Simple Epoxy Questions (epoxy as adhesive)

[James Jayko]

Hey all, I'm about to start gluing up a Morris chair I'm building. It feels like its going to be a relatively stressful glue up (see the dry assembly photo below). I'm going to do the leg assemblies individually and then connect the two sides as a third step.

I figure I should use epoxy given the amount of joints and the long working time, but I've got some basic questions, given that I have only used epoxy a handful of times.

1. Is there any real difference between the popular brands (System3, West Systems, Total Boat)? I see Total Boat the most on YouTube and whatnot, but I assume that's just that they choose to sponsor more content creators. But I don't know.
2. Do I need to use a thickener like Total Boat's silica thickener? Seems like it would probably stick to surfaces better as I'm getting these pieces assembled, but the joints fit pretty well so I'm not sure.
3. I'm going to try to be careful and only do the mortise to avoid squeeze out as much as possible. The chair is cherry; would you add a tint to whatever epoxy you're using? Or do you do both mortise and tenon on structural joints and just clean up with acetone? How would you attack this to ensure structural stability? With epoxy, I only get one shot for sure.
4. When looking at Total Boat's website, I see a "slow" and a "fast" curing option, but I can't find a clarification of what slow and fast actually mean (open time, clamp time, etc). I can't imagine it would take for than ~20 mins to get the legs together, but extra working time can't hurt given that I'm in no rush and if I had to leave it for 24 hours, that's fine.


I do realize that I might be wildly overthinking this. But I'm listening to any "epoxy as adhesive" advice you've got!

495125

[Richard Coers]

I'm not a fan of epoxy for joinery. Epoxy needs a fat glue line to reach full strength. Have too tight of joint and it will starve the joint. One company recommends .002-,007" thick bond line. That means a motive and tenon joint would have to be .004-.014" loose. That could mean doing a little alignment with all the joints until the clamps go on.

[Michael Burnside]

For the most open time I use the standard Thixo product line. It will give you 20'ish minutes at room temperature before you start seeing it gel up and harden. If it's going to be a smaller piece or easy glue-up I use the 4-minute epoxy which is usually plenty of time for a given joint.

Some things you should remember:
1) Expoxy doesn't need extreme clamping pressure, it's surface adhesion is off the charts compared to wood glue, so don't go nuts and you'll have little to no squeeze-out - this is the biggest mistake most people make, especially woodworkers
2) Less is more. Just lightly coat the surface
3) Use blue painters tape on anything you think might squeeze out
4) If you're going to sand the area anyway it's not a big deal
5) You usually have more glue-up time than you realize with expoxy.

I recommend if this is your first time I'd test a tenon/mortise on a junk piece just to get a feel for it. I use epoxy often for outdoor furniture or tricky glue-ups...works great.

[Matt Carr1]

Rarely use epoxy but I have west system with the slower hardner. When I looked into all this before what I found was the difference in slow vs fast was something of 10min pot life vs 20 min, cure time is still similar. The silica thickener is to turn it into more of a gel. And lastly is it’s expensive. West systems has a flow chart of products and descriptions on their website. I have mostly used epoxy for gap filling.

[andy bessette]

...Epoxy needs a fat glue line to reach full strength...

Entirely false.

OP--never add anything to epoxy that is not specifically recommended by the formulator.

Epoxy is an excellent choice for this type of project, for which I would use slow hardener (there really is no need to rush). Both surfaces need to be coated. Squeeze-out is essential to be certain of having no voids, but needs to be cleaned up immediately. Colloidal silica is used where necessary to thicken the mix to prevent running and to better fill any gaps. Avoid heavy clamping pressure--it is unnecessary.

Suggest you first read "The Gougeon Brothers on Boat Building".

[glenn bradley]

I really only use epoxy as an adhesive for outdoor projects or joints that need to slide during assembly. The longer open time of slower set epoxies may be helpful but I try to design things so that I can glue up sub assemblies that then glue together to make the whole piece. I find this less messy than gluing up a dozen piece assembly at once. For sliding dovetails, epoxy is great. It acts like a lube while sliding the parts together where water based glues can cause swelling, binding, or can just plain grab (by design) too soon. Take care that the videos you are watching are talking about adhesive use and not river tables or encapsulated slabs. The epoxies for those uses have different characteristics than simply sticking things together.

