Mega Tree Physics Question

[beeiilll]

Ha, no such thing as against the grain in this hobby!  I believe that the "think outside the box" style is why some of us do this in the first place.

Something that I wanted to throw in here was that while both methods (either a single 21' piece or 2 - 10 foot pieces with a sleeve and pin) will be acceptable for a center mast for a tree, the forces that can come into play with it are the biggest concern.   It may be easier for some to use or store the 2 pieces of pipe rather than 1 long piece so that can come into play as well.

 

I get more into the dynamics of the forces on the pipe as a concern.  If either the single or the two pieces stay absolutely vertical and don't move, then the load is the same.  Once you start to introduce any lean or sway into them, then the force on the pipe and the center connection point if using 2 pieces becomes more relevant.  As the pipe leans further away from true vertical, you begin to get concentrated force on the place where the 2 pieces are joined together more than on a single piece of pipe, although with enough lean (and/or weight) you can reach the point where that joint will fail before a single pipe would fail (but a single lenght of pipe an certanily buckle and fail as well).

Most of all it must be considered where the pipe or pole is located with respect to wind, weather, soil, weight of lights and materials, and how it is going to be guy wired off as to what will work and what will not.  Some folks can get away with an Aluminum flag pole while others may need a 2" galvanized steel pipe for the center pole.  Also some may only use 3 or 4 guy wires on the top while others may use 4 or more guy wires at the top and at the middle of the pole.

So anyone should make it a point to study all the factors before just tossing a 21 foot tall pipe out there and thinking that all is good with the world.  Not trying to scare anyone but a few minutes of study beforehand can save a lot of extra work or possibly a bad accident later on.  We also have to be careful because we all want to add more and more to our displays so while we may have a center pole that can handle the 30 strings ofs lights that we started out with, it does not take long before we are thinking of using 100 or more strings on that same setup.

I tend to overdesign to be safe but also so that I can make changes later on without any problems.

Just wanted to throw this "food for thought" into the conversation.

[caniac]

Ha, no such thing as against the grain in this hobby!  I believe that the "think outside the box" style is why some of us do this in the first place.

Something that I wanted to throw in here was that while both methods (either a single 21' piece or 2 - 10 foot pieces with a sleeve and pin) will be acceptable for a center mast for a tree, the forces that can come into play with it are the biggest concern.   It may be easier for some to use or store the 2 pieces of pipe rather than 1 long piece so that can come into play as well.

 

I get more into the dynamics of the forces on the pipe as a concern.  If either the single or the two pieces stay absolutely vertical and don't move, then the load is the same.  Once you start to introduce any lean or sway into them, then the force on the pipe and the center connection point if using 2 pieces becomes more relevant.  As the pipe leans further away from true vertical, you begin to get concentrated force on the place where the 2 pieces are joined together more than on a single piece of pipe, although with enough lean (and/or weight) you can reach the point where that joint will fail before a single pipe would fail (but a single lenght of pipe an certanily buckle and fail as well).

Most of all it must be considered where the pipe or pole is located with respect to wind, weather, soil, weight of lights and materials, and how it is going to be guy wired off as to what will work and what will not.  Some folks can get away with an Aluminum flag pole while others may need a 2" galvanized steel pipe for the center pole.  Also some may only use 3 or 4 guy wires on the top while others may use 4 or more guy wires at the top and at the middle of the pole.

So anyone should make it a point to study all the factors before just tossing a 21 foot tall pipe out there and thinking that all is good with the world.  Not trying to scare anyone but a few minutes of study beforehand can save a lot of extra work or possibly a bad accident later on.  We also have to be careful because we all want to add more and more to our displays so while we may have a center pole that can handle the 30 strings ofs lights that we started out with, it does not take long before we are thinking of using 100 or more strings on that same setup.

I tend to overdesign to be safe but also so that I can make changes later on without any problems.

Just wanted to throw this "food for thought" into the conversation.

I learned this lesson the hard way, had a "cheaper" telescoping flagpole and overloaded it to the point it is now junk in a landfill.  Got a better one but am finding out it is not ideal for anything more than 16 strands of lights.  used 2" rigid EMT last year and that works great, will be  using 96 strands of light this year plus a topper.

[AdamStavs]

I learned this lesson the hard way, had a "cheaper" telescoping flagpole and overloaded it to the point it is now junk in a landfill.  Got a better one but am finding out it is not ideal for anything more than 16 strands of lights.  used 2" rigid EMT last year and that works great, will be  using 96 strands of light this year plus a topper.

