reseal an acrylic sump? It doesn't look good !

[cracker]

So I have a custom fit acrylic sump I built myself. It passed all leak tests ! However, After several months it started a very intermittent, slow leak. So in my infinite wisdom. I pulled.& sun dried. Then I sanded the inside edges & applied Silicone. So it's leaking again in the front left corner. From what I learned today ,this sounds like like an effort in futiliity . Here is my plan .
I'll clean
Clean & dry inside & out along the seams.
I will silicone these inside seams
After all this I'm going to fill every seam with 2 part epoxy, (on the outside) !
Seeing how I have to try one last ! In fact it barely leaks now then stops for a month or so,

All that being said, What type /brand of 2 prt epoxy would You use. ? here's a few pics for Ya. this is the front left & front side

the 2nd left side.

 

[BornHandy]

Silicone is a no go. It will never be a permanent seal. Get your hands on some methylene chloride. I use IPS weld-on brand, but it is all the same. You can use the thickened stuff if your edges are rough, but if not, the IPS weld-on #3 or equivalent will do just fine. If you have leaks after that, use the thickened solvent to fill the holes. Hope that helps.

 

[cracker]

Thanks ! I need to take note .

 

[Crabs McJones]

Full disclosure, I may be wrong, but I thought I read or heard somewhere that silicone doesn't adhere to acrylic like it does glass. What about an acrylic cement? It more or less melts the pieces together fusing them creating a seal.

 

[saltyfilmfolks]

I’d double check the epoxy you are using.
I’m no acrylic wizard by any means. But I belive In acrylic construction you want to create a chemical bond between the two pieces.
When done incredibly well(not by me) you can sand it to appear clear the bond is so good.
Where epoxy is just holding the pieces tightly together.

Check these guys out

https://www.eplastics.com/accessories/plastic-adhesives/acrylic-glue

 

[Matthew Frost]

Silicone won't work, it won't bond with the acrylic. If a seem has started leaking the best bet would be to get some square rod and weld on 40. Cut a piece of square stock and fuse it into the corner with the weld on 40.

 

[laverda]

Bornhandy is correct. Silicone does not adhear well to acrylic at all. Weld-on should be available at local plastic supply houses or sign manufactures as well as amazon.

 

[cracker]

I think a big part is I didn't have enough bracing. So Iv'e heard good & bad things about the thick solvent.
Also no kind of 2 prt epoxy will stick? Iv'e had good luck in the past with roughing up the slick acrylic seemed to stick very well.
Also the small bottle & brush I have now ,states it contains Methol Ethol katone (MEK)

 

[BornHandy]

I am not 100% sure about any epoxy for acrylic, but I know that epoxy of any kind will be depending on the strength of the physical bond. The Methylene Chloride works completely differently. It flows between the bonding surfaces, dissolves both pieces of plastic, then evaporates - effectively welding the two pieces together to make one piece.

The thinner stuff works best, but if your cuts were a little rough, the thinner may not give you a water tight bond, so that is where the thicker comes into play. If I were in your shoes, I would use the thin to make the initial weld, then use the thicker just like you would use silicone to fill in any gaps that you may have missed. I have built a few sumps, and this method works in a pinch.

Here is a pic of my latest work, and I can tell you for sure, the weld-on works wonders. By no means am I a pro. My joints are far from perfect, but they do the job, and are plenty strong enough to hold up for a lifetime.

 

[BornHandy]

Also, regarding the MEK, it is a plastic solvent, mostly used in paint thinner, and it has no impact on acrylic. Acetone is the same way. It will dissolve plenty of plastics, but acrylic isn't on the list. If nothing else, order yourself a bottle of the Weld-on #3, the applicator bottle (should cost less than 10 bucks), and play with it on some scrap acrylic. I think you will like the results, and may even want to start from scratch if it is in the budget. This stuff is workable in 5 minutes, and fully cures overnight. It is pretty much a miracle when working with acrylic. There isn't anything else like it.

 

[davocean]

Weldon #16 is what I would use, and in bad situations you could even cut scrap acrylic and place at leak kinda like a bandaid/brace, weldon that down at seams or leak areas. It's not pretty but it works

 

[davocean]

I am not 100% sure about any epoxy for acrylic, but I know that epoxy of any kind will be depending on the strength of the physical bond. The Methylene Chloride works completely differently. It flows between the bonding surfaces, dissolves both pieces of plastic, then evaporates - effectively welding the two pieces together to make one piece.

