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best way to rough up the inside of 3/8" copper tube?
I'm making up some welding positioner clamping screws, and I'm gluing on copper
tubing to the exposed shanks so spatter won't stick to them. I'm finding that the bond to the inside of the copper isn't very strong, probably because the surface is so smooth. Anyone have a slick way to easily rough up the inside of copper tubing 3/8" ID? I don't have a real stiff brush or I'd use that. Do they make those? GWE |
"Grant Erwin" wrote in message
... I'm making up some welding positioner clamping screws, and I'm gluing on copper tubing to the exposed shanks so spatter won't stick to them. I'm finding that the bond to the inside of the copper isn't very strong, probably because the surface is so smooth. Anyone have a slick way to easily rough up the inside of copper tubing 3/8" ID? I don't have a real stiff brush or I'd use that. Do they make those? GWE A small (1/4" dia) sanding drum chucked into a Dremel. Use a fine grit sleeve and slowest speed. |
In article ,
Grant Erwin wrote: I'm making up some welding positioner clamping screws, and I'm gluing on copper tubing to the exposed shanks so spatter won't stick to them. I'm finding that the bond to the inside of the copper isn't very strong, probably because the surface is so smooth. Anyone have a slick way to easily rough up the inside of copper tubing 3/8" ID? I don't have a real stiff brush or I'd use that. Do they make those? GWE Run a 3/8 drill thru it? -- Free men own guns, slaves don't www.geocities.com/CapitolHill/5357/ |
Grant Erwin wrote:
Anyone have a slick way to easily rough up the inside of copper tubing 3/8" ID? rolling a rough round file in the tube. with the tube laying on the table? Nick -- Motormodelle / Engine Models: http://www.motor-manufaktur.de Ellwe 2FB * VTM 87 * DLM-S3a * cubic more to come ... |
Nick Hull wrote:
In article , Grant Erwin wrote: I'm making up some welding positioner clamping screws, and I'm gluing on copper tubing to the exposed shanks so spatter won't stick to them. I'm finding that the bond to the inside of the copper isn't very strong, probably because the surface is so smooth. Anyone have a slick way to easily rough up the inside of copper tubing 3/8" ID? I don't have a real stiff brush or I'd use that. Do they make those? GWE Run a 3/8 drill thru it? You didn't say what kind of "glue" you were using. I'd suggest trying epoxy, even the "5 minute" kind should work for your application. I suspect maybe the inside of that tubing has a film of oil on it. Try swabbing it out by pushing or pulling a small piece of cloth wet with acetone through it. Cleanliness is next to Godliness in the epoxying business. If you really want to scarify the inside of the tubing, here's a simple way to make a tool for that. Get a piece of rod about 3/16" diameter and long enough to go a bit more than halfway through the length of those pieces tubing. Saw a diametrical slit across one of the ends of the rod, continuing about 3/4" down the rod. Cut a strip of abrasive paper 3/4" wide and a couple of inches long, slide it's center into the slot in the rod and twist the rod clockwise looking at it from the unslotted end while smoothing down the abrasive paper so both ends of the paper wrap around the rod, abrasive side out. (Flip the paper over if it comes out backwards on the first try. Duh.) Stick the rod in a drill press or drill motor and have at the inside of the copper tubing with it, working from both ends as needed. HTH, Jeff -- Jeffry Wisnia (W1BSV + Brass Rat '57 EE) "Truth exists; only falsehood has to be invented." |
On Mon, 22 Aug 2005 14:33:05 -0700, the opaque Grant Erwin
clearly wrote: I'm making up some welding positioner clamping screws, and I'm gluing on copper tubing to the exposed shanks so spatter won't stick to them. I'm finding that the bond to the inside of the copper isn't very strong, probably because the surface is so smooth. Anyone have a slick way to easily rough up the inside of copper tubing 3/8" ID? I don't have a real stiff brush or I'd use that. Do they make those? 4" x 1/4" dowel, slit the end, put in a 1/2" x 1" strip of maroon scotchbrite and wire the split shut to affix the scotchbrite. Using either a drillmotor (very slow speed) or hand rotation, scuff the I.D. in a crosshatch pattern, like a cylinder wall. ---------------------------------------------------------- --== EAT RIGHT...KEEP FIT...DIE ANYWAY ==-- http://www.diversify.com/stees.html - Schnazzy Tees online ---------------------------------------------------------- |
