Learn all about how to waterproof fabric. The idea of waterproofing fabric is really appealing. There are so many uses for waterproofed fabrics and canvas in particular. The technique of waterproofing opens up a whole new range of ideas for outdoor projects and clothing too.

How to Waterproof Fabric
There are many commercial products available to waterproof fabric as well as several home methods you can use. This article will deal with the 4 main methods of waterproofing which are the easiest and most accessible.
- How to waterproof fabric with commercial products.
- How to waterproof fabric with wax
- How to waterproof fabric with alum
- How to waterproof fabric with vinyl
Items to Waterproof
Mats, table cloths, outdoor cushions, picnic bags and tote bags for the beach, canvas sneakers, kiddies play mats and maybe a beach ball, the list of ideas is endless.
How to Waterproof Fabric with Commercial Products
There are numerous commercial waterproofing products on the market. Most of these involve spraying the fabric. Scotchguard is a popular product used to waterproof couches and shoes.
How to Waterproof Fabric with Wax
Here is a good old fashion method using one of nature’s most natural waterproofing agents, beeswax. The beeswax has to be liquid, hot and painted onto the fabric.
WARNING - Handle the process with caution. This technique is not recommended for unsupervised children. It is hot and dangerous.
Getting started requires some equipment and of course the wax. Waterproofing uses beeswax and paraffin wax or candle wax melted together. The melted wax is painted onto the fabric.
With all waterproofing projects, the fabric to be waterproofed must be clean before you start.
Supplies
What you will need:
- A saucepan to boil the water to use as a double boiler concept.
- 4 oz of paraffin wax.
- 4 oz beeswax.
- Metal mixing bowl
- Spoon to stir with.
- A 1 inch (2.5cm) paintbrush.
Step 1 - Boil Water & Melt
You will melt the wax in the double boiler with the saucepan and the bowl on top.
Bring water to the boil in the saucepan and rest the metal bowl on top of the saucepan. The bowl should be big enough to fit inside the saucepan without the bottom of the bowl touching the water.
Put cut up beeswax into the small bowl and start to melt. Add the paraffin wax and melt the two together.
Step 2 - Warm the Fabric
During the melting of the wax, put the fabric into a dryer to tumble. The fabric needs to get warm to absorb the wax easier.
Step 3 - Brush on the Wax
Stir the chunks of wax to melt them. Use the brush to brush on the wax in small squares. Work in small sections to get the wax to be absorbed by the fabric.
Step 4 - Dry
Use a hair-dryer on high, to heat the wax further and get it to soak into the fabric. Smaller items like canvass shoes can go into a pillow slip and from there into a tumble dryer. This is another way to melt the wax in dry, hot air.
Step 5 - Cool & Cure
When the item is cool check for uneven spots. Hold the fabric up to the light to see how evenly the wax has penetrated. A second coat and second session of heating may be necessary.
Allow the newly waterproofed fabric to cure for 24 hours. Let the item air for a couple of days to lose the wax smell. You could put the wax fabric in a freezer for 24 hours to get rid of bad odors. When you take the fabric out of the freezer the waxed material should be watertight, odorless and ready for use.
How to Waterproof Fabric with Alum
Another DIY method uses laundry detergent and Alum:
What is Alum?
Alum is the shortened name for aluminum potassium sulfate which is a food additive. You can find it in grocery stores as it is used for pickling and baking. It is also found in baking powder.
Step 1 - Mix Water and Soak
Mix 1 pound (0.45kg) of laundry detergent and 2 gallons (7.5L) of hot water together in a large container. This container needs to be large enough to fit in all the fabric and have it completely submerged.
Soak the fabric in the detergent water until it is completely saturated. The fabric must be fully submerged. Push down any pieces of fabric that bubble to the top.
Step 2 - Dry
Take the fabric out of the detergent water to air dry outside in the sun. The fabric must not fold over itself in any way. Do not put on a hanger or double over. Stretch the fabric out to dry in single layers. It must dry hanging freely.
Step 3 - Add the Alum
Mix ½ pound of alum (0.25kg) with 2 gallons (7.5L) of hot water in another container. Stir the alum into the water to dissolve it. Alum can be bought at a grocery store.
Soak the fabric in the alum mixture for at least 2 hours. Once again make sure the fabric is completely submerged in the water.
Step 4 - Dry
Hang the fabric in the sun to dry in the same way that you hung it the first time. It must air dry freely and not touch other parts of the fabric.
How to Waterproof Fabric with Vinyl
Here is another method of how to waterproof fabric using iron-on vinyl. Vinyl can be bought from a fabric store. HeatnBond (Amazon link) is a popular brand of iron-on vinyl that gives a glossy appearance to the fabric.
Step 1: - Preparation
Get your fabric ready, but do not cut out your pattern. The whole waterproofed fabric can be used as a table cloth or cut up to make smaller items. Make sure the fabric is clean and most importantly wrinkle-free.
Step 2 - Cut the Vinyl
Cut the vinyl to fit the pattern you are using. If the vinyl is too narrow you may need to cut a few strips to fit the pattern.
Peel off the paper backing on the vinyl. The paper has a shiny side and a dull side. The vinyl has a sticky side and a smooth side. The sticky side of the vinyl goes onto the right side of the fabric. If the vinyl is not wide enough then overlap the vinyl by ¼ inch (6mm).
Step 3 - Iron
Cover the vinyl with the paper backing you removed and put the shiny side of the paper down onto the vinyl. The backing paper protects the vinyl while you iron it onto the fabric. You will iron on the backing paper to get the vinyl to stick.
You are going to iron on the backing paper. Set the iron to a medium stetting not a high setting. You do not want to melt the vinyl. Move the iron over the paper slowly and easily. Do not let the iron rest in one spot too long. Avoid using any steam.
Remove the paper. The heat of the iron should have melted the vinyl onto the fabric. Now you can use your waterproofed fabric with its vinyl coating.
How to Waterproof Fabric - In Conclusion
These four methods appear to be the cleanest, neatest ways of how to waterproof fabric. Fabrics you would want to have in your home or to use with your family. Other methods of waterproofing with linseed oil, turpentine and other chemical options would not seem to be the kind to choose for the tableware and other outdoor family orientated items.
The idea of a waterproofed table cloth or some table mats and a craft apron makes a great deal of sense. It is important to select the method suited to the item to make and the fabric itself. Always experiment on a scrap before venturing into the world of waterproofing.
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