Cutting Double Sided Foam Tape with a String (fishing line, floss, Kevlar, etc) Saw

I have seen posts where others have used fishing line or floss to cut through the foam layer of double-sided tape to remove items that were taped to a window for example. I had some items to remove and found that using the floss or fishing line was too hard for me to use. So a knotted cutting string was devised with 0.022" 30 Lb fishing line. Using too thick of a string would result in knots larger than the thickness of the foam tape. Oversize knots on the string saw could result in string breakage. Floss could be used but may have to be doubled or tripled up to be thick enough. I have used label removing chemicals in the past. After damaging a window sill and who knows what damage to the PLA camera holder/shield may have occurred. I decided to stick with mechanical removal methods.

The following pictures described my procedure, on the grouped picture, zoom in to see the detail.

Victor Maletic.


We just used WD40,plastic knife

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Never heard of it. What is a WD40,plastic knife?Is it WD40 and a plastic? I had not thought of using WD40 in that way.
I used ‘Goop Off’ along the top edges of a bonded area and found it taking about 5 min to release the bond and the plastic camera holder was discolored, affecting a future bond? I know not. I also was concerned about the ‘Goop Off’ getting on the window sill.
I have heard that isopropyl alcohol is good for releasing industrial grade adhesives. I will test later.
Thanks for comment.

WD40 is oil in a spray can,go look it up…plastic putty knife also look it up WD40 has been used for over 100 years with thousands of uses

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Thanks for the information kea4560. I did look up WD40, In 1953 after the 40th try the water displacing formula (WD) was brought to market by the Rocket Chemical Company. It was first used by Convair to protect the outer skin of Atlas Missiles from rust and corrosion.

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Ok and???

I guess WD40 is 69 years old instead more than a 100 years.

Pretty much the definition of “quality over quantity” are your write ups. Good description, nice visual aids outlining a helpful process that some may not have known in great detail. Thanks!

In my GoPro fanboy years I used a hair dryer on heat and some sort of pry tool to remove the foamy tape camera sticky mounts.

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I usually use dental floss with success, but it depends on the brand of floss … some are stronger than others. A little heat helps if it has been stuck for a very long time.

And I was just telling you what I know,my great grandfather used it and it was way older than that

Victor’s posts are like engineering porn (that’s a compliment). He does things so much more meticulously than I ever would. Who measure space between knots for a home grown single use string saw? :slight_smile:

Also, the result is similar to "survival saws*.

Although those probably would do your window glass no favors.

I also just use WD-40 equivalents, and cursing. The bottled stuff like Goo Gone seems messy. The Command strips work pretty well (when they are fresh!) to avoid this kind of thing going forward.


This replay is to everyone and @Customer

Customer Thanks for the promotion. I had no idea that I was posting ‘engineering porn’. Since 1961 I have been associated with, involved in, and practiced civil engineering with Caltrans, Structure Construction Division, for 42 years. And a consultant to the same division for 18+ years. I am still a consultant. So, I guess you hit the nail on the head, engineering can be highly addictive.

In my original post, I should have mentioned that I wanted to remove and reset a compound-angled Square Tube V3 camera holder as shown in the picture below. The outer glare skirt of the holder is 1.76mm thick. Being so thin could make it subject to chemical or mechanical damage during removal. Prying with a knife and chemicals was out, as was using commercially available saws whose hardened steel blades could damage the glass and the glare skirt. Using a thin fishing line for a knotted string saw results in knots no thicker than the foam tape to be removed, and the knots are hard enough to abrade the foam core of the tape while being too soft to damage the glass or the glare skirt. After the Square Tube holder has been separated from the glass, the remaining adhesive residue is easily removed with solvent of your choice (if you pick the right one). The Goop Off is no messier than WD40. Because of my advanced age, I have to be careful and avoid breathing in solvents. My response to ”Who measures space between knots for a home-grown single-use string saw?” is I do. I also measured the space between the fully tensioned knots. From these two values, one can calculate that 10” of knotted string will require more than two times as much plane string, say 30”. Most of the stuff I build is meant for more than one use.

The spacing for the knotting pins was solely based on the corrugation spacing of the cardboard I used, Even the cardboard template will not be discarded but kept in an odds-and-ends box for future use or cannibalization. Certainly, the cardboard is a neat solution to spacing and holding the knotting pins.

Soon I will post yet another kind of foam tape saw made from readily available materials that will work even better.

Stay tuned, Victor.

PS: Thanks for the promotion, It has a nice ring to it.


Has anyone ever drawn a caricature of you? If so, I’d love to see it. :slight_smile: :+1:

I have done more research on WD40 and found out that, while first formulated and sold to Convair (a government contractor) in 1953, it became available to the general public in 1958. If your great grandfather worked at the Rocket Chemical plant he could have brought some home from work from 1953 at the earliest.
So, no longer than 69 years ago WD40 was available to the government and 64 years ago, it was available to the public. I thought maybe your great grandfather was using the well-known multi-use product called VO5, probably not. It came out in 1955, three years before WD40 came out to the public.

This is the information I found in the public domain.