Silnet for twice the amount of product.
ANOTHER POINT TO NOTE: Discussions with the technical folks at McNett (the glue and sealant people) produced the following information:
1 part solvent(toluene)/ McNett Cotol 240 to 3 or 4 parts SilNet. The toluene being a component of SilNet should not damage the Silicon Nylon Fabric or Cuben Fabric, but in increased proportions it may so apply the dilution mixture to a test piece of fabric. Use this on MLD Mitts and found it to be superior than using it "straight".Feb 13, 2013 at 11:02 am #1953960
@ckrusorLocale: Northwest US
"If the silicone actually could be dissolved in something, it would be a different story."
"Thinning silicone resin with mineral spirits or anything else weakens the cured resin because the slurry structure interferes with the resin forming long polimer strings as it cures."
Hexane. I've thinned several kinds of silicone with hexane, and it makes a uniform mixture that is much smoother and more homogenous than any mixture I've seen with mineral spirits or any other solvent. It might or might not strictly be a proper solution, but it gives a perfectly clear, perfectly uniform liquid.
I've used this for airbrushing super thin coats of silicone onto things. The hexane flashes off rapidly, so the solvent is gone and only the unthinned silicone film remains on the part a few minutes later, so there is nothing in it to retard curing.
I also tried storing hexane-thinned silicone in a sealed container. What I got, the next day, was a block of jello-like cured silicone. I left the container open and the hexane evaporated from the silicone jello over about 36 hours, leaving a piece of silicone rubber shaped like a cup. The cured silicone cup was tough and I had a hard time scraping it out of the jar (it came out intact). So, even when the hexane remains in it, the silicone cures overnight, and the cured rubber is tough and bonds strongly to glass.
You can't get hexane at the hardware store, but you can get it on ebay:
If you get the technical or ACS grades, it won't contain anything else.Feb 13, 2013 at 11:36 am #1953974
@kenlarsonLocale: Western Michigan
She is one of scores of young workers in the city of Suzhou who were poisoned by the chemical n-hexane, which they say was used to clean Apple components including iPhone touch screens.
Wu Mei – who, like the others, asked the Guardian to use her nickname – recalled her fear as her health suddenly deteriorated last spring.
At first, she thought she was simply tired from the long working hours at Wintek, a Taiwan-owned electronics giant supplying several well-known brands. She was weaker than before and noticed she could not walk so fast.
"Then it became more and more serious. I found it very hard to go upstairs and if I squatted down I didn't have the strength to get up. Later my hands became numb and I lost my balance – I would fall over if someone touched me," she said.
By summer, she was admitted to hospital, where doctors struggled to diagnose the cause. "I was terrified. I feared I might be paralysed and spend the rest of my life in a wheelchair," she said.
Because she was using n-hexane directly, she was one of the first and worst affected.
But more and more workers from the same room were suffering headaches, dizziness and weakness, and pains in their limbs.
An occupational diseases hospital which saw several victims diagnosed the problem in August and Wintek stopped using the chemical. But thanks to the previous months of exposure, at least 62 workers would require medical care. Many spent months in hospital.
Some believe more employees left Wintek after being taken ill, before they realised what was wrong.
Prolonged over-exposure to n-hexane can cause extensive damage to the peripheral nervous system and ultimately the spinal cord, leading to muscular weakness and atrophy and even paralysis, said Paul Whitehead, a toxicology consultant and member of the UK's Royal Society of Chemistry. It can also affect male fertility. Recovery can take a year or more.
The chemical's potential risks are well-known in industry, as are safe exposure limits. But the Wintek manager who decided to switch from alcohol to n-hexane for cleaning – apparently because it dried more quickly – did not assess the dangers. It was used without proper ventilation.
The change was obvious; workers disliked the pungent smell of n-hexane. But they had no idea it might affect their health. "We hadn't even heard of occupational illnesses before," said Wintek worker Xiao Ling.
"I'm very, very angry," added Wu. "I thought they behaved too badly."
Asked if they knew what products they were working on, three of the affected Wintek employees said team leaders told them they were working for Apple. They instantly recognised pictures of an iPhone and said they were cleaning touch screens, adding that items for other brands were not affected because Apple had isolated its production line. A lawyer acting for 44 of the poisoning victims also said several had named Apple.
Wintek, which does not discuss its clients, said it had replaced the factory's general manager.
It now notifies workers whose jobs may involve risk in advance, has tightened procedures for the introduction of new chemicals, and carries out medical checks. It has paid medical fees for those affected and says it will pay compensation according to the law.
Given that the assessment and appeals process for compensation can take as long as a decade, lawyers hope the firm will pay quickly as well as fairly.
Other patients at the hospital say they too became sick while using n-hexane on Apple products.Feb 13, 2013 at 1:10 pm #1954026
@ckrusorLocale: Northwest US
That's quite a story, Ken.
I find it a bit funny when people try to make a point using an emotional appeal, but I do generally agree with Ken's message, although I don't think the message warrants quite the sense of urgency that Ken gives it. I'm often on the other end of this debate (as I was recently in a thread about using diethylene glycol as a cooking fuel). I think using a small amount of hexane for a few minutes outdoors or in a well-ventilated area is not a significant hazard.
Occupational use, which Ken colorfully describes, is a serious issue. In some industrial settings, solvents like hexane are used indoors and workers can be exposed for many hours every day. In Chinese factories, workers often live in dorms in the factory building, so they might even be exposed to the fumes at night as well. "Prolonged over-exposure", as Ken notes, can, over time, have serious health effects.