[Michael Burnside]

I'm not a fan of epoxy for joinery. Epoxy needs a fat glue line to reach full strength. Have too tight of joint and it will starve the joint. One company recommends .002-,007" thick bond line. That means a motive and tenon joint would have to be .004-.014" loose. That could mean doing a little alignment with all the joints until the clamps go on.

Not my experience at all. I have no idea where you're getting that from, it just doesn't make any sense. At least not with Totalboat in context. There is little to no difference in joinery difficulty. In fact I would argue expoxy is better as it has a tendency to prevent the joint from swelling. I'd use it more often if it wasn't so damn expensive!

[Holmes Anderson]

You probably don't have to glue all those joints at the same time so maybe it isn't as stressful as you imagine. I only use West System so couldn't tell you if there's a difference but I always use a thickener unless I am just wetting out a hull. West's 405 filleting blend is brown so it blends better with wood than microfibers or silica. You can also add pigments. Sanding is a pain so tape and then use denatured alcohol and your finger in a nitrile glove to work squeeze-out. The alcohol acts as a sort of lubricant, preventing the epoxy from sticking to your fingers. I never worried about minimum thickness for a joint. Solid mahogany can be laminated with epoxy and 405 adhesive filler for rub rails, for example, with a glue line similar to TB3 glue. The pot life for the hardeners is listed on the can. Fast kicks very fast. I mostly use epoxy for building boats so couldn't say exactly how those m&t joints will accept the epoxy but I wouldn't thicken to peanut butter consistency. Maybe more like mayo consistency. You could use West 105 resin with the 207 special clear hardener and wet out the entire chair to make it waterproof and then apply marine varnish (epoxy will be damaged by UV without protection).

[Kevin Jenness]

1. Is there any real difference between the popular brands (System3, West Systems, Total Boat)? I see Total Boat the most on YouTube and whatnot, but I assume that's just that they choose to sponsor more content creators. But I don't know.
2. Do I need to use a thickener like Total Boat's silica thickener? Seems like it would probably stick to surfaces better as I'm getting these pieces assembled, but the joints fit pretty well so I'm not sure.
3. I'm going to try to be careful and only do the mortise to avoid squeeze out as much as possible. The chair is cherry; would you add a tint to whatever epoxy you're using? Or do you do both mortise and tenon on structural joints and just clean up with acetone? How would you attack this to ensure structural stability? With epoxy, I only get one shot for sure.
4. When looking at Total Boat's website, I see a "slow" and a "fast" curing option, but I can't find a clarification of what slow and fast actually mean (open time, clamp time, etc). I can't imagine it would take for than ~20 mins to get the legs together, but extra working time can't hurt given that I'm in no rush and if I had to leave it for 24 hours, that's fine.



Marine epoxies are generally equivalent.

You don't need thickener for well fitted joints. If you do use it, wet out the surfaces without it, then add thickener to the mix and re-apply. Cellulose microfibers are good for gap filling, colloidal silica is good for thickening but it is hard to sand, and additives like microballoons make an easily sanded lightweight mix.

Wet out all the surfaces. You can remove all but a thin film on the tenons with a scraper.to limit squeezeout. If the parts are prefinished light squeezeout can be popped off after cure. Vinegar will cut freshly mixed epoxy as will alcohol. When the mix starts to get gummy acetone is needed. Butt joint gluelines are typically darker than pva due to absorption into endgrain. Tinting won't do much if your joints are tight.

I mostly use fast hardener unless temps are above 70*F. It's mostly about potlife. Once the glue is spread it gradually thickens up and you can typically still pull joints together within an hour. If you have an extensive glueup do it in sections and mix several small batches of epoxy rather than one big one. The reaction is faster in a concentrated volume so pouring the mix into a shallow pan will extend working time.

You may find that by breaking the assembly into sections you don't need epoxy.

I don't find that epoxy requires fat joints. Pvas work well with a .002" glueline as does epoxy. What it does need is a rough surface. West System recommends 80# for mating surfaces. I had several failures on dense woods with cleanly milled surfaces before learning this.

