Tag Archives: filler
One thing I like about building a true custom (not just bolting on shiny wheels and putting stickers on the windows) is that there are no rules. It's all about what looks good and what fits your vision of the final product that is YOUR project. One theme that I have with Project Pile House is to make the body less "busy" and give it a smoother overall appearance. These trucks were meant to be utility vehicles, so there wasn't much thought put into styling. Definitely not like their passenger car counterparts. All that anyone really cared about was that it was reliable, could haul a lot in the bed, and that the hood, doors, and tailgate closed and latched. So this means I need to fill and smooth a lot of body seams or body lines that are all over the cab and front end.
These seams need to be filled with metal, and should not be filled with body filler, no matter how tempting it is to just run a bead of filler along them. Occasionally you can get away with filling a seam by slowly stitch welding it shut, but this could require a few passes to completely fill the seam and it puts unnecessary heat into the panels around it. I've found that these seams can be easily filled by using TIG filler rod and a MIG welder. This tech tip should help you fill body seams quickly.
You want to start by removing any paint or rust around the seam, and then run a wire wheel in the groove to remove anything tucked into tight crevices. I found an angle grinder with a flap disc takes care of most of the process, but a thin wire wheel cleans out any remaining debris. If you're the overly cautious type you can spray some Self Etching Weld Thru Primer in the seam to help seal the area.
After you're down to clean metal, you'll want to find a TIG filler rod that will fill the seam and sit flush, or just below, the surface. You then want to set your MIG welder to a higher voltage or heat setting than normal for the metal you're welding. The idea is to produce a quick, hot spot weld that melts the filler rod into the seam and leaves a fairly flat weld on top of the panel. The flatter the final weld is, the less grinding will be required.
After you have a few spot welds holding the filler rod in place, you can then stitch weld the rod into the seam. Always remember to alternate your spot welds and allow the panel too cool in between welds. The seam should look something like below after it's completely welded.
With the seam filled, you can take a flap disc or low grit sanding disc and knock the "proud" welds down until they blend into the surrounding metal. You should be left with a seam that's filled with metal (and not filler!) and will require little bodywork when it comes time for paint.
When we're attending SEMA we talk to a lot of pro builders and fabricators. We want to know what the new trends, techniques, and products are that they used to get the results we've seen at shows and in the magazines that year. This is one of the ways we can bring you professional tools and products at affordable prices.
This year we noticed a trend with a lot of the builders. Getting the metal work "close" isn't enough anymore. Builders are now striving to make repairs and modifications that are literally seamless and invisible when they're done. Some of the photos I've seen are incredible. These guys are craftsman and the way they form, shape, and finish metal is an art. While I've been using MIG and TIG welders on and off to work on Project Pile House, I've slowly been learning that a TIG welder can be a really great tool for thin gauge sheet metal work.
Project Pile House had a VERY hard life and it was a true work truck before I got ahold of it. It's been used, abused, and modified to get the job done. This included adding lights, mirrors, hooks, brackets, and anything else that "Whitey" (the original owner) felt would help him along the way. This has required a LOT of patch panels to be made up. With the arrival of our new TIG 200 DC Welder, I decided to show you how to make a nearly (I'm no magician yet!) invisible patch panel with it.
The key to strong, visually appealing welds on any project is good "fit-up" of what you're working on. This is especially important when using a TIG welder. Some guys aren't even using filler rod! They're melting the two adjacent metals together only using the parent metals. This means they're making a patch panel that is such an exact fit that it's almost an interference fit (press fit or slightly larger than the opening). This allows the pieces to be melted together with out adding any filler metal. It also requires almost no grinding and yields a perfectly blended patch panel. In this tech article I'll show you the basics of how you can do this, but we'll stick with using filler rod sparingly for now.
This is the area I'm working with above. The truck had some marker lights added on the top of the fenders that were drilled and sandwich into the fender with a second piece of metal under the fender and a nut. Over time the light was bent and broken off, damaging the area around the mounting hole. Rather than work with the pre-existing metal, I decided to cut out the surrounding damage and make a new patch panel. I started by taping off the work area and using the cutting disc on the angle grinder to remove the damaged metal.
You can see above the piece I cut out and the slight curvature to it. I like to keep the original piece around to use as a basic guide for my new patch panel. Next I traced out the shape of the piece I removed (remember we want a tight fit and the part we cut out will be slightly smaller) and transferred it onto some aluminized steel out of our patch panel repair kit. I then used a set of electric metal shears to cut on the outside of the lines I made. This gives me more than enough metal to fit in the opening.
With the rough-cut patch test fitted, I marked out the estimated area that needed to be removed. I then trimmed it down with aviation metal snips and sanded it on the belt sander until I had a very tight-fitting patch panel. From there I put a slight curve in the panel to match the fender and used a metal file to smooth out the opening in the fender. The key here is take off enough metal that the panel will fit snugly without distorting the patch panel or the metal around it.
