Shawn Collins, 3M Senior Technical Services Engineer, shows panel bonding best practices.
Step 1: Remove the seam sealer from the host panel (01:11)
This will help you identify the welds. We’re using a file belt with a Scotch-Brite™ belt, which really highlights the welds.
Step 2: Grind and remove the welds (02:46)
We’ve switched to a grade 80 file belt for this. The most important thing here is to not get too aggressive. You want to make the top layer paper thin without going through and damaging the bottom host panel.
Step 3: Grind the weld nuggets down and abrade the surface to prepare for adhesive (04:40)
This is a great place to use the 3M™ Cubitron™ II Roloc™ Fibre Discs 786C. They’ll plane the surface down nice and flat. You want to grind this to bright steel.
Step 4: Clean everything off to get ready for adhesive (06:10)
Step 5: Prepare the replacement panel (06:35)
The replacement panel from the OEM typically has an e-coat or some kind of a primer. You want to remove any coatings and put that abrasive tooth in there to allow the adhesive to grab the surface a little better.
Step 6: Prep for the adhesive (07:33)
• First, make sure the surfaces are well cleaned. Techs often ask about existing corrosion. If you can’t remove all the corrosion entirely down to that bright clean steel, replace the part.
• Load the cartridge into a pneumatic gun. A pneumatic gun will give you more work time by getting the adhesive on the panel quicker.
• Equalize the cartridge into a paper towel, then extrude a couple inches to be sure you have an even mix.
Step 7: Apply the adhesive (10:20)
The key is to do three applications. Do a primer coat first on both the host and replacement panels. Then put another bead down, the squeeze-out bead. You want to force it out and spread it into the surface to cover all the bare metal. Leaving any exposed will open it up to corrosion. The third bead can go on either part. Apply a good eighth-inch to quarter-inch bead.
Step 8: Mate the parts and clamp them together (12:17)
It’s very important to clamp the parts nice and tight and keep them clamped during the clamp time. Don’t do anything to shift the panels. If the adhesive separates as it moves from a liquid or paste to a solid, it will not blend back together. And don’t pull the parts apart. If you need to move them a little, you can shift them by sliding. But if you pull it off, you’ll need to reapply because you’ll get air pockets. So mate the parts together and install your clamps.
Step 9: Clean up the adhesive while still wet (14:53)
This is especially important on corrosion-vulnerable areas. If you wait until it cures and then grind it, you’ll grind the edge down to bare exposed metal. Depending on where it is, it can then be difficult for the painter to cover with sufficient coatings. The acid brush is a great tool for cleaning between the clamps. This adhesive cleans off very easily while wet, even with soap and water.
Step 10: Apply any post-repair foams and cavity wax (16:12)
Observe the proper cure time first. One of the big advantages of this adhesive and its epoxy technology is that it heat cures very easily. As little as 40 minutes at 150 degrees will get you to almost full cure time.
Important note:
There are of course many factors and variables that can affect an individual repair, so the technician and repair facility need to evaluate each specific application and repair process, including relevant vehicle, part and OEM guidelines, and determine what is appropriate for that repair.
3M™ Panel Bonding Repair Tutorial SOP
www.3m.com/3M/en_US/collision...
Products used in this video:
3M™ File Belt Sanders for Body Repair
www.3m.com/3M/en_US/company-u...
3M™ Cubitron™ II File Belts 786F
www.3m.com/3M/en_US/company-u...
Scotch-Brite™ Durable Flex Belt
www.3m.com/3M/en_US/company-u...
3M™ Cubitron™ II Roloc™ Fibre Discs 786C
www.3m.com/3M/en_US/company-u...
3M™ Panel Bonding Adhesive
www.3m.com/3M/en_US/company-u...
For more advanced tutorials, check out 3M Collision Repair Academy
www.3m.com/3M/en_US/collision...
You’ll find courses that will expand your knowledge, deliver practical procedures that you can use right away, and, in many cases, earn you I-CAR credits.
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