As with any unfamiliar procedure, do some experimenting before committing to a major project. Wear gloves as epoxy is an irritant and some people develop a serious allergy.

[Scott Bernstein]

I like to use epoxy for joints in which I expect to have some gaps, and for projects where the glue-up is complex or tedious where I want some extra open time before it sets.

Unlike regular wood glue, a slight gap - or even a larger one - does not diminish the overall strength of the joint with epoxy. Of course the gap may not look great, but at least it will be strong.

Some epoxies are thicker than others. I find System Three T-88 to be very thick and it takes a long time to fully cure. West System epoxy is much thinner and takes less time to cure. If you find a particular epoxy is too thin and easily runs, you can certainly add an appropriate thickener or structural filler first.

[Richard Verwoest]

Ambiant temperature also plays a part with the open time o epoxy. Have you considered using hide glue? I build a similar chair a few years back using hide glue. I had the same fears you did. Hide glue worked great. And I used the ready to use hide glue.

[James Jayko]

Ambiant temperature also plays a part with the open time o epoxy. Have you considered using hide glue? I build a similar chair a few years back using hide glue. I had the same fears you did. Hide glue worked great. And I used the ready to use hide glue.

doesn’t hide glue go off VERY quickly?

[Tom M King]

If anyone ever uses the thickener for anything, wear a respirator. The stuff is really fine and light enough to float in the air. You don't want to breathe Any of it, and it will end up in the air around you regardless of how careful you are. It's Silica-not something you want in your lungs.

If you have never worked with epoxy before, I would absolutely advise against assembling a chair with it being your first use.

[Richard Verwoest]

No, hide glue has a solid 20 minute open time in my experience.

[Mel Fulks]

Richard , I suggest adding what kind of hide glue. The liquid at room temperature stuff sold ready to use from bottle is really slow set.
Hot hide glue granules are sold ,I think ,in 3 different strengths , I can’t remember if they have cure times.

[Maurice Mcmurry]

I love how the chair looks! I am a West System devotee. I almost always use thickener. Wood flour from the piece you are working on and slow hardener makes a good color match. The fast hardener ends up dark red. I mostly use epoxy for interior when I need gap filling. I would probably use Titebond III or Titebond Extend on a Morris chair. I used Franklin Liquid Hyde Glue on a tricky (to me) furniture repair recently and was impressed with the open time.

[Richard Coers]

Entirely false.

OP--never add anything to epoxy that is not specifically recommended by the formulator.

Epoxy is an excellent choice for this type of project, for which I would use slow hardener (there really is no need to rush). Both surfaces need to be coated. Squeeze-out is essential to be certain of having no voids, but needs to be cleaned up immediately. Colloidal silica is used where necessary to thicken the mix to prevent running and to better fill any gaps. Avoid heavy clamping pressure--it is unnecessary.

Suggest you first read "The Gougeon Brothers on Boat Building".
Entirely false? Why do epoxy companies say differently? How many sources would you like to see? Maybe you can show me links that say to have no bond line thickness?
https://focenter.com/bond-line-thickness-more-answers-to-common-epoxy-questions/
https://www.masterbond.com/techtips/understanding-bond-line-thickness
https://www.appli-tec.com/articles/controlling-bond-line-thickness/
https://www.sciencedirect.com/topics/engineering/bondlines
https://www.epoxyworks.com/index.php/bond-lines-adhesive-bonded-structures/
https://www.rockwestcomposites.com/shop/materials-tools/resins-adhesives/bond-line-controller
https://www.westsystem.com/instruction-2/epoxy-basics/bonding-clamping/ In this video West Epoxy narrator says to clamp with just enough force to hold the parts together . Too much clamping force will leave too little epoxy in the joint.
bond-line-controller (https://www.rockwestcomposites.com/shop/materials-tools/resins-adhesives/bond-line-controller) This company makes glass beads to control the bond line thickness of .008" to .013".
Bond line controller (also referred to as BLC or Spheriglass®) are fine solid glass spheres that are used as an additive in 3M & Loctite adhesives and other resin systems. Bond line glass beads will minimize galvanic corrosion as well as keep the bond concentric. To ensure a proper mechanical bond it is best to use 2 grams BLC with every 3 oz. of adhesive. Make sure you choose the correct size based upon the gap between your two parts. If you are specifying this gap to a machinist, we would typically recommend a bond line (gap) of around 0.008” to 0.013” which would use SKU 1031 and SKU 1030. Need help with surface preparation? Read our instructions below.

