This is a 3M Clean & Strip disk mounted on a pneumatic die grinder, great for removing pai
Q. Hi Ron, I've been watching your Chopping and Sectioning DVD and have some questions about metal prep and chrome removal. In the DVD, the metal on the truck is nice and clean. How did you get it that way? I guess more specifically I should be asking your opinion on the various paint and rust removal options, especially regarding the metal that will be worked before being painted. What process did Joe actually use on the Studebaker? Are there any other products you've had good luck with?
I'm also interested in reworking some bumpers to fit my truck. I'm assuming it's best to get each piece down to bare metal before cutting, fitting, and welding. Do you know of any good home shop methods to strip chrome bumpers? Is it best to send them to a plating shop to get them stripped? Do you have any comments, tips, or suggestions for building bumpers from scratch?
As always, thanks for the support. It really helps.
Via the Internet
A. One of my favorite tools for getting paint and light surface rust off of panels is the 3M Clean & Strip disks. They will remove paint (even if it's heavily caked), plastic filler, and surface rust. These disks are fairly fast-acting, and there is no risk of thinning the metal as you would have with sanding disks. Although you could do a complete truck body with these disks, I normally use them for cleaning smaller areas, such as prepping a fender or door for dent straightening or patch panel installation.
There are many brands of paint strippers that can be bought at most hardware stores, and they do a fairly good job of taking paint off of metal panels. They work especially well on broad, flat panels-it's much more difficult to get paint out of nooks and crannies, and inside grooves and channels. Be forewarned, since this is a messy, smelly, laborious process, you need to protect your skin against the stripping chemicals, and be sure to wear a good respirator. As good as this type of stripper is for paint, it doesn't remove rust.
Rust can be removed by sanding or sandblasting. The chemical dip process removes both paint and rust, so it has a lot going for it, although it is somewhat expensive. The smaller panels on Joe's truck (doors, hood, etc.) were sent out to a chemical dip stripping service. The cab was too big for this particular stripper's tank, so Joe sandblasted it.
Sandblasting will remove both paint and rust, but the work must be done carefully, ideally by an experienced sandblaster, or the panels can be easily warped! Sandblasting leaves a surface with some texture, and remnants of the crushed abrasive grains are left stuck on the surface of the metal-therefore, the metal needs to be carefully cleaned by sanding before any paint or filler is placed on the metal.
In addition to sand, there is a wide range of alternative media used for blasting, such as soda, dry ice, walnut shells, aluminum oxide, and many others. Check with a local blasting service to see what they offer and recommend for your particular project. The most extensive description I have ever seen about all the parameters of media blasting can be found on Dave Propst's Web site, www.davepropst.com. On the main page under the "Technical" heading, click on the "Sheetmetal" link, then scroll down to the link "Blast Cabinet Part 3-Function." This link will open up a new page that will give you the benefit of Dave's extensive research on the subject, which runs almost 13,000 words, with several charts!
Believe it or not, I've been told that molasses is a fairly good paint and rust stripper, but it may take a week (or more) for it to strip a part completely. You'll need a container large enough so the panel can be submerged completely in a 25-percent solution of molasses and water. If you don't have a container this size, there are several low-cost options, such as using a child's swimming pool, or a plastic fish pond. You can also make a temporary container by building a perimeter frame from four pieces of construction lumber (2x6s or 2x10s, for example), laying the frame on the ground, then draping sheet plastic over the frame and filling the center with the molasses mixture. The process is speeded up if you take the part out every day and brush down the surface lightly, which removes the scum from the surface to allow the molasses to get a fresh "bite" on the next layer. (Check with an animal supply store for buying molasses in bulk.)
The only way I know of to strip chrome from a part in a home shop is to sand it off, and chrome is pretty darned hard to sand! If you only need to sand local areas, as you would when filling a hole in a bumper or welding sections of the bumper together, it's feasible to remove the chrome by sanding. If the entire part needs to be stripped, I'd suggest sending it out to a chrome shop.