Downside To Deforming Head Hose?

[Delancey]

Originally Posted by Terra Nova

Since you haven't provided enough information, it isn't possible for us to judge the downside potential.

But I am really curious why you seem to often look for a way to Mickey Mouse something, rather than repair it correctly?

The answer to your not very friendly question is actually pretty simple, it's because I am a creative-type, a character trait that non-creative-types often have difficulty recognizing or understanding.

I have been trained in my profession to question authority and to dispute the status quo. This is how creative people operate and this mindset is essential to the process whereby we CREATE NEW THINGS as opposed to simply consuming or destroying like everyone else.

Smart people harness this creative energy in business and this is what leads to innovation in the marketplace. Just because my approach to things doesn't include blindly following the herd, does not make it invalid.

Yes, I could just buy a part online, wait a week for it to ship like a normal person.

Or, I could take the time and the materials I have available and experiment. The direct benefit of experimentation is an increase of my knowledge base and if you don't see the value in experimentation, than I feel truly sorry for you.

What you see as someone Mickey Mousing around is actually what it looks like when someone is in the process of making themselves more educated and more aware of the world around them.

So, it took twenty minutes of my precious time and deformed some hose and made a couple quickie test pieces. I did one where I expanded the hose in one shot and another one where I did it in steps. I cut the test pieces in half and examined the wall thickness and the interior surface. I did comparative destructive testing of both formed and unformed hose.

You know what I learned? I learned that for someone who wants to stretch 1-1/2" head hose to 1-3/4" the only real downside is that you might learn something that someday might be useful, like when you are actually out there cruising and not sitting behind your computer telling people they are doing something the wrong way.

[Delancey]

PS "haven't provided enough information"? I don't come here looking for speculation. I asked a specific question about a specific material.

If you don't specifically have experience heat deforming coextruded PVC head hose, or other related materials, then you probably don't have any useful knowledge to offer do you?

[jcapo]

I was unable to stretch 1-1/2" Trident VAC XHD hose onto a 1-5/8" fitting using hot water. Dunno if the Shields is the same as the Trident. Failure mode was the reinforcing band would part splitting the exterior of the hose where the reinforcing parted. The interior did not split but there is very little hose material covering the reinforcing band. I changed out the fitting to match the hose.

Try it, it might work for you.

[Hudson Force]

Delancey, I doubt that you need much to defend your position. Most of us would stand with your process of testing alternatives and comparing possible outcomes. When reading this thread I was interested in the possibilities of applying the mechanical stretching device, the hot water bath, the gradient diameter hose connector...... the various lubricants. I believe that any of these can be successful using good techniques; however, it's often best to use the techniques that we have already mastered and I would rather avoid the complexity of more stored parts and tools. My "tried & true" is the use of a hair dryer held about six inches from the hose end and blowing evenly at the hose aperature. I can swiftly slip the hot hose over the soaped barb without damage to the hose. Sure, it's possible to overheat and weaken the hose, but this is why you've done the prior testing and learned the nature of the process.

Matching your technique to the best application while considering the risks of hose damage, pressures, mechanical stress, and position relative to the waterline is not a "micky mouse" process.

[Hudson Force]

Originally Posted by jcapo

I was unable to stretch 1-1/2" Trident VAC XHD hose onto a 1-5/8" fitting ................

I should mention that I have not attempted heating reinforced wall hoses and expanding their diameters with sizes smaller than this. When I look back at my post supporting Delancy's attempts above, I should say that my successful tenchiques are with hoses of approximately 1&1/2 inches or more. Smaller hoses with reinforced walls can be more difficult. The material makes a huge difference in possibilities. It is very easy to expand Tygon tubing from quarter inch inside diameters that have pneumatic or vacuum tube applications.

[Terra Nova]

Originally Posted by Delancey

...I am a creative-type...
What you see as someone Mickey Mousing around is actually what it looks like when someone is in the process of making themselves more educated and more aware of the world around them...

Originally Posted by Delancey

PS "haven't provided enough information"? I don't come here looking for speculation. I asked a specific question about a specific material...

Easy there Sluggo. Perhaps these "experiments" of yours make you feel like a great inventor. That's OK. But installing a 1-1/2" hose on a 1-3/4" fitting could sink your boat and endanger the lives of your crew. So I still consider this Mickey Mousing. Worse, actually. Malfeasance, perhaps, depending on how many people might be endangered by your un-seaman-like repair.

You didn't say what the hose was to be used for, whether it was below the waterline or...? So you didn't provide enough information. Most anyone with any boat building experience at all knows how difficult it can sometimes be to install 1-1/2" white sanitation hose on a properly sized 1-1/2" fitting. So your plan to install it on a 1-3/4" fitting is ludicrous.

You came here asking for advice. I applaud you for that. But keep your experiments, ashore, where they won't endanger others' lives.

