too buoyant underwater camera rig

[stepfen]

Hello,

I recently got a Sony A5100 with housing (meikon), tray & two handles (flex-arm.com) and 2 cheap e-bay lights.

The whole rig is quite/very positively buoyant. How can I make it more neutral? Obviously I need to add weight but how?

All the other threads I fount were about how to make negative rigs more positive (floatings etc), but nothing on making it less buoyant. Any neat ideas?

Thanks in advance.

 

[Barmaglot]

First you need to figure out how much weight you need to add - put your rig in a tub of water, attach a satchel and start filling it with small objects of known weight - coins will do in a pinch. Once it is slightly negative (remember that in salt water, it will be a bit more buoyant than in fresh water), either weigh your satchel in the water using a hanging scale, or calculate your weights' total volume and substract it from their total mass to arrive at the final figure. Once you know exactly how much weight you need to put inside the housing to get it neutral, get a set of adhesive auto wheel weights and stick the appropriate quantity onto the insides of the housing.

Alternatively, consider bigger lights I have a setup similar to yours - Sony A6300 in a Meikon housing with a tray and the Meikon wet dome, and while it is slightly positive alone, the lights (Archon D36V) easily drag it down even with two 8"/60mm carbon fiber float arms (rated at 300g buoyancy each) attached - I'm planning to get 400g float arms before my next trip.

 

[outofofficebrb]

To follow up on @Barmaglot’s suggestion, I found sitting on the edge of a pool using a travel scale was really easy in determining how buoyant the rig is. Just make sure not to submerge the scale. I used some twine or rope to run the rig lower into the water without soaking my scale. If you don’t have one, they’re really inexpensive on amazon and worth their weight when traveling, especially internationally with so many different baggage rules that differ!

 

[tursiops]

Hello,

I recently got a Sony A5100 with housing (meikon), tray & two handles (flex-arm.com) and 2 cheap e-bay lights.

The whole rig is quite/very positively buoyant. How can I make it more neutral? Obviously I need to add weight but how?

All the other threads I fount were about how to make negative rigs more positive (floatings etc), but nothing on making it less buoyant. Any neat ideas?

Thanks in advance.

Test the buoyancy of the individual pieces, i.e. the camera/housing, the tray and handles, the lights. Probably it is the camera+housing. You can add tire weights to the tray, which puts the weights low on your system. Avoid putting the weights high, like on your lights, it will make the rig want to turn over.

 

[stepfen]

Thanks for all the suggestions.
For those asking the big problem is the housing. So far I had tested it with only one light because I had only one handle. Today I received the second handle and with a quick trial I did it seems much better - still with fresh water though. I will have a more thorough test soon.
I didn't know that adhesive weights exist - great idea.
Overall what is the suggested buoyancy? Positive buoyancy sounds awkward to me. I use an extensible clip to have the rig attached to me. I can't imagine I clip it to my chest d-ring (should I need to) and have it floating in front of my face/hands etc.

 

[KeithG]

Duct tape and a bunch of heavy coins. Tape the coins to the bottom corners of your housing. It is ugly but it works. Replace the tape as required.

At first glance using coins may seem expensive but they are readily available and will not rust.

Others may suggest using common washers but they will rust.

 

[northernone]

I just add things, tape (or ziptie or bicycle tube attach them later. Good ones include: Coins, tire weights, a couple wrenches. (Stainless, useful, about the right length to add to the bottom of a tray.)

 

[npole]

Check the main 3 parts separately and set the buoyancy individually: the camera housing with the handle; the left arm with the light; the right arm with the light.

The cheap lights are probably negative, so be sure to use the correct arms: if you bought the carbon arms from flex-arms, chose the ones that are buoyant enough to zeroing the light of each arm (they have several types of them). Ideally you should get neutral arms (not buoyant) and apply the floats directly on the light, but it's a much more elaborated solution and you other parts (floating foam).

When you finished with the arms, check the housing. If you bought the one with a dry port it will be very positive. On mine I needed around 400gr of lead to make it neutral. If it's the dry port, then it'll be positive in the front (the camera will tilt backward), you can apply the weight to the frame but the camera will still tilt and you need to compensate by moving the arms in front of it (very annoying and not ideal when moving the lights for macro shooting etc.), so apply the weight as much in front as possible. I've attached mine directly on the botton of the dry port and I used those weights you use to balance the truck wheels (pure lead is now illegal here for this usage, it's lead+copper but the weight it's almost the same):

 

[Scott from LongIsland]

fishing sinkers work and are compact

 

[MaxBottomtime]

You could zip tie some fishing weights or clip ankle weights to the strobe arms. I keep my housing slightly negative, but I always have it clipped off. I clip it to a caribiner off the side of the boat and then clip it to my chest D-ring before unclipping it from the boat. If I'm shore diving or diving from a boat without caribiners I clip it to myself before jumping in the water.