Celtic Knot Blowout Question

[Tage]

Newbie question here I'm sure but here it goes. I've made (I should say attempted) three celtic knot pens. The first one I did came out great (by my newbie standards). It was mahogany with maple veneer inlay. Tubes and veneer were glued with thick CA. Bolstered by my success, I decided to make two more (Gatsby style) as Christmas gifts. I did them in African blackwood with maple inlay, and pink ivory with maple inlay. I was out of the thick CA but used medium CA (changed brands but the viscosity seemed pretty close). I drilled the blanks without difficulty. When turning them, the pen blew out at the knot....large chunks down to the brass tube. (Sorry, no pics...I used my parting tool to turn them back down to the brass tubes.) I attempted to glue the pieces back in, but needless to say, that didn't work....they blew out again. This happened to both pens, an apparent glue failure. So my question is, what do you use to glue your tubes to the blanks and to glue the inlay in. My obvious first answer is to stick with the thick CA since that worked before. When turning pens without a knot, I've never had difficulty and have used both thick and thin CA to glue the tubes. I'm assuming the veneer compromises the strength of the blank so I need something stronger.

Would a two part epoxy be better for gluing the tubes in the blanks and the inlay. Seems like that may add a bit of strength, but I like the fast dry time for the CA, which allows me to do a blank and turn in the same evening.

Thanks in advance for your expert advice. Happy Holidays to all.

 

[seamus7227]

I'm exactly sure about the celtic knots, but I will say that 5 minute epoxy is what I use and I have excellent results! I agree about wanting to turn relatively quick, but whats 5 or 10 extra minutes anyway, especially if its the difference between half ass and quality workmanship. Just my .02

 

[Tage]

Seamus,
I hadn't thought of 5 minute epoxy. I'll have to try it. I've got some that takes much longer to cure, so that's where my impatience came in. Even the CA takes at least 5 minutes to cure when gluing the blanks in my (limited) experience. Thanks. I guess I really answered my own question. The epoxy (I think) would hold the tube more securely. I guess the question remains as to how to glue in the inlay.
Thanks for your input.

 

[Drstrangefart]

I have been taught to use thick CA on EVERY step of the knot until it's ready to be finished. Last one I did I backfilled everything with thin and accellerator to be sure and let it dry in a warm area for a while on each side. If your work area is cold, that could have had an effect on it, too.

 

[soligen]

On delicate blanks like that good glue coverage is essential. CA has been bad for glueing tubes in my experience - just not enough open time to ensure you have glue coverage everywhere inside.

The easiest way to get good coverage is with gorrilla glue, since it expands, but it is poor at filling gaps so your drilled holes need to be not too big. IF you are at all unsure on your tube fit, use epoxy. I have taken to applying the epoxy with a q tip both inside the hole and to the tube to ensure good coverage. You may have to clean some epoxy out of the tube doing this, but i'd rather clean out tubes than have the blank fail.

Even with 5 min epoxy, I'd wait an hour or 2 .... just make another celtic knot blank or 2 while you wait

 

[jedgerton]

I have to second the gorilla glue comment with one exception. I believe GG is excellent at filling gaps. As it expands, it will come out at the ends and through any holes you may have in your blank. In four years of turning, using GG for virtually every pen, I've had maybe four blow outs.

By the way, I use GG for the blank to tube interface. For segmenting like you are doing for the celtic knot, I use medium CA.

Just my two cents and worth every penny!

John

 

[IPD_Mrs]

Dave the other thing to think about with the CA is that it fails at around 165 degrees. You didn't mention if the blank got warm while turning or while milling but that could have an effect on it. Whenever you are turning a segment no matter what the pattern, it is best to use very sharp tools and take off a little at a time. The slightest catch can cause even the simplest of segments to blow. Good luck and keep us up to date on your progress.