Caniac - can I ask what your problem with the flag pole was?  I've heard multiple people suggest not to use them.  Was it just the telescoping portion of it?  Because I have a 25ft tapered (non-telescoping) aluminum pole (approx 6" on the bottom down to 2.5-3" on the top)...and I just can't see how this would be problematic, at least not due to weight.  I could see winds potentially bending it, but guy wires should fix that.  I plan on going with 96 strings right off the bat.

[caniac]

it is four 5ft sections that start out at 2.5 inches at the base and taper up to 1.25 inches.  they use a push button spring mechanism to lock into place as you raise the pole.  when you are putting a flag on it this works great.  I put up and American flag 9 months of the year, October it flies a Jolly Roger, November-December some part of the Christmas show.  The issues I was have is that the weight of more than 16 strands of lights was more than the push button mechanism could handle, the first one I had was a Sunsetter and it was crap (or at least for a mega tree), have a Tel-a-Pole now and though it works better (thicker gauge aluminum and stronger springs), it still isn't ideal.

[Greg Young]

The pole pin Darryl sells is a solid 8 inch long pin, which is divided euqally between the two10 foot sections of black pipe. There is no coupler joint per se, just a solid steel pin that both black pipes slide over.

The top of his tree is guyed in 4 directions (although 3 would have worked just as well).

More than a few folks have used his design over the years without any issue.

I doubt you would have any issue with it, assuming adequate guys at the top, and a good base.

Black pipe is pretty strong, as is galvanzied pipe.

I agree with the comments above to avoid pvc/EMT conduit if you are faced with any significant winds (and who among us isn't), as I have seen quite a few folks on the various forums report failures when using those.

Rigid conduit is fairly strong. I use that for the first 10 foot section of my pixel tree, with galvanized pipe making up the upper telescoping piece.

[Max-Paul]

Here is what I see with the use of any form of aluminum pole. And this is to also include EMT, Rigid electrical conduit and those cheap TV antenna poles. All are of a thin wall material that easily flex. When a pole has loading from the ends. Eventually a weak spot will allow the wall to stretch and flex. As for the pin. Like I said in my earlier post. This pin will survive any thing you can throw at it. It will be the pipe that fails first. If you think you can just bypass the pin and use a pipe coupler. I would not do it. This will become your weakest point on the mast. Remember that the threads are cutting into the pipe and you have lost some of the strength that comes with the wall thickness. Might even consider cutting off the threads before installing the pin.

 

Beeiilll and Greg Young make a lot of great points. And Jimswinder has been very helpful too.

[SteveMaris]

I had an issue with the pin

. it did not fit tightly in the hole causing the top ten foot section to tilt a tad.

Not a big deal, but it did annoy me that it was not perfectly straight. No issue with the lights hanging down.

If I had a choice between 20 feet pole or two tens, I would go with the one piece for that reason. 

 

And as long as we are on the subject, did any pin users have this issue? any fixes? 

[gmac]

I had an issue with the pin

. it did not fit tightly in the hole causing the top ten foot section to tilt a tad.

Not a big deal, but it did annoy me that it was not perfectly straight. No issue with the lights hanging down.

If I had a choice between 20 feet pole or two tens, I would go with the one piece for that reason. 

 

And as long as we are on the subject, did any pin users have this issue? any fixes? 

I had just the opposite experience...I used 2 pices of black pipe and I had to file the weld down to get the pin to go inside and I have to lubricate the pin each year to get it in (It's more than snugG (LOL)...I think it's the Chinese Pipe we import and there tolerences arn't that exact

[caniac]

Here is what I see with the use of any form of aluminum pole. And this is to also include EMT, Rigid electrical conduit and those cheap TV antenna poles. All are of a thin wall material that easily flex. When a pole has loading from the ends. Eventually a weak spot will allow the wall to stretch and flex. As for the pin. Like I said in my earlier post. This pin will survive any thing you can throw at it. It will be the pipe that fails first. If you think you can just bypass the pin and use a pipe coupler. I would not do it. This will become your weakest point on the mast. Remember that the threads are cutting into the pipe and you have lost some of the strength that comes with the wall thickness. Might even consider cutting off the threads before installing the pin.

 

Beeiilll and Greg Young make a lot of great points. And Jimswinder has been very helpful too.

