Repairing chewed up T slot, preventing ingress to channel with filler?

admin

Hello,I am welding an industrial fitting, it's a cast iron ring with a T slot around it. This was used with someone who loved to overtighten things as much as possible and really chewed up the inside face. I have had good luck making a suitable weld with stainless mig wire however my question is this:If I want to prevent intrusion into the wide area of the slot, would it be possible for me to pour some sort of filler in there which won't compromise the weld or be impossible to remove later? I was thinking some kind of sand, ceramic dust, etc or similar.  it's a 1in slot behind a 1/2in channel so it's not very easy to get in there if I make a real mess of it, but if I can pour something that can be removed after safely as a backing it might just really save me time.Anyone here ever tried something similar?Last edited by tastyratz; 09-09-2015 at 05:00 PM.
Reply:I cannot for the life of me picture what your describing :/
Reply:so imagine something just like that. it's not my picture but it's for demonstration purposes. There are bolts that slide in the slot and hold something to the other side. someone cranked those bolts down really hard and took chunks off the underside. I want to put a bead along the skinny part of the slot to fill in areas that broke off. The problem is I still want that to be a flat surface on the backside so I don't want to get any intrusion of the bead into the fat part of the slot. I don't want to have any weld flow into the space for "C/H2". the area to repair is the lip, "H1"I need some way to provide a backing I can weld against and then remove after, using some sort of casting sand or ceramic dust or even coal dust sandblasting sand of some type was first to come to mind but if it will ruin the weld and turn to glass plugging the slot forever it's no good to meLast edited by tastyratz; 09-09-2015 at 04:42 PM.
Reply:you can try copper, but if you melt into it, you will lock it in place and have a bigger problem, I would try soaking wet wood cut to the right size, it might burn a little but keep welder moving along and if the wood get stuck you can just let it dry out and it will shrink, and if its still stuck just burn it out..Of all the things I lost I miss my mind the most...I know just enough about everything to be dangerous......You cant cure stupid..only kill it...
Reply:Solid carbon bar or rods is another material that is often used to fill holes you don't want filled with weld material..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:You should try a cast iron stick Sent from my iPhone using Tapatalk
Reply:Copper was my first thought but I am pushing a pretty sizable puddle and a LOT of heat, I would probably be pushing my luck with copper. since it's a round channel without an open end I don't really have space to put a solid bar/rod in place. I might be able to cut something up into a few dozen slices but it would probably be pretty time consuming vs pouring in some kind of temporary dust. Wetting won't last terribly long with how much preheat I need to do.I might try laying a test bead on some scrap and see how bad it is.Adrian: I'm looking for a temporary backer, not permanent. Using cast iron wouldn't work. I'm happy with how the weld comes out for my resources and the needs for the part, It's the temporary backing/filler that I am in the air about.Last edited by tastyratz; 09-09-2015 at 07:02 PM.
Reply:So your running stainless mig on cast iron and pushing a LOT of heat ? I don't see this working well no matter what backer you use. Best case your filler just pops out from under bead cracking. Worst case you lose even more material from the t slots due to cracking. I don't know of a good fix but maybe some pictures would help.Lincolin Power Wave 450, Lincoln Powermig 255, Lincoln Pro Mig 140, Lincoln Squarewave Tig 275, Miller Big 40 G(with Hobart Hefty suitcase), Thermal Arc 95S and Esab PCM875 in an already full machine shop.
Reply:Already repaired a few pieces on the outside of this same piece with a lot of luck, no cracking, minor porosity. pre/post heat did well by me.This isn't an extremely loaded piece where it is, it's only going to see T head bolt compressive loads - nothing dramatic. I'm more doing this for a snag free slide.my test and prior repairs were satisfactory for my testing. I don't want to derail the intent of the post from suitable temporary backing.
Reply:How about some sort of clay?Some of the refractory clays won't melt until over 3000F.  So you'd be ok letting molten metal run against it, but it probably wouldn't survive a direct hit from the arc.You may need several days to let the clay get dry enough so it won't pop and blow out from trapped steam.  I'd try a very dry mix with just enough water to get it to pack and stay.  Or no water at all, if you can move the part so the t-slot is horizontal.Even if you get the clay hot enough to sinter, you still should be able to get it out with a chisel and hammer.I assume you can machine this after welding.  You probably won't get good surface against the clay.  Think of sand cast parts.Dynasty200DX w/coolmate1MM210MM VintageESAB miniarc161ltsLincoln AC225Victor O/A, Smith AW1ACutmaster 81IR 2475N7.5FPRage3Jancy USA1019" SBAEAD-200LE
Reply:Aluminum backer? Coated in anti-spatter gel / spray?Rich
Reply:I am planning to machine this after welding yes, although if it comes out only needing to be lapped I might be able to get away with a tiny flap wheel or something like that (probably not though).I can definitely move the part so the T slot is horizontal, I was originally thinking of semi loose fill and vibrating it to settle a flat surface. If I try to pack it too much I will end up filling the voids there and end up with the same issue after.Whatever goes in there will have direct bead contact, it will puddle and pool onto the backer during cooldown and be right against the arc. I'll be running this on a 170a hf 220 welder cranked all the way up.Good idea on adding anti spatter gel Steelsurgeon, I can see that being helpful.Last edited by tastyratz; 09-10-2015 at 08:52 AM.
