Going to try epoxy

[Andy Fox]

I'm about to glue up a cherry cradle that I've been working on forever. There's lots of mortise & tenon joints, and I'm thinking about using epoxy to avoid the repairability problem with yellow glue. Also, some of the joints have just enough slop that I'm a little uncomfortable using yellow glue.

Not wanting to buy resin and hardener in large quantities, I'm thinking of using the dual syringe packaged stuff with a 20-30 minute working time. It seems like I'll have a hard time getting a thin enough coating to avoid major squeezeout though?

As a finish, I'm going to apply a coat of boiled linseed oil then shellac. I thought I read somewhere that linseed oil-soaked rags could be used to disassemble an epoxy joint, but maybe that's the "unboiled" stuff?

[Howard Acheson]

Nothing wrong with the twin tube stuff. If you don't need much, it's fine. Don't try to thin it. With epoxy, don't tightly clamp the joints. Epoxy relies on a certain film thickness for its strength.

To wipe up squeeze out, use lacquer thinner or acetone.

Boiled linseed oil will have absolutely no affect on epoxy.

[Hank Knight]

Andy,

The two-part epoxy like West or System 3 is MUCH better than the stuff you get at the BORG in the dual syringes. You can get it in relatively small quantities and it has a pretty long shelf life. Once you use it the first time, you'll find lots of uses for it around the shop. I use West System epoxy. You can order it or it's available at your local marine supply. You can get two different hardners -a fast set and a slow set. With the fast set, you have about 10 to 15 minutes open time. The slow set gives you about 20 to 25 minutes. You can slow the reaction down and extend the open time with a bowl of ice. When the mixed epoxy starts getting warm, set the glue container in the ice for a couple of minutes to cool it down. Once it gets warm, the reaction goes pretty fast and the container you mixed the glue in gets so hot it will burn your fingers. It's messy and clean up is something of a problem, so don't use too much glue and let it squeeze out all over everything. I use acetone for clean up, but I understand white vinegar (acetic acid) also works well. I haven't had any problems with shellac or polyurethane over the squeeze-out areas. I've not tried oil over an epoxy joint. My guerss is that the oil won't penetrate into the squeeze-out areas very well, but that's just my guess. Maybe someone else can give you some info in this. I've never heard the trick of separating an epoxy joint with BLO. I'll give it a try.
Good luck with your project.

Hank

[Jim DeLaney]

I've had good luck with System Three's T-88 epoxy. I buy it in 8 oz kits - two squeeze bottles, 4 oz each. It has a longer working time that the so-called 'quick' stuff, and (I think) makes a stronger bond.

Several of the usual mail-order outlets have it. I get mine at a local hardware store, though.

[Mike Henderson]

The 20-30 minutes of that double tube epoxy can go by pretty quickly, especially in hot weather where you may only get 15 minutes of working time before the epoxy starts to get too "thick" to use. If you have a lot of joints to glue and want more time, I've used System 3 T88 epoxy. It takes about 6 hours to set, but the working time is less. I never really tested how long it will work, but I'm sure you'll get over an hour in hot weather.

I used it recently, in the middle of summer, to glue up a swing which had 20 slats (40 M&T joints). I don't remember exactly how long it took me but the epoxy was workable throughout the process.

Leave it clamped up overnight.

I don't know anything that dissolves cured epoxy glue.

Mike

[Chris Padilla]

www.raka.com (http://www.raka.com) is my favorite place for epoxy: works fine, price is good...but I use that twin-tube stuff from the local h/w store all the time for repairs of all sorts around the house.

Try the plastic resin glue...it works quite well.

See here, too: http://www.sawmillcreek.org/showthread.php?t=21822

Edit: The above link is the Bob Smalser's "Is your glue joint repairable?" thread....

[Cliff Rohrabacher]

Ditto on West Systems

However if the joints are a tad sloppy why not slip a little bit of peel from a nice clean hand plane stroke in with the glue?

[Jeff Horton]

... I'm thinking about using epoxy to avoid the repairability problem with yellow glue. ....

