Soldering Grain

[arian]

I tried to post this just as the website crumbled (I take full responsibility :) ), so in the meantime I asked elsewhere. Apologies if you've seen it before.

Back in this (http://www.cooksongold.com/forum/need-help-ask-experts/1265-soldering-grain.html) thread, the existence of soldering grain (http://www.hswalsh.com/search.aspx?s1=soldering&s2=grain&s3=&f=1&l=10) was revealed unto me. I'd never heard of it before, but it might just be the thing for one particular job.

I'm not keen on Walsh's price, so I thought I could put a kit together myself with a stainless steel Balti dish from Tesco and some grit from somewhere like UKGE (http://www.ukge.co.uk/UK/grits.asp) or Capital City (http://shop.ccabrasives.com/silicon-carbide-grain-121-c.asp). What size grit though? Anyone?

[ps_bond]

I've never tried soldering grain; I've got some 80 grit stuff around for blasting, but I'd have thought that would be blown around by the torch flame. Wet sand is OK - but it has a lot more mass.

What are you trying to solder that needs it?

[arian]

I'm making a box, the upper half of which is something like a frisbee in cross-section. The flat top forms a hinged lid. I'm finding it difficult to keep everything in place whilst I solder the knuckles. I've failed with investment plaster and stacks of pennies & feeler gauges.

[ps_bond]

Well, I did a bit of testing; the 80 grit in a tuna tin is OK at the lower pressures, but as soon as you go up to about 2 bar it does tend to blow about a bit. It also reflects extremely well it seems. None of my pumice is in small enough bits to use for this (and it's too useful in the sizes it is currently for me to mash any). I've used soldering weights such as the ones here (http://www.ganoksin.com/borisat/nenam/solder.htm) to hold tricky bits in position before - any use?

[arian]

Cor, haven't seen those soldering weights before. Thanks.

Thanks as well for doing the experiment. I've ordered 1kg of 14 grit. It it's too coarse, I'll attack it with a hammer.

I'll report in a couple of weeks.

[ps_bond]

Probably ought to add - take the tuna out of the can first.

Can't be too careful...

[arian]

Oh, I thought it'd be like making banoffee pie :).

[ps_bond]

I'm all for fusion cooking, but I'm not convinced that tuna brulee is going to be a winner...