Tricks to using CA glue & coffee grounds to fill voids?

[Bruce Page]

I've read that some of you use this technique to fill in cracks/voids in your turnings. I'd like to adapt it to filling in engraving done with my cnc router. So far my tests have not been encouraging.
My method is to spray the engraving with shellac, let dry, fill engraving with fine grounds, and drip in super thin CA glue. My biggest issue is the CA glue washing out the grounds, particularly where the engraving isn't very deep. Is there a way to help avoid this. Is there a better method?

[John Keeton]

Bruce, I assume you are going to sand or otherwise level the grounds after application. My best advice is to not use CA glue. I mix grounds with some Titebond and tamp it in to the void/recess with a small dowel, skewer or chopstick, leaving it proud of the surface. Of course, I am turning so it gets turned off, and I can fill any small holes with lacquer or CA, but usually I get a pretty good surface. You can thin the mixture with just a tad of water, but be aware that even with the Titebond, it can stain the surrounding area, so your idea for shellac is a wise move.

[Doug Rasmussen]

Correct me if this is wrong, but I've read several places not to use CA where it's to be permanent. Apparently, it has a usable life and will fail after x number of years. Inlace granules worked fine with CA glues, my experience only goes back several years though, and they may fall out some time in the future.

For permanent fills or repairs the recommendation is to use epoxy. Problem is, epoxy is more troubled with having to mix. Then you always mix too little or not enough.

John, which Titebond do you use.

[daryl moses]

I tried CA glue mixed with coffee grounds with negative results. I now MIX coffee grounds with 5 min epoxy and fill the voids a little proud of the surface then sand level when cured.

[John Keeton]

I have both Titebond III and the yellow (original?) on my bench and it depends on the color of the wood. III looks a bit better with darker woods.

[Ken Fitzgerald]

Bruce, you know me and my love of coffee.

I have a jar of Folgers instant my wife bought over 30 years ago. I crush the crystals and mix it with 5 minute epoxy. It has worked well for me.

It heartening to find a use for that instant coffee. I won't drink it!

[Bruce Page]

Thanks, I will try using Titebond, I don't have any epoxy on hand. For some reason I thought the CA was the way to go, I even bought the super thin just for this. Where do you buy the turquoise looking granules? I'd like to give that a try too.

[Jon Lanier]

If CA has a usable life and will fail afte x- years. I better watch out with my pens... because they are going on 10 years as a finish. I'm sure they are going to fall apart any day now.

[robert baccus]

The small twin tubes of epoxy are great for small uses--even lasts after opening for months. Epoxy is fast, permanent, nonstaining and best of all. Sands about like wood--CA can be like granite to level out. Leaves highspots and takes too much effort. I mix ingredients such as coffee, turquois, sawdust ect. to a paste and apply with a tounge depressor. The 5 min. and even 1 minute have you back to turning very quickly.

[Leo Van Der Loo]

I use coffee ground and CA, the reason I don’t use epoxy is that you can use only a small amount of other material mixed in with the epoxy or else it will not work/harden anymore.

With coffee ground and CA I can fill a void totally with the material, be it metal powders or coffee ground or other, I use masking tape to prevent the CA from flowing out/through, you can then also tape the ground down and fill with CA, or as I often do slowly flood the CA in and push the material down with a spatula (ice cream stick) or just my fingers, and sometimes drop some more material on top of the CA moistened material.

Oh yes like Jon Lanier mentions, my more than 15 year old pieces with CA in them must have falling apart by now :eek:, though nobody has mentioned it yet or did LOML that her bowl now has a split in it :rolleyes:

Here is a picture of a 24 inch Willow burl that did have the wood open up as it dried the contorted grain, so after a couple of years (2??) I then filled all the splits with fine coffee ground and CA, 10 years by now and still fine :)

342951

Also a Siberian Elm bowl that I filled both the rim and the side wall with coffee ground and CA.

342952

[david privett]

If you are wanting dark try weldwood plastic resin glue and mix with what ever for coloring, that stuff is tuff.

[Prashun Patel]

I appreciate the speed that CA glue offers, and the cost effectiveness that coffee grounds offer.

But I get the best results using two-part epoxy, slow drying, with a drop of Transtint black in it. Once I bit the bullet and bought a small 2oz life-time supply of black TT, I never looked back.

I dislike the look of voids that are large and bulked with a solid filler. They look grainy. Tinted epoxy has a cleaner look. You require so little dye, it does not in the slightest affect the dry time or curing of the adhesive.

If you really love CA, you can add the TT to that too.

[Mike Goetzke]

I have no experience with filling (yet), but, I did stumble across a blog with lots of good info including coffee/epoxy filling: linky (http://www.docgreenwoodturner.com/coffee.html)


Mike

[John Keeton]

Having used epoxy, it does work well, however, Titebond works just as well and no rushing, no need for quick cleanup, and your tools can be wiped clean with water. And, it looks just as good IMO. I have not tried, but I am reasonably certain that Transtint can be added to the mix if desired as the glue is water soluble when still wet.

[John K Jordan]

... My biggest issue is the CA glue washing out the grounds, particularly where the engraving isn't very deep. Is there a way to help avoid this. Is there a better method?

