Tag Archives: flap disc

  • How to Prep Metal For Welding - Quick Tip


    The key to any good weld is clean metal, but what is the best way to clean metal before you start welding? Depending on the tools you have and the overall goal of the project there are a few ways to prep your metal to get a nice clean weld every time.

    The best welds come from pure clean metal to metal contact,  any foreign materials in the welding area can cause welding imperfections.  Even brand new metal must be prepped before it can be welded because there is usually a coating put on new metal so it does not rust or oxidize during the shipping process.  This is a factor that is often overlooked and will always result in a weak and ugly weld.  Be mindful, once you remove this coating the metal is exposed to the elements,  if left out unprotected steel will begin to rust, even indoors.

    To start, the type of welding you are doing will determine how you prep the metal. Inherently MIG welding steel does not need the metal to be perfectly clean. On the other extreme, TIG welding aluminum requires contaminant free metal to create a strong clean weld.  In all of the examples below you can see the difference the dull color of the "new metal" (left) compared to how it looks after it is properly prepped (right).


    Angle Grinder with Flap Disc

    Using an angle grinder with a flap disc works great to prep steel for MIG or TIG welding.  Mild steel does not require the surface to be super clean to get a good weld.  In the picture above you can see the left side is brand new untouched steel, it may look clean but it has a thin coating like stated earlier.  Once you remove the coating with the flap disc, all it takes is a quick wipe down with Low VOC PRE or Acetone and you will be able to make clean and effective welds. This method works great for heavy welding on chassis parts, this area is always exposed to the elements which will build up contamination over time.  Take the time and clean the metal, you'll thank yourself later.

    Be careful a flap disc will remove a lot of material so don't use this on thin sheet metal, it may compromise the metals strength.



    Sand Paper

    Similar to using a grinder this method will work great for MIG and TIG welding steel or stainless, but it can be time consuming and does not always remove all of the coatings. Like using a grinder, you must wipe the metal down with Low VOC PRE or Acetone before welding.  In the picture above I used 80 Grit sandpaper,  it worked well by removing the coating but also left deep scratches that may not look good.



    Abrasive blasting

    If the metal you will be welding is very rusty and is not suitable to be sanded or removed with a grinder another option to prep the metal is to blast it.  After blasting the metal may look clean but it will still need to be wiped down with Low VOC PRE or acetone to remove and chemical contaminants.  The abrasive material can sometimes trap pieces of other metals that can cause the metal you are welding to rust or corrode.  Never rely on a blaster to prep aluminum for welding, it is very sensitive to contaminants that can get trapped even after wiping it down.



    Cleaning for aluminum TIG Welding

    When prepping aluminum there is a slightly different process that you will need to be mindful of.  Aluminum is very susceptible to contaminants therefore the cleaning process must be done in reverse to produce clean welds.

    First you must wipe down the metal with Low VOC PRE or acetone, this will remove any oils or grease on the surface.  The next step is to remove any oxides on the surface of the metal.  To do this use stainless steel wool or a stainless wire brush on the area to be welded.  Make sure that the Steel wool or wire brush is used exclusively for aluminum to avoid contaminants from other metals.  Once these tools come in contact with mild steel they can transfer steel bits into the aluminum which will eventually create rust.  Finally wipe down the metal with Low VOC PRE or acetone with a clean cloth or rag, from here you are ready to weld.


    It doesn't matter what kind of welding you are doing its always important to take the time to clean your metal before welding.  Not only will your welds look amazing they will be a lot stronger which is always an added bonus.


    Check out the Eastwood Blog and Tech Archive for more How-To's, Tips and Tricks to help you with all your automotive projects.  If you have a recommendation for future articles or have a project you want explained don't hesitate to leave a comment.

    - James R/EW


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  • How to Strip Automotive Paint- The Tools and Procedures

    One of the big, time consuming jobs on any project vehicle (unless you are building one from scratch with raw sheet metal,) is stripping off years of old paint, primer, and anything else on the body panels. There are as many different ways to strip paint as there are types of paint to apply. Many times, especially with older projects, there may be multiple layers of primer, urethane, lacquer and enamels between the bare metal and the outside world.
    Matt took an extra hood from a Chevrolet Monte Carlo that was a perfect example of this and used it to show the various mechanical, chemical and abrasive methods that Eastwood offers to take off old paints and primers. Here on the table you can see various sanding, grinding and other a mechanical methods to get the paint off the surface. Right by Matt’s elbow you can see several sizes of the Eastwood Gel Chemical Paint and Powder Remover. And on the right of the screen you can see the big blue tank of the Eastwood Abrasive Media Blaster, for spraying various grits of media at the panel that will eat the paint off.