 

[ctubbs]

GG is a good gap filling glue. You are correct in that it foams like crazy, but that is also the problem with GG. Find some that has expanded and cut it with your finger nail. It is soft. Yes, it fills the crack/gap but there is little strength in the fill. For myself, epoxy on the tube, either epoxy or CA on the knot/segment and thin CA as the turning progresses on the segmenting. Something like punky or spalted wood. I can make my knots stay together doing this, I just drill them off center and they all look like crap.
Charles

 

[Russianwolf]

GG is a good gap filling glue. You are correct in that it foams like crazy, but that is also the problem with GG. Find some that has expanded and cut it with your finger nail. It is soft. Yes, it fills the crack/gap but there is little strength in the fill. For myself, epoxy on the tube, either epoxy or CA on the knot/segment and thin CA as the turning progresses on the segmenting. Something like punky or spalted wood. I can make my knots stay together doing this, I just drill them off center and they all look like crap.
Charles

my expierence say soft is good in gluing pens. soft allows the wood to expand/contract as it wants to, hard mean more likely to crack.

 

[soligen]

I mentioned epoxy, but in reality I've had better luck with gorrilla glue, however I have only recently started using epoxy in both the hole and on the tubes.

My holes are usually pretty good so not much gap to fill. On plastic blanks I wet the inside or else it takes a long time to cure (DAMHIKT). On wood I do NOT wet the inside because it can cause the wood to swell up and the tube wont go in (DAMHIKT either)

CA is my usual for segmenting - just not tubes

 

[Tage]

Thanks for all the good advice. Reading the replies and analyzing my own process, I think my downfall was changing to the medium CA glue. Seems like the consensus for tube gluing is epoxy or Gorilla Glue. From the pens I've turned (again less than 30 as a beginner) it seems CA will generally "get you by" but I have noticed when turning down to the tube for some Comfort style pens, that the piece basically pops off the tube, so not a great hold there.

There seems to be a split in the replies between thick CA and epoxy for gluing the inlay into the blank. Again, I think gap filling is the key here. I will try again when I get some more kits after the holidays. The two I was turning for my wife and son were my last two that I had in stock.

Another lesson learned tonight -- I did those two pens without the knots as I am running out of time. I turned a stabilized maple burl blank, which also blew up on me. Sharp tool so that wasn't the problem. But what I learned was to keep stopping and checking for gaps as I go. As soon as I see a gap, and ESPECIALLY, if I see the tube, I should stop and fill with sawdust and CA. This method worked for the second burl I did and it came out very nice. I'll chalk them up as freshman mistakes. All part of the learning curve. When my son and I started turning pens, I told him not to stress when we blow one up or make a mistake....it's all part of the process. Thanks all for the good advice.

 

[okiebugg]

Epoxy

Thanks for all the good advice. Reading the replies and analyzing my own process, I think my downfall was changing to the medium CA glue. Seems like the consensus for tube gluing is epoxy or Gorilla Glue. From the pens I've turned (again less than 30 as a beginner) it seems CA will generally "get you by" but I have noticed when turning down to the tube for some Comfort style pens, that the piece basically pops off the tube, so not a great hold there.

There seems to be a split in the replies between thick CA and epoxy for gluing the inlay into the blank. Again, I think gap filling is the key here. I will try again when I get some more kits after the holidays. The two I was turning for my wife and son were my last two that I had in stock.

Another lesson learned tonight -- I did those two pens without the knots as I am running out of time. I turned a stabilized maple burl blank, which also blew up on me. Sharp tool so that wasn't the problem. But what I learned was to keep stopping and checking for gaps as I go. As soon as I see a gap, and ESPECIALLY, if I see the tube, I should stop and fill with sawdust and CA. This method worked for the second burl I did and it came out very nice. I'll chalk them up as freshman mistakes. All part of the learning curve. When my son and I started turning pens, I told him not to stress when we blow one up or make a mistake....it's all part of the process. Thanks all for the good advice.

If you will use a lamp on a flexible neck with a 75 watt or 100 watt light bulb, you can make the epoxy set faster. 5 minute epoxy will fully cure in about 10 minutes. Don't get the pen blanks too hot, or you will weaken them. Experiment!

 

[Drstrangefart]

Thanks for all the good advice. Reading the replies and analyzing my own process, I think my downfall was changing to the medium CA glue. Seems like the consensus for tube gluing is epoxy or Gorilla Glue. From the pens I've turned (again less than 30 as a beginner) it seems CA will generally "get you by" but I have noticed when turning down to the tube for some Comfort style pens, that the piece basically pops off the tube, so not a great hold there.

There seems to be a split in the replies between thick CA and epoxy for gluing the inlay into the blank. Again, I think gap filling is the key here. I will try again when I get some more kits after the holidays. The two I was turning for my wife and son were my last two that I had in stock.

