Is removal of tolex adhesive necessary?

[Randall]

I pulled the old tolex off a Marshall cab with a heat gun with good results. The adhesive Marshall used appears to be sprayed on, and is not very thick of a layer. I've seen it said both ways, either you must strip it down with solvent and sanding before applying fresh adhesive, or it's not needed because the new contact cement with re-actify the old adhesive. I'm using contact cement on the cab and 3M vinyl spray adhesive on the tolex. The original adhesive is still tacky.

What says you?

[eschertron]

I'm sure the answer is either 'yes' or 'no', depending on the circumstances.

My only experience with recovering a cab required me to scrape, chip, and sand - because the remaining glue from the initial covering was attached sporadically and was quite bumpy. Applying fresh glue without cleaning would have resulted in an unattractive surface. Could I have 're-wetted' the glue with fresh contact cement? Probably depends on the original formula, and who knows how much time. And I might have been tempted if the original application of glue had remained in a consistent layer. As it was, cleaning it all off was easy because the glue was hard and crusty. That's just my mileage. Yours may vary.

I'd suggest "testing a small spot in an inconspicuous area" as they say, to see if the new adhesive plays nice with the old.

[nosaj]

I'm sure the answer is either 'yes' or 'no', depending on the circumstances.

My only experience with recovering a cab required me to scrape, chip, and sand - because the remaining glue from the initial covering was attached sporadically and was quite bumpy. Applying fresh glue without cleaning would have resulted in an unattractive surface. Could I have 're-wetted' the glue with fresh contact cement? Probably depends on the original formula, and who knows how much time. And I might have been tempted if the original application of glue had remained in a consistent layer. As it was, cleaning it all off was easy because the glue was hard and crusty. That's just my mileage. Yours may vary.

I'd suggest "testing a small spot in an inconspicuous area" as they say, to see if the new adhesive plays nice with the old.

All I can say is don't use whatever adhesive fender used on the princeton 650 series rats chewed the tolex completely off to eat the glue.
nosaj

[Leo_Gnardo]

FWIW on a particularly nasty tolex removal, once I got the tolex itself off, the rest of the gunk quickly stripped away using a belt sander with a shagged-out belt on it. I figured "what's to lose?" For once, one of my go-to-hell moves worked particularly well.

That being said I'm not so sure the belt sander technique would work with sticky stickum still on the surface. Might gum up the belt real quick. Then again, if nothing else does work... break out the go-to-hell plan.

[Randall]

This would certainly be a solvent application first, no way I'd try to sand this. Removal wasn't bad, it pulled up pretty good with some heat, and it's not too rough or bumpy. I'm leaning towards not stripping. I will try it first on the back panel, see how that goes. That won't be too much Hell if it doesn't take and I have to strip it again.

[Chuck H]

You might be surprised at how far you can get and how fast you can get there with:

A little lacquer thinner

A putty knife

Just dump the lacquer thinner on a rag and rub it generously over your goo. Then go to the next side and do the same. When you get to side three go back to side one with the putty knife and don't be afraid to get a little aggressive. It should roll up onto the knife (with some effort) and at least leave you with a flatter surface to glue to. Once you're done scraping side one, soak side three and then scrape side two... etc. Sometimes it's necessary to double soak the adhesive to soften it enough. It probably won't take more than a half hour total even at that. Wear chemical resistant gloves if you're sensitive to hot solvents. Do it outdoors if you're sensitive to hot solvent fumes.

And,.. What you've read is true enough (sort of). If it's contact cement of some kind, as I suspect it must be if it's tacky, the new contact cement will adhere to it without issue, BUT, it probably won't re melt it into a smooth surface. So if you're lumpy you'll want to make it un-lumpy before you start.

[J M Fahey]

3 absolutely different and incompatible Tolex glues have been mentioned above.

Fender is basically *old* style animal hide glue, water based, applied hot, dries (actually cools, drying comes later) hard and can be sanded.
In principle water steam softens it and you could apply the putty knife but itīs easier and smoother to sand it.
All glues clog sander belts but this is the least offensive.
Being animal hide, rats find it very nutritious and tasty.

Marshall/Laney for the last 20 years or more has been spray applied water based "roof/tile sealant", just in jam/honey thickness, which sadly never fully dries, is always sticky, and some consider it a "glue".
I do not and hate it.
Maybe it holds in a dry climate, but here in the middle of the Humid Pampas I am sick of regluing large flaps which come loose.
Using real macho man solvent based contact cement of course, not the sissy "green/ecological" kind which is similar to what Marshall/Laney use.

It will *definitely* clog sander belts, specially as soon as friction rises local temperature, so there I would use, same as chuck suggests, either paint thinner wiping + a flat blade or a heat gun (even a propane torch) + flat blade.

If using thinners do it in a ventilated place and away from any flame,or late night News will report you as :

[Bill Moore]

I discovered 3M adhesive cleaner,(#051135-08984), when I worked for the power company, and had to remove the 3M door decals. I haven't used it to remove tolex adhesive yet, but it makes easy work of the most stubborn adhesives. I generally wipe the area with thinner before attempting to glue something else to the surface.

