Camera too positive Buoyant

[danhngo9594]

Hi there, I just test my camera setup today with an Acrylic Dome Port, my set up is quite positive buoyant in freshwater, mainly because of the dome port, how to offset that, make it neutrally buoyant?
Anyone has some tip? Also If I cannot change anything should I add few more pounds to my weight bell cuz this camera may affect my buoyancy

 

[emoreira]

every housing has a way to add some lead plates to adjust buoyancy. Besides, most housings has a nut in the lower part to fix the housing to an arm with lights. That nut is sometimes used to fix the lead plates.
Lead plates can be bought or you can make them and fix with a screw. Be careful with the screw. It must be of the required size, thread and lenght, otherwise you could break the integrity of the housing and flood.

 

[danhngo9594]

every housing has a way to add some lead plates to adjust buoyancy. Besides, most housings has a nut in the lower part to fix the housing to an arm with lights. That nut is sometimes used to fix the lead plates.
Lead plates can be bought or you can make them and fix with a screw. Be careful with the screw. It must be of the required size, thread and lenght, otherwise you could break the integrity of the housing and flood.

I work in a sheet metal shop, so getting a kind of sheet lead to wrap around the connection from housing to the dome port may do? Do you think so? I just worry putting too much force on the three screws that holding between the port and housing

 

[Chris Ross]

Try something like this: Trim Weight System for DSLR & Mirrorless Housings

you could either buy that item of make a copy with aluminium bar bolted to the tripod screw of the housing and attach a dive weight - probably only need the smallest one you can find. Placing it forwards will overcome the tendency to twist up from the dome. Add an anti-rotation feature as it'll twist off easily other wide if you only use a single tripod mounting screw to attach - a small piece of aluminium or plastic sitting against the housing/tray so the bar con't rotate.

 

[D_Fresh]

Could spend money on expensive underwater camera weights/systems, or you could be cheap and get some adhesive wheel weights from your local auto supply store and stick em to the bottom of the housing, dome, or both if needed....

 

[danhngo9594]

How much weight would you think I should add, cuz Gym pool is currently closed I can trim it no more, about 1lb? Or little more than that?

 

[jborg]

You should be able to test this out in a bathtub if you have one, or in the worst case your kitchen sink. My SeaFrog house with dome and A7+16-35 required about a kilo (no flashes and such attached). This was slightly less than one full box of tyre weights, as delivered by the local mechanics outlet.

 

[danhngo9594]

You should be able to test this out in a bathtub if you have one, or in the worst case your kitchen sink. My SeaFrog house with dome and A7+16-35 required about a kilo (no flashes and such attached). This was slightly less than one full box of tyre weights, as delivered by the local mechanics outlet.

View attachment 624899

Are you having an Acrylic Dome too? Cuz I know glass dome is heavier. I just scared to put too much weight on the dome port and zoom gear, with Ikelite housing domeport is only tighten with 3 set screws, I’m worried about those

 

[jborg]

Mine is acrylic, yes. I guess you need less weight if it’s glass. Anyway the point of the weighting is for it to be neutral underwater, so there isn’t any force on it due to the weights underwater.

 

[Chris Ross]

you should be able to test it in a bath-tub or a deep sink for buoyancy. Typically if the housing is positive you can put most of it attached to the tripod screws on the housing tray and add some trim weight to the dome if required to stop it twisting upwards. I don't know if you have a macro port as well or not or plan to get one if you do consider how you will change the weighting when you change ports.

If you have a vacuum system on the housing it will help with holding the port in place. If you don't have a vacuum system , I would suggest getting one - great insurance against flooding.