    Paint Removal 1

    Of course you always want to wear proper safety gear no matter what you are doing. Besides the normal dangers when you are grinding and sanding, working on old cars can expose you to lead paint and body solder, as well as rust and tetanus. You should at least have a pair of safety goggles on, and a filter over your nose and mouth to keep the dust out. A pair of sturdy leather gloves gives you something else to cut or burn before you get to your actual skin. When the particles really start flying, a clear fold down full face shield is a good idea as well.

    Paint Removal 2

    Hand Sanding with a Block
    This is the cheapest and easiest method, but that is only if you don’t value your time, or you are just looking for an upper body workout. Mister Miyagi had great luck with tricking local teenagers into doing this by promising to teach them karate.

    Paint Removal 3

    The advantages of the paper and sanding block method are that there is very little to buy before you get started, it is gentle to the metal, and you can get into really tight, irregularly shaped areas. The main disadvantage is that it will take what seems like a year to sand off the old paint on the whole car. After 30 seconds of work, Matt barely was able to get through the top layer of black paint and down to the white.

    Paint Removal 4

    Dual Action Sanding Disc
    Next up is the same 80 grit sand paper, but this time spun by a dual action sander, sometimes called a DA or random orbital. This works very much the same as the hand sanding, only the air or electricity provides a lot of the work, instead of your arm, shoulder and back muscles.

    Paint Removal 5

    As you can see, in the same 30 seconds the DA Sander was able to take off all the black paint, and in the one spot Matt focused on, three other layers to expose the base metal. The downsides of the DA method are you will burn through a lot of sand paper, you need a good air source, or an electric DA to keep up and do the whole car, and it’s really only suited for larger flat panels. The advantages over doing it by hand are obvious, but it’s not the best way to remove paint from a whole car.

    Paint Removal 6

    4 1/2 in Flap Discs
    The next item often used to remove old paint is the flap disc that attaches to your common angle grinder. It’s basically a flat disc with little pieces of sand paper glued to it in an overlapping pattern. All the edges of the paper give it a much more aggressive bite than just a flat disc like the one on the DA.

    Paint Removal 7

    The problem is it’s usually too aggressive. Sure this tool will make short work of all the old paint, but if you aren’t careful it will leave a ton of gouges in the metal. Use too much pressure and it will even grind grooves in it. All this means more work after stripping with filler or high build primer to undo the damage you just caused taking off the paint. The flap disc is especially dangerous around edges and body lines as they can grind right through the metal. They do work great though for grinding and smoothing welds and surface rust.

    Paint Removal 8

    Hook & Loop Cleaning Disc
    Next up is the Eastwood Cleaning Disc, which is like a super heavy duty version of the green scrubby you use to clean pots and pans when washing the dishes. It’s available in a similar form to the flap disc, glued to a fiberglass backing for use with an angle grinder, but for big jobs it’s much easier to use the Eastwood hook and loop version. The hook and loop kit has a dedicated disc that screws onto your angle grinder, and cleaning discs that stick to it with a heavy duty version of Velcro. The discs are available in 80 grit and a 320 grit and are easy to change.

    Paint Removal 9

    The woven material of these discs is great because it doesn’t come apart when you are using it and fling pieces everywhere. The flexible nature of the disc and backing pad make them much less dangerous to edges and body line too, and they don’t gouge if you push too hard. As you can see they make short work of blasting through all this old paint too. But if you use the disc in one place for too long it is possible to get the panel too hot and warp it, so keep moving.

    Paint Removal 10

    Hook & Loop Stripping Disc
    Next up is the less aggressive 320 grit hook and loop disc. This one does the same job it just takes more time. It’s less aggressive and more suited to taking off the clear coat and prepping a recent car with just 1 coat of paint on it.

    Paint Removal 11

    As you can see it leaves a smoother finish, but it takes longer to cut though the paint. Eastwood sells a kit with both discs and the hook and loop attachment for your angle grinder. It’s great to start out with the more aggressive 80 disc, cut through the old layers of paint, then smooth it all out with the 320 disc.

    Paint Removal 12

    Here’s a before and after on the same patch of hood we used the cleaning disc on originally, showing how you can use the stripping disc to finish the job and get down to smooth bare metal. Here is before.