Another lesson learned tonight -- I did those two pens without the knots as I am running out of time. I turned a stabilized maple burl blank, which also blew up on me. Sharp tool so that wasn't the problem. But what I learned was to keep stopping and checking for gaps as I go. As soon as I see a gap, and ESPECIALLY, if I see the tube, I should stop and fill with sawdust and CA. This method worked for the second burl I did and it came out very nice. I'll chalk them up as freshman mistakes. All part of the learning curve. When my son and I started turning pens, I told him not to stress when we blow one up or make a mistake....it's all part of the process. Thanks all for the good advice.

One thing I have encountered that's totally not CA related is getting too aggressive with the tools. Leaning on them too hard, trying to go too fast, etc. If you're unsure of a material, use the touch of a neurosurgeon. Also, try soaking the outside of the softer blanks with thin CA and letting it dry. Soak again halfway through the turning. It stabilizes the wood, and wood too soft WILL fly apart with less than no warning.

 

[Displaced Canadian]

I use thick CA for segmenting I have also found that your surfaces have to be clean of sawdust or the glue will not bond as well as it could. Also on some woods the glue will soak in and you may have to put a second coat on the joint.

 

[Tage]

Allan, Good points on how aggressive you can be on different woods and materials. I think I am finally learning that. Thanks for the tips on stabilizing with CA. You also mentioned shop temperature earlier...mine is a basement shop....pretty chilly this time of year. I'll address that.
Jim, Related to temperature, I'll try your idea with the lamp.

Thank you.

 

[Drstrangefart]

Allan, Good points on how aggressive you can be on different woods and materials. I think I am finally learning that. Thanks for the tips on stabilizing with CA. You also mentioned shop temperature earlier...mine is a basement shop....pretty chilly this time of year. I'll address that.
Jim, Related to temperature, I'll try your idea with the lamp.

Thank you.

Righto! Focus on improving one area at a time. My base/shop/ment gets a space heater for a while before I start working when it gets rock-bottom cold. If you can get your touch down pat on acrylics without sending shards flying everywhere, you can handle most other materials. For me the hardest part is not getting excited when I see a lot of shavings go flying and push for even more. Blown a few up like that.

 

[jttheclockman]

I will throw my 2¢ in here as well if you don't mind. A couple things come to mind. First off not all CA glue is the same and alot of people have better success with different brands. Second the woods you mentioned are oily woods such as the blackwood and the pink ivory and you mix that with a maple. You also have different density in woods such as the maple being more pourous than the blackwood. The CA glue will absorb at different rates. I would first wipe the oily woods down with acetone before gluing. It doesn't matter if you use med or thick CA. I would stay away from thin. If you choose epoxy you will get a telltale glue joint. We are talking about the knot right now. I would not use epoxy unless you were gluing metal to metal. CA is a brittle glue and any sudden jerk like a catch could explode the joint. I would however use epoxy in gluing the tube in. Again for the same reasons as CA being brittle.

Now the knot will have square edges so knock those off before turning so to relive added pressure. Always sharp tools and a soft but firm touch when using turning tools. After turning abit it would not hurt to douce the blank in Thin CA and hit with accelorator. Remember the fumes though. They are brutal.

You mentioned gap filling and I assume you are talking about burls and voids. There you would use thin CA and sawdust to fill. If you have gaps in your tube drilling you need to revisit your method there and that is another problem for another day. Good luck.

 

[fernhills]

Hi, before i discovered 5 min epoxy, i used thick c/a for every thing in gluing pens. After awhile when doing segments, it became a hassle to work with c/a, every thing getting stuck to early,the smell the expense of c/a. If doing wood or wood to acrylics, i use regular titebond ll. When i do acrylics i used c/a. I have not done any segments with 5 min epoxy yet, but i will. It is in my view, that it is a lot less dangerous and more pleasurable when working with a glue that wont hurt you if you happen to inadvertently touch a part of your lip or scratch your forehead I always wait a afternoon or a morning or even the next day before i work it. Carl

 

[paramount Pen]

I always use medium ca and a miter bond pen on one surface. then after i'm through I soak the blank with thin ca and if drilling 10 mm hole and smaller I soak the inside of the blank with thin ca after drilling. If drilling larger than 10 mm hole I encapsulate the blank on all 4 sides with 1/8 inch plywood and lots of medium ca. If working with buffalo horn I drill a 3/4 hole in a 1 1/4 inch sqare block of wood and ca the horn in the block and use plenty of water while drilling, I recently did an apollo with horn, so it was rough drilling a 9/16 hole in 3/4 horn. Oh and I use a small slab of corian with a 90 degree fence along the back and line it with wax paper to do the glue up on. I'll try to post some pics later today.

