Introduction: Easy Waterproof Clothing
While I was making my glow tie I realized that the solution I made to apply the glow power to the fabric was incredibly hydrophobic, which makes sense as it's silicone based. After some experimentation I found it was a great method for waterproofing all kinds of close knit fabrics, like tote bags and other large flat fabric surfaces.
I'm not that impressed with most commercial versions of waterproofing, and this method gives me full control of the efficiency of my waterproofing. Inexpensive, flexible, and easy to make, this homebrew solution is a great way to make almost anything waterproof.
Ready to waterproof all the things? Let's make!
Step 1: Supplies
Making your own waterproof solution requires 2 things:
- 100% clear silicone sealant (must be 100% silicone)
- Mineral spirits
You'll also need the following supplies:
The glow powder is added to a liquid medium which is then applied to the tie. The medium is made from silicone caulking which is diluted in mineral spirits.
You'll want to use 100% clear pure silicone caulking. Look for "silicone I" as "silicone II" has mold retarding agents, we want pure silicone. The silicone can be thinned with mineral spirits. You can find both the caulking and the mineral spirits at your local hardware store.
Step 2: Mixing Solution
To make a medium that can be brushed onto the fabric, we'll need to thin the silicone caulking with plenty of mineral spirits.
I started with a ratio of 5:1 - 5 parts mineral spirits to 1 part caulking. Put both into a mixing cup and mix thoroughly. At first this is going to look like too much mineral spirits and not enough caulking, but silicone is incredibly thick and after a few minutes of mixing the solution will begin to thin.

You're looking to achieve a very runny medium with no clumps, lumps, or anything even resembling the caulking. The GIF above should be the viscosity you are looking for, something like very runny maple syrup. It is also going to smell terrible, so make sure to work in a well ventilated area.
Step 3: Brush Onto Fabric
I used a bristle chip brush to apply the medium onto the tie. Chip brushes are meant for resin, acetone, and epoxy, so are a suitable choice for this application.

The brush was dipped into the mixture and generously applied all over the fabric. The fabric was hung to dry, making sure that the fabric was not overlapping anywhere - any overlapping fabric will bond together when it dries.

