How to remove a stainless tube from an aluminum clamp?

hilbert · Post by **hilbert** » Dec 23rd, '11, 16:29

I have a 2" stainless tube in an aluminum clamp, that are stuck together.

I need to reuse the aluminum clamp, but I will not need the full length of the steel tube.

Does anyone have a suggestion for removing the aluminum oxide and seperating the clamp from the tube?

sweet patootie · Post by **sweet patootie** » Dec 23rd, '11, 17:38

Try Sno-Bowl toilet bowl cleaner, but use it for short periods of time, and rinse thoroughly. Might take several applications of 30 seconds or so.

Might be better to just buy some new aluminum clamps??

jbenagh · Post by **jbenagh** » Dec 23rd, '11, 17:43

It might take more than a propane torch. If you can find an acetylene torch, that might be just the ticket.
A more excruciating method it's to saw out off and then grind a slit inside the pipe. Then you peel it off. It won't be easy with stainless.
Jeff

hilbert · Post by **hilbert** » Dec 23rd, '11, 17:58

The clamp (the gray piece with the two stainless steel bolts) is high-end cast aluminum.

Considering the value, an acetylene torch would be risky.
However, changing temperature can help to separate dissimilar metals. I am considering putting ice in the tube and using a propane torch (with care) on the aluminum clamp.

bottomscraper · Post by **bottomscraper** » Dec 23rd, '11, 21:08

Have you removed the bolts yet? I suspect they may not be as
hard to remove as you think. Spray with some Kroil or PB Blaster
first and let it sit a while before you try. Use 6 point rather than
12 point sockets if possible. Once you get the bolts out a wooden
wedge driven in between the sides of the clamp may be all you
need to break it free. A dense hardwood like maple would be
best for the wedges. Time an patience usually usually work for
stuck bolts, shafts, pulleys and the like. I would NOT us any
significant heat on the aluminum. A heat gun maybe.

Use Tef-Gel before you reassemble!

Steve Laume · Post by **Steve Laume** » Dec 23rd, '11, 21:43

I think Rich has the right idea. The Sno-Bowl might work great too but I have no experience with it.

A good soaking in penetrating oil, Remove the bolts and then you could drive wedges in from both ends. If hardwood doesn't seem to work you could use a pair of long tapered cold chisels. Once you apply some pressure with wedges you could also tap the clamp with a soft mallet. With the tube clamped in a vise, you could tap on the ends or to give it a twisting motion. If it doesn't pop right away, you could soak it some more and try again.

It's a long winter so don't rush it and break anything, Steve.

M. R. Bober · Post by **M. R. Bober** » Dec 24th, '11, 12:23

If you can cut the ss tubing near the bracket, and you have some time it might be worth it to put the bracket in the freezer and then heat it with a hair dryer. It will take dozens of cycles, but I have had success with this method.

Good luck and happy holidays.

Mitchell Bober
Sunny Lancaster, (Where topsides are the only white thing about this Christmas.) VA

tartansailor · Post by **tartansailor** » Dec 24th, '11, 19:09

Cut the bolts with a Dremel

Ben Coombs · Post by **Ben Coombs** » Dec 25th, '11, 08:45

But I suggest a hack saw... Takes a bit more effort, but it'll take less time, and the blade will cut both at the same time.

hilbert · Post by **hilbert** » Dec 25th, '11, 20:06

I am not too concerned about the bolts. I believe that they will come off in time with liberal and repeated applications of penetrating oil, tapping, etc. The issue at hand is separating the clamp from the steel tube. The clamp may be tight on the tube to start with. The clamp has an "opener", a middle hole that can take a bolt to pry the clamp open for assembly. Over time, the aluminum is "welded" to the tube, by corrosion. While the "opener" may help in disassembling the parts, excessive force could crack or break the casting.

I found this in the tips page of the manufacturer:

OXIDATION - The Hydrovane is not designed to be absolutely immune to corrosion. In fact we allow for a bit of oxidation to occur in certain joints of the bracket assembly - it strengthens it - like a weld. Although the aluminum used is the most corrosion resistant because of a high magnesium content oxidation eventually occurs. Although these old units can have some oxidation, none of it is damaging to the extent of compromising its strength or integrity. The exceptions are in situations where electrical current was allowed to pass through the bracket or the brackets were permanently submerged in salt water.

The tricks to loosen those frozen parts:

*Bathe in Penetrating Oil - Frequent spraying or, better yet, immersion over a period of time. Far better than WD40 is Alumiprep No. 33 from Aircraft Spruce & Specialty Co. - http://www.aircraftspruce.com/catalog/c ... miprep.php - in California but they ship worlwide - only $32 for a gallon.
*Boil it - Yes, like vegetables. The heating and contraction of the differing metals can cause a separation.
*Heat - Better than boiling it, but riskier, is putting a blow torch onto the frozen segments. Take care not to overdo it.
*Impact Tools - Machinists use special 'impact tools' that twist a screw or bolt just a fraction on impact.
*Skilled Machinists - We have yet to see a unit that we could not take apart. Before damaging it you might consider taking the unit to a qualified machine shop where they have the proper tools and savoir faire.

I know where to order the Alumiprep No. 33, but where does one find savoir faire?

Steve Laume · Post by **Steve Laume** » Dec 26th, '11, 10:25

So I suppose the best recomondation so far is to drag your unit around to a few machinists and ask if the have the proper savoir faire to deal with your problem.

Please report back to us on how you make out, Steve.

bottomscraper · Post by **bottomscraper** » Dec 26th, '11, 10:40

where does one find savoir faire?

On the internet!

www.savoirfaire.com

(Yes it is a real web site but no it won't help with this.)

Skilled Machinists - We have yet to see a unit that we could not take apart. Before damaging it you might consider taking the unit to a qualified machine shop where they have the proper tools and savoir faire.

For this job I would want the old guy, not the young kid drinking Red Bull with the big hammer.

Dick Villamil · Post by **Dick Villamil** » Dec 27th, '11, 10:40

I have freed many salt water corrosion fittings using vinegar - let soak for a while then rinse then repeat until the corrosion is gone. Then penetrating oil and then use gentle persuasion. Vinegar is a mild acid that will dissolve the corrosion salts.

hilbert · Post by **hilbert** » May 5th, '12, 19:17

Savoir Fair Is Everywhere.

After a lot of fussing, all the brackets have been disassembled. I soaked the parts in different dilutions of Alumiprep No. 33 for varying length of times. A 50% solution for two days worked well in removing the visible aluminum oxide. I then power washed the pieces and put them in boiling water. It took a long time to find the proper force to apply when knocking out the bolts from the heated assembly. Over several weeks, I started with a plastic hammer, graduated to a 1 pound hammer, turned in frustration to a 2 1/2 pound hammer, which was the proper persuasion.

Soaking in Alumiprep:

Disassembled brackets:

The Cape Dory Board

How to remove a stainless tube from an aluminum clamp?

How to remove a stainless tube from an aluminum clamp?

Lots of heat

a new clamp is expensive

Dremel

I second the bolt cutting

Manufacturers Suggestions

stuck fittings

Re: How to remove a stainless tube from an aluminum clamp?