Investment Plaster, is there another name for it?

[Little fish 2]

Hello there,
I am new to the forums and thought I would start by asking if anyone knew if this is called something else as I can't seem to find anything in this country with this title.
I would like to make a mould for a silver framework / basket so it can be soldered, but obviously I need the plaster?
And lastly, after looking in Cookson and typing in different searches, nothing appears that resembles a plaster substance for jewellers to use, my hunch is there is a substance, but the name is different.
I hope someone can help, thank you.
Jenny

[ps_bond]

https://www.hswalsh.com/categories/investment-powders

HTH

[Little fish 2]

Hello,
Thank you for that link, most helpful.
Jenny

[Dennis]

Or if you want a smaller amount to try out, Sutton tools have some:

http://www.suttontools.co.uk/catalogsearch/result/?q=caasting+investment+&x=23&y=12

[Little fish 2]

Hello,
Thank you Dennis, I did think a 22.5kg sack was rather a large quantity and the price a bit costly, I suppose the large quantity is for workshops with a lot of people in.
I actually tried Sutton tools just on the off chance, but wasn't sure as the description is a bit limited and no image.
Thank you both for your help.

[Patstone]

Another Devon jeweller, whereabouts are you then. Love to have a look and see what you make, what is Investment plaster, is it stuff you make a mould with, just guessing.

[Dennis]

Hi Pat. Investment, is plaster of Paris with additives, so that when set and dried it will withstand heating to casting temperatures without cracking.

It can be used for making moulds, using the lost wax process, or a resin which will burn out, or even organic things like flies.
Special investments will have compensation for the shrinking of metal when they cool.
It can also be used in various ways for holding pieces of metal firmly in place for soldering. Dennis.

[Patstone]

Quite useful stuff then. Not having much luck with the melting of scrap (back to a previous conversation,) it kept flaking bits off. Certainly couldn't make a ring with it.

[josef1]

I may of read the question wrong ? Do you require a substance to hold the parts while you solder them ? If so I would say the its not investment that you need that's for casting objects after firing in a kiln, I'm not saying it cant be done just never heard of it been used like this before, its like cream when correctly mixed ? so I don't see how you could put the parts in it to hold ? Soldering commonly done by binding with wire or holding in a third hand unless I'm missing a trick !!! Its also nasty stuff it contains silica you need a good quality mask when mixing it

[ps_bond]

Yeah, you can use it that way - embed the parts in the plaster so the bits you want to solder stick out.

http://www.ganoksin.com/borisat/nenam/soldering-jig.htm

Tack welding works too.

[ShinyLauren]

Oooh, that's clever about the soldering. Wouldn't have thought to use it that way!

Might have a go with that (until I can afford the PUK for tack welds of course Peter!)

[Dennis]

Toxic or not, investment soldering is as old as the hills. Older than me at any rate.

A short cut is to use Technoflux, a heat protecting paste. Squidge some onto your block from the tube and it can be used straight away.

It is stiff enough to hold wire and components in contact for soldering, provided enough metal projects for heating it to soldering temperature. Dennis.

[josef1]

Thats great you learn something everyday thanks !

[Patstone]

Is that the same constituency as Thermogel, because that is quite wet. Good idea, I am forever having trouble holding wire etc still, then of course with my sight problem in one eye, or rather lack of it, I push it to get it a better fit and mess it up and have to re-position it again. It is quite testing at times.

[Dennis]

Yes similar Pat and if you have it you can try a blob of that.

I prefer Technoflux, because it is easier to dispense, is a little stiffer and forms a crust when heated. http://www.cooksongold.com/Jewellery-Tools/Technoflux-Heat-Insulating-Paste---120ml-prcode-999-AAH

[Patstone]

I will give it a try next time I have a Cookies order. Thanks.