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Thread: I need a very slow set epoxy

  1. #1
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    I need a very slow set epoxy

    Iím going to make an end grain cutting board for a wedding gift. It will involve a couple of hundred little blocks of contrasting wood. I would like to do the whole board in one gluing session so I need at least an hour before clamping and I think thatís pushing my luck. Two hours would be fantastic.

    my alternative would be to glue up three or four rows at a time and then glue the sub assemblies together.

    Does anyone know of a very slow cure epoxy?

  2. #2
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    If the board is actually going to be used, I would not use epoxy. I would use titebond extend or something similar.

  3. #3
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    I would like to suggest gluing up in sections using tite bond 3. You can thin it to give more open and gets smaller glue lines.
    The epoxy I use is system 3 . Itís expensive and found it to be so thin that I get a darkness around joints from the epoxy seeping in the wood. Iíve also had large batches harden quickly because the air temperature was too high.
    Epoxy is great for some stuff but definitely not the cure all especially for visible glue lines.
    Good Luck
    Aj

  4. #4
    I use a lot of epoxies at work for various prototype builds.

    3M makes DP-190, which has a pot life of 90 minutes. It comes in gray or translucent color. the gray is much higher viscosity than the translucent.

    Also, most epoxies get harder as you approach the end of the pot life, so I would say the actual usable pot life is just over an hour.

    Steve

  5. #5
    Some vendors have slow hardeners, like West System 206. Any epoxy mix can be slowed by working in a cool environment, spreading the mix out in a thin layer in a tray, putting the tray on ice and doing a series of small batches through the glueup process. Because the thickening process is progressive you can usually get your pieces coated and clamped while the adhesive is still fluid enough to flow under pressure. Once spread into a thin film the setup slows compared to the mix in a pot or tray. Gluing up in stages is a valid option.

    The wicking effect Andrew describes can be an issue, so do a sample before committing to epoxy.

    Be aware that epoxy bonds best to sanded or sawn surfaces. West System recommends sanding @ 80#.
    Last edited by Kevin Jenness; 04-02-2021 at 12:46 PM.

  6. #6
    The West System Epoxy has a slow hardener. You can extend the pot time by putting the epoxy in a container and then sitting that container into a pan of ice.

    Mike

    [Oops, I see Kevin said the same thing.]
    Go into the world and do well. But more importantly, go into the world and do good.

  7. #7
    Even West "fast" epoxy gives you plenty of open time. But, I doubt the speed of your adhesive is the big hurdle here. Clamping up a bunch of little blocks is going to be a beast. Typically, these things are glued up into substructures first. This also allows for flattening between glue ups for tighter seams.

  8. #8
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    Does not epoxy weaken with heat? Hopefully the board will not go in the dishwasher but it will probably get into hot dishwater. What about Unibond 800 or DAP Weldwood? Just asking.

  9. #9
    Quote Originally Posted by Roger Feeley View Post
    Iím going to make an end grain cutting board for a wedding gift. It will involve a couple of hundred little blocks of contrasting wood. I would like to do the whole board in one gluing session so I need at least an hour before clamping and I think thatís pushing my luck. Two hours would be fantastic.

    my alternative would be to glue up three or four rows at a time and then glue the sub assemblies together.

    Does anyone know of a very slow cure epoxy?
    First watch a couple you tubes on making end grain cutting boards. They aren't made up from individual blocks, but laminated strips, which are cross cut to yield rows of already glued up blocks. For glue, use TiteBond type 3, instead of epoxy. Use a router sled to flatten tops and bottoms before sanding ( a lot!)

  10. #10
    I donít know how you will be able to glue up individual blocks perfectly; every single block in each row has to be exactly the same size. I agree that they are usually more easily done by gluing strips, cross cutting, rearranging, then regluing.

    Either way, I would do them a couple rows at a time. Easier to keep things flat.

  11. #11
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    Thanks to all. I think trying to do the whole thing in one session is just too much. I’ll work out a way to divide and conquer.

    the happy couple are both engineers and very computer literate. I plan to convert their names and wedding date to a precursor to ASCII called Baudot which was used for stock tickers and teletype type machines back when 110 baud was fast. I’ll use contrasting wood for mark and space bits. At a glance it should be a nice random pattern.

    I’ve done this sort of thing before. The cutting board we have was a sort of inside joke. I took a rubbing of the ceramic tile backsplash at our old house and recreated it block for block in an end grain cutting board. You wouldn’t see it unless you know it’s there. Now we are in a different house so it’s just a nice random pattern of three colors of wood.
    Last edited by Roger Feeley; 04-02-2021 at 10:32 PM.

  12. #12
    Quote Originally Posted by Roger Feeley View Post
    Thanks to all. I think trying to do the whole thing in one session is just too much. I’ll work out a way to divide and conquer.

    the happy couple are both engineers and very computer literate. I plan to convert their names and wedding date to a precursor to ASCII called Baudot which was used for stock tickers and teletype type machines back when 110 baud was fast. I’ll use contrasting wood for mark and space bits. At a glance it should be a nice random pattern.

    I’ve done this sort of thing before. The cutting board we have was a sort of inside joke. I took a rubbing of the ceramic tile backsplash at our old house and recreated it block for block in an end grain cutting board. You wouldn’t see it unless you know it’s there. Now we are in a different house so it’s just a nice random pattern of three colors of wood.
    Are you going to make the code look like strips of teletype paper tape? That would be cool and would be the way it would be read.

    Mike
    Go into the world and do well. But more importantly, go into the world and do good.

  13. #13
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    +1 for West Systems. Hide glue also has a long open time. Regular white glue has an edge over Titebond.

    I think making a project specific gluing jig and wedges (or veneer press hardware) would help significantly to reduce glue up time and increase accuracy.
    Regards,

    Tom

  14. #14
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    Quote Originally Posted by Thomas McCurnin View Post
    +1 for West Systems. Hide glue also has a long open time. Regular white glue has an edge over Titebond.

    I think making a project specific gluing jig and wedges (or veneer press hardware) would help significantly to reduce glue up time and increase accuracy.
    But "regular white glue" has almost no moisture resistance & the board will begin to fall apart in a hurry.

  15. #15
    There is no possible way to rationalize taking TWO hours to assemble/glue-up a cutting board, no matter how elaborate the pattern. It is a simple matter to have all the different pieces organized beforehand, ready to assemble in their natural order, so that assembly can be done in an efficient manner.

    Use WEST Epoxy Extra Slow Hardener if necessary, though the need for that seems highly doubtful. Also the use of WEST's Special Hardener seems more appropriate, as it is lowest in toxicity and therefore used in constructing water tanks.
    "Anything seems possible when you don't know what you're doing."

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