Mortise chopping guide blocks

Viewing 13 posts - 1 through 13 (of 13 total)
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  • #314662
    Harvey Kimsey
    Participant

    I’m trying Paul’s technique of just gluing a perfectly square guide block on to my work to serve as a chisel guide when chopping mortises. I’ve tried Krazy glue (widely available in the US) but I get significant tearout of the work when I chisel off the guide block. I’m working in American Cherry. What is the glue Paul uses! I’ve never seen an instant glue that comes with an accelerant. Anyone else confronted this issue???

    I’ve also tried thinned out hide glue but it wasn’t strong enough.

    Thank you!

    #314663
    Adam Welker
    Participant

    Instead of glue, could you not pinch them together in a vise as Paul did in the recent mortise and tenon video? If you don’t have a vise you could also use clamps to hold the guide to the piece. I often glue temporary clamping blocks onto odd forms with regular pva glue and a piece of newspaper in between. The newspaper let’s glue form a good bond but still pops of easily with a chisel. Hope this helps.

    #314673
    Harvey Kimsey
    Participant

    Great idea! Let me try that….Thanks!

    #314676
    Ed
    Participant

    I’ve used CA glue (cyanoacrylate glue) to hold guide blocks on oak without a problem. There’s a little gunk left behind and a couple torn fibers, but no more than would come off during finish prep. Rather than chiseling off the block, I give it a smart rap with a hammer. CA glues fracture under sudden shocks. Can’t remember if I’ve tried this with cherry.

    A number of CA glues have accelerants; Titebond, for example. It’s a separate purchase, though. It’s more of an “instant freeze” than an accelerant.

    I think Krazy glue is CA, but am not 100% sure.

    #325562
    Jim Sculley
    Participant

    Super glue is great in tension but not so great in shear, so Ed’s suggestion to hit it from the side takes advantage of that fact.

    One trick I saw in a guitar maker video is to put a strip of masking tape on each piece and then apply the super glue between the masking tape, keeping it away from the edges so that it doesn’t ooze out on to the wood. When you pry the boards apart, either the glue will give way between the tape or the tape will pull off.

    Here’s a link to the video

    #325565
    David B
    Participant

    Fwiw, Woodcraft sells glue accelerant.

    https://www.woodcraft.com/search?q=accelerant&button=search

    #326235
    deanbecker
    Participant

    Some ca glues dont seem to work with accellerants
    The woodcraft ca glue works pretty good i dont chisel it loose i just pop it with a hammer sideways and it comes loose with no damage. You do have to scrape the dried glue off the parts

    #327899
    Harvey Kimsey
    Participant

    Thanks for the replies. In the end I had pretty good luck using a limited amount of CA glue and also clamping the piece for 5 min or so. Yeah, a mallet blow to release it is a lot better than using a chisel as a wedge.

    #327945
    David B
    Participant

    You could try a hot glue gun too-it comes right off.

    #328028
    Larry Geib
    Participant

    Alcohol or acetone will dissolve ca glue, though not very fast. It might be the difference in tearout. Wild Turkey isn’t just for breakfast.

    Baking soda is a good accelerant and a good filler with superglue.

    Also, a close fit and clamping will speed up the cure, as the thinner the glue, the better. It cures with humidity Or condensation on the wood, so just breathing on the surfaces will help.

    #333040
    jamestrang
    Participant

    The original post indicates chiseling off the guide, try taking a hammer to knock the guide off. Following this approach, as shown in various videos here, works for me.

    #339240
    Richard Kelly
    Participant

    I liked the idea of a guide, but conscious that I might not make that many mortises the same distance from an edge, I figured that some toothed wedges might do the job in both supporting the guide plate and facilitating adjustment (for different distances from edge or wear and tear)

    #339808
    Harvey Kimsey
    Participant

    Very interesting method!

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