"Grant Erwin" wrote in message ... I'm making up some welding positioner clamping screws, and I'm gluing on copper tubing to the exposed shanks so spatter won't stick to them. I'm finding that the bond to the inside of the copper isn't very strong, probably because the surface is so smooth. Anyone have a slick way to easily rough up the inside of copper tubing 3/8" ID? I don't have a real stiff brush or I'd use that. Do they make those? GWE You can buy wire brushes for preparing tubing for soldering that size. Greg |
I am not an adhesives expert, but played one at work. We did not have
any copper things to bond, but I do know that most adhesives don't do well with copper. The copper kill the curing agent or something like that. You might do some searching on Google for the reasons, or just go to your local hardware store and buy some epoxy that is formulated for copper. You can find it in the plumbing area. Getting a rough clean surface is probably not going to work with regular epoxy. Of course having a clean surface is going to be needed, unless maybe you use an industrial polyurethane adhesive. Dan Jeff Wisnia wrote: You didn't say what kind of "glue" you were using. I'd suggest trying epoxy, even the "5 minute" kind should work for your application. HTH, Jeff -- Jeffry Wisnia (W1BSV + Brass Rat '57 EE) "Truth exists; only falsehood has to be invented." |
Okay, I did try googling and did not find out much. If I recall
correctly, some epoxys do not work well with copper. I would clean and rough up some copper and see how well your adhesive works with it. I think that some curing agents corrode copper and therefore you don't get a good bond even though you started with a clean surface. Dan |
"Grant Erwin" wrote in message ... I'm making up some welding positioner clamping screws, and I'm gluing on copper tubing to the exposed shanks so spatter won't stick to them. I'm finding that the bond to the inside of the copper isn't very strong, probably because the surface is so smooth. Anyone have a slick way to easily rough up the inside of copper tubing 3/8" ID? I don't have a real stiff brush or I'd use that. Do they make those? GWE Simple. Using coarse media, sand blast it. It may not look like you've done much, but it will rough it up enough to create good tooth, providing you don't heat the installed pieces enough in use to cause them to expand to the point where you break the bond. I assume you're applying the tubing in one piece, by sliding it over the exposed portion, not two halves. A spring hose clamp might be a better choice in that case. Harold |
In article ,
Grant Erwin wrote: I'm making up some welding positioner clamping screws, and I'm gluing on copper tubing to the exposed shanks so spatter won't stick to them. I'm finding that the bond to the inside of the copper isn't very strong, probably because the surface is so smooth. Anyone have a slick way to easily rough up the inside of copper tubing 3/8" ID? I don't have a real stiff brush or I'd use that. Do they make those? GWE Get a chunk of all-thread just slender enough to fit inside the copper tube, but way too long. Chuck it in a fast drill, slip it into the tube, and let 'er rip! The all thread will start to wobble around, and do all kinds of terrible things to the inside surface. Kind of like what a socket does to a stud when you take off a nut too quickly with an overpowered impact, but backwards. You could probably enhance it a bit by beating the **** out of the all-thread before starting. Wear gloves and glasses. A flak jacket can't hurt either. (: -- B.B. --I am not a goat! thegoat4 at airmail dot net http://web2.airmail.net/thegoat4/ |
B.B. wrote:
