On Saturday 25 August 2012 04:15:33 dave did opine: > 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.
That pint of CP I bought to make the bluing with, did fume when I opened it the first time. SG was above 1.78 when it was bottled. By the time it quit fuming, I've read it will be down to around 1.72, depending on the temps. Or my memory is fuzzy. I have never seen its strength in percentages, always in S.G. That of course was back in a different day and time, I actually bought it off the display shelf of the main downtown Rapid City drug store. I had to sign the dangerous chemicals waver book for both it and the hydrochloric CP, but it was on the shelf! CVS & Rite Aid will probably call the DHS if you even ask about either today. No damned wonder this country is going to hell. > 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. I wondered about that. I also wonder how fast it would wear used straight. It's pretty tough stuff. > > 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. ;-) > What, you don't breath? > > 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 Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> is up! BOFH excuse #372: Forced to support NT servers; sysadmins quit. ------------------------------------------------------------------------------ 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 [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
