Hide Glue Pot assistance sought

[Acorn]

A while ago, I purchased an old, rusty cast iron (steel?) hide glue pot. I plan to put it into service as a hide glue heater. I removed all of the rust from all surfaces and treated the externals to a coat of high temp manifold paint as a rust retardant. The inside of the inner pot is now pretty pristine metal. Any thoughts on keeping rust out of the inner part? Should I coat it, if so, with what? Should I just put hide glue in and hope for the best?

I've heard of "tinning" the interior (coat of solder?) Is that best?

Any thoughts welcome.

[Chuck Nickerson]

I hope someone answers. I've got three small pots awaiting the same treatment.

[Mr Eddie]

I wouldn't put hide glue in it. Use it as a double boiler - put water in the pot and glue in a bottle. Put the bottle in the pot. That's how most of the people I know do it. Much easier to clean up and makes it simple to keep leftover glue. Put the lid on and put it in the fridge.

Lonnie

[Rob Young]

Mr Eddie said:

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I wouldn't put hide glue in it. Use it as a double boiler - put water in the pot and glue in a bottle. Put the bottle in the pot. That's how most of the people I know do it. Much easier to clean up and makes it simple to keep leftover glue. Put the lid on and put it in the fridge.

Lonnie

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This. Also lets you put a lid on the glue when done and store in fridge.

[Monsieur Medlar]

The old pots I have used that actually held the glue were aluminum, heavy cast aluminum. But they must have used steel before that. I use the aluminum pot in a crockpot with water. Its a pain to clean because the aluminum is all rough after years of cleaning out hard glue I suppose.
Toby

[kwigly]

There doesn't seem to be any surface coatings on any of my old cast iron glue pots, just rusty pitted iron.


Lee Valley's version is in stainless steel http://www.leevalley.com/en/wood/page.aspx?cat=1,110,42965&p=74043

[AHill]

I'm going to guess that if the pot itself is cast iron or steel, any coating would have been to prevent rust. Given the pot is usually filled with or sitting in warm water, that would make sense. It would also explain why more modern glue pots are made from non-corrosive materials e.g. aluminum, copper, ceramic or stainless steel. Heavy cast aluminum for the heating part makes sense because aluminum is a better heat conductor than cast iron (like 2.6x better). Aluminum was darned expensive compared to steel when it was first starting to be used, so an aluminum outer pot is either modern or was a luxury.

[Acorn]

The pot in question I believe was indeed a hide glue pot. The outer pot is, I believe, cast iron as is the inner.

Cast iron will hold heat much longer than aluminum and probably was used for that reason in some of these. Typically boiling water is poured into the bottom to heat the glue. I understand that about 140 degrees F was the temperature needed so boiling water may cool down that much when in a heavy iron enclosure. Most of these that I've come across are heavily rusted like the three shown above. Perhaps they were so cheap that it didn't matter if they rusted out. Still I'm perplexed as to whether any lining is needed on the inner pot to prevent rusting. It may be that the glue is the "coating" that prevents rust.

[Bob Rozaieski]

Old glue pots were mostly made of cast iron, but were also sometimes made of copper or tin. I've never seen one made of aluminum.

The cast iron double boilers had the inside surfaces of the inner pot tinned. This kept the inner pot from rusting but more importantly it kept the glue from discoloring. Putting glue into a pot that has lost its tinning won't likely hurt the strength of the glue, but it makes it turn very dark, in some cases, almost black. The tin coating keeps this from happening.

[Acorn]

I asked Steve Hay (Australian woodworker with a youtube series called woodworking masterclass) and here is his reply.

Hi David,

You will find if you use the Glue Pot a lot rust is not a problem.

I definitely wouldn’t put any sort of coating in the inside of the inner pot as it will contaminate the glue.



The only thing I do differently to our predecessors is I use a small amount of Radiator inhibitor in the outer

pot that way rust never forms and I seldom need to change the water.



Hope you enjoy using the hide glue. I much prefer it over any other form of adhesive although from time to time I must admit I’m thankful to

have the odd tube of Super Glue and Bottle of PVA around.





Cheers



Steve

(I thought the idea of radiator inhibitor a good one.)