I am on version 3.0 of my mega tree, this version (which I used last season) starts with a 10ft piece of 2" rigid EMT.  I then took a piece of 10ft piece 1.5 rigid EMT and wrapped it in several places with Duck Tape so that when I slid it in it was a snug fit.  I then placed three eye bolts thru where the 1.5 slides into the 2 inch piece and use these for guide wires at the mid section.  I have a WowLights star topper and use guide wires with it (this is being replace with a hook head this year).  Do you see any issues with this setup?  It survived 50mph winds this past winter with no issues.

[plasmadrive]

Here is what I see with the use of any form of aluminum pole. And this is to also include EMT, Rigid electrical conduit and those cheap TV antenna poles. All are of a thin wall material that easily flex. When a pole has loading from the ends. Eventually a weak spot will allow the wall to stretch and flex. As for the pin. Like I said in my earlier post. This pin will survive any thing you can throw at it. It will be the pipe that fails first. If you think you can just bypass the pin and use a pipe coupler. I would not do it. This will become your weakest point on the mast. Remember that the threads are cutting into the pipe and you have lost some of the strength that comes with the wall thickness. Might even consider cutting off the threads before installing the pin.

 

Beeiilll and Greg Young make a lot of great points. And Jimswinder has been very helpful too.

aaahhh.. Max.. I am a bit confused by your first two sentences..   Are you talking about aluminum conduit?  I wasn't aware of any aluminum rigid conduit...  Regular rigid is the same as galvanized water pipe except for the threads are not tappered.. I believe..   That is what I use and it is plenty strong..

I also use the pole piece from CLS and I ground a "flat" on the pole piece so it will insert in the pipe without the pipe seam being an issue.. that pole piece goes up far past the threads and seems plenty strong.  Not sure the threaded part would really have much to do with the strength.. at least from what I have experienced..  have you had problems with any of them? 

I am on version 3.0 of my mega tree, this version (which I used last season) starts with a 10ft piece of 2" rigid EMT.  I then took a piece of 10ft piece 1.5 rigid EMT and wrapped it in several places with Duck Tape so that when I slid it in it was a snug fit.  I then placed three eye bolts thru where the 1.5 slides into the 2 inch piece and use these for guide wires at the mid section.  I have a WowLights star topper and use guide wires with it (this is being replace with a hook head this year).  Do you see any issues with this setup?  It survived 50mph winds this past winter with no issues.

Caniac,  Did you use EMT or Rigid?  Not the same thing..

[caniac]

aaahhh.. Max.. I am a bit confused by your first two sentences..   Are you talking about aluminum conduit?  I wasn't aware of any aluminum rigid conduit...  Regular rigid is the same as galvanized water pipe except for the threads are not tappered.. I believe..   That is what I use and it is plenty strong..

I also use the pole piece from CLS and I ground a "flat" on the pole piece so it will insert in the pipe without the pipe seam being an issue.. that pole piece goes up far past the threads and seems plenty strong.  Not sure the threaded part would really have much to do with the strength.. at least from what I have experienced..  have you had problems with any of them? 

Caniac,  Did you use EMT or Rigid?  Not the same thing..

Rigid, thought it was Rigid EMT or at least that is what the dude at Lowe's called it. 

[gmac]

aaahhh.. Max.. I am a bit confused by your first two sentences..   Are you talking about aluminum conduit?  I wasn't aware of any aluminum rigid conduit...  Regular rigid is the same as galvanized water pipe except for the threads are not tappered.. I believe..   That is what I use and it is plenty strong..

I also use the pole piece from CLS and I ground a "flat" on the pole piece so it will insert in the pipe without the pipe seam being an issue.. that pole piece goes up far past the threads and seems plenty strong.  Not sure the threaded part would really have much to do with the strength.. at least from what I have experienced..  have you had problems with any of them?

Sheese........Sur' wish I would of thought of that..... I'm embarrased to say how many hours I had filing the freakin weld down inside that pipe

[Shubb]

Rigid, thought it was Rigid EMT or at least that is what the dude at Lowe's called it. 

 

By Rigid EMT he means galvanized pipe sold at electical supply houses. It is the same as plumming supply stores except it comes in 10' lengths (electical) instead of 21' (plumbing). Rigid conduit has the same taperd NPT threads as galvanized plumbing pipe.

 

EMT (electrical metal tubing) is thin wall steel pipe used only for electrical conduit.

(and Mega Tree's)

[Max-Paul]

I agree with Tom, EMT is usually the thin walled stuff. Tell me this gents, can you put galvanized pipe in a bender (heavy duty type) and pull a 90 on it? You can with the rigid conduit that we use in electrical wiring. I think that the two are different metals or heat treating. One is malleable and the other is not. Sure galvanized pipe will flex a bit, but suspect that it would split, crack or fold if you tried to bend it.