[andy bessette]

Entirely false? Why do companies say different? How many sources would you like to see? Maybe you can show me links that say to have no bond line thickness?
https://focenter.com/bond-line-thickness-more-answers-to-common-epoxy-questions/
https://www.masterbond.com/techtips/understanding-bond-line-thickness
https://www.appli-tec.com/articles/controlling-bond-line-thickness/
https://www.sciencedirect.com/topics/engineering/bondlines
https://www.epoxyworks.com/index.php/bond-lines-adhesive-bonded-structures/
https://www.rockwestcomposites.com/shop/materials-tools/resins-adhesives/bond-line-controller
https://www.westsystem.com/instruction-2/epoxy-basics/bonding-clamping/ In this video West Epoxy narrator says to clamp with just enough force to hold the parts together . Too much clamping force will leave too little epoxy in the joint.
bond-line-controller (https://www.rockwestcomposites.com/shop/materials-tools/resins-adhesives/bond-line-controller) This company makes glass beads to control the bond line thickness of .008" to .013".
Bond line controller (also referred to as BLC or Spheriglass®) are fine solid glass spheres that are used as an additive in 3M & Loctite adhesives and other resin systems. Bond line glass beads will minimize galvanic corrosion as well as keep the bond concentric. To ensure a proper mechanical bond it is best to use 2 grams BLC with every 3 oz. of adhesive. Make sure you choose the correct size based upon the gap between your two parts. If you are specifying this gap to a machinist, we would typically recommend a bond line (gap) of around 0.008” to 0.013” which would use SKU 1031 and SKU 1030. Need help with surface preparation? Read our instructions below.

If your links have any references whatsoever to the "FAT GLUE LINES" you mentioned (which I rightly claim is pure BS) please quote them here, as I am not about to read through all the lengthy articles shot-gunned into your post. When you mentioned "I'm not a fan of epoxy for joinery." I presume you mean you don't have a lot of experience with it, which is OK.

Over the past 48 years of using barrels of WEST Systems epoxy, as a professional, I can assure you there were no fat glue line issues unless I failed to fit the joint properly. :)

I'll include a few examples of my work on yachts. Though the photos don't prove anything, epoxy glued wood joinery satisfies some of the fussiest people in the world--wealthy yachtsmen. It is also perfectly well suited for a chair.

https://i.postimg.cc/4dQ7bF5q/bandit-2.jpg (https://postimages.org/)
https://i.postimg.cc/Jn0c7kPT/cstar-table-1.jpg (https://postimages.org/)
https://i.postimg.cc/jj1D4Fhv/surf-8.jpg (https://postimages.org/)
https://i.postimg.cc/nc5RMh1h/IMG-1543-1.jpg (https://postimg.cc/WhG6HjKB)

[Richard Coers]

If your links have any references whatsoever to the "FAT GLUE LINES" you mentioned (which I rightly claim is pure BS) please quote them here, as I am not about to read through all the lengthy articles shot-gunned into your post. When you mentioned "I'm not a fan of epoxy for joinery." I presume you mean you don't have a lot of experience with it, which is OK.

Over the past 48 years of using barrels of WEST Systems epoxy, as a professional, I can assure you there were no fat glue line issues unless I failed to fit the joint properly. :)

I'll include a few examples of my work on yachts. Though the photos don't prove anything, epoxy glued wood joinery satisfies some of the fussiest people in the world--wealthy yachtsmen. It is also perfectly well suited for a chair.

https://i.postimg.cc/4dQ7bF5q/bandit-2.jpg (https://postimages.org/)
https://i.postimg.cc/Jn0c7kPT/cstar-table-1.jpg (https://postimages.org/)
https://i.postimg.cc/jj1D4Fhv/surf-8.jpg (https://postimages.org/)
https://i.postimg.cc/nc5RMh1h/IMG-1543-1.jpg (https://postimg.cc/WhG6HjKB)

I did quote the last one. You don't even want to read my whole post? I have a lot of experience. I've been woodworking for 50 years. When you try something and don't like it, why would that indicate I have no experience. I'm not going to argue. So what if you don't want to agree the companies that manufacture the products. You don't want to read, why would I think you want to listen.