[Delancey]

Plastics is a big subject to cover in a single thread, so to stick to the topic at hand here’s what I have learned over the years through research, observation, and experimentation specifically regarding PVC-

Common household PVC has a softening point around 195F, which is the point at which the material may be deformed readily without adversely affecting its physical properties. This is distinct from a melting point, which not all plastics have.

Again, plastics is a big topic, so as a reference I would cite Epoxy and Polyester Resins as examples we all know and are familiar with. These are “thermosetting” resins where an irreversible reaction occurs during polymerization, and is this distinct from the “thermoform” plastics which like metal can be re-melted and re-formed theoretically indefinitely.

I have heard of the hot water softening method for working with head hoses, but understood that “warm” water doesn’t really cut it and that unless you were using boiling water it might not be worth your time. I have always used a heat gun instead as being a lot easier for me than setting up a pot on the stove and watching it come to a boil, but boiling water should get you there if that’s what’s available to you.

As far as I can tell the manufacturer’s advisement against heat is a CYA. If they didn’t and people went around BURNING hoses, they would likely have a problem as is understandable. So far playing around with my hose I have heated and reheated without any discernable change in the physical properties at the temps I have been working with. For comparative destructive testing I have taken heated and non-heated samples and clamped them in a vice before using pliers to grab the reinforcing part of the coextrusion and pulling until the reinforcement tears away from the softer, more plastic part of the coextrusion.

Based on feel, the same amount of force is required to split the heated and unheated samples. I kinda thought the heated sample might have been easier to get the tear started, but I think this is subjective and a function of how I was grabbing with pliers and twisting turning to get the tear started, and in fact once the tear is started the force to continue was the same which makes me question that initial observation. I might set up a precise clamping method and a beam to confirm or deny this.

Attached is a photo of the tool, pretty simple and easy to use. As I expected, going all the way in one shot produces less than desirable results and a slow stepped-method works much better. One thing I thought was interesting was to see that initially, the hose has a fair amount of memory and that as long as it is not deformed beyond a certain limit, upon reheating it will shrink back to its original form. Beyond that limit, it will it will shrink upon cooling as would normally be expected. These are results which mirror my past experience working with this stuff.

While uniform in its manufacture, the general hose dimensions vary from coiling and the wall thickness varies by virtue of the coextrusion so I found it difficult to measure in any meaning full way. I have not seen any appreciable difference in the wall thickness and on the stepped sample the only observable mark off was a slightly embossed surface on the inside of the pipe at the location of the channel for the O-rings that hold the wedges together, something I consider inconsequential. The stepped-expanding method also would seem to allow for a tapered transition in diameters.

My initial conclusions from all of this Mickey Mousing around is that anybody contemplating a head hose project should not for a minute dismiss a heat gun or boiling water if they want to make their life easier, and that it is possible to heat deform this type of hose from 1-1/2” to 1-3/4” using a pipe expander tool.

Whether or not someone else wants to do this is up to them. I haven’t decided for myself, but I have enjoyed the process and I hope you have too. Who knows, may come in handy someday. I’ll probably work up a piece later today if I have time, otherwise it will have to wait til I get down to the boat. When I do I will post some pictures of the existing five-or-ten-year-old-connection-that-hasn’t-failed, because you know, such a thing is ludicrous.

PVC Suction Hose Plant - YouTube

[Cheechako]

If you are talking about the white shields hose NEVER heat it and don't expand it much. It fails readily in service if you do.

[Delancey]

BTW, all this talk of deforming reminds me of the fact that PVC can be readily bent with localized heating by packing the interior with sand in a method similar to hydroforming. Something to think about if you ever contemplated running PVC instead of hose.

[FlyingCloud1937]

I am also a creative.

I have also been around the marine repair since 1969.

I have replaced a number of hoses exact same type, where someone has expanded to fit.

My experience is that the hose will develop a shoulder at the interface of the expansion to the larger fitting. At this shoulder is where it splits between the harder coil, and the softer fill.

If it's head effluent, then you have a stinky boat, if it's below the water line you can sink your boat.

I never use this hose for below the water line fittings, I always use the rubber with wire coil, that is lined with pvc. I use the right size hose, and fittings.

Creativity isn't part of the process, functionality is.

Lloyd

Originally Posted by Delancey

Plastics is a big subject to cover in a single thread, so to stick to the topic at hand here’s what I have learned over the years through research, observation, and experimentation specifically regarding PVC-

Common household PVC has a softening point around 195F, which is the point at which the material may be deformed readily without adversely affecting its physical properties. This is distinct from a melting point, which not all plastics have.

Again, plastics is a big topic, so as a reference I would cite Epoxy and Polyester Resins as examples we all know and are familiar with. These are “thermosetting” resins where an irreversible reaction occurs during polymerization, and is this distinct from the “thermoform” plastics which like metal can be re-melted and re-formed theoretically indefinitely.

