General welding questions that dont fit in TIG, MIG, Stick, or Certification etc.
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Thanks man! I fixed one of those tiny plastic wire clips that always snap the first time you open them to release the wires. Another $8 + shipping saved :D I used my Portasol butane soldering iron with the heat tip to do that since it's so small and has less air CFM. Worked very well and it's flexible again :)
One thing you truly can never have enough of in this life is SkillZ! Even n00b to novice is fine because they can always be refined as needed.

Finally the last important things I didn't mention was a bit more expansion on the 80/20 for heating filler/part as you lay your bead down or melt whatever you found for filler. It does change slightly depending on the thickness of filler and work but still you're doing a small area so a 70 on part to 30 on filler can help sometimes but always start with 80/20.
The other would be what you're watching for. ABS and most plastics get a wet shiny sheen to them as they hit a good melting temp. Once they bubble you've overheated it. You're looking for a glassy appearance about 1-2x the width of your bead on either side of your bead. Really 1x is about best. You're also looking for your filler to do the same and you want to heat you filler first and then lay into it. If your filler is really thin then you may just want to start your filler right on the part and then weld on. If your filler is exceptionally thin, and your part is kinda thick, you might want to move to more a 50/50 heating but this is something you'll really only understand as you learn since plastic doesn't come in standard thicknesses and shapes like metal so there's not really general averages except the amount of heat that comes from the welder since that's fairly universal for all thickness; it's just material specific.
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Man,
I jist paid $40 for this piece of dung about two weeks ago and its already leaking around the top edge. Its a bleeder valve for a 2000 dodge intrepid and it's a real bitch to change out, just like everything else on that lemon of a car. Its leaking around the top edge.....ever so slightly, directly in front of the bolt on the right side as evidenced by that white crusty crap. That's the reason why I changed out the last one which was leaking in front of the bolt on the left side. Is this a good candidate for welding with a soldering iron? If so then what do I use for filler? I'm worried that it's gonna blow out while I'm rolling down the road. These things are plastic, made in chineeze garbage. It's under 15 lbs of pressure before the radiator cap sends coolant to the overflow bottle. I just noticed this little gremlin today.
Also this is the only soldering iron that i have to work with. I'm poor until I find another job. If worse comes to worse then I can always put the other one back on. This car is a damn sight impossible to work on while on the side of the road and requires all manner of specialty tools and techniques. It's probably the biggest pain in the ass and worse design for an internal combustion engine in the history of automobile manufacturing.
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Raymond
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All cars come with Gremlins, it's just a question of how many and how long will they wait to come out of hibernation ;)

That's definitely ABS so it should be a good candidate for the task. The real question is where is it leaking from. If it's coming out from the bolt then that tells me it's the mating surface from the top to the bottom piece that has some warpage or perhaps some of that scale built up underneath it allowing water from the inside portion of the bolt to leak through. Did you use black Permatex on it? If so did you goop it or use a thin layer because gooping usually causes leaks due to uneven distribution and too much gap. If you can see there's a layer but you can still see the surface not just pure black goop, then you've done it right. It's not quite like the diff cover of a big truck axle which you should still use a thin layer on ;)

Welding over just the bolt would be about the same as using some goop on it but both will likely leak soon. If you have the last one then you might be best taking it apart then comparing them and also validate that you have a good mating surface. From here you can decide which piece and where to weld because you may need to do some build up on the inside to shave it down. I think the soldering iron will be difficult if you're doing build up of a flat surface though since you're likely going to bubble it and distort it more.

If you have a butane torch, you can try to modify it by adding a length of tube and a couple sink aerator screens to diffuse the flame so you're just pushing out hot air/gas. Careful here though, don't need to blow those money makers off your wrists. You might even be able to take a hair dryer and with some tubing/flashing/foil? :D reduce the hot end to a smaller size. Less than 1/4 would be the goal, and I think 1/8 is probably spot on. Again, be careful because the back pressure may be too much and you only want to use the low blower high heat setting.

ABS can't handle over 500F directly very well. You need to be around 350F to 450F. I'm welding at 350-360F and 3d printing which is extruding ABS at 456F. 456F is basically your max because around 460F it begins to cook and anything higher is unstable plus will likely be brittle since you cooked the natural oils out.

If you have some other ABS laying around then you can use that as filler. If you don't and since you don't like your car much, you can find some portion of a plastic trim panel that you can take a strip off. Just make sure you clean that strip off. You can also go to goodwill and find the something made of ABS for a $1 and sacrifice that. Just go to the car/electronic section since most of that stuff will be ABS. Once you have your donor, just razor blade off a strip hopefully the length of your full weld plus an inch or two. You'll want to practice this whole process on your donor first too especially since you're going the soldering iron route.

You'll need a razor blade so you can shave off a bit of your problem area to expose fresh ABS. Like 1/4 of a mm is plenty. If it's a clean black or if it's white then you've shaved enough i.e. not dirty.

To keep that soldering iron tip "clean" (you need to tin it man! :D I just learned how to do this after about 15 years of soldering... ) you might consider using some Al foil folded over a couple times and use it as a drag pad for the soldering tip on the plastic or you can use it to cover the tip. This might help with smoothing out and building up that flat surface with the soldering iron.