Toluene, which was also recommended in this thread, and is the solvent in SilNet, is more hazardous than hexane by most accounts. The Cal OSHA safe exposure limit for hexane is 50 ppm, but it's 10 ppm for toluene:Feb 13, 2013 at 2:52 pm #1954077
"You miss the point Franco"
no in fact I don't. I am perfectly aware that Permatex works for you, the missing bit is that there is no pre-mixed solution that can work for me even at the ideal temperature and humidity level.
That is because I use a different dilution for stitches than I do for the floor and certain smaller hard to do areas.
So if I used Permatex I would still need to dilute that for some areas and may or may not be too diluted already for others.
But again I do tents pretty often, one every few years would be a different story.
(I will be doing a Moment a bit later on today. Expected temperature 31c (88f) 78% humidity (predicted) so I will need to start with a higher than standard dilution and keep adding thinner as I do it..)
Feb 13, 2013 at 2:58 pm #1954079
Curious. Have you ever tried it. You have not said.Feb 13, 2013 at 3:52 pm #1954094
Why would I want to try a product that is 5x more expensive than the one that works for me ?
(Permatex 44ml $6.95, Selleys 300ml $8.95)
Curious :Have you ever seam sealed a tent at both 45f 30% humidity and 90f 80% humidity and all sorts of in between combinations ?
Neither of those combinations are the extreme here in Melbourne but I give up at above or below those( or do them inside…)
Anyway this is not directly related to the OP's question and how I or you do it may not apply to others.
Just a reminder , the question was about THINNING Silicone…Feb 13, 2013 at 5:49 pm #1954136
"Curious :Have you ever seam sealed a tent at both 45f 30% humidity and 90f 80% humidity and all sorts of in between combinations ?"
I have used that product at work at all of those conditions, yes. When it is cold,-50f, I put the tube in my pocket for a while before I use. Other than that, no problems. Last two shelters I did do in the house because there is no odor with the Permatex and it is more comfortable inside.
I'll stop with the drift on this thread. Though all of the information does pertain to the actual task of sealing seams. Might be helpful.Feb 13, 2013 at 6:10 pm #1954145
@scfhomeLocale: Chocorua NH, USA
If I understand you correctly, the thinner soup makes for faster application. That makes sense to me.
The part about different consistencies for different parts of the tent kind of lost me though.
SamFeb 13, 2013 at 7:19 pm #1954168
I did a quick search on google and found the following:
"Camp Stove fuel (Coleman Fuel, Calumet Lantern Fuel) – contains components that are much less volatile than gasoline (such as naphtha). Coleman fuel contains about 50% naphtha, 50% aliphatic petroleum distillates, 2% xylene, 2% toluene, 0.5% benzene, "
Xylene, toluene, and benzene, are probably all missing from Klean Strip green Odorless Mineral Spirits. Xylene and toluene are often used as solvents according to wikipedia.
Naphtha according to wikipedia contains:
In petroleum engineering, full range naphtha is defined as the fraction of hydrocarbons in petroleum boiling between 30 °C and 200 °C. It consists of a complex mixture of hydrocarbon molecules generally having between 5 and 12 carbon atoms. It typically constitutes 15–30% of crude oil, by weight. Light naphtha is the fraction boiling between 30 °C and 90 °C and consists of molecules with 5–6 carbon atoms. Heavy naphtha boils between 90 °C and 200 °C and consists of molecules with 6–12 carbons.
So white gas probably has some Hexane in it as well as many other hydrocarbons that may have solvent properties similar to Hexane, toluene, and Xylene. So much of what was useful in ordinary Mineral Spirits for disolving Silicon rubber are probably not present in significant quantities in the Klean Strip green oderless mineral spirits. White gas however does have them although probably not in the same quantities as in standard mineral spirits. So white gas is probably the best option in California.
I tried Klean Strip a year ago and didn't get good results but at the time I thought that my mix might not have be right. I'll have to give it another try but with white gas.Feb 13, 2013 at 9:42 pm #1954217
> 1. Thinning silicone resin with mineral spirits or anything else weakens the cured
> resin because the slurry structure interferes with the resin forming long polimer
> strings as it cures.
That's what I found too.
> 2. If you want thinner silicone sealant, buy a thinner silicone sealant. It will be
> a unitary formulation containing no thinners, just a thinner formula of resin.
> 3. I just cut the end of the applicator as small as possible, squeezed out a bead
> onto the seam and smoothed it out with the index finger of my other hand.
But getting all this from a knowledgeable vendor rather than from users just experimenting is very good info – thanks.
CheersFeb 13, 2013 at 9:52 pm #1954219
> (Permatex 44ml $6.95, Selleys 300ml $8.95)
Well, yes, but the initial costs are not really relevant in my experience.
What I found was that a tube of something like Permatex (or several other brands of sealants sold in small squeeze tubes) lasts for years – literally. It does not go off. Cap the end, come back in 6 months, it's fine. I might lose a tiny plug 5 -10 mm long in the nozzle: that's all. But the stuff cures very well in the open.
The stuff in cartridges goes off in a month or two after I have opened the cartridge, no matter how carefully I try to seal the end. I have tried several brands, and they all end up as solid blocks. That ends up more expensive and very frustrating.
If you can use the cartridge up in a few weeks then it may be cheaper, although I don't think it bonds as well to silnylon fabric. The runny sealants found in those little tubes seem to work much better for me.
What I can add as a fact is that there really are hundreds (if not more) of formulations of 'silicone'. All are different.
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