I have heard of the hot water softening method for working with head hoses, but understood that “warm” water doesn’t really cut it and that unless you were using boiling water it might not be worth your time. I have always used a heat gun instead as being a lot easier for me than setting up a pot on the stove and watching it come to a boil, but boiling water should get you there if that’s what’s available to you.

As far as I can tell the manufacturer’s advisement against heat is a CYA. If they didn’t and people went around BURNING hoses, they would likely have a problem as is understandable. So far playing around with my hose I have heated and reheated without any discernable change in the physical properties at the temps I have been working with. For comparative destructive testing I have taken heated and non-heated samples and clamped them in a vice before using pliers to grab the reinforcing part of the coextrusion and pulling until the reinforcement tears away from the softer, more plastic part of the coextrusion.

Based on feel, the same amount of force is required to split the heated and unheated samples. I kinda thought the heated sample might have been easier to get the tear started, but I think this is subjective and a function of how I was grabbing with pliers and twisting turning to get the tear started, and in fact once the tear is started the force to continue was the same which makes me question that initial observation. I might set up a precise clamping method and a beam to confirm or deny this.

Attached is a photo of the tool, pretty simple and easy to use. As I expected, going all the way in one shot produces less than desirable results and a slow stepped-method works much better. One thing I thought was interesting was to see that initially, the hose has a fair amount of memory and that as long as it is not deformed beyond a certain limit, upon reheating it will shrink back to its original form. Beyond that limit, it will it will shrink upon cooling as would normally be expected. These are results which mirror my past experience working with this stuff.

While uniform in its manufacture, the general hose dimensions vary from coiling and the wall thickness varies by virtue of the coextrusion so I found it difficult to measure in any meaning full way. I have not seen any appreciable difference in the wall thickness and on the stepped sample the only observable mark off was a slightly embossed surface on the inside of the pipe at the location of the channel for the O-rings that hold the wedges together, something I consider inconsequential. The stepped-expanding method also would seem to allow for a tapered transition in diameters.

My initial conclusions from all of this Mickey Mousing around is that anybody contemplating a head hose project should not for a minute dismiss a heat gun or boiling water if they want to make their life easier, and that it is possible to heat deform this type of hose from 1-1/2” to 1-3/4” using a pipe expander tool.

Whether or not someone else wants to do this is up to them. I haven’t decided for myself, but I have enjoyed the process and I hope you have too. Who knows, may come in handy someday. I’ll probably work up a piece later today if I have time, otherwise it will have to wait til I get down to the boat. When I do I will post some pictures of the existing five-or-ten-year-old-connection-that-hasn’t-failed, because you know, such a thing is ludicrous.

[Delancey]

Originally Posted by Cheechako

If you are talking about the white shields hose NEVER heat it and don't expand it much. It fails readily in service if you do.

This is exactly why I posted the OP. Can you please site references or substantiate this statement in some way?

[Delancey]

Originally Posted by FlyingCloud1937

I have replaced a number of hoses exact same type, where someone has expanded to fit.

Great, again this is why I asked the question. Presumably you are saying you have first hand experience replacing expanded coextruded PVC hoses that have failed, and not replaced ones that hadn't.

What size hose and how were large were they expanded? Do you know the method which was used to expand them?

[Cheechako]

Originally Posted by Delancey

This is exactly why I posted the OP. Can you please site references or substantiate this statement in some way?

Personal experiences. I thought that stuff looked like the next big thing. And started using it a lot. It has a tendency to run small and very difficult to get on fittings. I had two actual failures, one a 3/4 hose and one a 1.5 hose. One was forced on using hot water to soften it. The other was forced on using a heat gun to soften it. Both were fine initially, but failed in service within a year, one spraying salt water all over. The crack, or split I guess, was circumferential, and I believe in between the embedded stiffener.

[Delancey]

Thanks for the response Cheechako. I wonder if you wouldn't mind elaborating a little bit?

Like you are on the boat one day when out of the blue a hose lets loose, or were the hoses inconveniently located in a locker where you tended to throw stuff on them, or possibly there was repeated flexing involved?

I don't doubt what you said, its just that hoses can fail for lots of reasons. Maybe one failed and you weren't sure why, then the other failed and you immediately knew?

[Cheechako]

No stuff sitting on the hoses, Very little if any movement. On one, I just heard this hissing sitting at anchor. Low and behold I found it... salt water spraying in a fan shape out the split! The stuff appears so tough you wouldn't think this would happen. I think once it reaches the stretch point required to fit on some fittings, it just has failed internally and will just be a matter of time. One thing about black rubber... it's very forgiving.
The best hoses I've ever seen were on my Taiwan built 44 footer. No wire wound hose on that boat, but the hose wall thickness was like 3/8" plus... so it didn't need wire to keep it from folding/collapsing in a bend. You could stretch to fit a lot with no wire or other reinforcement. Like an Idiot, I replaced it all with USA made wire wound when rebuilding the boat.
When the job was complete I found myself asking why I did it. One can be too anal about this stuff.