Reply:What about silicon carbide blasting media? melts over 4000degaluminum oxide is up around 3700
Reply:As I understand it, this is a circular t-slot.  Do you insert t-bolts at points from the back of slot?  If so, are the access slots large enough to insert a solid backup.  If so, you could waterjet cut a piece of ceramic kiln shelf to the correct shape.  Make it thinner than dimension H2 and block it up to the bottom of the T.Dynasty 300DXSmith He/Ar gas mixerMM350PHobart Handler 120Smith LW7, MW5, AW1A
Reply:Plaster of Paris? Sent from my SM-N915W8 using Tapatalk
Reply:Just use a copper flat bar, maybe 6" long. Put a hole at each end and use a bolt to hold it at the top of the slot right where you want to work, then move it around to the other repair areas.
Reply:Plaster of paris will revert to powder at molten iron temperatures.That's how they make the stuff.  They dig up gypsum, then roast it in an oven break out the water.  When you add water it recombines to make gypsum again.Last edited by AndyA; 09-11-2015 at 04:41 PM.Dynasty200DX w/coolmate1MM210MM VintageESAB miniarc161ltsLincoln AC225Victor O/A, Smith AW1ACutmaster 81IR 2475N7.5FPRage3Jancy USA1019" SBAEAD-200LE
Reply:I really don't see this going well no matter what you use. I'm confused how welding this is going to get you a snag free slide. If it's snagging, there's something that needs to be removed, not welded. And what do you mean it's a round channel without an open end? So how do you get the T-nut in there? I'm assuming I misunderstood this statement and there is an opening. You say you have access to machining equipment? Then you could weld in the cracks, not worry about the weld getting into the channel, and then run a T-slot cutter in a mill through there very carefully. Otherwise you're just pissing into the wind.John 3:16(2) Miller Pheonix 456(2) Millermertic 252Dynasty 210DXHobart 210MVPDoringer D350 SA Cold SawScotchman 350LT Cold SawWebb 10x50 MillWebb 15x40 LatheGeka Bendicrop Ironworker
Reply:Fireclay and sand are used for cast iron molds.  Maybe a nearby pottery supply place will sell you a half cup of fireclay.  Might mix in a bit of Milk of Magnesia (Magnesium hydroxide).  Let it all dry and pre-heat the hell out of it."USMCPOP" First-born son: KIA  Iraq 1/26/05Syncrowave 250 w/ Coolmate 3Dialarc 250, Idealarc 250SP-175 +Firepower TIG 160S (gave the TA 161 STL to the son)Lincwelder AC180C (1952)Victor & Smith O/A torchesMiller spot welder
Reply:Maybe you could use ceramic weld backing? It comes in a lot of profiles and sizes including flat. Gullco Kat back is one brand.
Reply:so today was experimentation day and I thought I would share some results. Hopefully helps someone else in a similar position too.I took an old brake rotor and welded over the holes with different filler/ backer materials to see what happened. I didn't preheat, didn't post heat, didn't really even clean that great. I wanted to see what survived a direct puddle exposure and what it's surface was like.migging this was a challenge because the gas wanted to blow away anything I put in there.block of pine wood.This was the absolute worst all around. the wood burned out nearly instantly and the puddle worked it like butter. i might as well have welded over a piece of ham, but the ham would have tasted better this charred. 1/4in blob stuck out.dry all purpose sandThis produced the least contaminated looking weld but the second worst as far as intrusion goes. the sand all wanted to blow out of the hole from the gas and it mostly did. did not turn to glass or even really require any cleaning. 1/16th ish variations in what stayed, complicated post cleanupdry plaster of parisThis reeked noxiousness when welding. it stayed better than the AP sand but not by far and really burned up and through.wetted and mostly hardened plasterThis produced the best quality surface evenness so far and did not go anywhere. it did however highly contaminate the weld and left a very porous light gray metal surface. it may be possible to use this set lower with the expectation of milling the surface clean. once the puddle cooled I could chop this out very easily as if it was just dry powder. it returned to it's natural form. maybe 1/32nd variations but pocked and dirty, you will want it gone.3x3 1/16th copper sheet squaredid not survive direct puddle exposure. so wet formed plaster is a maybe with post cleanup, and wet play sand is a maybe with likely less cleanup required. will have to continue experimenting.Last edited by tastyratz; 09-26-2015 at 02:41 PM.
Reply:I/m wondering if there won't be a small pop or explosion at some point with damp plaster?"The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt
Reply:Originally Posted by SandyI/m wondering if there won't be a small pop or explosion at some point with damp plaster?
Reply:You could machine graphite into the T slotOnce your done, if it sticks in you can bash it to bits and get it out.
Reply:Must be top secret or you are trying to corner the market.  25 posts and still no pictures of what your project is?  30+ yrs Army Infantry & Field Artillery, 25 yrs agoMiller 350LX Tig Runner TA 210, spool gunLincoln 250/250 IdealArcESAB PCM 500i PlasmaKazoo 30"  vert BSKazoo 9x16 horiz BSClausing 12x24 lathe20T Air PressOf course 1/16" copper isn't going to work. I still think ceramic weld backing would be an easy solution. That's what it's basically made for although not specifically for repairing T slot tables.
Reply:Graphite, known as " carbon plate" is made just for that purpose. Cuts and machines easy. Slide it in and weld away, take a steel rod and knock it out when finished.