Cracked Pressurized Reservoirs

[HBWW]

Has anyone had any actual experience repairing cracked PR's? I've tried all sorts of epoxy across different blasters (Putty, Plastic Welder, etc. on Max-D 2000, Storm 750, and recently a Liquidator) and every time the job fails rudimentary pressure tests.

However, epoxy seems to work perfectly on pipe cracks/leaks, and the finished product can hold normal water blaster pressures for a long time.

I hypothesize that the reason PR's aren't cooperating is because they are designed to expand when pressure builds up, similar to how a soda bottle is very stiff before opening. I decided to try something else today - silicone. However, the flexibility may not be enough especially if it can't hold against pressure. I will test after 2 days when the stuff sets, and if it doesn't work, I may try a combination: epoxy surrounded by silicone, which will take even longer to apply and set.

Perhaps someone else here has successfully repaired a cracked PR? Just to be clear, I'm talking about reservoir cracks (often on the ridge line of the reservoir), not pipe cracks which are easily resolved with epoxy.

Edit: Had a well-needed review of this page: http://www.sscentral.org/repairs/glue.html

The epoxy-silicone combination may be a good start, but I may need that special plastic solvent welder mentioned on the page.

[isoaker]

Never successfully repairs a cracked pressurized reservoir, but then again, haven't had to deal with them much, either. That said, if gluing the crack does last, I wonder whether a plastic patch glued over top to assist with the seal might help.

[Drenchenator]

I haven't repaired any cracked chambers, but I thought I should chime in on a technique that may help.

isoaker's recommendation is good. Generally, I wouldn't trust using just an epoxy, adhesive, or solvent without something to reinforce the crack. This something could be as simple as a strip of plastic to cover the crack. The problem is that just closing a crack does nothing to prevent it from reopening. A patch would prevent it from reopening.

The problem with a patch is doing it correctly. Clean the crack to ensure a good bonding surface, glue/epoxy/close it shut, and clamp it in such a way to provide constant force holding it shut. After it is entirely finished/cured, sand/clean the general area around the crack, glue/epoxy/attach the plastic patch, and clamp it again. After waiting again, the chamber should be functional.

[Neptune]

I've repaired cracked air systems by sanding, super glueing, sand the super glue, then 2 part epoxy resining it. That may help.

[SEAL]

All three of my SS 300s PCs have cracks in them (water also leaks from somewhere in the internals). I've been trying to seal them up with various types of glue, but I haven't had any luck. Maybe I should try some of these methods.

[HBWW]

I'm skeptical of using a covering piece, since the cracks are tiny and a piece doesn't seem like it would prevent the epoxy from unbonding. That said, I'd try snake oil at this point, so there's no reason not to.

[Drenchenator]

Just because the crack is tiny now doesn't mean it will stop growing. If there is enough stress for the crack to grow, it will continue to enlarge, and the problem will only get worse. A patch should help prevent crack growth. Without a patch, force perpendicular to the crack will continue to open it. But with a patch, force perpendicular to the crack will open it on one side and close it on another, keeping it shut. Still, I'd say a patch is still only buying time. Ultimately, the best thing to do would be to replace the chamber entirely since the material is already compromised.

There is actually a lot of research into preventing crack growth. One of the ways that can stop a crack, but introduce other problems, is drilling holes into the crack's end points. This should prevent the crack from spreading, but it may still encourage failure by introducing a stress concentration. I don't recommend this, since we obviously want the chamber to seal and drilling a hole into the chamber only makes the problem worse, but it is a cheap and easy method to stop crack growth.

[HBWW]

Epoxy pipe repairs have evidently bought a lot of time. Epoxy seems to stop those sort of leaks for quite a while.

In any case, it seems that the vast majority of repairs we make are just buying time. But If it's a decent amount of time, then it's well worth it. Replacing an entire PR's tank is a ton of work in itself, and then the weakest link of the blaster simply moves elsewhere.

Edit: I tested out the silicone. It lasted longer than epoxy, but still gave way, so I will definitely have to patch things up.

I'm thinking that silicone is the way to go for the patch-up. Stick whatever patching piece over and connect with silicone, then reinforce with epoxy and/or superglue. Another method I thought of was surrounding epoxy with silicone, but I never tried that out. (Didn't think of it.)

Anyway, like I said, the cracks do not open up to any visible amount. The problem is that some of them occur along ridgelines. I'm more concerned about the cracks growing than opening wider, so that hole-drilling idea is actually very appealing but could make things worse in the end. I guess all I can do at this point is, as mentioned earlier, buy time. Perhaps I should prepare some PVC PR solutions, but those seem overkill and I can just make a homemade PR anyway.

[GJIV]

I have successfully repaired some SS 300 Pressure Reservoirs, but after several tries I found out only one(but really good working) methode to get these cracks seal again:

Make sure the pieces are completely free of any fat or dust(use alkohol or something else),
use some kind of sand paper to get the surface rough(improves and increases the effective surface)
get some Cyan Acrylat glue ( or semthing else like superglue) right over the crack(s), may you can even force the crack open a little bit to get some glue inside/between, also put glue right around the reservoir(circle-wise)
be quick then, take some rubber band(the bigger the dimension the better) and put it right around the reservoir, several times. Try to get quite much force on the band while putting it around the reservoir. Make sure to cover the cracks + more(for safety), you can also put some glue and the rubber band and just go right over it again with further rubber band.

The idea here is to make a seal and strong glue-rubberband-composit. The glue guarantees sealing, the rubber band brings in elasticity(as Cyan Acrylat glue or superglue is quite brittle). Only methode yet to get such problems seal again, but till now it always worked fine. Have a try and better use too much superglue to make sure everything is in contact with glue and rubber band.

Good luck, 99,9 % work when done right