DIY light cannister, ABS or PVC?

[miketsp]

I'd like an explanation as to why abs cement won't work. I have yet to put mine in the water, but can't see any reason it won't work.

I remember researching this subject a few months back using Google and most of the articles I found were from car repair shops for abs bumper repair. I found a lot of comments that people were giving up on the adhesive type repairs as they looked ok initially but did not last. A lot of guys that were enthusiastic about adhesives initially, changed their minds as they gained experience and ended up moving to welding solutions.
Obviously there are many grades of abs and new adhesives come out all the time. You may be lucky.

PS: I have just spent 20 minutes researching ABS adhesive applications and I have not found any for high pressure applications.
All the manufacturers have adhesives for drain, waste and vent systems (DWV), conduit, and sewer applications.

These are not pressurised applications. This does not inspire confidence.

 

[bcsean]

Well, I'll be diving my canister with lead first time around to make sure there are no problems. Looking at 1/4" wall with over an inch of material glued into the end connectors, I'm not too worried about it holding up.

Will post when I finaly get around to diving it.

 

[Capnsnott]

I'm wondering about the cement, the ABS cement should bond with the pipe like any other lue would. It doesn't have to hold back pressure per se, it just has to hold to it's self and the pipe.
I'm going to glue up a mock canister, stick it on a rope and drop it to the bottom of a lake.

It would be nice to have one more option for doing the canisters. I really don't want to fool with the clear stuff.
Greg

 

[Capnsnott]

Let me elaborate on that real quick.
The pressure "in" on the end cap will press onto the end of the pipe. We can't have any expansion. The only possibility I see is for the pipe to flex in from the sides and pull away from the cap. So in essence, the cement has to have enough cohesive strength to hold this joint together.
Does this make sense?
So the question is going to be, can the cement bond to the pipe well enough to not pull away when the pipe swueezes in.

Is the horse dead enough yet or does it need more beatings?????????

 

[bcsean]

how much you think 1/4" thick tube is going to flex? I highly doubt it's gonna be a problem, which is why I built it this way. If I'm wrong, I'll happily post results here.

 

[miketsp]

In general I just avoid the issue. If the unit has a dichroic lamp (halogen) with a life in excess of 2000hours and the battery is rechargeable I seal the unit with silicone fillets.

I just put a smaller tube inside the larger tube but about 2 inches shorter. This inner tube serves as a distance spacer. The front lens made of 1/2" polycarbonate and the back plate made of 1/4" high grade aluminium alloy are cut as disks, diameter equal to the internal diameter of the outer tube. These 2 disks go inside the outer tube, up against the inner tube which stops them from going inwards. Then just silicone them in place with a nice large fillet. Really simple. No holes, no leaks.

 

[PRL]

Not sure. But is it a good idea charging a battery in a sealed container?
If memory serves than I'm pretty sure that when a battery is charged it
produces H2. Mixed with the little air in the container and possibly a spark
from the swith. And you just turned on a stick of dynamite.

Not sure about this, but it seems logical

 

[GJ DIVER]

I was looking for info on where to find "dive companion" book on building diy can lites and ran across this thread. I am a plumber (from Denver) and would like to comment on plastic pipe. PVC pipe is inherently stronger because it is a solid pipe. All abs pipe nowdays is a foam core pipe unless its really old.If you cut it you will see the structure on the end of the wall. It is still pretty strong though. PVC though stronger is much more brittle especially when cold.All pipe is much stronger to pressures exerted from the outside than that exerted from the inside which is what the useage ratings pertain to. I have used drainage pipe for temp applications that were left in use for years that were subject to INTERNAL pressures in excess of 50 psi. External pressure limits should be much higher. The smaller the pipe the stronger and glue should not be an issue with either pipe except that abs glue should be applied sparingly so as not to soften the pipe. AS to the exploding lite this is probably good advice, however there are hydrogen absorbing pellets such as those in many std dive lites. Don't know if they are sufficient to handle a closed charging application. So does anyone know where to find that book?

 

[PRL]

Go to http://www.airspeedpress.com/ for The DIVELIGHT COMPANION
You also can check out this thread
http://www.scubaboard.com/t57488.html

 

[PRL]

Also I suggest that you check out Padipros news group http://groups.msn.com/Divelight