[Tom M King]

Andy, would you recommend a chair assembly as a first project for getting used to working with epoxy? Some factors you have to keep in check dealing with epoxy only come with experience for most of us, I would expect. I would hate for those lessons to come from putting together a chair.

[andy bessette]

Andy, would you recommend a chair assembly as a first project for getting used to working with epoxy? Some factors you have to keep in check dealing with epoxy only come with experience for most of us, I would expect. I would hate for those lessons to come from putting together a chair.

Judging from the carefully dry-fitted assembly pictured in the OP's first post I would surmise he is no beginner to wood joinery--only to the use of epoxy as glue. Also the OP showed wisdom in asking the questions he did before simply rushing into it. I have already suggested that he read "the bible" on joining wood with epoxy: "The Gougeon Brothers on Boat Building", though he can no doubt gain the knowledge required by reading the pertinent chapters. And his particular project indeed lends itself virtually ideally to the use of epoxy glue, due to its very long working time.

This chair design is rather straightforward and appears to also lend itself to assembling in stages such as time allows. It is also a very simple matter to do a quick trial run on some of the exact scrap from the chair build. So indeed I think epoxy is an excellent choice for this project. Remember, each glued joint is simply two pieces of wood glued together.

An example of what long working time allows.

https://i.postimg.cc/XvxnyyHf/surf-4.jpg (https://postimages.org/)

[Stan Calow]

I use epoxy all the time for joinery. It's slicker than PVA so things slip around if you're not watching when you clamp. Yes to using painters tape around all joints - and watch out for runs. Dont get it on your clamps.

[Richard Verwoest]

The hide glue I use is from Titebond.

[andy bessette]

... Yes to using painters tape around all joints - and watch out for runs. Dont get it on your clamps.

I never tape bare wood as epoxy can easily bleed under the tape. Instead I immediately clean off the excess using a narrow putty knife and small bits of paper towel, following up with acetone-soaked PT bits. But you must do a careful and thorough job to avoid staining.

Epoxy glue on clamps can be chipped off after fully curing.

[Ed Mitchell]

1. Is there any real difference between the popular brands (System3, West Systems, Total Boat)? I see Total Boat the most on YouTube and whatnot, but I assume that's just that they choose to sponsor more content creators. But I don't know.

Yes, but no. You get what you pay for, but remember, an epoxy like West Systems was developed and tested for marine applications, such as the layup of a boat's hull. When you're out at sea, and have huge waves smashing into your hull, you're glad you didn't buy some cheapo-brand epoxy. Are you going to sail to Ecuador aboard your Morris chair? I didn't think so. Total Boat seems to be a decent furniture epoxy, I've used it myself a few times with good results thus far, but I'm unaware of long-term results, so buyer beware.



2. Do I need to use a thickener like Total Boat's silica thickener? Seems like it would probably stick to surfaces better as I'm getting these pieces assembled, but the joints fit pretty well so I'm not sure.

No, thickener is for filling gaps and fairing. If your joints are GTG, just use the straight stuff. Having said that, thickener can be helpful, so if you have it, feel free to use it. Titebond sells a glue that doesn't drip down vertical surfaces, you can use thickener for epoxy to get the same kind of property from your epoxy. And of course if you have a loose joint, you can fill it with thickened epoxy and the joint will be extremely strong, but the epoxy will be visible, so you have decisions to make there.


How would you attack this to ensure structural stability?

I'm not sure what squeeze out has to do with structural stability. Same with any glue -- take steps to deal with squeeze out. Fine Woodworking has had a number of articles over the years.



I do realize that I might be wildly overthinking this. But I'm listening to any "epoxy as adhesive" advice you've got!


