Galley tank drain plumbing cracked

[Jvictor]

Hey All,

I have a crack in my 1 3/4” plumbing that comes out of the bottom of the tank. The one elbow is cracked but it is attached to another elbow that goes into the tank. Anyone replaced this? Would a heat gun work to disconnect the two elbows? Not sure how to replace this one, I need to get the elbows separated but can’t cut anything away at the tank, the second elbow connects right to the tank. Thanks in advance for any help.

[chuckster57]

Welcome to the forum

That is ABS pipe and it is glued together. You MIGHT get lucky if you clean the crack real good, spray it with brake cleaner and then using the ABS glue brush, coat it with fresh glue.

[Jvictor]

That’s a good idea, I will have to give that a try and see if it will hold for now. Thanks Chuckster57.

[JRTJH]

I've had some luck with making my own "ABS paste" to paint cracks like that. I take some "saw filings" from cutting an old ABS pipe, in this case, probably a tablespoon full of "ABS sawdust" and mix it with about 3 tablespoons of ABS joint glue. Stir until it's dissolved, then paint it on the "THOROUGHLY CLEAN AND DRY" crack. Let it set up overnight and see if it needs a second coat. If it looks good, then give it a "leak test"...

[Jvictor]

I’ve seen this recommended to try, I will give it a shot to keep it working for the rest of the season. I can leave the valve open, that’s fine, it just drips the grey water. It looks like the one elbow may turn like a residential trap on a kitchen sink but I can’t get it to budge. I’ll try the paste, thanks for the reply.

Jesse

[bobbecky]

That ABS pipe and fittings are actually 1 1/2” , not 1 3/4”. All readily available at most any hardware, plumbing, or HD or Lowes.

[Jvictor]

Thanks for that, much appreciated.

[flyingjack]

JRTJH: many years ago when you could get real MEK I used drilled shavings and made a paste that worked very well. Apparently, new watered down MEK and Acetone won't melt abs shavings. Didn't know about using glue- good tip.

[JRTJH]

Originally Posted by flyingjack

JRTJH: many years ago when you could get real MEK I used drilled shavings and made a paste that worked very well. Apparently, new watered down MEK and Acetone won't melt abs shavings. Didn't know about using glue- good tip.

There is a lot of confusion (with me for sure) about which type of "pipe solvent" to use and which ones work for which type of plastic pipe.

There is "red label, blue label, purple label, green label, yellow label and gold label" (at least those are the ones I can remember off the top right now)... Each "label color" has a specific application and only works for SOME of the plastic pipe types sold in "plastic plumbing supply departments"....

Every time I think I know what I need, I end up reading labels and getting even more confused, not because I can't interpret the labels, but because I can't confirm that what pipe I have at home is which type on the label....

So, You're right, some types of solvent won't dissolve ABS shavings (if it's a PVC solvent) and other types (by label color) will work for either, but only to fuse them together, not to melt the shavings....

So, ask the "hardware store expert" (if they have one) what you need for the pipe work you're trying to do.....

Trust me when I say that I get more confused trying to remember which one I need than I do just "hoping I picked up the right solvent as I'm smearing it on my fittings"....

[Squanto]

I use the green stuff made to join ABS to PVC. I figure if it can do that, it must be able to join ABS-ABS or PVC-PVC as well.

Saw a video where a guy was installing a new black tank and it had cracked in shipping so he patched it with fiber glass. That may bond to the ABS also.

[Jvictor]

Thanks again for all of the replies. I think if you are in a pinch and on the road, this mix is the way to go. My spot is more permanent and in reality I can leave the valve open. It would just drip when a sink drained and would smell. Here’s how I fixed it:

1. Cut the cracked elbow close to the other elbow that goes into the tank with a sawzall. A hack saw would have been better, more accurate.

2. Cut the drain pipe near the support bracket so the new coupler would be near the support.

3. Used a 1 1/2” ram but socket saver from Amazon (27.00). I went at straight as I could and reamed out the piece stuck in the elbow I didn’t want to remove. Not long and it was out. I dry fitted the new elbow and it was nice and snug. I would have liked to go a little straighter with the socket saver but it still worked.

4. Then I glued the coupler on the the existing line, then the new elbow to my splice piece. Then measured and dry fit to the elbow that comes right off the tank. It fit well so I glued it all together.

I would recommend the socket saver to anyone. Just make sure it’s nice and straight.