Whether you need to repair a crack or join pieces of plastic, welding is the solution.The task of welding at home is relatively easy since plastic is soft and flexible.To complete the repair, you need an electric welding gun and a welding rod.Use the heat of the gun to melt and join the plastic after you clean it.A fix that is stronger and cheaper than a new piece of plastic can be created by smoothing out the welds.
Step 1: Dust and fumes can be mitigated by setting up a workspace in aventilated area.
Before you start welding, there are a few safety concerns to address.If you can, work outdoors.Fans can be used to air out the area.Wear a dust mask and glasses for extra safety when preparing plastic.Don't let other people in the area until you're done working.
Step 2: Gloves and long-sleeved clothing are required for protection.
You need a pair of gloves made from leather.Put on long-sleeved clothing, pants, and a pair of closed work boots.Use a clear welding visor to protect your face.There is no need to wear a full welding mask.Plastic welding torches do not give off a harmful light.
Step 3: The plastic needs to be cleaned.
Start by scrubbing off as much debris as possible with a sponge soaked in warm water.If that doesn't work, wash the plastic with dish soap or detergent.Since the plastic could weaken the weld, remove dirt, grease, and other debris.When you are done, wash the plastic with a lint-free cloth.You can get a liquid solvent called MEK online or at a hardware store.Remove the stain from the plastic with a clean rag and solvent.Don't use any industrial-strength detergents.They leave a soapy film behind.
Step 4: The plastic has a letter identification on it.
Many plastic products have letters printed on them.Look for the letters PE, PP, or PVC.Pick a rod that matches the plastic you plan on welding.You would need a rod to join the pieces.You can fix a crack on a single piece by melting plastic around it, but have a welding rod on hand to cover any gaps.
Step 5: If you don't know what kind of plastic you have, use a welding rod testing kit.
There are different types of plastic welding rods in a rod testing kit.Pick a rod that resembles the plastic and use the test.Attach the rod to a clean spot on the plastic by heating the end of it.Use a pair of pliers to pull the rod off the plastic.It is the same material if it stays attached.Only a single rod will stay welded to the plastic since you can only combine the same type of plastic.Refer to the letter marking or the test kit manual to find out what type of plastic the rod is.Testing kits can be found online or at many hardware stores.
Step 6: Paint can be removed with a piece of sandpaper.
If the area you want to weld has paint on it, you need to scrub it off.Rub the sandpaper across the surface, pressing down with light but consistent pressure.You should expose the plastic underneath the paint.You could use a sanding wheel that is attached to a drill.A paint scraper can be used to remove paint.Don't scratch the plastic underneath the paint.
Step 7: Attach the plastic pieces together to hold the joint in place.
Before you turn on your torch, form the joint.Push the plastic pieces as close together as possible on the bench.The pieces should be pinned to the table with C-clamps.Wrap foil tape around the pieces to keep them pressed close together, but don't cover the area you want to welds.Make sure the joints are secured tightly.As you focus on the weld, you don't have to worry about adjusting them.
Step 8: The welding gun needs to be Preheated for at least 2 minutes.
Setting your welding gun up correctly is important because plastic can vary in temperature.You need a temperature between 200 and 300 C.It burns the plastic or doesn't melt it enough if it goes beyond that range.The welding gun should be set to 300 C.The heat setting should be adjusted to about 275 C.The heat should be set to about 265 C.
Step 9: Attach the plastic together with tack.
Attach loose plastic together by melting the ends of the joint.Attach a tack welding nozzle to your welding gun and apply some heat.When the plastic starts melting, join the pieces of plastic together.As you complete the weld, this will keep the plastic from moving.A tack welding nozzle has a fin on it.To melt it together, press the fin against the plastic.The only thing you need to do is melt the plastic.For additional security, tack weld spots every 1 ft along the joint.
Step 10: Attach angle cutting pliers to the end of the welding rod.
It is very easy to trim a rod.The pliers should be held toward the end of the rod.To hone the rod, cut it to a point.If you don't have pliers, you can use a trimming knife.Giving the rod a pointed end increases the chances of getting a smooth, steady weld without a big bubble of plastic where you start.Before changing nozzles and welding rod, you can let the welding gun cool off.The gun should heat up again before starting the weld.
Step 11: A welding rod can be inserted into a speed nozzle.
As you melt the welding rod onto the joint, a speed nozzle has an opening.You can buy one without the heat gun.Feed the rod into the second opening of the heat gun after fitting the nozzle.You can use the clipped end when starting the weld if you put it in first.If the tack nozzle is still hot, make sure you don't touch it.Either wait for the nozzle to cool or swap it with a pair of pliers.You will need to feed the rod into the opening with a speed nozzle.You could use a technique called pendulum welding, where you sweep the gun or torch back and forth to melt the rod over the joint.It's great for tight spots.
Step 12: Move the tip of the gun slowly over the plastic.
Start at the top of the crack.The edge of the nozzle should be touched by the gun at a 45 degree angle.The plastic will begin to melt when you heat it.Feed the welding rod into the joint as you push the torch along.Consistency is the key to success with welding.You can melt the plastic and welding rod just enough to bind them without burning them if you move at a deliberate pace.If you see plastic burning or changing colors, move the torch at a faster pace.You will end up applying too much heat if you let it linger on the plastic.
Step 13: If you are doing a pendulum weld, swing the gun back and forth.
Hold the nozzle above the crack and tilt the gun at a 45 degree angle.The welding rod should be positioned from the opposite side.When you hold the rod in place, sweep the nozzle back and forth to melt it.As you move down the plastic, keep doing this.If you don't have a plastic heating gun with a speed nozzle, Pendulum welding is useful.It is possible to do it with a basic torch.You can't easily reach a tight joint with a speed nozzle.Since you have to control both the torch and the welding rod at the same time, this part is a little more difficult than with speed welds.The torch should be moved to prevent the plastic from burning.To melt the plastic, swing it back and forth across the joint.
Step 14: Wait at least 5 minutes for the plastic to cool.
Before you work on it, make sure the plastic comes back to room temperature.You can wait as long as you please, but welded plastic doesn't take long to cool down.The welded plastic will turn solid.You are ready to work on it if you don't feel any heat coming off of it.Before the weld cools, the best time to fix it is.A smooth and consistent weld is what a good one looks like.If you need to smooth out the melted plastic with your gun, add more of the welding rod.When you are done, set your welding gun aside.Place it in a heat-resistant holster until it cools.
Step 15: The welded joint should be sanded down.
To make it look like the rest of the plastic, smooth out the rough ridges on the weld.Light pressure should be applied to the weld, rubbing the back and forth across it.To get the weld to look level, be careful to avoid scratching the plastic around it.If you want a faster way to do this, use a sanding wheel.Plastic is easy to scratch, so be careful.
Step 16: The plastic should be finished with 180 and 320-grit sandpaper.
If you want to neaten out the weld, you need to use fine grits of sandpaper.If you are not careful, higher-grit sandpaper can still scratch the plastic.Rub the weld down until it feels smooth to the touch, like you did with the 120-grit sandpaper.The first thing to do is use the lower-grit sandpaper.It wears away more of the plastic because it is coarser.The higher-grit sandpaper is used for finishing.