I can't answer your coffee grounds filling question (I don't like filled cracks in turnings and they sometimes separate after a few seasons of wood movement) but for future reference on applying thin CA glue: Have you used the capillary tips that can be added to the CA glue bottle? Woodworking places sell them or google "ca glue applicator tips". These give more control and let you apply the tiniest drop exactly where you want it. I use them mostly to apply thin CA to small areas in wood prone to tearout.

How big are the voids you want to fill in the engraving? Do you want the fill to be flush with the surface or just darker to highlight the engraving? When I texture turnings it usually makes very shallow impressions in the wood. With light wood I use a dark walnut grain filler then remove it on the surface and leave it in the texture marks. If I don't want to sand, I apply finish (either before or after turning), then rub with a cloth before the filler dries completely. If needed, I brush the filler into the texture with a small glue/acid brush with the fibers cut off short so they will be stiffer.

JKJ

[Wes Ramsey]

Personally I've had better luck with thin CA and coffee grounds than epoxy and coffee grounds. In my experience the CA not only soaks into the grounds, but also the wood around it, creating a stronger bond. The same solution using epoxy doesn't bond as well with the surrounding wood and I've had more inlaces turn loose when hit with a gouge than I've been able to smooth and finish. Plus, it is much easier to fill tiny cracks with CA than with epoxy - just rub some near-powder coffee grounds (or powdered metal/stone) into the crack and put just enough CA on it to soak in, wait 2 minutes, sand a touch and you're back in business.

It will soak in and stain wood where you don't want it to so be careful how much you use or seal the piece with shellac/wax/DO/lacquer/etc so it doesn't soak in. Thin CA will cure almost instantly when it meets coffee grounds, so on larger voids I will make a dam around the void with coffee grounds and if the CA runs it will stop and harden as soon as it touches the dam. And if you have some uncured CA sitting on top of your fill you can sprinkle some coffee on it and it will cure instantly.

I also prefer the more consistent density and appearance of coffee grounds with CA over (untinted) epoxy. It looks more natural to me, but appearance is subjective. In the end you should use what you're familiar with and what works best for you. In all fairness I've only used QuickCure 5-minute epoxy from Lee Valley. The slow-cure stuff may work better, but this is what I have and my experience with it.

If I think about it tonight I will take some close-ups of some fill jobs I've done and post them up.

[robert baccus]

This is probably cutting frog hairs but it is what it is. CA sands like granite .... I have a ship model of basswood and CA that started falling apart at 20 years of age. The book agrees. Ca stains light colored woods and an open void sprayed with a film finish is made to let go. A crack is different. In lab tests all the common glues were essentially the same tensil strengths except for gorilla glue. It was about 1/2 the strength of the other glues. Significantly, only two glues developed good strength without firm clamping of the glue joint. Epoxy and CA need no clamp pressure. Only CA held full strength on wet wood (thank goodness). Water based glue strength is compromised to some degree?? Leo, After using epoxies on boats, cars and turnings (barrels) I find that only overly generous thinning with LT or Ace. or dyes slow down the hardening. Temperature is much more important than other influences. All old boat owners have a gallon can of epoxy.(solid) with a brush sticking out indicating the point when they learned that rising temps or too much volume reacting at once generated ferocious temps which then speeds up the batch. Maybe this is how they discovered "critical mass".

[Leo Van Der Loo]

Robert my youngest son is an electrical engineer that works for a company that makes satellite communication equipment, and other special products, I know that they would fasten antenna with Epoxy that had a “short good for lifetime", they would heat the epoxy to IIRC 60 degrees centigrade (140F) to get the epoxy to harden quicker and get a good and consistent hardening, so yes Epoxy is temperature sensitive, and it will harden up very fast if too much is used in one go, as it will accelerate heating itself, DAMHIKT :eek: :D

[John K Jordan]

... so yes Epoxy is temperature sensitive, and it will harden up very fast if too much is used in one go, as it will accelerate heating itself, DAMHIKT :eek: :D

Back in the '70s I ran a small metallography lab, potting sections from neclear reactor elements in epoxy so I could grind and polish. The sample forms held perhaps a cubic inch or so of epoxy. Once I must heated a sample a bit too much before putting it in the vacuum chamber. The reaction was incredible, the thermal "runaway" caused the epoxy to smoke and crack with pops and snaps, turning it a dark burnt brown in seconds once the reaction started. Learned that lesson!

JKJ

[Doug Rasmussen]

Correct me if this is wrong, but I've read several places not to use CA where it's to be permanent. Apparently, it has a usable life and will fail after x number of years. .................................................. .................................................. .................................................. ............................

Okay, I attempted to find articles where I read about the useful life of CA glue joints. One easy find was an article in American Woodturner, 26.4:24, quotes by both David Ellsworth and Richard Raffan. The article concluded with : "If what you are making needs to stand the test of time, be aware that CA glue has not been in use by woodturners for long enough to say with authority that glue joints will last. "

Realizing those were only opinions not based on extensive testing I did call a CA glue manufacturer (don't recall which one). The tech guy confirmed a joint does have a lifespan, but how long "depends" (whatever that means?).