As for the aluminum pipe, we are talking about those telescoping flag poles or for bird houses. But there is conduit made of aluminum pipe also. And actually Plasma, I reread my post and I believe that there is a period between the aluminum poles and all of the other pole materials. So, I am kind of confused about your confusion. And about my comment about the pipe threads. If the pin should be a wee bit loose inside the pipes. At what points does the pin press against the inside of the pipe? Those points would be the very end of the pipe and about what 6 or 8" inside of the pipe, at the end of the pin. Ok is going to happen when the pipe receives flexing forces at the joint. Cause the pipe is very thin in the first inch or so. I think what could happen is that the pipe will start to split at the end. This splitting starts a rift that weaks more pipe material further from the end. My thoughts are to cut off this weak area so if a split is going to start, it will have to do so at the full thickness of the pipe not at a thinner threaded area. Maybe I am anal, but I made it through one year and we had a very windy day that had my light strings making like a sail. And as I said I only have 12 channels that make 24 runs from top to bottom. Each run is made of 3 strings of C6 lamps 50ct each.

[Shubb]

I agree with Tom, EMT is usually the thin walled stuff. Tell me this gents, can you put galvanized pipe in a bender (heavy duty type) and pull a 90 on it?

 

Yes.  It's done all the time.

[jsholla]

I just use 1 5/8" chain link fence tubing and buy appropriate fittings from here:

 

http://www.creativeshelters.com/Fittings/Canopy-Fitting.aspx

 

Works great!

[Klayfish]

I am on version 3.0 of my mega tree, this version (which I used last season) starts with a 10ft piece of 2" rigid EMT.  I then took a piece of 10ft piece 1.5 rigid EMT and wrapped it in several places with Duck Tape so that when I slid it in it was a snug fit.  I then placed three eye bolts thru where the 1.5 slides into the 2 inch piece and use these for guide wires at the mid section.  I have a WowLights star topper and use guide wires with it (this is being replace with a hook head this year).  Do you see any issues with this setup?  It survived 50mph winds this past winter with no issues.

Caniac,

How far down into the 2" EMT do you slide the 1.5"?

Edited March 1, 2013 by Klayfish

[Ron Boyd]

I plan on using the Monkhouse Portable Hole: http://www.magicchristmasnews.org/portable%20hole%20ii.pdf and then use 2) 1 1/4" x 10' Rigid conduit with CLS 12" Pole Pin: http://www.christmaslightshow.com/pole-pin.html

(I am trying to get away from using PVC (gray or white). I had several pieces break during take-down this passed year)

I was not planning on guy wires, but after reading this forum, I'm re-thinking that.

 

On the Monkhouse portable hole, he tested his mast (pg.7) at 20' and over 70#s pull and it only flexed. He is, however using his designed "Jump Pole", http://www.magicchristmasnews.org/monkhouse%20jump%202010%20version0001.pdf which uses the Pipe in pipe method. I may rethink my 2 pole idea and go with the Jump version.

My tree will be ~20ft with 80 strings of 70ct lights. I live in TN and we do occasionally get snow or ice, but rarely. We do get some high winds from time to time.

[Shubb]

I am on version 3.0 of my mega tree, this version (which I used last season) starts with a 10ft piece of 2" rigid EMT.  I then took a piece of 10ft piece 1.5 rigid EMT and wrapped it in several places with Duck Tape so that when I slid it in it was a snug fit.  I then placed three eye bolts thru where the 1.5 slides into the 2 inch piece and use these for guide wires at the mid section.  I have a WowLights star topper and use guide wires with it (this is being replace with a hook head this year).  Do you see any issues with this setup?  It survived 50mph winds this past winter with no issues.

 

I have almost the same set-up just 1 size smaller pipe.

I use 2" on the bottom then 1 1/2" and 1 1/4" on top.  Each pipe slides in about 1 foot into the larger piece.

The 1 1/4" fits pretty snug into the 1 1/2"

3 Eye bolts are slid though the connection point for guy wires.

 

This allows me to hang all the lights from a short ladder and then 2 of my strongest friends help lift the center pole to full height.

 

Then we lay on the ground and huff and puff while we catch our breath and swear this is the last year we do it like this.

At least, that's the way it's been for 7 years now.

[caniac]

Caniac,

How far down into the 2" EMT do you slide the 1.5"?

4-5ft