Steps for a Good Inside and Outside Patch at the Same Time
Turn off all ignition sources like pilot lights. Do all repairs in the shade.
You do not want to glue your boat together, and drips are going to happen with an inside patch. So hold the tube open with a pair of vice grips that are suspended from something like a ceiling rafter, or oar tripod. Place some visqueen (construction plastic) or wax paper or a bread sack or garbage bag inside to catch the drips. Make some test patch material to test your reactivation, and to test the glued patch for inactivity. If doing a river patch, make certain that you have as much moisture out of the tube as possible. Water vapor is the enemy of a good glue job.
Follow these steps in sequence:
- Place the part on a flat surface before starting your work. Ammo can lids work good on the river.
- Mask the area around the outside patch for looks.
- Cut your inside and outside patches to size. A good rule is to have 2 inches of overlap on all sides of the tear for strength when deciding how big to make a patch.
- Raise the patch area off the ground with the suspended vice grips.
- Slip the garbage bag inside to catch drips.
- Prep the inside and outside with MEK or acetone.
- Prep the patches and the test pieces.
- Coat the inside of the tube. If you use plastic food handler’s gloves you will get less glue on your hands. Double and triple them up they tear easily. Latex is desolved by the glue. Glue the outside of the patch with the first coat.
- Wait for 1 hour, then recoat with the second coat, inside outside, and on the patches.
- Allow the glue to dry 2 hours, then check to see if the glue has gone to the inactive state.
- At this point your test pieces will not stick together. However the glue on the inside of the tube may be too fresh still. Carefully check an edge with your test patch. They should not stick together.
- When you are confident they will not stick, draw a line on your inside patch to help center it on the tear, and make some cross hatches to help line the patch up at the end of the tear.
- With the glue inactive you will be able to align these marks to get it in a good place.
- Boil some water (you can be doing this while waiting for the glue to dry). Use a large sauce pan with 6 qts of water so there is a lot of thermal mass.
- Test the reactivation of your glue by applying heat with the bottom of the pan of hot boiling water on the test patch. If you wait for 10 minutes after heat reactivating and rubbing it out, you can try and pull the test patch apart. Now you will see how well this will work.
- Place the inside patch lined up properly, and the outside patch inside of the masked glue area. Remember that they are not active.
- Place the hot water on top for at least 2 minutes to allow the heat to soak into the plastic. This will not melt or hurt your plastic or glue in any way, provided you do not get them wet.
- Rub out the patch on the flat surface. Your patch is done. Allow as much time as possible for the glue to reach full cure before inflating. If you let it set overnight you can pump it tight. If you allow only 10 minutes get the boat as firm as you need to be safe. Remember the glue will continue curing for 2 days. It is a good idea to use a cool wet cloth on the patch if the patch is exposed to hot sun.
You can leave the plastic inside if you wish. Some times it is easier to do that than try to pull it back out again.