Glue block question

[Dave Cullen]

I'm a spindle turner about to enter the vortex of bowls. I've read about glue blocks and I'm wondering what kind of paper and glue to use. Craft paper and CA gel? Copier paper and yellow glue?

... or does it matter? Just don't want to get hit in the head with my first bowl blank.

[mike ash]

When I use a glue block, I glue it directly on to the bottom of the bowl with wood glue and when the inside and outside are to shape and sanded, I reverse the bowl via a jam chuck or even pressing against a flat mounted disk at the head stock end(meaning the the tail stock is against the glue block) and turn it off except for a very small nub where the tail stock is pressing against. The nub is easily sanded away. This process allows me to shape the underside of the bowl to whatever design I want.

Hope this helps.

[John Keeton]

I do as Mike describes, and I use 5 minute epoxy, unless I am at the end of the day. If that is the case, then Titebond overnite. No paper in the joint.

[Robert Henrickson]

Yet another doing as described by Mike and John, though I simply use Titebond only and leave it overnight. So far I have not used paper in any glue joint. I very rarely use CA for any purpose anymore -- the fumes are too noxious for me -- but never used it for attaching glue blocks even when I used it more often.

[Dale Gillaspy]

The problem with CA in this instance is that it is brittle, and doesn't withstand lateral loads well. One good catch and your bowl could become a projectile. I'm with John and the other thoughts….No paper, and epoxy or Titebond. I use Titebond II, but I think the original would work fine as well. The only thing I would add is that your surfaces need to be flat and oil/solvent free to give the glue a good surface to bond to.

[John Keeton]

I would add that I use Vince's 1" back up pad (http://vinceswoodnwonders.com/back-up-pads/) in my Jacobs chuck to sand off the nub on the bottom, using an 80 grit disc. Just put the drill chuck in the headstock spindle, at relatively low speed, and hold the nub against the sanding pad. I make all my bottoms a bit concave, and that works well with this method. Then, just sand the bottom by hand starting with 150.

Sorry for the fuzzy pic - it is from Vince's site and I didn't realize the pic quality until I uploaded it! But, you get the idea.

[Thomas Canfield]

I will add that my glue blocks are made from solid lumber (poplar, yellow pine, etc) depending on size of piece. I try to have grain in same orientation as block and consider it a "waste glue block" and turn it completely off down to the nub discuss earlier. A friend uses a lot of end grain small limbs, trunks, etc for end grain glue blocks. I do not use glue blocks on green wood due to shrinkage potential problems if rough turning.

[Lee Koepke]

I will add that my glue blocks are made from solid lumber (poplar, yellow pine, etc) depending on size of piece. I try to have grain in same orientation as block and consider it a "waste glue block" and turn it completely off down to the nub discuss earlier. A friend uses a lot of end grain small limbs, trunks, etc for end grain glue blocks. I do not use glue blocks on green wood due to shrinkage potential problems if rough turning.I tend to keep things I never need, and I have a box full of 'plugs' from using my hole saw bits. they are round, generally 3/4" thick, and have the pilot hole in the middle for lining up the tailstock to remove the glue block when I flip the bowl over.

[Dennis Ford]

+1 on gluing block directly to bowl blank with Titebond (allow to cure overnight) IF the bowl blank is dry.
For wet blanks that need a glue block (rare for me), I use Gorilla glue. It is not as strong as Titebond and dry wood but will work. CA glue will also work on wet wood but be sure to use fresh glue (old CA glue may result in flying bowl syndrome).
If you feel that a paper joint is needed for some reason; use craft paper and yellow glue with a fairly large surface area AND BE CAREFUL.

[robert baccus]

Roger that on Ford's comments. I would add that woodglues must have clamping pressure and are not gap filling or wet wood tolerant. Have used CA on 100#+ green vase blanks with no troubles. Dry wood is rare in my shop? Also use really strong woods for GB---no scraps.

[Dave Cullen]

Thanks for the replies. A waste block without the paper interface then it will be. I'm suprised nobody uses the paper trick, it seems to be popular at least in the books.

[Robert Henrickson]

Thanks for the replies. A waste block without the paper interface then it will be. I'm suprised nobody uses the paper trick, it seems to be popular at least in the books.

If you use the paper trick, you can remove the waste block entirely. But in the case of, for example, a bowl bottom, you are then faced with the problem of centering the bowl to finish its base in whatever profile you might choose. I find it easier to leave the block/tenon in place and simply turn it away, as this maintains the centering of the item to the end.