    Paint Removal 13

    And this is after.

    Paint Removal 15

    3M Plastic Bristle Disc
    Next is the plastic bristle disc from 3M. These bristles are very tough and come attached to a disc that screws onto a common 4 1/2 inch angle grinder. It works exactly the same as a wire wheel would, only the discs don’t fall apart as easily as wire wheels do and they are gentler on the metal.

    Paint Removal 15

    As you can see, it’s a little more aggressive than the red stripping pad, but not as much as the hook and loop cleaning pad. And look at how smooth it leaves the metal after the paint is all gone! These bristle discs are very durable too and last a long time, so they are great for big jobs like a whole car. Be careful around edges though, because the bristles can catch an edge and get broken off, and they will hurt if they hit bare skin, so wear long sleeves and a face shield.

    Paint Removal 16

    Roloc Quick Change Surface Conditioning Discs
    These little discs are very similar to the hook and look stripping discs, only they mount differently and they are more flexible for sanding irregular surfaces. On the back on these discs is a little threaded stud that screws into a flexible rubber mandrel you can attach to any drill.

    Paint Removal 17

    The softer, flexible nature of the mandrel allows you to use these for areas that aren’t flat. Also because these are so small, they are great for getting in tight areas like window frames and such. They are available in 2 and 3 inch sizes, and are commonly referred to as “cookies.”

    Paint Removal 18

    That’s it for the mechanical methods of stripping old paint, but there are other ways to take off paint that don’t involve spinning discs.

    Eastwood Paint & Powder Stripper
    Guys often wonder about stripping paint off with chemicals. How well does it work? Is it safe for the panel? It is safe, and it works great, especially in areas that have tight curves or something that would prevent you from getting a cleaning disc or bristle disc in there.

    Paint Removal 19

    You do need to wear rubber gloves though, because if you get this stuff on your bare skin it will burn.

    Paint Removal 21

    Then it’s just a matter of brushing it on, use these acid brushes that are made of a plastic that won’t melt in the chemicals.

    Paint Removal 20

    Wait 30 minutes or so and start scraping it off (Matt cheated and applied the stripper before the cameras started rolling so it would be ready now.)

    Paint Removal 22

    As you can see the first application took off almost all the layers of paint. You could use mechanical means to strip the rest down to the metal, or apply the stripper again and you should have a totally clean bare metal surface. To make it even more effective, especially if dealing with modern clearcoat, use the DA sander to scratch through the surface first, then apply the stripper.

    Paint Removal 23

    Media Blasting
    Finally, the last best method, and the most expensive to get set up to do, is media blasting. Media blasting sprays various small particles like ground glass, aluminum oxide, silicon carbide, and walnut shells, at the panel with high pressure air. For softer surfaces like fiberglass and urethane, soda blasting does the same thing with a softer media similar to baking soda. You do have to be careful though because media blasting can still warp a panel if you stay in one spot for too long and it gets hot. You also need to tailor the media to what you are stripping. Use too coarse of a media on a soft metal like aluminum or pot metal and you will be left with a rough surface that will take a ton of work to correct.
    Eastwood offers big, pressurized media blast tanks that are great for doing entire cars, or blasting a frame and chassis if you are doing a frame off restoration.

    Paint Removal 24

    If you don’t want to spend the money and make the commitment to a big set up like this, Eastwood also offers a Small Blast Kit that is very affordable, and great for doing just the problem areas of the body panels.

    Paint Removal 25

    The best places to use the Small Blast Kit, or any media blasting really, are problem areas like these intricately shaped edges of the hood. There is no way you are getting a cleaning disc or wheel in there, which means you could be there for hours with a piece of sandpaper stripping the paint by hand. The media blaster will make short work of this.

    Paint Removal 26

    Eastwood Fast Etch
    Once you are down to bare metal, you need to make sure you protect it so it doesn’t rust immediately. Eastwood Fast Etch not only helps eat away minor surface rust and prep the bare metal for paint, it also leaves a protective phosphoric coating. The coating will protect it for a good long time, and can easily be wiped off with PRE painting prep with just a rag before painting.

    Paint Removal 27

    If you do have surface rust on bare metal, you can spray the fast etch, let it work for a few minutes, then just wipe it off. Here is before.

    Paint Removal 28

    And this is after. Obviously it could have used a few more minutes.

    Paint Removal 29

    To use Fast Etch as a protective coating, just spray it on and leave it on. It will eat into the metal, then react to create that phosphoric protective coating.

