Hi
I recently had a fairly complex glue-up to do with some splined mitres among other joints and decided to go with epoxy adhesive.
Since i've not found much first-hand information regarding the use of epoxy in regular woodworking projects i've decided to write down my
(limited) experience with it trying to higlight advantages and disadvantages i've found.
I've used Araldite AY103 (plus the corresponding hardener), not the normal household stuff.
advantages:
- araldite ay103 turned out to have a very convenient viscosity when mixed. it does not drip easily but it still can be applied with a stiff brush.
this is nice if you have to apply adhesive to several vertical surfaces before assembly.
- it has over an hour of open time (90 min. according to the manufacturer but I didn't take that long). so no more stress during the glue-up.
I had plenty of time to apply the adhesive, reach for that extra clamp, assemble and adjust the joints.
- I've found that after applying the adhesive the joints go in more smoothly than when doing a dry run, as if the glue somehow lubricates them.
I've had a similar experience with liquid hide glue.
Regular PVA has the opposite effect since the water contained in the glue swells the joints (that was the cause of my biggest glue-up fail occured while
assembling a softwood door when I managed to reach a state of cannot-force-the-joints-together-cannot-pull-them-apart)
- the mix is yellowish but transparent and after drying it goes unnoticed even after applying oil based finish. I've cleaned all the excess glue
with acetone and it somehow altered the appearance of the wood as if it has been wetted. I was afraid that it would show up after the oil
based finish was applied but it blended out very well. like hide glue it is much more forgieving if you miss removing a spot of
dried adhesive before finishing.
- it is more gap filling than regular PVA glue. dried epoxy beads on my bench got hard in an uniform way and didn't seem to loose
much volume after setting.
disadvantages:
-price. this epoxy thing is expensive. I've managed to get a bargain on a can that was near the end of shelf life, but according to my
calculations it's about 8 times more expensive than titebond III. arguably the coverage is better with
epoxy because it does not shrink as much as PVA when set, but I didn't measure that.
-you have to estimate the amount of the mix you'll be using, and that often leads to more wastage.
-the stuff doesn't clean with water. I used acetone, but meths will do as well, anyway for the environmentaly impaired the use of solvents
is a minus point.
-I wouldn't use it for gluing panels as the manufacturer recomends a glue layer of about 0.1mm thick to get max strength, which means that,
to be effective, a glue line must be visible. probably not a problem with darker woods, but something to
take into account.
I recently had a fairly complex glue-up to do with some splined mitres among other joints and decided to go with epoxy adhesive.
Since i've not found much first-hand information regarding the use of epoxy in regular woodworking projects i've decided to write down my
(limited) experience with it trying to higlight advantages and disadvantages i've found.
I've used Araldite AY103 (plus the corresponding hardener), not the normal household stuff.
advantages:
- araldite ay103 turned out to have a very convenient viscosity when mixed. it does not drip easily but it still can be applied with a stiff brush.
this is nice if you have to apply adhesive to several vertical surfaces before assembly.
- it has over an hour of open time (90 min. according to the manufacturer but I didn't take that long). so no more stress during the glue-up.
I had plenty of time to apply the adhesive, reach for that extra clamp, assemble and adjust the joints.
- I've found that after applying the adhesive the joints go in more smoothly than when doing a dry run, as if the glue somehow lubricates them.
I've had a similar experience with liquid hide glue.
Regular PVA has the opposite effect since the water contained in the glue swells the joints (that was the cause of my biggest glue-up fail occured while
assembling a softwood door when I managed to reach a state of cannot-force-the-joints-together-cannot-pull-them-apart)
- the mix is yellowish but transparent and after drying it goes unnoticed even after applying oil based finish. I've cleaned all the excess glue
with acetone and it somehow altered the appearance of the wood as if it has been wetted. I was afraid that it would show up after the oil
based finish was applied but it blended out very well. like hide glue it is much more forgieving if you miss removing a spot of
dried adhesive before finishing.
- it is more gap filling than regular PVA glue. dried epoxy beads on my bench got hard in an uniform way and didn't seem to loose
much volume after setting.
disadvantages:
-price. this epoxy thing is expensive. I've managed to get a bargain on a can that was near the end of shelf life, but according to my
calculations it's about 8 times more expensive than titebond III. arguably the coverage is better with
epoxy because it does not shrink as much as PVA when set, but I didn't measure that.
-you have to estimate the amount of the mix you'll be using, and that often leads to more wastage.
-the stuff doesn't clean with water. I used acetone, but meths will do as well, anyway for the environmentaly impaired the use of solvents
is a minus point.
-I wouldn't use it for gluing panels as the manufacturer recomends a glue layer of about 0.1mm thick to get max strength, which means that,
to be effective, a glue line must be visible. probably not a problem with darker woods, but something to
take into account.
