If you cannot fit cardboard between the plastic, like if the hole is in a gas can, this can still work, but it may not have as solid of a hold.
Wear plastic gloves to avoid getting super glue stuck on your hands.
Other powders like sawdust or chalk powder may also work.
You can try mixing colored powder or food dye with the baking soda to resemble the color of the plastic more closely.
Wear a face mask so you don’t breathe in any plastic particles as you work.
Keep your hands away from the heating end of the plastic welder to avoid burns. Find a rod that closely resembles the color of the plastic you’re fixing.
Hold the plastic welder 1⁄2 inch (13 mm) away from the rod. You want it to be malleable, but not for it to melt completely.
Do not leave a depression in the plug, since this could compromise its strength and integrity.
If you want to get rid of any file markings, hold the plastic welder just above the area to smooth it out. Cut away any large pieces that are too big to file with a small razor blade. [12] X Research source
Fiberglass patches can be purchased at hardware stores or online.
Wear disposable gloves when working with epoxy, since it may cause skin irritation. Lay cardboard or another disposable liner underneath the plastic, in case it drips through the mesh.
There should be enough epoxy so that the entire fiberglass patch sticks to the plastic.
Fiberglass patches are flexible and should conform to the shape of the plastic you are mending.
This entire process can be done once more with more fiberglass pieces if you need to add more integrity to the plastic.
Epoxy can be painted afterward to match the color of the plastic.