    So those are basically the most popular methods of removing paint and getting down to bare metal. Of course if you don’t want to do it all yourself you can always send the whole body out to be media blasted by a professional. There are also places with tanks of stripper so large a whole car can be submerged to eat away the paint and rust, but there is no way you are going to do something like that at home.

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  • Patch Panels with a TIG Welder- How to use your TIG welder for rust repair

    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!


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  • How to repair rust- Fixing a rusty windshield cowl

    So you decided to give your car a refreshing new look and it's time to strip it down to prepare the car for paint. You can count on finding some sort of surprise when tearing the vehicle down. Whether it's hidden accident damage, previous repairs, or the mummy of a dead animal; it's always an adventure when stripping a car or truck down for paint or bodywork.

    I recently started tearing into my "clean" (for the east coast at least!) 1977 VW Scirocco I've owned for a few years. It had some wear and tear and some bubbling paint I wanted to address before it got a fresh lick of paint. When I began removing the fenders I was pretty surprised to find some rot in the inner fender and windshield cowl. I decided to take some photos as I repaired this area and share some tips for making a repair that will look original when done.

    Here is the offending area when I removed the fender. The worst rot was in an area that sandwiched between the fender and cowl and was covered with weather stripping. So from first glance it just looked like some bubbled paint, but that was the tip of the iceberg.

    I first cut out the area that was rotted until I got to solid metal and a nice seam where I could weld and blend the panel into the original metal.

    I started making my patch panel by bending up a piece of construction paper to the rough size I needed, then I transferred the rough shape over and cut it out of 20 gauge aluminized steel. Next I measured the other side and marked out the bend line I needed to make.

    In order to make a clean bend in the new metal I needed a metal brake. I decided to use the Versa Bend Sheet Metal Brake and put a crisp 90 degree bend in the panel on my line.

    With the patch panel now formed into the rough size I needed, I took it to the car and trimmed it to fit the opening. It's here that you want to make sure the patch panel fits tightly so that you don't need any excessive welding to fill voids.

    I then setup the MIG 135 with .023 Solid Core MIG Wire so I could lay small, flat spot welds on the patch panel. Setting the machine up on a similar piece of scrap metal helped me get my spot welds laying flat and penetrating correctly. After finessing the panel with Eastwood Hammers and Dollies and blending the welds with a flap disc on an angle grinder I was satisfied with the repair. I'm happy to say the patch panel looks close to original and the repair should be invisible once it has primer and a top coat on it. Now onto the next surprise!

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  • Chopping the top on a 1950 Dodge Pick-up – Eastwood’s Project Pile House- Part 1

    One of the next big projects planned for Project Pile House is performing a mild chop and smooth job on the cab and roof. We started the process in a previous post where we showed you How to Shave and Smooth Unneeded Holes in the bed and cab. Today we decided to really dig into this next part of the project.

    Since the roof will need to be worked and modified in a number of spots, I decided to use our 7 Inch Cleaning and Stripping Disc Kit on an Electric Angle Grinder to quickly strip the top half of the cab and doors down to bare metal. This will allow us to easily mark, cut, and weld the roof as we get it situated in it's new, lower position.

    Next I decided to remove the drip rails. This modification isn't a new one in the Hot Rod, Street Rod and custom world, but it's definitely one that's always debated. The original drip rails were in pretty sad shape, and I prefer smooth customs; so I decided to remove them with the angle grinder. I'll come back with a Flap Disc and bring the rough-cut edge flush with the roof. The drip rail is composed of 2 pieces of metal pinched and folded over, so I will have to weld the two pieces together and blend them before the truck is "done", but we'll wait until the chopped roof is back in place to finish that portion of the job.

    While we were on a roll, Mark R. (of Eastwood R&D Corner fame) helped me measure out the lines for where the chop would take place. After a little head scratching, and test fitting me (the driver) in the truck, we decided on a 3" chop that would take place below the rear windows and bring the lower "reveal" or contour of the rear window openings down to match the height of the lower door window sill. This would also bring the roof seam down to match with the top of the door, and make the size of the side door glass close to the that of the rear and cab-corner windows (I really like symmetry in custom cars!). With the lines laid out with painters tape, I'll be gearing up to make the cuts in the next week or two. Stay tuned, we'll be filming and posting a DIY video showing how we chop the roof. We're excited to see how Pile House looks with a fresh chop and shave!


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