.....I thought I read somewhere that linseed oil-soaked rags could be used to disassemble an epoxy joint, but maybe that's the "unboiled" stuff?

Unless someone knows something I don't, once expoxy sets there ain't nothing going to make that joint come loose except heat. And that isn't good for the wood. If you think you may need to do a repair by taking a joint apart, I think your looking at the wrong glue.

Might want to look up Bob Smalsers recent post on glues.

[Dave Richards]

I can second the Raka epoxy. I've had excellent results from it on two boats and numerous other projects. Straight up it is thin enough to coat faying surfaces and with a bit of wood flour or even wheat flour you can get a good gap filler. Add enough fumed silica and it becomes thixotropic--won't sag or run.

Also invest in some clear packing tape for masking. The epoxy won't stick to it.

As has been mentioned, you don't want high clamping pressures. Just enough to close the joint.

Use a plastic mixing cup. When the epoxy hardens in it, flex the cup and pop out the epoxy. Use the cup again.

[chris del]

I built this Cherry cradle for the birth of my first in April......
I find that if I get carried away with my mortice and tennons and end up with a sloppy fit, polyurethane glue does a great job at filling the gap....
As far as the spindles go, there is no need to glue them in, they are held captive.
also, fyi finish is 3 coats of polymerized tung oil.

[Matt Meiser]

I used the West System epoxy on my daughter's bed for some of the same reasons as you. To deal with squeezout I took the time to mask all the joints with blue painters tape like David Marks does. I then cleaned up when the epoxy was almost hard using a sharp chisel to separate the squeezout from the tape and peeling the tape away. Time consuming, but the bed turned out great and is rock solid.

[Cliff Rohrabacher]

once expoxy sets there ain't nothing going to make that joint come loose except heat. Correct-o-mundo


And that isn't good for the wood.
Ahhh matza matza The heat needed is less than most commercial wood kilns use. The glue will soften at about 200 Deg F (even lower often) and goes all to pieces at 350.

My Melie dishwasher destroyed all the Epoxy in some things that my wife washed in it.

[Mike Henderson]

I find that if I get carried away with my mortice and tennons and end up with a sloppy fit, polyurethane glue does a great job at filling the gap....

If by polyurethane glue you mean something like Gorilla Glue, it may fill gaps with the foam, but the foam has no structural strength. Epoxy has gap filling capability and has structural strength in the gap.

Mike

[Howard Acheson]

>> The two-part epoxy like West or System 3 is MUCH better than the stuff you get at the BORG in the dual syringes

What is he basis for this statement? I've used gallons of various epoxy adhesives over the years. As long as it is fresh, there is no material difference in it. When you need just a small amount, the syringe big box stuff is as good as anything else.

Most suppliers of epoxy are packagers, not manufacturers.

[Ben Grunow]

Andy- use some small throw away brushes for the epoxy. It is thin enough to brush without leaving too much.

I have used tons of epoxy working on boats and I dont think there is a big enough difference between mfgrs to be noticed. I like the West System because they have good support and they make a great product line (no affiliation) with easy to use instructions for different applications.

AFAIK, you can use oil base finishes over epoxy but the parrafin "blush" (sheen of parrafin that form on the surface of the epoxy after it cures) must be removed by sanding the sheen off the epoxy.

I suggest you test your finishes all together before diving in. This all sounds complicated but if you glue it up, wipe the excess with acetone and sand everything well you shouldnt have any problems-forever. Good luck.

[Frank Hagan]

Try a test piece first ... I've found that epoxy can darken some woods, so you might have to be careful (I don't know specifically about cherry). Adding wood flour will color the epoxy, depending on the wood flour (maple wood flour turns the epoxy dark brown).

I use RAKA epoxy, but System Three would be my second choice. I've found the 2:1 mixing ratio easier to use than West's 5:1.

[Andy Fox]

Thanks for the many helpful suggestions.

If the epoxy is a little thick, could/should I thin it out by heating it on the wood with a hair dryer? :confused:


I've never heard the trick of separating an epoxy joint with BLO. I'll give it a try.

