Can a glass "patch" be safely siliconed to plug a hole?

SeanT · 08/24/2009, 02:51 PM

I have a 125 I would like to convert into a growout tank.
The problem is, that at the end of the tank there is an odd sized hole.
A little bigger than a 1" bulkhead and too small for a 1-1/4" bulkhead.

If it were an acrylic tank I could easily weld on a patch, but this being glass...

I am wondering if I could silicone a glass patch to the outside and inside of the tank and expect this not to leak.

Any thoughts on the pros/cons of this?

Thanks,
Sean

nsamouroux · 08/24/2009, 03:13 PM

I've done this once with a smaller tank (20g that became a refugium), and only used a "patch" on the inside. I used a lot of silicone between the panel and patch and then pressed the patch up against the hole. After it was cured enough to hold I added a bead of silicone around the edges. I doubt a patch on the outside would make any real difference... The thing that would worry me (if you're using halides on the tank) is degradation of the silicone... I would think it would be MUCH safer in your case to drill the hole to the next larger bulkhead size, put a bulkhead in it, and then put a cap on the bulkhead... I have used clear Sch40 bulkheads in the past which might make the "plug" less noticeable, but if this is just a growout tank for you that might not be a concern?

EDIT: You didn't mention in the original post, but did you try sch80 bulkheads to plug the hole? These always require larger diameter holes than sch 40, and might do the trick for you if you were trying to insert a sch 40 bulkhead in 1" or 1 1/4" size.

SeanT · 08/24/2009, 03:27 PM

Thanks for the input.
I have T5's and not halides so that is good.

I have both the thinner walled and Hayward (SCH 80) bulkheads...none will fit.
Very odd.

stripevt · 08/24/2009, 03:35 PM

You could use a diamond drum too with a dremel and make the hole bigger.

unbreakable · 08/24/2009, 03:48 PM

id be scared of cracking it. same thing with a 125 im upgrading to, has two holes drilled but are the size of a quarter, theyre patched up on the inside with glass and silicone. i guess im going to find out how well it holds

SeanT · 08/24/2009, 03:54 PM

I want to patch...just want to be sure.

Shane Hoffman · 08/24/2009, 04:30 PM

I have patched holes like you mentioned above. I see no need to put a patch on theoutside. Silicone as mentioned above and you will be fine. Try to get a piece of glass that is atleast one inch outside the OD of the hole....

Also dont worry about silicone degrading under halides....if thats a major issue there is a whole lot of us that need to start worrying..

get the pieces of glass as clean as possible...also if ehstetics are not an issue rough it up in the area you will be putting silicone, for better adhesion.......good luck

pIankton · 08/24/2009, 05:43 PM

I did it in my sump / fuge but it's high enough so that it never really touches the water. I used a piece of scrap acrylic, slathered it in silicone and squished and twisted it in place. I like the twist as it pretty much ensures a watertight seal. Do it on the inside - not the outside.

SeanT · 08/24/2009, 06:04 PM

Thanks gang.

To clarify, I am going to do it on the inside.

My thoughts about patching it on the outside, as well, are that IF there were a leak in the seal from the inside patch, the outside patch should help to contain that.

Aesthetics are not an issue at all.

Will sandpapering the glass really help the silicone to bond more firmly?

Thanks,
Sean

lombard0 · 08/24/2009, 06:27 PM

Quote:

posted by SeanT

Will sandpapering the glass really help the silicone to bond more firmly?

Thanks,
Sean

Not really. But make sure it's free of dirt, greese, etc. and it should do just fine.

Cheers!

SeanT · 08/24/2009, 07:24 PM

Will do.

SkyPapa · 08/24/2009, 09:23 PM

I patched 2 1.5 inch holes 2 inches apart in the bottom of my 75g sump from the inside.
Just an oversize piece of glass and lots of silicone.
No leaks.

SeanT · 08/24/2009, 10:30 PM

Well I had some time tonight so I went ahead and did it.
Here are a few pics from my phone.

SeanT · 08/24/2009, 10:31 PM

sedor · 08/24/2009, 10:40 PM

I see you've already patched, but I was going to suggest removing the entire panel and putting a new one back in. It would be a lot of work and you would probably to to re-silicone the entire tank, but you'd have yourself a brand new tank. You could even go crazy and get a starfire front or something.

SeanT · 08/24/2009, 10:57 PM

Hey Ryan,
That would have been a posibility.
But this is just a growout tank in the garage.

Sean

08/24/2009, 02:51 PM	#1
SeanT Premium Member Join Date: Jul 2002 Location: Wilmington, North Carolina Posts: 13,860	Can a glass "patch" be safely siliconed to plug a hole? I have a 125 I would like to convert into a growout tank. The problem is, that at the end of the tank there is an odd sized hole. A little bigger than a 1" bulkhead and too small for a 1-1/4" bulkhead. If it were an acrylic tank I could easily weld on a patch, but this being glass... I am wondering if I could silicone a glass patch to the outside and inside of the tank and expect this not to leak. Any thoughts on the pros/cons of this? Thanks, Sean __________________ My tank was cool. Current Tank Info: Barebottom (the tank not me...at least not at the moment).

