Hi.

Those seals in medieval and later documents, is it 'wax'?   Seen them in liquor bottles also. They are hard as rock.  Anyone knows how to prepare a small amount for obtaining a relief pattern to yield a negative ?  Should be not sticky and dry hard.  Or any other plasticky modern material.

-Image borrowed from the web.-

It's called sealing wax. Available in craft stores and on the web.

I think some of the bottling material is not actually wax, or there are additives to it.

 

19 minutes ago, Externet said:

Hi.

Those seals in medieval and later documents, is it 'wax'?   Seen them in liquor bottles also. They are hard as rock.  Anyone knows how to prepare a small amount for obtaining a relief pattern to yield a negative ?  Should be not sticky and dry hard.  Or any other plasticky modern material.

-Image borrowed from the web.-

This is called "sealing wax". Details of composition etc here : https://en.wikipedia.org/wiki/Sealing_wax

You can buy sticks of it. But I wouldn't use it to take an impression, because to do its job of sealing it has to stick to things, obviously.

41 minutes ago, Externet said:

Anyone knows how to prepare a small amount for obtaining a relief pattern to yield a negative ?  Should be not sticky and dry hard.

Childrens' modeling clay would do it, and probably cheaper than sealing wax. Candle wax, or paraffin for sealing preserves might be just as good.

2 hours ago, Externet said:

Anyone knows how to prepare a small amount for obtaining a relief pattern to yield a negative ?  Should be not sticky and dry hard.  Or any other plasticky modern material.

One trick I learned with silicone caulk (very sticky but soft when dry) is to use an ammonia-free glass cleaner on the area I DON'T want the silicone to stick to. I spray my tools and fingers too. I wonder if the same trick would work on the item you want to take an impression of, and make your wax easy to remove? 

Thanks, gentlemen.  The word "wax" does not play well with its characteristics.

Will check if the "sealing wax" product available at a nearby "Hobby Lobby" store is hard enough when dry/set and not too sticky when applied as to allow release.

---> https://www.hobbylobby.com/Scrapbook-Paper-Crafts/Card-Making/Wax-Seals/Glue-Gun-Sealing-Wax/p/WS7812

48 minutes ago, Phi for All said:

I wonder if the same trick would work on the item you want to take an impression of, and make your wax easy to remove? 

If not, they make release agents for use with epoxy. Suspect it would work here too since epoxy sticks to everything 

Or, if the mold material is acrylic, cooking spray.

Of course, now I have to wonder, given the fancy crest 'n' all, what it is you need an imprint of. I had an acquaintance one who carved European family crests into gem stones for seal rings.

Edited September 30, 20214 yr by Peterkin

The avatar has nothing to do with it. 😱

 Trying to make a coupling disc from CGA870 to CGA850 valves to fill high pressure cylinders.  The double sided impression resulting "coin" to be given to a machinist to be replicated in metal.

Tried other way with blueprints, and they give up or break my tooling, or claim not to have the proper equipment.

52 minutes ago, Externet said:

The avatar has nothing to do with it. 😱

 Trying to make a coupling disc from CGA870 to CGA850 valves to fill high pressure cylinders.  The double sided impression resulting "coin" to be given to a machinist to be replicated in metal.

Tried other way with blueprints, and they give up or break my tooling, or claim not to have the proper equipment.

Some kind of epoxy or resin might achieve this. Soft (possibly liquid) until it’s cured. Probably ends up harder than sealing wax

Probably not the answer you're looking for, but why not cut a cga850 and a cga870 adaptor and have them welded by the machine shop. 
( I don't think an adaptor is available commercially )

Any coupling disc you have made will more than likely leak, and will still need to be replaced every couple of fills.
For filling hi-pressure, hi-purity Phosphine we only use coupling discs once at our plant.
Then again, you don't really want 600-700 psi Phosphine leaking; Oxygen may be different.

2 hours ago, Externet said:

The avatar has nothing to do with it. 😱

 Trying to make a coupling disc from CGA870 to CGA850 valves to fill high pressure cylinders.  The double sided impression resulting "coin" to be given to a machinist to be replicated in metal.

Just a mental association. When I saw sealing wax, I thought of those rings and seals with intricate designs that would require a very fine material for a good imprint. I'm still going with the modelling clay as best option. You can easily cut it into sections, if need be.

Thanks, MigL. The intention is to be able to fill and empty cylinders with CGGA870 from a CGA850 terminated hose. Cannot rely on someone doing a 4000+psi safe welding.

Thinking now on disemboweling/machining threads to the pertinent section of a CGA870 regulator (green) and buying a spare CGA850 valve to join them and achieve your suggestion.  Will explore the safety of that; would be a clumsy bulky contraption.

Edited September 30, 20214 yr by Externet

2 hours ago, Externet said:

 Trying to make a coupling disc from CGA870 to CGA850 valves to fill high pressure cylinders. 

I once got asked to analyse the stuff found on the inside of a burst gas cylinder.
They were trying to work out what had happened.
There had been a witness- very very briefly- but he wasn't telling us anything anymore.
 

(re)filling high pressure cylinders isn't as easy as people thing.

It's also often illegal.

This is not the sort of thing to do with "string and sealing wax" as the phrase goes

https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10309/1030908/Whatever-happened-to-the-string-and-sealing-wax/10.1117/12.2283713.short?SSO=1

Edited September 30, 20214 yr by John Cuthber