Large umbrella durability.

[Ozarker]

I like to use Westcott 72" umbrellas when shooting. The problem is that the weight puts a scary strain on the umbrella shaft. I'm always afraid the shaft will break.

Has anyone rigged something to help with this? Thought about getting an aluminum tube to slide over about 2 feet of the shaft to help with rigidity. I wish somebody made a solid aluminum shaft instead of the thin hollow tube Westcott is using on that heavy umbrella.

 

[Valvebounce]

Hi CanonFanBoy.
From my distant past (30 something years ago) I remember (in that fuzzy kind of I remember ) a motor mechanics lesson where we touched briefly on the physics of why propshafts are hollow.
For the same mass (weight) of the same material a hollow tube is significantly stronger than a solid bar, I have no idea if a solid bar of aluminium would be stronger than the thin wall tube currently used on the umbrella. However I think to get the same weight even from aluminium the shaft would have to be smaller diameter and don't forget things are designed to meet weight constraints as well as all the other requirements including lasting long enough that you consider them good value, not so long that you don't need to buy a replacement! ;D

Cheers, Graham.

 

[Ozarker]

Hi CanonFanBoy.
From my distant past (30 something years ago) I remember (in that fuzzy kind of I remember ) a motor mechanics lesson where we touched briefly on the physics of why propshafts are hollow.
For the same mass (weight) of the same material a hollow tube is significantly stronger than a solid bar, I have no idea if a solid bar of aluminium would be stronger than the thin wall tube currently used on the umbrella. However I think to get the same weight even from aluminium the shaft would have to be smaller diameter and don't forget things are designed to meet weight constraints as well as all the other requirements including lasting long enough that you consider them good value, not so long that you don't need to buy a replacement! ;D

Cheers, Graham.

Always a pleasure, Graham! You might just have something there. It's just that the shaft actually bends a little and a little bouncy if that makes senses. It really does always seem to be on the verge of breaking. Those umbrellas are $100 USD, so not something I like to replace. Had to replace one already, but from the stand falling over.

I would guess that slipping an aluminium tube over the shaft would strengthen it. The aggregate would still be hollow. I had smaller umbrellas, but they didn't have the flexing problem. It is something to see.

I never knew prop shafts were hollow. Very interesting. Love trivia like that! Thanks Graham

 

[BobG]

Hi CanonFanBoy,
Try a search for fishing umbrellas, they usually have two pole sections the upper section being an aluminium tube, the lower either an aluminium tube or solid aluminium with a ground screw. The only issue is that I doubt you will find a 72 inch as they are usually 45 to 60 inches.

I often use one with some extra camo material as part of a makeshift hide and weighs about 3kg

 

[eosuser1234]

For the ultimate in durability I would look at a: http://www.euroschirm.com/

I have had one for close to 10 years, and it just refuses to break.
Many sizes and styles for all needs.

 

[LDS]

I guess the OP is using a lighting umbrella, not a plain umbrella.

 

[BeenThere]

I agree with OP that sliding on an additional aluminum tube over the existing one would give significant added strength. I would try to find a diameter that is a snug fit over the existing tube. Good insurance and some piece of mind.

 

[Besisika]

I agree with OP that sliding on an additional aluminum tube over the existing one would give significant added strength. I would try to find a diameter that is a snug fit over the existing tube. Good insurance and some piece of mind.

I broke mine shooting outdoor. The wind blew, the light felt down with the umbrella first and broke the tube. I have never broke it due to the weight of the umbrella itself though.
I would be interested in an additional safety as well. Good thinking.

 

[Ozarker]

Hi CanonFanBoy.
From my distant past (30 something years ago) I remember (in that fuzzy kind of I remember ) a motor mechanics lesson where we touched briefly on the physics of why propshafts are hollow.
For the same mass (weight) of the same material a hollow tube is significantly stronger than a solid bar, I have no idea if a solid bar of aluminium would be stronger than the thin wall tube currently used on the umbrella. However I think to get the same weight even from aluminium the shaft would have to be smaller diameter and don't forget things are designed to meet weight constraints as well as all the other requirements including lasting long enough that you consider them good value, not so long that you don't need to buy a replacement! ;D

Cheers, Graham.

LOL! Read your post again, "From my distant past..." I've started saying, "Just after the middle of the last century..." Hate getting older, but I am enjoying my role as a new grandfather to no end!

 

[Ozarker]

I agree with OP that sliding on an additional aluminum tube over the existing one would give significant added strength. I would try to find a diameter that is a snug fit over the existing tube. Good insurance and some piece of mind.

I broke mine shooting outdoor. The wind blew, the light felt down with the umbrella first and broke the tube. I have never broke it due to the weight of the umbrella itself though.
I would be interested in an additional safety as well. Good thinking.

I'll try and hunt up my micrometer this weekend or maybe the guys at the hardware store can help out. I'll post the size for the Westcott 72" when I know. Great umbrellas for what they do, just that the shaft seems a little under-engineered.

 

[pwp]

Like any piece of hardware, if you're careless with it then its useful life will probably be limited. Wind is the biggest enemy of any umbrella, large or small. It will act as a sail, responding to the mildest puff of wind. I learned my lesson the hard way a long time ago when I put an Elinchrom 500 mono up a bit high, outdoors with an umbrella. Result: an expensive, disruptive crash. Even using lightstands with a big wide footprint, plus sandbagging is probably not enough. If your project's budget allows you really need an assistant (or friend) standing with each lightstand/umbrella/modifier. I've learned to keep them low as practical, sometimes lashed to a tree, pole or whatever.

