Bowls On the Loose!!!

Well, glue doesn't dry in the bottle, so no reason why it would dry deep inside the seam.

You mention a paper separator - why? Just glue the blocks directly on, and cut them off with the gouge later.

Also, try a two-part epoxy. It doesn't require water or air to cure.

When I use yellow glue on the lathe, what I end up doing is this: I rub on an even coat of glue using my fingertip. Then I use the tailstock to compress the two parts slightly, and turn one of them (i.e. spinning the glue). I lock the headstock for this. As I turn the wood around, I increase pressure on the tailstock. Between the pressure and the motion, I get most of the excess glue out, and leave a very consistent glue thickness behind. When the glue seems to "stick" and it gets hard to turn the wood any more, I move it to its final orientation (I'm usually gluing up segmented rings) and tighten the tailstock a bit more. I can true rings after an hour of drying, but for a bowl blank I'd remove it after 10 min or so and let it dry the rest of the way overnight.

I would try the Gorilla glue but IMO what you are trying to do is the Achilles heel of glue blocks. Great things if the wood is reasonably dry but if it's wet then I don't trust them. Some people dry the bottom of the bowl blank with a hair dryer first and then get the roughing done quickly. CA glue is also water tolerant in the short term but you might be better with medium CA than the real thin stuff.

Be careful, a flying blank can be very dangerous!!! Make sure you have a faceshield as a minimum and stay out of the line-of-fire until you get a better understanding of what works for you.

billh

I haven't used Gorilla Glue on the lathe, but I have used it for outdoor projects- be advised that while it claims to be able to fill gaps, it "fills" them by turning into a soft foam that doesn't have much holding power. This worked fine for a park bench I built that I carefully hand cut moritses in and clamped in stages, but on another kind of rushed shelving unit I made out of pine, the glue did not hold (the dadoes were about 1/32" too wide, and the shelves did not stick in place very well)

I guess the point it you should be careful to make sure that the mating surfaces match perfectly, and clamp the blank very tightly until it cures.

FWIW, I've also used the Elmer's Polyethylene glue, and for whatever reason, it seems to hold a little better, and is a buck or two cheaper per bottle.

I've also heard a lot about using hot glue on glue blocks.

I've been using glue blocks on a regular basis for many years. I use CA glue, medium visc. When using CA you can mount the piece on the lathe immediately. It works well on wet wood.

When using glue blocks, both surfaces must be flat and true as for any other glue joint. Use plenty of glue. Use a few seconds of hand pressure when applying. No clamps. If you've used enough glue there should be some squeeze-out. If a CA glue joint fails it's nearly always because not enough glue was used. Forget using paper. I part the finished piece off with a parting tool. When parting and the glue joint is smaller than a nickel just pop the piece off with the heel of your hand.

Works for me and it's worked for over 300 students in my classes.

Wally

Check my web site for using hot glue on a glue block. It works a treat but if using it on wet wood, dry the wood with a heat gun first. Also turn the piece immediately. Moisture can wick to the glue surface and ruin the bond. For wet wood I have often used a medium to thick viscosity CA. Put glue on the block, accelerator on the piece and force them together for a minute or so.

Thanks All--Lots of good ideas. Will review what I'm doing and see if I can stop dodging bowl blanks.

Walt C

What's wrong with screwing the bowl to the face plate ??, I had to do that for decades, just turn the screw holes away when done or plug them up, we used to glue felt backing on the foot also.

Of course a little Talon chuck would be helpfull also.

Have fun and take care Leo Van Der Loo

That's "rule" number one - stand out of the throw zone.

Make the best you can with the hand you're dealt. How about _not_ removing the tailstock to begin hollowing, but using it until the bowl is near final thickness and in best balance? Also puts you out of the throw zone, because of the tool angle.

Plunge while rotating, pull back toward the rim. Works on the other side of the gouge in the other direction. The pillar on my stuff is hollow for the pin chuck, but solid with center mark will do as well. If you need more support, taper an opening and use the conical part of your tail center to help with centering and support. Not only are you getting help when you're hogging hard, but if you are going to rough absolutely green and allow to dry, you can leave your center available for later use.