The thinner stuff works best, but if your cuts were a little rough, the thinner may not give you a water tight bond, so that is where the thicker comes into play. If I were in your shoes, I would use the thin to make the initial weld, then use the thicker just like you would use silicone to fill in any gaps that you may have missed. I have built a few sumps, and this method works in a pinch.

Here is a pic of my latest work, and I can tell you for sure, the weld-on works wonders. By no means am I a pro. My joints are far from perfect, but they do the job, and are plenty strong enough to hold up for a lifetime.

Nice job, that is clean.
My limited knowledge of acrylic is the #16 is for sloppy joints and larger gaps, which fits my acrylic diy skills!lol

 

[lapin]

So I have a custom fit acrylic sump I built myself. It passed all leak tests ! However, After several months it started a very intermittent, slow leak. So in my infinite wisdom. I pulled.& sun dried. Then I sanded the inside edges & applied Silicone. So it's leaking again in the front left corner. From what I learned today ,this sounds like like an effort in futiliity .
All that being said, What type /brand of 2 prt would You use. ?

You do have an issue. Like stated above silicone is the wrong product. I do not think that MC or weld on 3 will help you. The seams are all ready set. It might fuse them together if the gap is "not big". It is a solvent not a gap filler. I would use a thick product. I hate weld-on 16. Its like model airplane glue and makes a mess. My choice is weld on #40. Its 2 part and has a 15 min working time. Not only does it melt the acrylic but it fills in gaps up to 1 mm. It flows like gear oil. You can tilt the piece so it will settle into the inside gap so you have a seam like if you used your finger to smooth a silicone. If the seam has structural problems and needs more bracing you can weld in a piece of square acrylic rod. Do this at the same time you are filling the gap with the #40. Pour extra into the gap. Run a thin bead on the 2 sides of the rod to be welded or on the sump side surfaces. Push the rod into place. hold in place for 10 min to let it set up. You can also use it to fill in outside gaps if needed, but inside is where you need to seal it.
This is my suggestion based on what you told us.

 

[jsker]

Weldon #16 is what I would use, and in bad situations you could even cut scrap acrylic and place at leak kinda like a bandaid/brace, weldon that down at seams or leak areas. It's not pretty but it works

I was going to say the same thing link The #16 is thicker than the welding #4 . run the 16 on the inside edges and let it fill in.

 

[cracker]

@BornHandy , You have been a wealth of info for for me & real nice build !
@jsker problem is I have already siliconed the inside seams I could try to cut out the silicone also I "might peel right up " Big Maybe "
onsidering using the thinner stuff 1st then fill with a thicker blend maybe ? Or vicsersa?

 

[jsker]

@BornHandy , You have been a wealth of info for for me & real nice build !
@jsker problem is I have already siliconed the inside seams I could try to cut out the silicone also I "might peel right up " Big Maybe "
onsidering using the thinner stuff 1st then fill with a thicker blend maybe ? Or vicsersa?

Us it on the outside seams then.

 

[davocean]

@BornHandy , You have been a wealth of info for for me & real nice build !
@jsker problem is I have already siliconed the inside seams I could try to cut out the silicone also I "might peel right up " Big Maybe "
onsidering using the thinner stuff 1st then fill with a thicker blend maybe ? Or vicsersa?

As mentioned before silicone will not really bond to acrylic, and it will prevent bonding at that spot where silicone is even if you now use weldon.
I would remove all silicone w/ a blade, and then use rubbing alcohol to remove any residue, and that will probably mean several wipe downs in doing so, and when you think you got it all, do it a couple more times!lol
Then try weldon.
If you use scrap pieces like I mentioned it will bridge over areas where you might have missed some silicone deep in seams

 

[MARK M. DAVIS]

Silicone is a NO GO! I had a seam issue in my acrylic sump. Dry out completely. Then, use acrylic rectangular rods and glue in the corners with Weld On. Like an L in the corner with two pieces of rectangular rod. Strengthen the top with acrylic plates in the corners so there's structural support.

 

[cromag27 Verified Sponsor]

sorry man, but trash it and get s new one! not even worth the risk. acrylic expands when saturated with water over time and that’s what can cause leaks after the initial leak test.

 

[cracker]

sorry man, but trash it and get s new one! not even worth the risk. acrylic expands when saturated with water over time and that’s what can cause leaks after the initial leak test.

Thanks i didn't know this . I was already taking a chance before even starting . The acrylic was real old 3/8 th thick & my 1st build of this size. I would like to have a very simple sump made but I'm funds limited & have no idea what it would cost. So I'll try one last time & go from there. You feel like giving me an estimate?