glue blocks

[mat_au]

so i know lots of ppl use this method, and i want to try it. just wondering how safe is it and what are the do's and don't s

[brendan stemp]

A bit vague as to what exactly you want to do but generally speaking, if done properly, glueing work to a scrap block is a lot safer than holding the same piece in a chuck.

As an example I am presently doing a 500mm diam redgum bowl and, after roughing out the outside shape, (using a faceplate to hold blank onto lathe) I turned it around and glued it onto a piece of pine with some pva glue. Many years ago (with Vic Wood) we even had pieces 1000mm in diam attached to the lathe in the same way. It is all about using basic timber glueing principles, so, if the join was sloppy and I tried to use pva, then I would be courting disaster. Snug joins and some pressure to hold the pieces together while the glue is drying is essential. I used the tail stock to provide the pressure.

A lot use hot melt glue which is also very good. The problems arise when the glue cools down too much before the two pieces being joined are brought together. I use a hot air gun on the glue, especially on big surfaces, when using hot melt glue. Otherwise make sure your glue gun has had plenty of time to heat up to its max before squeezing out the glue.

Hope this helps.

[mat_au]

yeah sorry didnt really put much info in the post. was looking at trying hot glue for my bowl turning and hollow forms just been told it can be better than a chuck but just wanted to get some infor on it first

[Hermit]

yeah sorry didnt really put much info in the post. was looking at trying hot glue for my bowl turning and hollow forms just been told it can be better than a chuck but just wanted to get some infor on it first

Just don't use hot melt glue on wet/green timber. It won't hold. And for a gun, it's worth buying a decent high-powered one, (100W, 120W), not a 20W eBay cheapie. Faster heating, if nothing else. (I bought a 120W Stanley.)
And apparently 11mm glue sticks are better than 7mm because of the higher flow rate. You can get the job done more easily while the glue is still liquid.

[powderpost]

I use the waste glue block regularly because I like to determine the size of the base and not be dictated to by a chuck. I make sure that the two surfaces are flat and apply an even coat of glue. I use external aquadhere because it dries harder than standard aquadhere. The standard aquadhere is quite satisfactory. Give the glue time to dry properly, this is why many people use chucks, much quicker. I always cut the job off the waste block with a hand saw. I used to use a parting tool for this, but seeing a nice bowl reduced to numerous bits on the floor from a spinning lathe, does not induce rational or placid behavior.

Jim

[aussiepens]

I use glue blocks occasionally but with a piece of newspaper in between. When finished turning you can soak in water and the two parts will prize apart much easier than if glued wood to wood.

John

[powderpost]

I use glue blocks occasionally but with a piece of newspaper in between. When finished turning you can soak in water and the two parts will prize apart much easier than if glued wood to wood.

John

I used this system once and once only. On that occasion, the glue joint parted at the exact wrong moment causing me extreme consternation. The paper insert makes for a very weak joint, and I certainly would not soak a project in water. I would not recommend this system, it is dangerous.
Jim

[Mobyturns]

The size of the waste glue block still has too be appropriately sized for the load placed upon it. So does the screws through the faceplate into a waste block / or the waste blocks tennon size if used in a chuck. I use PVA (Titebond I or II, AVXL Plus, Aquadhere etc), hot melt glue (Bostick) and even epoxy depending upon the load, and how I wish to reduce the waste block during the turning process.

Be very cautious with hot melt glue if you wish to remove a lot of the waste block during the turning process for three reasons -

1. you can inadvertently transfer enough heat into the glue to soften it enough to fail when the glue interface becomes smaller in diametre;
2. it often forms voids of air especially near the centre if you do not place the "hot melt glue lines" so that air escapes fully when the joint is made;
3. joints still need to be well formed - if the glue joint is wide there is a higher risk of failure.

Brendon Stemps demo on the use of holt melt to hold his multi axis pieces is well worth seeing if you get a chance.

[steamingbill]

Hello,

This is kind of related and might be of interest to some.

This chap cuts a morse taper onto a piece of hardwood, leaves a big chunk at the end, and then can use that chunk to make a jam chuck or a mandrel or a socket or a glue chuck.

This could be useful if you havent got a heap of chucks and faceplates etc.

http://www.woodturner.org/community/youth/projects/morsetaper_1.pdf

The morse taper on the wood fits into the morse taper on your headstock.

Anybody ever tried this ? Might not grip well and rotate inside the taper when you apply the chisel ?

Haven't got a morse socket otherwise I'd give it a shot.

Bill