which one method?

[GEPPETTO]

Hi All,

Yesterday I was at the point to glue plywood sides at an old furniture composed in a poplar frame with plywood stuck over.
The glue chosen was hide glue.
I prepared the glue in the normal way: it was soaked over the night and warmed until 140 °F.
When I brushed all the frame, I seen that glue was just gelling.
However I ended to brush the frame and after I put the plywood panel(50cmx160cm) when the glue was almost cooled.
I re-actived the glue with a warm iron passed on the plywood.

Do you think it's the correct procedure when we glue an an extended surface or not?

 

[Chris Knight]

Gabriele,

It sounds basically fine but of course, depending how thick the plywood is and how large an area it is, it may be difficult to reactivate the glue uniformly. for a large area it is useful to have a hot air gun available too, I find this a bit easier on large flat surfaces. You will still need the iron of course to apply pressure.

You can also extend the gelling time with urea or salt.

It is not good to get the glue too hot but for a non-structural piece I am happy to overheat the glue somewhat too. I get it hot enough to run like water off the brush. Don't reuse glue that you have heated this way though, it will lose strength if heated too much too often.

 

[GEPPETTO]

Gabriele,...
You can also extend the gelling time with urea or salt.

Hi Waterhead37,

my plywood was 3 mm and the furniture frame was achieved (is achieved) with rails of 4 cm. Therefore it was not difficult to reactivate the glue.

You say:"You can also extend the gelling time with urea or salt."
Please, how much urea and salt(kitchen salt??) and how much time it extends the time? :?

Many, many thanks for advices.

 

[Chris Knight]

Gabriele,

If using salt about 1/2 to one tablespoonful per cup of dry glue (2 to 5% by weight) will extend the time by several minutes. If you add more(up to 20% by weight) you can make a liquid hide glue (ie it stays liquid like the stuff you can buy from Titebond but I don't use it like that).

Another thing you can do is to warm the work before applying the glue.

 

[GEPPETTO]

Gabriele,

If using salt about 1/2 to one tablespoonful per cup of dry glue (2 to 5% by weight) will extend the time by several minutes. If you add more(up to 20% by weight) you can make a liquid hide glue (ie it stays liquid like the stuff you can buy from Titebond but I don't use it like that).

Another thing you can do is to warm the work before applying the glue.

re- thanks :wink:

 

[Barry Burgess]

Gabriele,...
You can also extend the gelling time with urea or salt.

my plywood was 3 mm and the furniture frame was achieved (is achieved) with rails of 4 cm. Therefore it was not difficult to reactivate the glue.

I was just about to glue 3mm plywood(large) to MDF and was going to use contact adhesive. What is this glue and would it be better to use?/
Thanks
Barry

 

[Chris Knight]

Barry,

Hide glue is one of the many forms of animal protein that goes by a hundred names like Scotch glue, pearl glue, etc. There are differences between the types but none that need concern us here.

Animal glue was the only kind anyone used in the past but modern glues have largely displaced it except for specialist users like restorers and instrument makers. It is reversible with heat and moisture which is why restorers use it and it provides a very strong, rigid glue line which is why instrument makers like it. However, it is a bit of a hassle to use for everyday purposes and is unlikely to be better than contact cement for your purpose.

If you Google for it, you will find dozens of treatises on its use. I use it a fair bit but only for particular jobs - usually veneering and attaching beading to furniture.