If, however, I were doing a split turning, I might well use the paper trick. So far I have not done any split turning which might benefit from that approach.

[Dave Cullen]

If you use the paper trick, you can remove the waste block entirely. But in the case of, for example, a bowl bottom, you are then faced with the problem of centering the bowl to finish its base in whatever profile you might choose. I find it easier to leave the block/tenon in place and simply turn it away, as this maintains the centering of the item to the end.

If, however, I were doing a split turning, I might well use the paper trick. So far I have not done any split turning which might benefit from that approach.

Understood. It was my intention to use a faceplate and turn the outside and bottom, then mount a glue block and chuck it up do do the inside. Afterward the block gets peeled off and the residue scraped or sanded away. I figured that if the block is smaller than any details in the bowl foot the bottom wouldn't need anything more. Is that logical?

[robert baccus]

Dave, for removing glueblocks & thick CA you can knock off small ones with a putty knife. Larger GB I simply part off down to 1/2" and saw off. After turning around, a sharp small detail or bowl gouge will cut the bottom clean. I use a 1/4" point on the tail stock end and an internal or external friction drive on the headstock. The 1/4" nubbin is your problem. Using GB's, paper and wood glues were popular 25 years ago before CA use became common.

[Jon Finch]

What are folk's opinion on hot glue in this application?

[charlie knighton]

only use hot glue if you are going to use at least 2 screws 1/4 inch into blank, i use this method with multi-axis turnings on large piece of mdf where i hot glue just around the edges of blank and to the mdf, but always use 2 screws with hot glue

[John Keeton]

What are folk's opinion on hot glue in this application?Others may differ, and I respect their opinion, but I would not use hot glue for anything other than to secure a very small and lightweight piece for some detailing. I would not use hot glue for a waste block to fully turn a piece.

[Peter Blair]

I use all the above, including hot glue and have never had a failure. Hot glue does let me 'get to it' a lot faster than Titebond.

[Scott Hackler]

:) Ask Malcolm Tibbets on how long he waits from gluing a ring on to putting a tool to the wood! It is surprisingly NOT very long. Titebond bonds a lot quicker than most folks know.

Having said that, and knowing the forces on a piece of wood while hollowing, I still clamp and let sit overnight or longer a wood to wood glue block, with Titebond II.

NEVER EVER would I ever use CA glue for a glue block. The shear strength is terrible for CA glue and while you might get away with it for a while, but someday your gonna be dodging a chunk of wood. I wouldn't use hot glue either, just because I don't trust it's bonding ability for turning.

[Tim Leiter]

+1 to what John and Scott said. I wouldn't trust the CA or the Hot Melt Glue either. I don't believe they were designed for that application and you would be taking a big chance on getting hurt and ruining your blank. JMHO........................Tim.

[Jon Finch]

Thanks for the hot glue advice! I was wondering if I just didn't use it properly based on my last experience using it. The piece didn't fly off, but I was able to release it from the glue block when there was, at least to my eyes, still plenty of glue area.

[Dennis Ford]

Mr Baccus uses CA glue on glue-blocks all the time, it can work. I have used hot glue on occasion BUT only when there was a large glue surface area (such as a platter). The trick to hot glue is temperature, the bond must be made while the glue is hot (it cools very quickly when applied to a cool surface). I have trouble recommending either CA or hot glue for beginners but will continue to select from; Titebond, CA, Gorilla glue, hot glue & double sided tape. The choice is a judgement call based on wood type, moisture content, size / shape of blank & time available.

[Ron Page]

I only see one post referring to using glue blocks for end-grain turning. Is this done with any regularity? End grain joints are the weakest joint I know of and I'd be concerned about flying wood. That said, I remember some articles about Gorilla glue that said it worked good on end grain because it expanded into the end fibers.

Way back in the 70's, when I was teaching high school woodworking, we regularly added paper between the glue block and bowl - but I didn't let the kids do this with end-grain. Usually the glue was yellow carpenters glue and the paper was a textbook cover (basically craft paper). Worked great.

Guess this is my first post. Been lurking and absorbing as much of the knowledge here as possible as I try to expand my time with the wood lathe. This forum has become one of my nightly cruises.

[James Combs]

I only see one post referring to using glue blocks for end-grain turning. Is this done with any regularity? End grain joints are the weakest joint I know of and I'd be concerned about flying wood. That said, I remember some articles about Gorilla glue that said it worked good on end grain because it expanded into the end fibers.