If that's just a bleeder valve for the radiator itself and you're willing to risk making that part a permanent piece of your radiator then you can weld those seems together. If you do that you'll want to take it apart and clean things up but then you can "tack weld" the pieces together first. With plastic welding, tacking is still not using filler but you're running a continuous run along the entire area you plan to weld. The welding aspect is when you add filler. So if you tacked it up (that Al foil might help give you a good smooth line here too and you might even consider just doing only a layer of the foil around the welding area rather than the drag pad or covering the tip) then it's just time to add filler. If you start from the back of the left to the front then to the back of the right, you'll probably hold the soldering iron in your right hand and filler in your left since you have to heat the front of your welding path and the filler itself. If you want to go the opposite direction, then you're gonna need to switch hands. You can switch hands half way through and this is where plastic welding is cool because you have the time to do it unlike real welding where usually you just have to stop where here you can swap and keep running.

You're going to push as straight down with your filler as you can and since you're not using heated air, again I think that foil tip might help because you need to be able to mostly heat your filler, which is difficult with soldering iron's pressure pushing it the opposite direction you want to weld in while you're trying to push your filler down. I'm guessing a 45 degree angle is what you'll want for the heat and almost always a 90 degree for the filler. So try to move that tip back and forth from your weld path and your filler and it should weld.
If you have a friend or some creative way to prop a hair dryer to face your welding area, it will help a lot and the closer the better.
Plastic will melt with heat but the reason a hot air based plastic welder works better than a heated piece of metal is the air acts like the arc force for arc welding where it creates the pressure to create penetration and force the weld. Shaken not stirred ;) In this case you're replacing that air pressure with physical pressure but much like blowing 150 degree wind in your face vs. having a 150 degree piece of metal put to your face, the air has a more even distribution, not as focused like the metal tip so the air heats a larger area vs. the metal which is gonna leave one nasty focused burn. This will translate into valleys and bubbles for plastic.
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Last thing... You could also just try pure Acetone but again you'll be pulling it apart and cleaning it up. Then just get both sides wet with Acetone, slap em together and bolt them down quick. That'll be very low strength but the full surface weld might be enough. I think I even saw a video around where a guy fixed a similar part using Acetone. Didn't watch it since I know the process but might be worth while for you to youtube too.
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entity-unknown wrote:All cars come with Gremlins, it's just a question of how many and how long will they wait to come out of hibernation ;)
At least the late AMC had the honesty to actually name a car "Gremlin"... :lol:

Steve S
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This piece mounts directly to the top side of the engine block. Top radiator hose is piped into it. The bolts have nothing to do with the leak. The problem is that it is molded in two pieces.....the body and a top cover similar to an AK47 receiver. Not sure how the top cover is attached but I don't believe that it is welded, probably some type of glue (made in chineeze crapola). The leaks are coming from the edge of the top cover because this is the weak point.
Here are some photos of the old piece. It looks like I can probably bond these two pieces together without filler since there is so much material to work with, then run some black RTV sealant around the inside. That top cover is 1/8" thick.
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Side view. That big gap between the top cover and the body (just below my finger) is where they both developed leaks. $40 for this junk. That white crap in the crack is dried antifreeze.
Side view. That big gap between the top cover and the body (just below my finger) is where they both developed leaks. $40 for this junk. That white crap in the crack is dried antifreeze.
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Where the leak is coming from. You can see how it has been escaping from the top cover due to a really crappy bond.
Where the leak is coming from. You can see how it has been escaping from the top cover due to a really crappy bond.
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Bottom view where the gaskets seat.
Bottom view where the gaskets seat.
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Raymond
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Otto Nobedder wrote:
entity-unknown wrote:All cars come with Gremlins, it's just a question of how many and how long will they wait to come out of hibernation ;)
At least the late AMC had the honesty to actually name a car "Gremlin"... :lol:

Steve S
Wayne and Garth had a stretch Pacer. Isn't that about the same thing as a Gremlin?
Raymond
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Yeah I didn't think the bolt was the problem, just the underside of the part where they mate at the bolt point. I think you got the right idea with the tack weld all around and some RTV. I'd brass/nylon wire brush all that white stuff out of there too since that will gap your gasket and cause the leak. After that, a thin layer of RTV on those gaskets and you should be ready to rock n roll (n fix the next thing on your list ;)
In a pinch, you could use some WD-40 to and a papertowel to clean that stuff out since I'm sure you've got both. A tooth pick will help get the crap outta the corners of the gasket seats as well if that brass/nylon wire brush isn't hand. Don't do anything more coarse.
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The halves of that part were either welded ultrasonically or with RF, with poor quality control. ABS does not solvent-weld well in tension, though it does quite well in shear. I agree this is a candidate for welding.

Steve S
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Ultrasonic plastic welding is pretty neat! I saw that a while back. They're responsible for those PITA packages like the ones they put knives in that requires a knife, some wit, and possibly some gauze to open. Also that's how your tooth paste tube is pressed at the end.
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There are plastic welding machines that are equall to MIG welders in size. They use compressed air or a tank of nitrogen. If you own one get a proper training video. It is for automotive collision work or autobody.
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