FWIW my pair of Paul C Buff 86 inch umbrellas are close to ten years old, used a lot and still as good as new.

Another scenario where big/long shafted umbrellas can get damaged is during transport. I keep mine in tubes made from strong white 125mm plumbing tubes. I've glued a permanent cap on one end and a screw cap on the other. Cost was around $12.00. Cheap! And very durable.

HTH...

-pw

 

[MayaTlab]

How much an umbrella's shaft bends depends on various factors. Your idea of doubling the umbrella shaft is something umbrella manufacturers have already had . I don't know about Westcott, but the Paul Buff PLMs that I have already have an inner shaft inside the 8mm one (something that I know since one of the end tips conveniently fell off to reveal the inner design ). Shaft materials come in various grades and umbrellas that look similar may use different materials with differing qualities. Also, the weight of the umbrella's construction is decisive. A Paul Buff PLM soft silver is quite a bit heavier than a similar looking Cactus 105cm silver umbrella.

Now, because it's made of metal it probably won't break, but it might bend. I've had to straighten a few shafts over the years.

One solution, among possibly others that I don't know or forget : when I want added security, I like to use a grip head (ex : Avenger D200, but there are other alternatives) and grip the umbrella closer to the sliding runner, and independently grip the flash.

 

[old-pr-pix]

Graham is on target... in a cylindrical structure the majority of the stress is carried at or near the surface - the core material is just along for the ride. Hence, using a hollow tube is a good way to save both weight and cost while maintaining good stiffness or strength. As in all, it can be taken too far. A paper thin tube would have little chance of success. Aluminum also comes in multiple grades from really soft and bendy to much harder and stiffer. The better grades are often referred to generically as 'aircraft grade.' Putting a snug fitting aircraft grade tube over the existing tube would help mostly because it would be increasing the effective diameter as well as wall thickness. Sliding one inside would be of less benefit - it's more like filling in the core. Putting a stiffer material inside - such as a higher grade aluminum or even steel - could be beneficial though. (Likely the PLM approach.)

The thing with aluminum is that it can bend frequently but will develop tiny, microscopic cracks. Neuro could show them to us, but we would not see them with the naked eye. Those cracks over time will lead to serious cracks and eventual failure. Bending is fine (just watch an airplane's wings) but the cracking isn't.

 

[dadohead]

You can find carbon tube in various IDs at most hobby stores or TAP Plastics. Lighter and stronger, especially in flex, than aluminum or steel pound for pound. This will provide the rigidity you're looking for, even as a somewhat snug press fit. Glue it in place with epoxy and it will be even stronger.

 

[privatebydesign]

Or find some rod to jamb up the middle, ive seen wooden dowel used to stop crushing when small clamps are used.

 

[geekpower]

late to the party, but as others have implied, a larger diameter hollow tube is stronger than a smaller diameter solid bar, of the same mass, because leverage. not sure what diameter tube you have, or how big your clamps are, but an over tube would definitely be more helpful than an inner bar, if your clamp can handle it. even a tight wrap of kevlar tape could help. remember that the difference between a tube bending and folding is the sides blowing out.

 

[Talys]

@CanonFanBoy - I know exactly what you mean. I own a 7' umbrella, and I love it, though it is often too awkward for me. I often use a 48" umbrella or a 60" rear-illuminated bowens mount softbox (like an octa) instead.

Most of the time when I'm using the 7' umbrella, the shaft is parallel to the ground. In this case, an easy work-around is to use another light stand behind, with a Magic Arm (articulating joint + clamp) propping up the back and releiving it of any stress.

Another possibility is to use a large clamp to hold the umbrella, like the one pictured at the end of the boom here:

https://www.amazon.com/Neewer-Adjustable-Reflector-Photography-Monolight/dp/B01GUQUBEW/ref=sr_1_1?ie=UTF8&qid=1523596294&sr=8-1&keywords=cstand

The reason being, this holds the shaft solidly over a wide clamp that is a few inches in size, instead of gripping it by a small (tiny) surface area as with a strobe or umbrella/flash holder.

 

[Ozarker]

@CanonFanBoy - I know exactly what you mean. I own a 7' umbrella, and I love it, though it is often too awkward for me. I often use a 48" umbrella or a 60" rear-illuminated bowens mount softbox (like an octa) instead.

Most of the time when I'm using the 7' umbrella, the shaft is parallel to the ground. In this case, an easy work-around is to use another light stand behind, with a Magic Arm (articulating joint + clamp) propping up the back and releiving it of any stress.

Another possibility is to use a large clamp to hold the umbrella, like the one pictured at the end of the boom here:

https://www.amazon.com/Neewer-Adjustable-Reflector-Photography-Monolight/dp/B01GUQUBEW/ref=sr_1_1?ie=UTF8&qid=1523596294&sr=8-1&keywords=cstand

The reason being, this holds the shaft solidly over a wide clamp that is a few inches in size, instead of gripping it by a small (tiny) surface area as with a strobe or umbrella/flash holder.

Great idea Talys. Thanks!