08/24/2009, 03:13 PM	#2
nsamouroux Registered Member Join Date: Dec 2008 Location: Seattle, WA Posts: 147	I've done this once with a smaller tank (20g that became a refugium), and only used a "patch" on the inside. I used a lot of silicone between the panel and patch and then pressed the patch up against the hole. After it was cured enough to hold I added a bead of silicone around the edges. I doubt a patch on the outside would make any real difference... The thing that would worry me (if you're using halides on the tank) is degradation of the silicone... I would think it would be MUCH safer in your case to drill the hole to the next larger bulkhead size, put a bulkhead in it, and then put a cap on the bulkhead... I have used clear Sch40 bulkheads in the past which might make the "plug" less noticeable, but if this is just a growout tank for you that might not be a concern? EDIT: You didn't mention in the original post, but did you try sch80 bulkheads to plug the hole? These always require larger diameter holes than sch 40, and might do the trick for you if you were trying to insert a sch 40 bulkhead in 1" or 1 1/4" size. __________________ 360g mixed reef tank / 500g system. 60% DIY: Bruised knuckles, sore back, and loopy from PVC glue! Current Tank Info: 360g mixed reef

08/24/2009, 03:27 PM	#3
SeanT Premium Member Join Date: Jul 2002 Location: Wilmington, North Carolina Posts: 13,860	Thanks for the input. I have T5's and not halides so that is good. I have both the thinner walled and Hayward (SCH 80) bulkheads...none will fit. Very odd. __________________ My tank was cool. Current Tank Info: Barebottom (the tank not me...at least not at the moment).

08/24/2009, 03:35 PM	#4
stripevt Registered Member Join Date: Jan 2007 Location: blacksburg Posts: 286	You could use a diamond drum too with a dremel and make the hole bigger. __________________ Shawn "who ever said nothing is impossible, has never tried to slam a revolving door now have they" unknown Current Tank Info: 6.5 gallon restart

08/24/2009, 03:48 PM	#5
unbreakable D: Join Date: May 2007 Location: ? Posts: 2,868	id be scared of cracking it. same thing with a 125 im upgrading to, has two holes drilled but are the size of a quarter, theyre patched up on the inside with glass and silicone. i guess im going to find out how well it holds __________________ INTERNET= Serious Business!

08/24/2009, 03:54 PM	#6
SeanT Premium Member Join Date: Jul 2002 Location: Wilmington, North Carolina Posts: 13,860	I want to patch...just want to be sure. __________________ My tank was cool. Current Tank Info: Barebottom (the tank not me...at least not at the moment).

08/24/2009, 04:30 PM	#7
Shane Hoffman Registered Member Join Date: Mar 2009 Location: 45 mins from Chicago Posts: 2,009	I have patched holes like you mentioned above. I see no need to put a patch on theoutside. Silicone as mentioned above and you will be fine. Try to get a piece of glass that is atleast one inch outside the OD of the hole.... Also dont worry about silicone degrading under halides....if thats a major issue there is a whole lot of us that need to start worrying.. get the pieces of glass as clean as possible...also if ehstetics are not an issue rough it up in the area you will be putting silicone, for better adhesion.......good luck __________________ A wise man once said "Never play leap frog with a unicorn" Current Tank Info: 150 gallon glass with 20 gallon sump, 175lbs of coraline covered live rock, EuroReef skimmer rated for 250gal, 25watt Aqua UV sterilizer, Fluval FX5, Hamilton 3x250watt MH, 160 watt Blue actinic....Mixed reef

08/24/2009, 05:43 PM	#8
pIankton Registered Member Join Date: Aug 2007 Location: Virginia Beach, VA Posts: 556	I did it in my sump / fuge but it's high enough so that it never really touches the water. I used a piece of scrap acrylic, slathered it in silicone and squished and twisted it in place. I like the twist as it pretty much ensures a watertight seal. Do it on the inside - not the outside.

08/24/2009, 06:04 PM	#9
SeanT Premium Member Join Date: Jul 2002 Location: Wilmington, North Carolina Posts: 13,860	Thanks gang. To clarify, I am going to do it on the inside. My thoughts about patching it on the outside, as well, are that IF there were a leak in the seal from the inside patch, the outside patch should help to contain that. Aesthetics are not an issue at all. Will sandpapering the glass really help the silicone to bond more firmly? Thanks, Sean __________________ My tank was cool. Current Tank Info: Barebottom (the tank not me...at least not at the moment).

08/24/2009, 07:24 PM	#11
SeanT Premium Member Join Date: Jul 2002 Location: Wilmington, North Carolina Posts: 13,860	Will do. __________________ My tank was cool. Current Tank Info: Barebottom (the tank not me...at least not at the moment).

08/24/2009, 09:23 PM	#12
SkyPapa Premium Member Join Date: Aug 2007 Location: Central Florida Posts: 994	I patched 2 1.5 inch holes 2 inches apart in the bottom of my 75g sump from the inside. Just an oversize piece of glass and lots of silicone. No leaks.

08/24/2009, 10:30 PM	#13
SeanT Premium Member Join Date: Jul 2002 Location: Wilmington, North Carolina Posts: 13,860	Well I had some time tonight so I went ahead and did it. Here are a few pics from my phone. __________________ My tank was cool. Current Tank Info: Barebottom (the tank not me...at least not at the moment).

08/24/2009, 10:31 PM	#14
SeanT Premium Member Join Date: Jul 2002 Location: Wilmington, North Carolina Posts: 13,860	__________________ My tank was cool. Current Tank Info: Barebottom (the tank not me...at least not at the moment).

08/24/2009, 10:40 PM	#15
sedor Registered Member Join Date: Sep 2007 Location: Charlotte, NC Posts: 4,689	I see you've already patched, but I was going to suggest removing the entire panel and putting a new one back in. It would be a lot of work and you would probably to to re-silicone the entire tank, but you'd have yourself a brand new tank. You could even go crazy and get a starfire front or something. __________________ Ryan

08/24/2009, 10:57 PM	#16
SeanT Premium Member Join Date: Jul 2002 Location: Wilmington, North Carolina Posts: 13,860	Hey Ryan, That would have been a posibility. But this is just a growout tank in the garage. Sean __________________ My tank was cool. Current Tank Info: Barebottom (the tank not me...at least not at the moment).