 

[Tage]

I will throw my 2¢ in here as well if you don't mind. A couple things come to mind. First off not all CA glue is the same and alot of people have better success with different brands. Second the woods you mentioned are oily woods such as the blackwood and the pink ivory and you mix that with a maple. You also have different density in woods such as the maple being more pourous than the blackwood. The CA glue will absorb at different rates. I would first wipe the oily woods down with acetone before gluing. It doesn't matter if you use med or thick CA. I would stay away from thin. If you choose epoxy you will get a telltale glue joint. We are talking about the knot right now. I would not use epoxy unless you were gluing metal to metal. CA is a brittle glue and any sudden jerk like a catch could explode the joint. I would however use epoxy in gluing the tube in. Again for the same reasons as CA being brittle.

Now the knot will have square edges so knock those off before turning so to relive added pressure. Always sharp tools and a soft but firm touch when using turning tools. After turning abit it would not hurt to douce the blank in Thin CA and hit with accelorator. Remember the fumes though. They are brutal.

You mentioned gap filling and I assume you are talking about burls and voids. There you would use thin CA and sawdust to fill. If you have gaps in your tube drilling you need to revisit your method there and that is another problem for another day. Good luck.

I never mind anyone's 2 cents. Good points....as far as variations in various brands of CA glue I had thought about that as well. That's the other changed variable this time. Previously I had purchased PSI's thick and thin glues. Used thick for gluing the tubes and inlay (for one pen) and thin for finishing. I needed more glue and decided I didn't want to place and order for just glue and pay shipping, so I used a local hobby shop's glue (Jet brand?). They didn't have thick, so I got medium. The thin is much thinner than PSI's glue, however, I like it for finishing, I feel I have more control. I'd be open for recommendation on quality CA glues and sources.

As far as filling voids, yes, I was talking about voids in burls. I had much luck filling with CA and sawdust. The CA fumes with the super thin stuff especially, are brutal. I'm thinking about a respirator. ESPECIALLY for my son. I do the CA finishing now because of fumes.

I had wondered about a visible glue joint using epoxy for the inlay. I'll experiment and come up with a system.

To all others, great advice abounds on this site. Thanks for all the input, I'm learning a lot.
Dave

 

[Tage]

I always use medium ca and a miter bond pen on one surface. then after i'm through I soak the blank with thin ca and if drilling 10 mm hole and smaller I soak the inside of the blank with thin ca after drilling. If drilling larger than 10 mm hole I encapsulate the blank on all 4 sides with 1/8 inch plywood and lots of medium ca. If working with buffalo horn I drill a 3/4 hole in a 1 1/4 inch sqare block of wood and ca the horn in the block and use plenty of water while drilling, I recently did an apollo with horn, so it was rough drilling a 9/16 hole in 3/4 horn. Oh and I use a small slab of corian with a 90 degree fence along the back and line it with wax paper to do the glue up on. I'll try to post some pics later today.

I'm sorry, I don't understand what you mean by "a miter bond pen". Can you explain? Using CA as you described to essentially stabilize the inlay makes sense to me.

 

[Drstrangefart]

All of the CA I have used comes from Woodcraft. It's the store brand, and the only issues I've run into have been user error. I may look into the thinner medium, though. Make user error on the finish less likely.

 

[Tage]

Hi, before i discovered 5 min epoxy, i used thick c/a for every thing in gluing pens. After awhile when doing segments, it became a hassle to work with c/a, every thing getting stuck to early,the smell the expense of c/a. If doing wood or wood to acrylics, i use regular titebond ll. When i do acrylics i used c/a. I have not done any segments with 5 min epoxy yet, but i will. It is in my view, that it is a lot less dangerous and more pleasurable when working with a glue that wont hurt you if you happen to inadvertently touch a part of your lip or scratch your forehead I always wait a afternoon or a morning or even the next day before i work it. Carl

Yeah, CA definitely has its downsides. The super thin stuff I've been using for finishing really vaporizes and smells. I was thinking of getting a respirator. I also have it all over my fingers this morning tinted red after filling some gaps in buckeye burl.

