Separating rusted parts

[Rolyata]

We've got a steel hammock stand that's been outside all summer. The parts slot together and before assembling them in the spring, I liberally coated them with grease - however it would appear that it wasn't liberal enough.

All the joints nicely pulled apart except for one.

I've tried using WD40, pouring hot water over the sleeve part to make that part expand and clamping one tube in a workmate ( long way along the length of the vice ) while whacking the joint in the opposite direction with a large rubber mallet. I've also tried tightening a rope around it with a strong cross piece to get some leverage. So far the pipe is winning.

So what other techniques might work ?

The steel tubes are very thick, maybe 35mm diameter with a wall thickness of about 3-4mm. Most of the pipe is powder coated and I'd like to keep it that way by not using fierce tools on it. The parts that slide together are bare metal and they slide into a suitably wider tube. I guess that some moisture has got in over the summer and started some rust that fixes the pipes together.

One part has a welded cross member to form feet ( and a convenient way to get leverage ), but the other part is a 4 foot length of straight tubing.

I'd rather take it apart as otherwise it's annoyingly bulky to store over the winter.

[The3rd Earl Of Derby]

Pouring hot water on it would not have made one Iota of difference, try and use a paint stripper on it or gas blowtorch for at least 4/5 minutes around the circumfrence of the tube.

-- Sir Benjamin Middlethwaite

[Newshound]

I would try and soak the joint in penetrating oil (better than WD40). There may be constraints on the geometry, but if it was just two straight tubes perhaps you could slide a polythene funnel over the joint, seal the funnel to the outer tube with sealant (inside) or PVC tape (outside), then stand it vertical and fill the funnel with penetrating oil so that it gradually soaks through the rust by gravity and surface tension. This should reduce friction enough to disassemble it. Or perhaps you could seal one end and fill the tube with oil to "soak" it from inside. In that case you might dilute lubricating oil with white spirit or paraffin. Leave it soaking for a week or so. You could get more aggressive with the rust using weak acids but I generally find the problem is friction from the dry rust. For the "inside out" strategy you could increase the driving force by pressurising it using a couple of rubber bungs, a schraeder valve and a bicycle pump.

[The Wanderer]

Look for some 'Releasal' oil. It's blue in colour, applied liberally and left to stand for a while it will help. Must admit, I've had my tin for quite a few years, I guess it's still available.

[mike ring]

T

Google don't think so

mike

[mrcheerful]

releasall (note the double L) is still available stateside. (according to google)

You could fill it with diesel, that is a very good penetrant, and cheap too.

mrcheerful

[Rob Morley]

Soak it in PlusGas (dismantling lubricant) for a few days, then try to twist the tube - use something like an old innertube wrapped around it a few times to get a good grip without damaging the finish. Once you can twist it back and forth a few times soak it a bit longer then try twisting and pulling.

[Peter Taylor]

I bet it's not rusted too badly - just needs a little help. I'd try the penetrating oil first like others have suggested, but if that doesn't make any difference:

Did you try holding it upright and banging one end hard on the ground? It's pushing the inner tube further in, but it might free up the joint so you can pull it out.

What about a pair of big stillson wrenches (or even one wrench and a vice) to twist and free the joint that way? You might need to put a bolt through each tube to get a better grip.

Last resort, could you drill a hole in the outer tube just beyond the end of the inner tube and use a lever through the hole to push on the end of the inner tube?

[Chris Bacon]

If you greased the joint I shouldn't think it will have rusted sufficiently to bind in this time - it's probably just got stuck. Is it a tent-pole like joint, i.e. the end of a pole is reduced in diameter so that it can fit into the one on top?

Get two other people, and have them pull each end, nice and steadily, while you grasp the joint in the middle and pull it from side to side. Turn the pole as you wiggle it. If there's any looseness, that will do it.

If no joy, clamp the top bit, and welt the bottom "foot" near the tube with a hammer, not a rubber mallet. This will of course damage the finish, but it'll need shock to move the thing, which you won't get with a RM. The feet should be easier to touch in than the pole, & less obtrusive. Heat should help, too, but you need to get it rather hotter than you are (which might damage the paint).

[Anna Kettle]

I would attack the joint with a hot air gun. The metal will expand and so the rust will collapse. Not entirely of course but enough to let you part the pipes

Anna

[John Schmitt]

You could also try borrowing a dead-blow hammer with a polyurethane face. The head is partally filled with lead shot, which on impact moves down to the end of the chamber, giving a sustained and powerful blow. The polyurethane face prevents damaging steel. We had some apparatus with a very precisely machined SS ram passing through a bronze bush, lubricated with castor oil. Don't ask. It was surprisingly effective at unsticking stuck rams.

John Schmitt

[Ian Stirling]

As a guide. Look closely at the surface you are playing the blowtorch over. When cold, you will see condensation. As the surface passes 100C, you lose this. I find WD40 handy for this. It boils at 150C or so, so I spray WD40 in, heat the joint till it starts bubbling out, then as the WD40 has now displaced much of the air, by evaporating, remove heat and spray with more WD40, allowing the joint to wick more in, when the air/vapour inside cools and contracts. DO NOT DO THIS WITH ANY LARGE CONTAINERS, it could kill you as the explosion bursts it. Not to mention the whole fire thing.