Gary Lewis Posted June 12, 2019 Author Share Posted June 12, 2019 They don't rust AND they're much less conductive than most metals. So they don't transfer much heat from the pads to the fluid behind them. Yes, I think phenolic pistons are the way to go. Hadn't thought about it heretofore, but it certainly makes sense. Link to comment Share on other sites More sharing options...
Steve83 Posted June 12, 2019 Share Posted June 12, 2019 Turns out the rust is tenacious and it'll take another 30 minutes to make it ready for powder - if I were to do that. But I'm not sure I want to start that for this project. Thoughts?1) I think I'd be shopping for remans with modern coatings (like good galvanizing, or yellow phosphate) 2) I think it's time to replace your blast media. I don't do as much as you, but I'm liking the GlassBeads I got last year: https://www.tptools.com/Most-Popular-Abrasives.html Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted June 12, 2019 Share Posted June 12, 2019 Turns out the rust is tenacious and it'll take another 30 minutes to make it ready for powder - if I were to do that. But I'm not sure I want to start that for this project. Thoughts?1) I think I'd be shopping for remans with modern coatings (like good galvanizing, or yellow phosphate) 2) I think it's time to replace your blast media. I don't do as much as you, but I'm liking the GlassBeads I got last year: https://www.tptools.com/Most-Popular-Abrasives.html Well, if you're going to plate them there's no need to media blast them at all. After the detergent bath they go into a hot pickling (acid) bath before being rinsed and plated. Maybe that's why some rebuilds are offered that way? Link to comment Share on other sites More sharing options...
Gary Lewis Posted June 12, 2019 Author Share Posted June 12, 2019 Well, if you're going to plate them there's no need to media blast them at all. After the detergent bath they go into a hot pickling (acid) bath before being rinsed and plated. Maybe that's why some rebuilds are offered that way? Steve - I have several bags of crushed glass media, so need to use that before changing. But, I probably do need to dump what I have and add some new. Might do that before I blast anything else. But, I will say that the glass has REALLY cut down on the dust over the coal slag. As for plating, I want to use the calipers I have given how good they are in the bores. But I do have some epoxy powder that I might use instead of the polyester. It doesn't have as much UV stability, but there's not much UV behind solid wheels. Jim - Plating sounds like a lot of work with chemicals I don't have. Think I'll stick to powder. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted June 12, 2019 Share Posted June 12, 2019 Steve - I have several bags of crushed glass media, so need to use that before changing. But, I probably do need to dump what I have and add some new. Might do that before I blast anything else. But, I will say that the glass has REALLY cut down on the dust over the coal slag. As for plating, I want to use the calipers I have given how good they are in the bores. But I do have some epoxy powder that I might use instead of the polyester. It doesn't have as much UV stability, but there's not much UV behind solid wheels. Jim - Plating sounds like a lot of work with chemicals I don't have. Think I'll stick to powder. Gary, I wasn't suggesting you do plating.... I was rationalizing why rebuilders might plate their calipers, besides the 'Oh, shiney!' aspect of sales, they can't damage bores with abrasive media and the rustproofing of plating makes for happy customers. ETA: Parkerizing or phosphate treatment IS pretty easy to attain in the home shop. Kits are available from Midway shooters supply. https://www.midwayusa.com/s?userSearchQuery=Parkerizing&userItemsPerPage=24 Link to comment Share on other sites More sharing options...
Steve83 Posted June 12, 2019 Share Posted June 12, 2019 Gary, I wasn't suggesting you do plating.... I was rationalizing why rebuilders might plate their calipers, besides the 'Oh, shiney!' aspect of sales, they can't damage bores with abrasive media and the rustproofing of plating makes for happy customers. ETA: Parkerizing or phosphate treatment IS pretty easy to attain in the home shop. Kits are available from Midway shooters supply. https://www.midwayusa.com/s?userSearchQuery=Parkerizing&userItemsPerPage=24 OFF-TOPIC... Are you into that? I've been thinking about getting into nitrocarburizing/bluing/etc. at home, but I haven't done any research into it yet. Is there a forum like this for it? Link to comment Share on other sites More sharing options...
Gary Lewis Posted June 12, 2019 Author Share Posted June 12, 2019 Gary, I wasn't suggesting you do plating.... I was rationalizing why rebuilders might plate their calipers, besides the 'Oh, shiney!' aspect of sales, they can't damage bores with abrasive media and the rustproofing of plating makes for happy customers. ETA: Parkerizing or phosphate treatment IS pretty easy to attain in the home shop. Kits are available from Midway shooters supply. https://www.midwayusa.com/s?userSearchQuery=Parkerizing&userItemsPerPage=24 Jim - Makes sense. And, while Parkerizing is fairly easy from what I've read, what I think I'll do is to give them a phosphate coating and then powder coat them on top of that. The phosphate tightly bonds to the iron and gives powder more tooth, or surface area, to grab. My grandtwins are here and I'm spending time with them. But this afternoon they were playing outside so I slipped out to the shop for a few minutes. Another 20 minutes in the blast cabinet got the one that I'd started on to the point shown below. It think it is ready for the phosphate spray. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted June 12, 2019 Share Posted June 12, 2019 OFF-TOPIC... Are you into that? I've been thinking about getting into nitrocarburizing/bluing/etc. at home, but I haven't done any research into it yet. Is there a forum like this for it? Steve, I've only done some cold bluing and parkerizing. Never anything like color case hardening or nitriding. There are LOTS of gunsmithing forums, and quite a few dealing with restoration and collection of military memorabilia. There are lots of experts willing to share their knowledge. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted June 13, 2019 Share Posted June 13, 2019 I think I'll do is to give them a phosphate coating and then powder coat them on top of that. The phosphate tightly bonds to the iron and gives powder more tooth, or surface area, to grab. I never thought of phosphate as a coating. More of a chemical treatment that converts the surface to iron phosphate, not adding a film thickness. Similar to flash rust (iron oxide) or case hardening (carbon diffusion into the steel itself) At any rate, I see you're getting good use of those Home Depot totes. Link to comment Share on other sites More sharing options...
Gary Lewis Posted June 13, 2019 Author Share Posted June 13, 2019 I think I'll do is to give them a phosphate coating and then powder coat them on top of that. The phosphate tightly bonds to the iron and gives powder more tooth, or surface area, to grab. I never thought of phosphate as a coating. More of a chemical treatment that converts the surface to iron phosphate, not adding a film thickness. Similar to flash rust (iron oxide) or case hardening (carbon diffusion into the steel itself) At any rate, I see you're getting good use of those Home Depot totes. I guess you are right, it isn't a coating but a treatment. Thanks for the correction. As for the totes, those are actually from Sams, but appear to be the same as HD's. I've decided that instead of looking for cardboard boxes as we leave Sams I'll buy a tote to bring the things home in. Works out nicely. That one has more than I care to lift in it, including D60 spindles, knuckles, spring hangers & shackles, IDI perches, u-bolts, shock mounts & towers, dust shields, etc. Consolidated a lot of stuff, but is way too heavy to carry w/o help. Link to comment Share on other sites More sharing options...
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