 

[Drstrangefart]

Hi, before i discovered 5 min epoxy, i used thick c/a for every thing in gluing pens. After awhile when doing segments, it became a hassle to work with c/a, every thing getting stuck to early,the smell the expense of c/a. If doing wood or wood to acrylics, i use regular titebond ll. When i do acrylics i used c/a. I have not done any segments with 5 min epoxy yet, but i will. It is in my view, that it is a lot less dangerous and more pleasurable when working with a glue that wont hurt you if you happen to inadvertently touch a part of your lip or scratch your forehead I always wait a afternoon or a morning or even the next day before i work it. Carl

Yeah, CA definitely has its downsides. The super thin stuff I've been using for finishing really vaporizes and smells. I was thinking of getting a respirator. I also have it all over my fingers this morning tinted red after filling some gaps in buckeye burl.

You get less and less of that with practice. You can get it off with your razor using an old cratridge and shaving it off like hair under hot running water. It doesn't get ALL of it off, but it's a huge improvement. Feels a little odd the first time. Pure acetone can clean a bit up, and a long shower letting your fingertips go all pruney helps. If you do much manual work, wear leather gloves as much as you can, too. It makes CA disappear after a few hours.

 

[paramount Pen]

Miter bond pen

A miter bond pen is a product that comes with 3 bottles of thick ca and 1 pen that is like a magic marker but contains an accellerant. Google miter bond products. http://www.rockler.com/gallery.cfm?Offerings_ID=25458&TabSelect=Details

I always use medium ca and a miter bond pen on one surface. then after i'm through I soak the blank with thin ca and if drilling 10 mm hole and smaller I soak the inside of the blank with thin ca after drilling. If drilling larger than 10 mm hole I encapsulate the blank on all 4 sides with 1/8 inch plywood and lots of medium ca. If working with buffalo horn I drill a 3/4 hole in a 1 1/4 inch sqare block of wood and ca the horn in the block and use plenty of water while drilling, I recently did an apollo with horn, so it was rough drilling a 9/16 hole in 3/4 horn. Oh and I use a small slab of corian with a 90 degree fence along the back and line it with wax paper to do the glue up on. I'll try to post some pics later today.

Also I use Mannies glue. The cheapest I've found with fast shipping and he's a member of this site. I havn't had any problems yet with his products http://woodenwonderstx.com/WWBlue/NewGlueWS.html


I'm sorry, I don't understand what you mean by "a miter bond pen". Can you explain? Using CA as you described to essentially stabilize the inlay makes sense to me.

 

[Gary Beasley]

I use thick CA on my knots and on the tubes. When glueing a tube in a knot blank I always swab the inside of the knot area with thick CA on a Q-tip to ensure the glue gets where it's needed. Haven't had a blowout since starting that procedure.

 

[ctubbs]

I have tried CA and epoxy from many sources, Tower Hobbies, Hobby Lobby, Wal-Mart, Lowes, Dollar Store, you name it and have found the absolute best quality, price and service from one place, Monty's. His CA is always fresh and constant and his epoxy is as good as any I have tried. Here is his website;
http://woodenwonderstx.com/WWBlue/index.html
Fine print time; I have no financial or personal connection to Monty.
That should make Curtis happy, hehehe. Sorry Curtis.
Anyhow give him a chance the next time you need glue. He is an IAP member and does good work. There are many members that offer quality products for our use.
Thin CA inside the hole to stabilize softer or punky wood, on the outside of the same and burl is almost always a good idea. Apply CA, take a short walk, turn a little, apply CA, walk, turn, apply, walk turn, you get the picture. It works, it is a poor man's stabilizing process. It also works on segmenting like those darn knots.
Charles

 

[Tage]

Thanks all for the responses. I guess it's back to work on the knots. Fred, thanks for the clarification on the miter pen.

 

[uncltodd]

For gluing wood to wood you can't beat plain ole Titebond II. I know it is not as "cool" as using CA in it's various viscosities and it's not fast (best to let it cure over night) but if you don't want the thing to come apart stick with a tried and true method.

 

[fernhills]

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