Applying RTV Silicone

[biggsgolf]

I need to apply rtv to secure the cylinder into the resin bulkhead channel, how can I do that? Somehow put rtv into the channel then press cylinder into it?, just put rtv on the cylinder? How would you guys proceed and how would you apply the rtv?

[Das Boot]

I need to apply rtv to secure the cylinder into the resin bulkhead channel, how can I do that? Somehow put rtv into the channel then press cylinder into it?, just put rtv on the cylinder? How would you guys proceed and how would you apply the rtv?

Does your bulkhead have gaskets? If not, place the RTV on the bulkhead.

[biggsgolf]

it does not, this is the inner ballast tank assembly

[Das Boot]

it does not, this is the inner ballast tank assembly

Can you post a picture? Generally, the two ballast tank bulkheads call for gaskets on both. Putting RTV on them is a crap shoot, unless I’m mistaken your setup. Those are the most important places to keep out leaks from the equipment tray and battery compartment.

[biggsgolf]

Oops, sorry, thought I did, but didn't..... R&R cylinders do not have gaskets on these

[Das Boot]

Got ya. I would definitely put the RTV on the caps, not inside the cylinder. First off, it’s better to have too much on the cap than not enough, and if you put too little in the cylinder, it’s going to make a big fat mess. Of course that’s my opinion, I’m sure you’ll have someone with a better idea come in. Your project looks good by the way. Keep up the good work.

[biggsgolf]

Got ya. I would definitely put the RTV on the caps, not inside the cylinder. First off, it’s better to have too much on the cap than not enough, and if you put too little in the cylinder, it’s going to make a big fat mess. Of course that’s my opinion, I’m sure you’ll have someone with a better idea come in. Your project looks good by the way. Keep up the good work.

Thanks, I really appreciate the compliment

[biggsgolf]

Just sure how to get silicone in the channel with out making a mess! Lol

[redboat219]

RTV silicone usually comes with applicator tips, just cut off the very end so you'll just get a a small bead of siicone.

You could transfer the RTV into a syringe with a 14 to 16 gauge dispensing needle .

https://www.amazon.com/Reuseable-Craft-Syringe-Silicone-application/dp/B00ZY5E278

[QuarterMaster]

1. 1-If you place an appropriate bead of RTV inner wall of the tube, say 50-75% of the final distance in, as you push it in place, the RTV will form a seal as it is pushed deeper into the tube, pressure from inside the tube will push against that attempting to push past the plug, effectively trying to seal itself. I tend to put a 4-5mm 45 deg chamfer at that edge which will fill with RTV providing a seal which compresses against the cylinder and plug even more. This provides a good seal. Make sure you have a close fit.
2. If this is a permanent install to the tube, as I don't see why not, I would also add JB Weld in that groove I think I see where the tube seats for strength and a backup seal. Though RTV will do as well, or better yet 3M 5200 or similar.

Think...
Tube applied: Plug pushes RTV pushed deeper.
Plug applied: RTV will be pushed towards the end of the tube trying to squeeze out.

Either way you do get shmutz (did I spell that right?) between the tube and plug (given the tolerance gap) from the application point to the final rest point.

This is what I do, Murphy's Law is a "Clear and Present Danger" in my life and "Failure in an RC Sub is NOT an Option"...except with a certain USS TEXAS SSN-775 sailing at Sylvan Rodriguez. (Ed ducks...)

[biggsgolf]

1. 1-If you place an appropriate bead of RTV inner wall of the tube, say 50-75% of the final distance in, as you push it in place, the RTV will form a seal as it is pushed deeper into the tube, pressure from inside the tube will push against that attempting to push past the plug, effectively trying to seal itself. I tend to put a 4-5mm 45 deg chamfer at that edge which will fill with RTV providing a seal which compresses against the cylinder and plug even more. This provides a good seal. Make sure you have a close fit.
2. If this is a permanent install to the tube, as I don't see why not, I would also add JB Weld in that groove I think I see where the tube seats for strength and a backup seal. Though RTV will do as well, or better yet 3M 5200 or similar.

Think...
Tube applied: Plug pushes RTV pushed deeper.
Plug applied: RTV will be pushed towards the end of the tube trying to squeeze out.

Either way you do get shmutz (did I spell that right?) between the tube and plug (given the tolerance gap) from the application point to the final rest point.

This is what I do, Murphy's Law is a "Clear and Present Danger" in my life and "Failure in an RC Sub is NOT an Option"...except with a certain USS TEXAS SSN-775 sailing at Sylvan Rodriguez. (Ed ducks...)

Very cool, thanks Ed!

[Subculture]

Can't you just make some grooves in the caps and use o-rings, then it's easy to take apart for cleaning etc.

[Das Boot]

If I understand this right, he said this ballast tank is modeled after the R&R. Are their ballast tanks not designed with one lexan cylinder and two end caps for the ballast tank, and then another lexan tube that slips over the whole thing, with two more caps? So I don’t know what you mean by 75% of the final distance, when the ballast tank has two end caps. I’m pretty sure he’s not talking about the standard Merriman WTC, where the ballast tank has two bulkheads on the inside of the ballast tank that have gaskets and are held in place with screws. Or am I on drugs or something?

[Das Boot]

Isn’t this the WTC we’re talking about? The ballast tank is in the middle with two end caps and its own lexan housing. His original post, he only mentioned the ballast tank assembly.