On Fri, 2012-08-24 at 12:45 -0400, Gene Heskett wrote: > On Friday 24 August 2012 12:26:40 dave did opine: > > > On Fri, 2012-08-24 at 08:12 +0200, Jan de Kruyf wrote: > > > > I have never seen such a material on this side of the pond, Jan. > > > > Where does one get it? > > > > > > DuPont makes it if I am not mistaken. It is used to make bearing > > > bushes for valves and the like. > > > The price is not quite up to Moglice standards. But $100 is also > > > quickly paid for that stuff. > > > > > > I forget what the etching liquid is, but it is quite aggressive and > > > very nasty (only for use in 3rd world :) > > > The supplier always makes me wait a few days "for the weather to get > > > right for etching". > > > > > > In any case I see you are of the generation of "the wooden ships and > > > the iron men" > > > I learned my trade on the iron ships, see. > > > > > > cheers, > > > > > > j. > > > > > > > > (with an etched > > > > > surface, otherwise the glue does not hold) onto the running > > > > > surface of a taper gib. > > > > > > > > Etched with what acid? > > > > Found this on the web. > > > > 40g water > > 25g potassium dichromate > > 500g concentrated sulfuric acid > > Interesting. Why such a puny amount of water? 40g of water in 500g of > Sulphuric CP will only reduce it to about 1.65 SG. > > One would assume concentrated means fuming, or C.P. acid. I'd have to look > around to find the potassium dichromate though. C.P is probably slightly less than 68%, fuming is 100% and nasty stuff. Lots of mineral dissolution is done in conc. sulfuric/nitric and in a good hood unless you want to cough your guts out and mess up your lungs. > > > A note of caution: as usual add the sulfuric to the water, slowly with > > stirring and cooling. > > > > This etches the delrin ..... so epoxy has a chance of adhesion. > > I see, I was wondering how that was managed. > > > I think > > I'd test before I did a real piece. > > > > As for a moglice work-alike I think I'd try a slow-curing epoxy loaded > > with moly disulfide. Mix the epoxy by weight to get the proportions > > correct. (kitchen digital scale :-)) > > Devcon's old one can of black and one can of white epoxy steel with some > added moly might work well. I have bedded quite a few guns with it. Stable > too, Bertha's recoil lug is as tight today as it was in the '70's when I > last re-bedded it after a fresh Douglas tube was screwed into it. I suspect that the Devcon is about as loaded as they dare get it. That is why I suggested a non-loaded epoxy. > > Or a modern reloaders scale. I have a Hornaday Lock & Load automatic these > days, but be sure to breath heavy on the air guard cover over the pan, else > its static charge from handling can lighten the pan by 2 or so grains, > throwing an overcharge :( More accurate when you know its limits. You have to breath on it with your humidity. Hate to think what I'd have to do. ;-)
> > I have that moly powder in bulk as I do my own moly coating of bullets. Big > Double grin for that... > > Thanks Dave. > > Cheers, Gene ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