Way back in the 70's, when I was teaching high school woodworking, we regularly added paper between the glue block and bowl - but I didn't let the kids do this with end-grain. Usually the glue was yellow carpenters glue and the paper was a textbook cover (basically craft paper). Worked great.

Guess this is my first post. Been lurking and absorbing as much of the knowledge here as possible as I try to expand my time with the wood lathe. This forum has become one of my nightly cruises.
Welcome to the creek Ron. How about starting a thread and telling us about yourself.

[James Combs]

I understand the OP's question but don't see anyone mentioning not using a glue block at all. I tried a couple glue blocks back when I started turning in 2009 but didn't really care for it especially after I found that turning a short(1/8"-1/4") tenon on my blank between centers then using a chuck was so much faster. A tenon is all I use now and have never looked back. I believe there are some that use the inverse(aka recess) and I can see where it would be similar speedy but I don't trust expanding in a recess. For end-grain turning there is nothing better(safer) IMHO then a tenon clamped in a chuck. Yes you loose a little of your blank, the 1/8" to 1/4", but to me it is insignificant. As to trimming off the tenon(or the recess) I will do it as mentioned by several posts above if the wood has voids or holes, but as long as I have wood without voids I will reverse chuck my project with a vacuum chuck.

[robert baccus]

Glues like any line of products have their funny characteristics that must be addressed. Wood glues are great but have very limited strength on endgrain hold. Non on wet wood and require clamping for good strength. Ca is often criticized for strength but I assure you it is very strong--it doesn't like a shock load. I often knock off small glueblocks with a hammer/putty knife but only to about 2" dia. I've tried larger ones with big tools and forget that. I have turned 50+ long vases of 100-130# with a 3.5" glueblock and thick CA. This with fresh cut wet soft woods such as SG and willow. I've knocked vases in half and busted bowls but never with did the CA fail.. I think the failures with CA come from too little glue, untrue glue surfaces or old glue. Try a 1 minute test is your glue is in question. Also forget poplar and scrap wood for GB. For heavy pieces I use dogwood. beech or. elm in 2" thicknesses. With good hard GB's I use a small faceplate or the standard 5/8" nova single screw. It is very difficult to hold the base of wet weak woods with any other method--takes a lot of screws to hold wet endgrain and I lost several of these years ago. PS gorilla glue was the lowest rated glue in a fine woodworking test of 6 popular glues. Hot glues are fine for small pieces but the process is easy to screw up.. Ca is strong enough for tool inserts and industrial applications. Ca does seem to fail at 20 years of age so I would avoid segmented pieces for sure. On the plus side it requires no clamping pressure and is gap filling. It shares this with epoxy glue.

[robert baccus]

The problem with wood glues is that it holds crappy on end grain and non on wet woods. I usually turn local green pieces which may take years to dry. Do a quick test with 2 cylinders glued both ways. Fresh data beats opinion every time.

[robert baccus]

I have done a thousand with CA but then I don't sniff mine either. Gives me a hangover everytime.

[Dave Cullen]

My original question stemmed from not wanting to lose the wood thickness of a proper tenon, and not having the means to reverse the bowl to remove a tenon or permanent glue block. The paper interface is shown in all the turning books, and I'm suprised so few have used them. I think on end grain I'd opt for a different solution but for a small side grain bowl I'm willing to give it a whirl.

[Peter Blair]

Hey Dave.
When I started tuning, lots of years ago I used paper and a glue block but I soon found that it was really difficult to finish the bottom unless of course you can reverse chuck it as has been suggested above. What I was doing in those days to save a lot of time and trouble was I would split the glue block off then glue on a piece of felt to the bottom . . . this is a practice that I no longer think is suitable for most of the things I make.
What ever you decide to do, good luck.

[Leo Van Der Loo]

I hardly ever use a tenon, most times a recess, however if the piece is thinner and I like to keep all there is (though 1/8" is not really much to loose, and enough for dry sound wood) I have used hot glue and CA as well, works just fine,However with hot glue, the wood has to be dry and the glue-gun hot, I would then also use my propane torch and heat the glue-block and the bottom this would assure a good glue-line and a strong bond, however it is too much of a hassle IMO and so it is either CA glue or a very shallow recess.Like everything else, you have to do it right, and if you don't trust it, there are always other ways of doing it, haste is a bad habit that will bite you in the (a*s) end

[robert baccus]

You obviously speak from experience and not opinion Mr Loo. Good words and a good practice for posters yeah.