Special attention was given anywhere there were stitches, since this will be a weak spot in the waterproofing. After drying, multiple coats were applied to the fabric to ensure a good waterproof seal. Additional coats were put on seams and stitches to make them more durable.
The smell from the caulking is still pretty terrible even after a day of drying, but goes away after about a week.
Step 4: Hang Dry
The fabric was left to dry for an entire day after each coat, allowing the silicone to cure completely.
Step 5: Waterproofing Thoughts
This was a fun exploration into homebrew waterproofing. The process is simple, and the results are much better than commercial options. However there's a significant drying time between coats, which makes this a good waterproofing option if you prepare ahead of time, not in the heat of the moment.
Share your comments and results below.
Happy making!
152 Comments
3 years ago
Could this be used in a spray bottle instead of brushing
Reply 2 years ago
Yes you can. I mixed a quart of oderless mineral spirits ( even though there's still an oder LOL) and a whole caulking tube of 100% Silicone and thought maybe it would be too thick to spray. I poured the mixture into a 1-gallon spray bottle after a thorough mix with a paint stick, pumped it up and squeezed the trigger and a fine to medium spray came out! It couldn't have been better! Waterproofing my canvass BBQ cover, but should have bought extra mineral spirits + a standard tube of silicone to add to fully cover the whole BBQ cover. I sprayed it about an hour ago and it's starting to dry already and look natural to the area I didn't hit. Luckily I find that I can mix more and start off where I left off. YES, I recommend using the spray bottle!!!!! NO MESSY BRUSHES and cuts your time sign=significantly shorter and sprays much more evenly!! Now I'm trying to see if I can salvage my spray bottle after a heavy rinse. If not, fine. I'm thrilled anyway!
Reply 6 months ago
Hey Scott, can this mixture you talk about stored? Cause I prepared mine and applied it succesfully on a test area with a spray bottle but the next day was impossible to spray, the silicone was very viscous and I had to use a brush. I tried adding more solvent but didn´t work. Also after 2 or 3 days of preparation was impossible to apply with a brush cause the mixture was like a gum or a slime. I mean, should this product be used ONLY the same day of preparation or can be stored or modified to be stored? of course these sillicone tubes are made to dry and toughen to glue stuff but did you keep yours or did you throw it away the same day?
Reply 3 years ago
Possibly, but I think it might be too viscious
4 years ago on Step 5
I question using this on indoor furniture - is this fire-retardant?
Reply 2 years ago
Mineral spirits are petroleum-based products like naphtha which is highly flammable!
Reply 1 year ago
True, but the mineral spirits evaporate in the drying process so those are not relevant for the indoor stuff when drying is over. It is the silicone you should think about. According to wikipedia polydimethylsiloxane is non-flammable, however it does score a 1 in the fire diamond. Cellulose, the main component of cotton, also scores a 1. So I guess that should give an idea, it is probably not more flammable than fabric itself.
Reply 1 year ago
Most informing - thank you for taking the time to help me understand things better. Cheers!
Reply 4 years ago
Think twice about doing this to your indoor furniture. It may leave permanent streaks on darker fabrics. Flammability depends on the silicone you're using. Most silicones can be flammable, but there are specific one's that aren't.
Question 1 year ago on Introduction
How long will this solution last on a jacket? Does it wash off
1 year ago
Will this work on nylon/tent fabric? I was concerned that the solvent would possibly dissolve the fabric.
Reply 1 year ago
Test on a small piece of item in an inconspicuous location.
4 years ago
It's a decent instructable, but spoiled by the use of a meaningless term for the solvent. The term 'mineral spirits' has no concrete scientific interpretation and may refer to a proprietry product you can buy easily in the US, but isn't sold under that name in the UK. Here we have water-immiscible solvents like turps and white spirit although what they are exactly I don't know. I guess they're products of the petroleum fractionation industry, just like petrol and diesel. Then we have water-miscible solvents like the various alcohols: methyl, ethyl, iso-propyl ( even butanol, I think ). The stuff we call 'meths' AFAIK is actually ETHYL alcohol with about 5% methy alcohol ( the purple colour is pyridine which stinks ) If you are able to buy 'alcohol' I think it's ethyl alcohol plus 5% water: pure ethanol isnt available to the public. And 'dry-cleaning' solvent is ( as the guy said ) trichlorethanol. The chlorinated alcohols are another brand of solvents, but I don't think they come from petroleum distillation. None of them is water miscible. So, what is mineral spirit?
Reply 1 year ago
I can help you out with that one in order to un-spoil the 'meaningless' instructable.
This is a really spiffy trick that few people know.
1)On a computer, open up google.com.
2)In the search bar type "wikipedia mineral spirits".
3)A wikipedia link should appear. Click on that.
3)Read the material.
Reply 2 years ago
Mineral spirits is petroleum based solvents such as naphtha (highly flammable). The organic alternative is turpentine which is distilled tree resin.
Reply 4 years ago
One of the pictures shows the label on the bottle of the mineral spirits used, that includes the brand name of the product. In the era of internet it should not be too difficult to find out, or at least to get a good idea what is in the particular product by searching the internet or obtaining the contact email of the manufacturer. You can derive some additional info from its MSDS sheet. The ingredients will not be clearly given there but you can find some answers.
To defend the author - he used the actual name of the product as written on the bottle.
I like this instructable very much personally. Good job and thank you!
Reply 4 years ago
Mineral Spirits is a fancy name for "White Spirit", same stuff available all over the world. I used odorless white spirit and it worked like a charm.
Reply 4 years ago
the same solvent used to clean up oil paints.
Reply 4 years ago
https://en.wikipedia.org/wiki/White_spirit
It would be white spirits for you.
Reply 4 years ago
I'm not certain, but I believe it's Meths.