3M Spray Adhesive "cure" time?

Discussion in 'Amp Central Station' started by TelenTubes, Mar 26, 2020 at 7:40 PM.

  1. TelenTubes

    TelenTubes Tele-Meister

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    So, the material came in for my budget Fender Stage 160 recover. Speaker cloth is vinyl coated fiberglass and went on easily with some double sided tape and staples. I have a little fine tuning to go on the corners of it, but I'm really happy with it.

    The fabric for the cabinet is heavy upholstery cloth, but has no backing, and is probably not quite as rigid or tightly woven as amp tweed, FYI.

    I bought Titebond II and 3M77 glues to test some of the fabric for the amp on a piece of wood. Results were less than spectacular. I tested them at lunch today, roughly 6 hours ago. The Titebond II is now holding on with a death grip, but there were spots where it bled through and has dried yellow. Don't want that.

    The 3m77 was sprayed on the wood sample and the cloth, and I waited the requisite 30 seconds for it to tack up. It took about a minute instead. I then pressed the cloth onto the board and firmly rolled it out. I was happy to see that some repositioning is possible. However, after 6 hours, the hold is not quite as strong as the Titebond II. I can peel it, though it's a firm hold.

    I will say, when I ripped the tolex off this amp, it peeled off relatively easily. So maybe this isn't even a problem.

    Questions:
    So, does the 3M77 hold get any stronger if I wait, say 24 hours? Clearly I'll find out tomorrow at noon, but just asking.

    I plan on coating this with clear shellac and then coating with wipe/brush-on satin poly. I know shellac isn't known for its strength, but will it or the poly add any more adhesion to the wood (actually Fender particleboard)?

    IMG_0531.jpg
     
    Last edited: Mar 26, 2020 at 7:50 PM
  2. Ringo

    Ringo Poster Extraordinaire Silver Supporter

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    You did spray both the material and the wood? A couple even coats on both? maybe a bit more on the wood? It should tack up and be ready to work with in a few minutes , and I'd think the bond will be stronger after it completely cures overnight.

    I only use commercial solvent spray grade contact cement but that's not an option for your project.
     
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  3. stormsedge

    stormsedge Tele-Afflicted Gold Supporter

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    I've used the 3M spray glue quite often...never had a issue with it holding. 6 hours should have been plenty of time for it to set/dry.
     
  4. TelenTubes

    TelenTubes Tele-Meister

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    Yes, held the can about 8" away (as best I could estimate) and sprayed both the wood and the fabric. Yes, I spent three days after the fabric arrived reading about glues, and kind of limited to either Lowes, Home Depot, or Michael's craft store.

    Will definitely test it in the morning.
     
  5. TelenTubes

    TelenTubes Tele-Meister

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    I said "less than desirable" results initially. But, to be honest, I've never peeled tweed off an amp, so I have nothing to reference this against. As best I can describe it, there's no way this would sag (ignoring sitting in a hot car or something extreme) and it was fairly hard to peel off. It's just not as strongly stuck as the Titebond II, which I kind of expected. In hindsight, it might be on par or a little harder to peel than the original tolex was. But that amp is probably 17 years old, give or take?
     
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  6. TelenTubes

    TelenTubes Tele-Meister

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    Update after 18 hours - the hold is much stronger this morning. So apparently, when it says it bonds in 30 minutes, that's NOT the strongest bond it will achieve. Maybe this test will be useful for someone else thinking about using it.

    I'm going with it on this amp.
     
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  7. psykobilly

    psykobilly Tele-Meister

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    Get the highest bond strength you can that won’t damage your cloth, I would imagine you could use the 90, but the 77 will prolly suffice. Spray a generous coat on both and let tack. I don’t go by the time thing, humidity and temp can cause this to vary. My method is way more scientific, let it dry till it doesn’t stick to your finger when you touch it. After applied it will get stronger with a little time. You could also get a laminate roller and roll it out, they are about 10.00 at Lowe’s here. I used to be amazed when making counter tops how much difference rolling the laminate out made.
     
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  8. Chipss36

    Chipss36 Tele-Meister

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    Just my thoughts on this.
    I used 3m, white glue, some very expensive neoprene stuff...
    It all kinda sucks...seams show up in a week or so because well rubber flexes, white glue is better, but tac time is longer, and it’s hard to work with, but dries nice.

    Finally asked myself , what would Sam Hutton do?
    I now use hide glue to build all my cabs, and cover them as well, it’s tricky to use, and has a learning curve...
    However, the glue can be reconstituted with steam, as it dries, in literally sucks things together.
    All seams stay exactly how you had em....
    I love hide glue for tolex...!
     
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  9. TelenTubes

    TelenTubes Tele-Meister

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    Thanks! I definitely rolled the sample. With a old rolling pin from the kitchen! Now that I'm single again, nobody's mad at that, lol, and it washed up just fine.


    I'd try the hide glue if there was some to be had locally. Going to test some white glue today, because there are some inner corners and places where I'd rather brush on the glue.
     
  10. Ricky D.

    Ricky D. Doctor of Teleocity

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    Don't spray it on too thick. If it's too thick, the surface will skin and trap a wet layer underneath that can't dry.
     
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  11. Axis29

    Axis29 Poster Extraordinaire Ad Free Member

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    Another thing you can do is seal the cabinet first, if you haven't already.

    I've found that no matter what adhesive I use, it is best to seal the wood first. I use shellac...
     
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