Sat Sep 03, 2022 7:07 pm by mrjim2017
KB5 DRIVERS SIDE FENDER REPAIRS - Part 1
Took more time than I wanted as the upper 90's heat, high humidity, and rainy weekends made it a bit uncomfortable to be outside working away on the truck, but I am still moving forward.
Both fenders are well beat up with dents, heavy rust pitting, and rust holes. My aim is not to restore them to concours quality, just make 90% better than what they are. Have a lot of hours invested in what you will see in just this 1 fender alone. Used some techniques that I felt were acceptable, time saving, and would work for this truck.
Pic #1 - The fender in its POR-15 coating I gave it to protect it after it came back from the sand blaster. I used it as just a protective covering to prevent any rusting until I could get to the repairs. My intention was to sand it all off leaving the bare metal and leaving the POR-15 to fill in the pitting and further seal off the pitting from any further rusting even though the sand blasting did get the pitting cleaned up.
Pic #2 - The front/side of the fender. If you look hard, you can see how dented and beat up that fender is - hey, it was a city delivery truck, so it got bumped a bit. No, it got bumped up a lot. LOL
Pic #3 - Sanded off the POR-15 and you can see how bad the fender is. The dark spots and lines highlight all the denting and you can see the black speckling of the POR-15 left in the pitting areas.
Pic #4 - Looking straight on at the front. Damages above the headlight bucket, pitting below it, at the lower fender, and denting. I only sanded off a section at a time to make it easier to work the fender and get an area repaired that I could start and finish on my weekend time off.
Pic #5 - Looking a little better. I used a hammer & dolly to knock out and smooth many of the dents. Took some time to get the fender into shape and the better the shape, the less the bondo. Once I felt I got the fender to its best condition, I sanded the metal to rough up the surface allowing the fiberglass bondo to grip. You never want a smooth surface. I used a 60-grit paper on a hand held electric sander and also used my electric grinder with a coarse metal grinding disc. It is now ready for the filler.
Pic # 6 - First coat of fiberglass bondo. You can see how I covered the large area with this application and then I will sand a lot of it off to shape the fender curves and then make smaller applications of the bondo as needed and sand these spots. Takes a lot of time to shape the curves and not over-sand the bondo so you wind up with a bunch of flat spots - old fenders like these got curves. I prefer to use the fiberglass bondo versus a plastic bondo - just my choice as either would work. I use the 60-grit and my hand sander to do most of my sanding/shaping. Once I get the first application sanded, I apply another coat of bondo and let it cure.
Pic #7 - I work several areas at a time when I can. As the second application of bondo is setting up, I jump over to the front of the fender and sand off the POR-15 down to the bare metal and you can see how pitted this section is by all the speckled POR-15 left in the pits.
Pic #8 - I go back to sanding the second application of bondo. The electric hand sander has a small sanding pad and it can easily create those flat spots in the bondo that you don't want. So I use an autobody flat sanding board which used a long piece of paper, probably 14" long by 2 1/2" wide. The purpose of this is you can lay it flat over a longer area to pick up the curvatures of the fender and follow these curves when sanding the bondo - so the bondo takes the same curves. Takes a little skill to work the board and shape the fenders, but you use your hands/palms to "feel" the shape and you can feel when there is a depression, flat spot, or high spot, and then you continue to work it by either more sanding or filling in just the low areas to build them up and then sand them smooth.
Once the bondo has been shaped and "feels" to follow the contour and curves of the fender, glazing putty is applied in a thin even layer over the sanded bondo. The glaze is a 2-part mix having a base and accelerator you mix together, just as you do with bondo, or JB Weld. The more activator you use the faster it cures on you and outside temps add to the speed of the cure, so once it is mixed you want to work fast in applying it before it "freezes" up and becomes cured.
In this picture I have applied the glazing putty on the sanded bondo and over the pitting. The glazing putty can be applied directly over bare metal - again it has to be roughed up so it will bite onto the metal surface. It gets sanded with a finer grit so you do not leave scratches in the putty. Once sanded smooth, it will be painted with your primer and any scratches, pin holes, or rough texture left in the glazing putty will be seen in the primer and in your paint color coat. So I use a 220-grit and my long board on the fender and my electric sander on the pitted area to sand the putty. Like bondo, you can apply more to fill in any spots, scratches, or imperfections you see after sanding and then sand the new layer of putty smooth. It can sometimes take several light applications, so don't be concerned if you do. What you don't want to do is have to build up the putty like bondo. If you have to do that, then you did not apply/sand the bondo correctly. The putty should b a light layer with most of it being sanded off smooth.
Pic # 9 - This is what you are left with after sanding away all the glazing putty and leaving a light layer to fill in the deep pitting. Primer will go over the area to cover the putty and leave a smooth surface. If you still have some pitting shown through the primer, you can sand the primer and use the primer as a fill media and then apply another layer of primer, or you can use another thin application of putty on top of the primer after you rough it up by sanding it, and then sand/prime the putty again.
Pic #10 - Here is what the bondo/putty looks like when finish sanded. A nice smooth surface ready for an application of primer. I primed the area with spray bomb primer from a can to protect the area and continue the work the next weekend. So that front area repair was a weekend job.