[Leo_Gnardo]

I discovered 3M adhesive cleaner,(#051135-08984), when I worked for the power company, and had to remove the 3M door decals. I haven't used it to remove tolex adhesive yet, but it makes easy work of the most stubborn adhesives. I generally wipe the area with thinner before attempting to glue something else to the surface.

"makes easy work of the most stubborn adhesives." Ohh boy, Imma have to put that on my shopping list. Thanks for the tip Bill!

Sound like the kind of stuff one had better use in well ventilated areas, well away from sparks & flames.

[R.G.]

As a step sideways - look at cabinet scrapers. These are not the handled putty-knife sort of thing. They are a square of thin steel, hardened and spring tempered. You use a whet stone to grind one edge straight and at right angles to the surface of the sheet, so the square corner is SHARP but still a 90 degree angle. To use it, you hold in both hands on the ends, thumbs toward you and fingers around the ends. You set the sharp/flat edge on the wood to be scraped, and flex the scraper toward you slightly, then pull the scraper toward you, holding it flexed and flat against the surface.

Scrapers can do both coarse flattening and with good sharpening very fine surfaces. It's more work than sandpaper for fine finishes, but it's essentially invulnerable to the material being scraped as long as the material is not abrasive enough to eat steel. It amounts to a very fine spokeshave with a straight edge.

[Bloomfield]

Thanks R.G. that was my thought too and you did a great job of explaining it. Scrapers are one of my favourite tools; cheap and versatile. They are good for keeping nice true surfaces where sanding will often leave ripples where the softer areas sand away faster. When I had access to a shear I used to just cut them off rolls of blue spring steel shim stock and file up the edges. I tend to push more than pull when scraping up gummy stuff, but either way works. For rougher work like scraping contact cement off I just file the edge staight and square; it cuts a bit more aggressively that way. Watch you don't burn your thumbs.

Andy

[Randall]

I did a test patch on this, which as I said was not very bumpy at all, and still tacky. I applied two coats of contact cement, and two coats of 3M vinyl adhesive, and rolled down a 6 inch patch. Let it set overnight, and next day it looked and felt just fine. I do believe the contact cement played nice with the tacky Marshall adhesive, and made a nice looking, strong bond. Given that every flap will be stapled and held in by the baffle an back cover board, I am not worried this will not work. I am proceeding without stripping.

[Chuck H]

Done that sort of thing a few times. Experience will tell you when you can get away with it. Usually it works (often if you have the experience of a failure ) Sometimes it doesn't and something comes up you didn't foresee. That's why so many guys will tell you how to "do it right" so often. If you take every known step it WILL work... And you may go broke in the process if you do this stuff for the money

[J M Fahey]

I did a test patch on this, which as I said was not very bumpy at all, and still tacky. I applied two coats of contact cement, and two coats of 3M vinyl adhesive, and rolled down a 6 inch patch. Let it set overnight, and next day it looked and felt just fine. I do believe the contact cement played nice with the tacky Marshall adhesive, and made a nice looking, strong bond. Given that every flap will be stapled and held in by the baffle an back cover board, I am not worried this will not work. I am proceeding without stripping.

Yes.
"Green/ecological" water based contact adhesive is weak and tends to self unglue, but in general large flat surfaces hold well (or Marshall/Laney wouldnīt use it) but flaps are more complicated.
I *often* reglue loose flaps in amps I repair, without the owner asking or even noticing it.
The beauty being that since in general those are internal or poorly seen areas, even if adhesive adds up a little thickness and surface is uneven/bumpy itīs not a big deal anyway.

Now carpenterīs/Elmerīs glue which is also water based, holds like crazy, you often tear Tolex in strips trying to remove it, IS bumpy so must be sanded or softened with paint thinner and scratched away.

Only problem is that having NO tackyness at all you need to hold parts in contact (usually stapling along the edges) until it dries (or forever).

*Sometimes* I was forced to use it because solvent based contact cement is controlled here and toluene/xylene, its proper solvent, is all but fobidden.
TONS of red tape and applications must be approved by DEA, not kidding.

Funny think is I must jump through hoops to buy 1 liter (maximum allowed monthly amount) but when TV crews film seized Drug Labs they show dozens of 55 gallon drums , go figure.

[R.G.]

It's a sad commentary that many governments "fix" problems by simply making something illegal, and saying to the public "There, I fixed the underlying problem by making some minor aspect of it difficult to do for ordinary citizens who would never take part in it anyway. Sadly, this does nothing to cure the issues with people who do [whatever] massively, with criminal intent. So you should vote to re-elect me so I can "cure" the problem some more by further interfering in the lives of people who are not really part of the problem anyway. But it will get fix-ed-er. So vote for me and maybe I can parlay this into a long career being professionally outraged and eventually get rich on lobbying and a government pension."

Uh-oh. I was cynical there, wasn't I? Sorry. It's been a tough day.