Plastic Welding Methods
The Eastwood kit’s Speed Tip uses a heated tip that allows you to push the welding rod through it so it comes out soft and hot on the other end. Other methods include hot-gas welding, which uses hot air to heat the plastic and welding rods and is normally used on PVC piping; hot-plate welding, which works with a jig that presses two heated pieces together and is used for geometrically complicated pieces; and extrusion welding, a heavy-duty version of the Speed Tip.
<strong>01.</strong> This is Eastwood’s Airless Plastic Welder (item 14013), which retails for $229.99. There are lower-priced plastic welder kits available from Eastwood, but this one is the most complete and includes rods for all the different types of plastic.
02. We also used Eastwood’s Hot Stapler Plastic Repair kit (item 13650), which retails for $159.99. It’s perfect for structural holds, like plastic brackets and flanges.
03. Here is a fan shroud with a broken mounting tab from an older Chevy truck. In most cases, it would be cheaper to buy a new shroud rather than repair it, but the Eastwood tools are great for applications for which reproduction parts are not available.
04. If you still have the piece that broke off, it’s easiest to reattach it using the Hot Stapler (skip to step 11). In this case, we fabricated a new piece using four pieces of metal mesh, provided in the kit, in a shape slightly bigger than what was missing on the shroud. We used the other top bolthole as a reference.
05. We created the block by melting rods onto the mesh, letting the hot plastic dry, then melting again four separate times, cross-hatching the mesh every time. We did this on a clean, flat, metal workbench.
06. Here is our ugly block of replacement plastic.
07. Next, we cut a straight line in the shroud on which to mate the new piece.
08. We cleaned the area and then filed a notch for the plastic welding rod to fill in.
09. Eastwood’s kit includes a chart that explains what type of plastic to use in various applications—this is very important. The welder also has a heat dial labeled for different plastics. Find your plastic and its heat range.
10. Holding the new piece in place, we used the tool to slowly massage the plastic into the notch created in step 08. It’s similar to soldering.
11. This is a piece that requires strength, so we decided to staple it together, which we would not have done on a smaller, cosmetic piece. We used the Hot Stapler to press different metal staples between the two pieces. Eastwood offers corner, long-gap, and tight-gap staples. We pressed as many as we could fit: three corners, three tight gaps, and one long one on the side.
12. We cut off the ends of the staples and trimmed them down further with a disc grinder and file. ">
<strong>12.</strong> We cut off the ends of the staples and trimmed them down further with a disc grinder and file.
13. While cleaning it up, we measured and cut off the excess.
14. Now came the tedious part of sanding and filing, starting with a course file and gradually stepping down to finer files. If you are patient and can deal with clogging up sandpaper, you can sand down the piece until it looks very similar to the rest of the plastic, without needing to paint it.
15. Here we drilled for the bolt.
16. This is the finished product with a light coat of paint. This is a rough part on a rough truck, so cosmetic appearances aren’t important to us, but lots more time could have been spent to make it look nice. The welding rods closely match the color, so with enough patient sanding, you might not even need paint.