Not sure about that, thought I read it somewhere, and I think I read "linseed oil" as in "unboiled".... :confused:

[Chris Padilla]

Yes, warm up the epoxy to thin it out. If you read the large thread that Bob Smalser started (I posted it above in post #6), he likes to first soak the wood with thinned epoxy (done by warming it up) to get deep into the fibers (especially on end-grain) and then he uses the epoxy at normal room temperatures to complete the glue-up.

Pick yourself up a nice hot-air gun (Milwaukee makes a very nice one) if you find yourself doing this a lot. You can set it for very, very hot air on a very low speed and it isn't near as noisy as a hair-dryer nor does it blow everything in sight around.

[Voytek Jarnot]

Yes, warm up the epoxy to thin it out. If you read the large thread that Bob Smalser started (I posted it above in post #6), he likes to first soak the wood with thinned epoxy (done by warming it up) to get deep into the fibers (especially on end-grain) and then he uses the epoxy at normal room temperatures to complete the glue-up.

Pick yourself up a nice hot-air gun (Milwaukee makes a very nice one) if you find yourself doing this a lot. You can set it for very, very hot air on a very low speed and it isn't near as noisy as a hair-dryer nor does it blow everything in sight around.

Does warming up the epoxy cut down on the open time? I have heard of putting epoxy in the fridge before using it to extend open time, I'm guessing the reverse will also apply.

[Dell Littlefield]

Ben, the blush on epoxy is amine blush, not paraffin and should removed with plain water. Few epoxies blush. West and Raka both advertise non-blushing epoxies.

[Chris Padilla]

Does warming up the epoxy cut down on the open time? I have heard of putting epoxy in the fridge before using it to extend open time, I'm guessing the reverse will also apply.

Yes, in most cases it does. Just be aware of the open time of your epoxy. If it is an hour, heating up a small amount is no big deal. If it is 5-minute epoxy, it could be troubling....

Experiment a bit before glue-up...just like applying a finish...experiment on scrap! :)

[Hank Knight]

>> The two-part epoxy like West or System 3 is MUCH better than the stuff you get at the BORG in the dual syringes

What is he basis for this statement? I've used gallons of various epoxy adhesives over the years. As long as it is fresh, there is no material difference in it. When you need just a small amount, the syringe big box stuff is as good as anything else.

Most suppliers of epoxy are packagers, not manufacturers.

Howard,

My comments about syringe-mix epoxy were based on my own experience with it. I used to keep it around the house for household repairs, but I found it awkward to use and the syringes were pretty much a one-use item. When I tried to use a previously-opened syringe, I invaribly found the contents to be cross contaminated and the syringe hopelessly plugged even though I had dutifully cleaned the syringe before I put it away. Moreover, the repairs were never satisfactory, but this may have been attributable to my trying to use it to repair things that were essentially unrepairable. One would think, however, that ceramics could be repaired effectively with epoxy.

Then I bought a quart of West Systems epoxy for a woodworking project, with the pump dispensers for the resin and the hardener. I found the pumps to be easy to use and accurate. The glue performed well on my project, so I tried it on some household repairs. It performed well on those too. As an example, my wife broke her favorite ceramic coffee mug. I glued it back together with West's epoxy and she's still using it 4 years later, after numerous cycles through the dishwasher. I've tried to repair ceramics with syringe epoxy in the past, but the repairs inevitably failed. I came to regard them as temporary fixes at best. The West System repair appears to be permanent - or close to it. I have developed a lot of confidence in West System epoxy for all kinds of glue jobs, confidence I never had in the syringe-mix stuff. They may all be the same product behind the labels, but you couldn't prove it by me.

I'm not affiliated with West or any other glue manufacturer, packager or seller. These remarks are based strictly on my own observations and experiences.

Hank

[Ben Grunow]

Dell you are making me blush- thanks for clearing that up for everyone. I know that the surface of epoxy needs to be ground away in order to allow new epoxy to stick to cured epoxy and I think this is because of the (amine) blush that is on the surface.

Similarly, I thought that this blush needed to be removed to paint over epoxy (and fiberglass)- not that anyone would ever paint over glass smooth epoxy without roughing it up with sandpaper anyway. Is this true?