In article , Grant Erwin wrote: I'm making up some welding positioner clamping screws, and I'm gluing on copper tubing to the exposed shanks so spatter won't stick to them. I'm finding that the bond to the inside of the copper isn't very strong, probably because the surface is so smooth. Anyone have a slick way to easily rough up the inside of copper tubing 3/8" ID? I don't have a real stiff brush or I'd use that. Do they make those? GWE Get a chunk of all-thread just slender enough to fit inside the copper tube, but way too long. Chuck it in a fast drill, slip it into the tube, and let 'er rip! The all thread will start to wobble around, and do all kinds of terrible things to the inside surface. Kind of like what a socket does to a stud when you take off a nut too quickly with an overpowered impact, but backwards. You could probably enhance it a bit by beating the **** out of the all-thread before starting. Wear gloves and glasses. A flak jacket can't hurt either. (: You forgot to tell him to stick the whole works in a bucket of sand before you start the drill.... |
"Greg O" wrote in message
... | | You can buy wire brushes for preparing tubing for soldering that size. | Greg I was gonna suggest a battery terminal brush, if he had one already. |
You didn't mention the size of the tubing, but a battery terminal
cleaning brush works fine on 1/2"-1" sizes. For smaller sizes saw slit 3/16"+/- rod and insert steel wool, then chuck it in a drill and scrub away. Bugs |
On Tue, 23 Aug 2005 05:45:22 GMT, the opaque "carl mciver"
clearly wrote: "Greg O" wrote in message ... | | You can buy wire brushes for preparing tubing for soldering that size. | Greg I was gonna suggest a battery terminal brush, if he had one already. They're too large in diameter, Carl, but some of the bayonet socket cleaning brushes (for lamp sockets) might be small enough. ---------------------------------------------------------- --== EAT RIGHT...KEEP FIT...DIE ANYWAY ==-- http://www.diversify.com/stees.html - Schnazzy Tees online ---------------------------------------------------------- |
Grant Erwin wrote: I'm making up some welding positioner clamping screws, and I'm gluing on copper tubing to the exposed shanks so spatter won't stick to them. I'm finding that the bond to the inside of the copper isn't very strong, probably because the surface is so smooth. Anyone have a slick way to easily rough up the inside of copper tubing 3/8" ID? I don't have a real stiff brush or I'd use that. Do they make those? GWE Grant, How bout a bore cleaning brush on a cleaning rod for a .38? Ken. |
This is kinda thinking outside the box, but have you thought of other
ways of attaching the copper tubing to the shanks. I don't know what kind of a fit you have-interference, press, loose fit, etc. but if the fit is good you might be able to silver solder it, just like regular plumbing pipes. They also make epoxy specifically designed for copper. To rough up the inside of tubing, mostly PEX for various gadgets, I use a wire brush attachment in my dremel, or the sanding wheel, or a fine riffler (pattern maker's rasps). |
woodworker88 wrote:
This is kinda thinking outside the box, but have you thought of other ways of attaching the copper tubing to the shanks. I don't know what kind of a fit you have-interference, press, loose fit, etc. but if the fit is good you might be able to silver solder it, just like regular plumbing pipes. They also make epoxy specifically designed for copper. To rough up the inside of tubing, mostly PEX for various gadgets, I use a wire brush attachment in my dremel, or the sanding wheel, or a fine riffler (pattern maker's rasps). Lot of great ideas have been posted. You bring up the issue of fit. Well, I couldn't find 3/8" hard copper tubing (the straight stuff) at any local easy places like Home Depot or McLendon (a real good local hardware store) so I just bought some soft 3/8" copper tubing. The problem with soft roll copper 3/8" tubing is it's actually a lot bigger than 3/8" inside, at least .385". So what I thought would be a slip fit wound up being a rattle fit. I wish I knew where to buy 3/8" copper pipe -- that's 3/8" ID, 1/2" OD. I'm sure Alaska Copper has it downtown, but I'd probably have to buy a 20' section and I only need 1' so I'd be paying 20X the price which is something I ain't gonna do. I used JB Weld. I made up 4 pieces, and on 2 of them, the copper was so far off center that I had to try to turn it so it would clear, and when I was turning it in the lathe, it broke loose. Pilot error probably, the other two pieces seem strongly bonded so maybe it isn't really true that this is a copper bonding problem. Thanks, everyone. GWE |