Epoxy is a great choice. In summer, the slowest curing hardeners are very much your friend for complicated glue-ups. The poster above who mentioned epoxy needs a fat glue line to reach full strength is....giving you advice that will mislead you. From his own link: "A general guideline for minimum bond line thickness is between 25 to 150 microns (1 to 6 mils)". Well, 25 microns is 1 thou, and if you watch this William Ng video (https://youtu.be/NutwD7B6tmE?t=436), you'll see you can barely force together a joint that tight. So in woodworking, we don't use nor want joints that tight, and the nice, tight joints we want (mortise width maybe 4-6 thou wider than tenon, so 2-3 thou per side) leaves plenty of room for epoxy of sufficient "fatness", even according to that poster's own link.

More importantly, we have years of actual woodworking data with epoxy and joint strength tests :https://www.youtube.com/watch?v=LfS-l9u-OuI and you can see that epoxy (he is using West Systems) is perhaps the best choice on the market according to his tests.

The mfrs recommendations exist generally to ensure that the layperson doesn't starve the joint, leave voids or areas where epoxy was not applied to the joint, or have uneven application. If you just use common sense, you'll be fine. Also remember -- epoxies in the past were created because we needed an adhesive that could handle higher-stress applications than the glues which existed at that time. If hide glue could be used to build spacecraft, we would have just used hide glue. The point to remember is that a high-quality epoxy, like West Systems, is generally made for stresses that no furniture is expected to ever see. So what is "normal" for an epoxy like West Systems is above what's needed for a lifetime of service from a Morris chair, which means that their recommendations might be much more than you need.

[Tom M King]

I've used wax free paper food cups for mixing epoxy and polyester resins for decades. They're cheaper than any I've seen sold as resin mixing cups, and cheap enough to have a bunch of different sizes on hand.

https://www.webstaurantstore.com/choice-8-oz-white-double-poly-coated-paper-soup-hot-food-cup-pack/999SOUP8WB.html?utm_source=google&utm_medium=cpc&utm_campaign=GoogleShopping&gclid=CjwKCAiA85efBhBbEiwAD7oLQNENeR5gkzRtciOP8zuf HU13m4zClq7JoOULDnvouBweVGjZv_hGVxoC2ZsQAvD_BwE

For mixing very small quantiites of golf club epoxy, I do use the little 1 oz. plastic cups, but for everything else:

https://www.webstaurantstore.com/choice-8-oz-white-double-poly-coated-paper-soup-hot-food-cup-pack/999SOUP8WB.html?utm_source=google&utm_medium=cpc&utm_campaign=GoogleShopping&gclid=CjwKCAiA85efBhBbEiwAD7oLQNENeR5gkzRtciOP8zuf HU13m4zClq7JoOULDnvouBweVGjZv_hGVxoC2ZsQAvD_BwE

I buy the commercial wooden mixing sticks too. They come in boxes of 500. Two sizes of those have been plenty for anything I do, and a box of 500 will last me for years.
https://www.ebay.com/itm/123857046664?epid=27008337677&hash=item1cd6748c88:g:xhMAAOSw7spgf1Aw:sc:Shipping MethodStandard!27842!US!-1&amdata=enc%3AAQAHAAAA4JxsNmN9ss6WIDUhvsLnSzO1NMBNQ T8fjcw%2Bav%2BFC7yHOrUGuZqvzt4atdQiMEJ%2FyenQ8rLnj nplqKQZyoiwySwXVWcUD8KQBRTdO7KVZrbtaZhWoRtRIn8ynVJ QTq7SIkqD7pduRXjFQWkg%2BX4KdmVpoF7H3EFhPhk8J8EULCW miMQSbO43UpxDa4zf2AlnS1UUJhGI1yw6ZLAnlrTxBAKpFeonB N2ZlnvgqkbiqpWH8PDIIeovCd7VfUvvu1S1DcXGSLJBI1I%2Fd nD9tJTzeqee%2FQq4oRCh0wRqq3yBlcUu%7Ctkp%3ABFBM1oCC x8dh

For Nitrile gloves, I don't like them less thick than 7 or 8 mils, and thicker are too thick for me.

Buy a gallon of Acetone to start with, and have a roll of paper towels ready to go.

