I couldn't find the serial number on my Model A frame. It's a late '31 and it just didn't seem to be there. What with the cop shows and a few things that have been said here I decided to search for a "solution". Found an outfit called "Sirchie" that sells a product called "Restor-a-gel" that will "raise" the numbers "even if they have been ground off". Well, I bought some and have tried it and It been somewhat success-full. So far I've been able to find where the number was and identify all but two digits. I've seen a number of posts on this subject and thought this stuff might work for someone else. www.sirchie.com. Norm
Sounds promising, can you post a photo of a few of the characters that you were able to raise? How did it work (process)?
Another method that works well is to find the original stamping location. Starting with a 100grit sandpaper and ending up with about 600 wet paper, progressively sand the area until until it's highly polished. For engine blocks and heavier pieces, fire up the O/A torch and slowly apply heat to the area until the numbers pop up as the stress is relieved in the metal. For thinner items, such as motorcycle and bicycle frames, don't use the torch, but prep the area the same way. Using a 12v battery, ground the negative pole to the frame and connect a 14awg (multi-strand) wire to the positive pole. Attach an alligator clip to the loose end of the wire and clamp a cotton ball (real cotton;not polyester) in the mouth of the clip. Dip the ball into a mild sulphuric acid solution. Swab the prepped area with the wet ball. The electrolytic process will tend to plate the area, but it will also release the numbers. Be careful as acid burns skin and clothes. Rubber gloves and safety glases are the order of the day. Make sure that the area is well-ventilated, as it ain't so great for the lungs either.Other acids may work also. It's not like these numbers will jump out like the original stampings. You will have LOOK in most cases. Once you are able to see a number, you should record it. The best way to preserve it is to take a "lift", which is akin to lifting a latent fingerprint. With a very soft longer-bristled artist paint brush, GENTLY brush a small amount of graphite dust over the numbers. Swirl the dust around, but use as little pressure as you can so you dont smear the image. Once the stamping is revealed, gently blow off the excess dust. Next, procure a piece of clear packing tape that is longer than the stamping. Being care not to put any finger prints or folds in the tape, place it over the stamping and carefully press it down to remove air bubbles. When you're happy with the image you have, carefully lift the tape starting at one end and slowly working to the other as you would pulling masking tape, again making sure you don't get fingerprints or folds in the tape. Then stick the tape down on a clean sheet of printer paper or file card to save it for posterity. Practice this on a broken engine block or hacked up bike frame first. It doesn't take long to perfect the skill. Mike
Mike Wow, great information and some more things to try. I applied more gel to the area and will try reading it again. I'll supply pictures IF I can, but they are very faint and in some cases only part of a numeral. I need to identify enough features of the numerals to know what it is. The problem I'm having is the frame I'm working with had a wood framed body (Briggs) and the wood rested on the area of the serial number. The rubbing and the moisture caused rust and a rubbing away of material. Norm
This is sorta how the Feds reveal the serial number on a gun that has had the SN ground off... only way to defeat this is to grind it off then use a punch over the area to upset the metal....
Well, there is another way,,,,but I'll save that for another time. Sirchie has been around for 25/30 years, primarily as a supplier for law enforcement products. Fingerprint, ultraviolet marking, things like that. You can just use a mild acid to bring up the numbers as the "punched" part is harder than the surrounding steel and doesn't erode away quite as easily.
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