How about _not_ removing

That was before HSS and motors on lathes, right Leo? *g*

Mac

I do a lot of this. I gave up on paper separators for glue blocks on large bowls (anything bigger than 8") years ago, they fail, even if the wood is dry.

no squeeze out sounds like it's not flat. Check with the block dry and look for light through the crack before you glue. Use a hand plane to make them flat, or match curvature. Sometimes even not flat can match well if you rotate the block.

Don't use Gorilla glue for this application. I've had a few large pieces fail with the gorilla glue. previous post about foam is right on. Titebond is the best, but wait several days, even a week if you're concerned about the moist wood.

Epoxy works well. Super glue can work, but super glue has to be done quickly and there may not be time to clamp before it crystallizes, I wouldn't use it for a large bowl.

The more I think about this the less I understand what is happening, a not unusual occurence for me. If you are roughing the bowl why are you using a glue block at all? Either there should be enough scrap at the bottom of the piece for a faceplate or certainly enough for a spur center. I rough entirely between centers, exterior and interior. If you are finsihing the bowl green and letting it warp this is a different matter. In that case I would rough between centers using a face plate at the base and remove the tenon with large jaws, a jam chuck or other means, The chances of flight are minimal to say the least. (The tenon "could" split.) Occasionally I have turned a hollow form from green wood when the screws for a face plate would remove too much of the piece. In that case I heat the bottom of the piece with a heat gun to dry it and use hot glue. I have also used CA with equally good results.Make sure the surfaces are flat and dry.

Hi Mack

No the HSS has been around a little longer, but lathes without motors was still the norm, when I was a boy, overhead drive shafts with idler pulleys and wide leather or canvas belts would drive lathes, drills, grinders and forging hammers etc.

Wood turning has changed more in the last 30 or 40 years than in the preceeding 3000 years I would think.

And some of the ways of holding the wood are still very good and safe ways of doing that, there might be better or easier and quicker ways, if you have the tools and equipment, but screwing blanks and rough turnings to face plates is still a very viable way of doing that.

With big bowls and wet wood there is usually enough extra wood to use screws for holding, 6 or 8 screws, 1/2" deep in sound wood is all thats needed, and I have used 1/4" depth successful on rough turned bowls enough times, when I needed to use screws on thinner bowl and platters.

I certainly trust screws more so than glue, but that might be just me.

Have fun and take care Leo Van Der Loo

All this discussion of adhesives got me thinking: would properly applied contact adhesives work for this? Or are they too susceptible to releasing under stress?

Max

Me, too... I know that glue has really improved in the last decade, but I'd rather use good screws....

This thread reminded me of a club demo a while ago on the skew... the guy doing the demo was a retired shop instructor and when he needed a "steady rest" for a spindle turning he used a solid piece of hardwood with a curve cut in it... that's old school!

Mac

there should

for a spur

l.vanderloo wrote:

You guys sure are quick to suggest other people waste their wood! I don't usually screw into the wood because I want to make them as large as possible. Waste not, Want not.

Mark,

Mount the wood with the side that will become the top of the bowl, on a face plate. Then your initial turning will be to shape the outside and add a tenon or recess for the chuck. Screw holes on the top of the bowl do not matter since they will be removed when the bowl is hollowed.

BTW, in spite of the face plate, bring the live center in contact with the blank. It will add a bit to the overall holding power and will leave a center mark that should be useful when rechucking the piece.

Harry

You make a good point, but why use the faceplate at all, glue block or no if you have a chuck? It's pretty easy to turn a tenon between centers and part off. Or it that something a guy has to do with one of those stubby bowl lathes? (I don't have one, and haven't looked at them closely)

Just curious.

I rarely use a faceplate. I mount the blank between centers. It is easier to get it balanced that way and that is the way we learned in the David Ellsworth workshop. I rough turn the outside and create the tenon this way. Then reverse it in a chuck to do the inside. With green wood and a really rough piece of wood, the drive center cuts into the wood and the tailstock needs to be tightened regularly. On the bright side, the drive center does some of the hollowing for you! And, with both centers dug into the wood, there is little chance of the blank coming off the lathe.

Harry