Pure orange oil cleaner will clean it almost as well as Acetone but don't get the watered down stuff in spray bottles.

When I had a boat repair shop, it had an oversized air conditioning system. I could cool it down quickly to 65 for doing layups, and then back to normal for curing. Temperature is important.

To start with especially, you will get it on stuff that you don't want it on. Don't get in a race with it. You won't win all those races.

[Cameron Wood]

No stake in this, but from Richard Coers' first link:

What is the recommended minimum bond line thickness?

A general guideline for minimum bond line thickness is between 25 to 150 microns (1 to 6 mils) – as a starting point.



AFAS the chair, I don't see where there needs to one complicated glue up. I would use regular glue on a section at a time, and dry clamp the rest to maintain alignment.

[Kevin Jenness]

No stake in this, but from Richard Coers' first link:

What is the recommended minimum bond line thickness?

A general guideline for minimum bond line thickness is between 25 to 150 microns (1 to 6 mils) – as a starting point.

Some say this and some say that. I know from decades of experience using epoxy in close tolerance joinery that as long as the joining surfaces are rough the glueline doesn't need to be thicker than if using yellow or hide glue.

On that Morris chair, the exposed tenon ends are going to get some epoxy wicking into the endgrain which is not coming out. Prefinish them or wet them out completely for a uniform look.

[James Jayko]

Took everyone's advice into consideration! Got the System Three epoxy (what they stock at Woodcraft). Glued up the two leg sub assemblies yesterday, went very smoothly and seemed to workout just as I'd have hoped! Big thanks for the acetone heads up; definitely game in useful!

[Gordon Stump]

Simple Epoxy question. Simple Epoxy answer: T-88
Some of my nightmare glue ups involved dowelling. The holes were not deep enough; bad alignment; bad woodworker!

Dream solution: T-88 or similar slow curing 2 part epoxy.

Glue-up rule for you younger folks with kids. Never glue-up when the kids come home from school. They want to talk and I want to listen!

[Jim Becker]

Yea, T-88 is a good "structural" epoxy especially designed for joinery and with decent open time for complex assemblies. I keep some in the shop specifically for those kinds of needs.

[Tom M King]

The only failure I've ever had from any epoxy was from heat. I've used a lot of it working on old houses, buying the large West Systems 4.something gallon kits several times, and no telling how many gallon kits. The failure I had was on the second story on a window sill close to a chimney that heated that spot up pretty good from the Sun. I replaced that sill with a cast in place concrete one.

I mainly use West because it and I are old friends. For small jobs, I have bought the two bottle kit by Locktite sold in box stores, and no complaints with that either. I wouldn't hesitate to use any sold by a reputable company. Jamestown Distributors markets the Totalboat stuff, and I have confidence in anything they sell. I expect I've bought more West Systems from them than anywhere else.

I just don't use any that's going to get any sort of unusual heat. The gold club head gluing epoxy is engineered to break down at about a hundred degrees below the epoxy used in graphite shaft layups, so it is possible to pull and change a head. It comes in black, and when I need black epoxy I use golf epoxy from Golfworks.

[James Jayko]

How long do you need to keep things in clamps? When can you handle it? Not to stress or anything, but its glued up in a shared workspace. Can I remove clamps and move the chair in ~8 hours?

[Kevin Jenness]

How long do you need to keep things in clamps? When can you handle it? Not to stress or anything, but its glued up in a shared workspace. Can I remove clamps and move the chair in ~8 hours?

Depends on conditions. Usually you can pull clamps in 6 hrs or so. Leave a thin puddle of mixed resin out; when you can't dent it with your thumbnail you know it's fine to unclamp an unstressed assemby.

[Michael Burnside]

Don’t “work” with it for 24 hours but I usually remove clamps 4-8 hours after.

[James Jayko]

On that Morris chair, the exposed tenon ends are going to get some epoxy wicking into the endgrain which is not coming out. Prefinish them or wet them out completely for a uniform look.

didn’t read this until after the glue up but this is so right. I was careful to only get it on the sides (not the endgrain), which I’m gonna have to sand off. But thankfully I didn’t make this mistake!