Now that the patch is in place I set the TIG 200 DC to about 80 amps max. If using the finger switch on the TIG welder, I like to set the machine to a fixed 50-60 amps for sheet metal work. With the pedal I'm able to fluctuate the amperage to get exactly the size weld and penetration I need. I use a 1/16" "red" electrode and either .030 or .035 TIG filler rod. The thin filler rod allows you to make a very small puddle and takes very little heat to flow (melt) the filler rod into the weld puddle. This is nice for thin gauge butt welds like we're showing here. If you need to fill a small void (bad fitment, blown through joint, gaps between welds) I've used silicone bronze filler rod to smooth out a patch panel joint. This filler rod is extremely soft and easy to hammer weld and grind.
After jumping around and fusion welding each side of the patch panel (and happy with the fitment), I began laying very short welds around the panel. Ideally you should only run 1" passes at a time at most (less depending on the patch panel size), letting the panel fully cool between welds. You can also decrease the heat soak across the panel by using thermal paste around the work area.
In between weld passes it's a good practice to "hammer weld" the seam. This is to both flatten the soft weld bead, and also flatten out or correct any heat warpage at the joint. Some like to do this after the panel is fully welded, but I feel it's easier to keep a handle on warpage by hammering the welds as you go. I used the Eastwood pro hammer and dolly kit since it has the hammer and dollies I needed to work the patch panel.
Once the seam was completely welded, you can begin flattening out any "proud" (taller than level) welds with a flap disc on the grinder or with a hand file. If possible try and grind across the weld and only knock the weld down to level. If you are too heavy-handed with the grinder you can easily burn through or warp the metal surrounding the work area and cause a bigger mess than you started with!
Once the seam is pretty level and the panel is free of warpage, you should have a patch panel that is pretty close to invisible. At this point you may even have a panel that is ready for primer and top coat. But for us mere mortals, you can now choose to use body filler or body lead to fill in any small imperfections before primer.
After you pick up the basics of TIG welding thin gauge steel, you can begin welding up patch panels without all of the extra heat, sparks, and mess of a MIG welder. I won't throw my MIG welder away just yet.. but I'm enjoying the lack of holes in my clothes from the sparks and slag it produces!
Recently we added another "arsenal" to our auto body product line. Sometimes after hours, days, and even months of sanding filler and primer, you start to see "things". It makes you feel as if you are a shipwrecked sailor. You know the feeling, you're fine-tuning a dent that you had hit with the stud welder, laid some thin layers of filler over, and sanded diligently in between. All while running your hand along the panel to feel for low spots... before your eyes new low spots seem to "appear" and the original dent you started with seems to get even bigger!
I've found that using a small bit of guide coat over a area you are filling or priming is very helpful in eliminating the doubts of a phantom low spot. Especially one that might show itself only after the car is painted and shiny. This is especially true for someone like myself that is a "novice" in the auto body field.
Below I took some pictures of one of the bedsides on my 1981 VW Rabbit Pickup project. This truck originally had dealer installed bed rails that were used and abused to the max! So much so, that they had even pulled some of the threaded inserts out of the bed sides. Once I removed the bed rails, the bedsides looked similar to the water in your swimming pool after the kids have been playing in it for hours! Because I am going with a "clean" look for the truck, I will not be running bed rails in the future. This means I won't be able to hide the "waves" and oblong holes with the bed rail feet. So I began by using our hammer and dolly set to smooth out the major dents and high spots around the mounting holes. I then welded up the old mounting holes. I was then left with some smaller "waves" and low spots (and a couple pin holes in the welds), This is where the "sanding, filling, sanding more, filing more, sanding again" process occurred.
Above you can see my first layer of Rage Extreme filler has been laid down. This Evercoat product is very user friendly. It is the first "pinhole free" body filler of it's kind according to them. I was a little skeptical, but after using it numerous spots on the body of this "field find", I had quickly forgotten about my glazing putty. I then blocked the area to 320 and I still felt like there was a small low spot right near the back end of the bedside. I sprayed the black guide coat (it also comes in TAN for those of you using a dark colored filler, or black primer) over the entire top of the bedside. I've found doing a extremely light coat over the area, holding the can about 12" away works best. You can see in the last picture it looks like a light bit of dust over the top of the beside.
You can see in the first picture the sanding process halfway through. As you sand lightly, the majority of the guide coat sands off quite quickly. You will notice that low spots will leave behind the guide coat and pretty much outline the remaining low spot. In the second picture you can see as I had suspected, a noteworthy low spot. It is right where one of the mangled mounting holes for the bed rails was. I even took a picture of this area before I started the guide coat process (last picture in the series). Following this, I reapplied another concentrated coat of filler over the dent, block sanded to 320 again, and repeated the guide coat process. This eliminated the worries I had of having a the tops of the bedsides all wavy. I will surely be using the guide coat quite a bit when I put the body in primer next week!
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