You might want to try Loctite. If the fit is loose the bearing
retainer type might work better. If the fit it too loose and you epoxy to fill then you do have to roughen the inside. I have some old water damaged 24 and 36 grit sanding belts and disks that I use for this sort of thing. They're pretty stiff but you can roll them up in sort of a spiral tube and pull them through the tubing a couple of times. Good luck, Kelley On Mon, 22 Aug 2005 14:33:05 -0700, Grant Erwin wrote: I'm making up some welding positioner clamping screws, and I'm gluing on copper tubing to the exposed shanks so spatter won't stick to them. I'm finding that the bond to the inside of the copper isn't very strong, probably because the surface is so smooth. Anyone have a slick way to easily rough up the inside of copper tubing 3/8" ID? I don't have a real stiff brush or I'd use that. Do they make those? GWE |
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On Tue, 23 Aug 2005 15:00:12 -0700, Grant Erwin
wrote: Lot of great ideas have been posted. You bring up the issue of fit. Well, I couldn't find 3/8" hard copper tubing (the straight stuff) at any local easy places like Home Depot or McLendon (a real good local hardware store) so I just bought some soft 3/8" copper tubing. The problem with soft roll copper 3/8" tubing is it's actually a lot bigger than 3/8" inside, at least .385". So what I thought would be a slip fit wound up being a rattle fit. I wish I knew where to buy 3/8" copper pipe -- that's 3/8" ID, 1/2" OD. I'm sure Alaska Copper has it downtown, but I'd probably have to buy a 20' section and I only need 1' so I'd be paying 20X the price which is something I ain't gonna do. Need 3/8" tubing? Check at your friendly local refrigeration supply house - even in Alaska people need AC and refrigeration systems... They use 3/8 and all the other odd "in-between" sizes in their lines, in both hard and soft copper tube - the refrigerant has to move through the lines at the right velocity to move the oil back to the compressor, so they need a broad size selection. If they don't have any 'damaged' lengths, they might know a local contractor who has ordered that size recently, and can fish some cut-off pieces out of his Copper Scrap pile. -- Bruce -- -- Bruce L. Bergman, Woodland Hills (Los Angeles) CA - Desktop Electrician for Westend Electric - CA726700 5737 Kanan Rd. #359, Agoura CA 91301 (818) 889-9545 Spamtrapped address: Remove the python and the invalid, and use a net. |
Grant Erwin wrote:
I'm making up some welding positioner clamping screws, and I'm gluing on copper tubing to the exposed shanks so spatter won't stick to them. I'm finding that the bond to the inside of the copper isn't very strong, probably because the surface is so smooth. Anyone have a slick way to easily rough up the inside of copper tubing 3/8" ID? I don't have a real stiff brush or I'd use that. Do they make those? GWE A coarse-cut half-round file. Or a piece of coarse sand-paper wrapped around a piece of 1/4" rod or dowel. Or heat it until you get good oxide formation, then pickle in dilute sulfuric acid or a sodium bisulfate solution. Bert |
Too late now, but if you have a sissor type knurler, you could have
swaged the copper tubing for a slip fit. Might have to make smooth wheels or claim you wanted the extra surface for cooling. Dan |
Grant Erwin wrote:
I'm making up some welding positioner clamping screws, and I'm gluing on copper tubing to the exposed shanks so spatter won't stick to them. I'm finding that the bond to the inside of the copper isn't very strong, probably because the surface is so smooth. Anyone have a slick way to easily rough up the inside of copper tubing 3/8" ID? I don't have a real stiff brush or I'd use that. Do they make those? GWE Stainless bore brush for a .38 pistol? John |
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