What do you use to clean/prep a tank before silicone?

[targaboy78]

Hi guys,

I've read on some sites that you should use acetone to wipe the glass or plexiglass prior to applying silicone. However, I have also read that you can use rubbing alcohol.

Is this information correct ?

Are both suitable ?

Any benefits of one over the other ?

 

[loganj]

silicone

I know that acetone will evaporate quickly leaving behind no residue. Rubbing alcohol is about 70% water so it might take longer to evap. As long as the glass is clean and dry, I don't see any problem...I have never used either of these solvents prior to applying silicone. I would caution you about using silicone on acrylic though. It doesn't stick very well at all. Acrylic needs to be put together with an acrylic glue. I have found that the Weld On #16 works well to seal gaps and cracks. The #3 is very thin and relys on capillary action to seal the acrylic...the parts must be a perfect fit for this to work. If I had to use silicone on acrylic, I think I would scuff the area where it would be applied with some sandpaper first. That would improve adhesion, but I wouldn't trust it to hold two pieces together under any pressure.
Logan J

 

[SleeplessLwd]

Just to let you know Acetone and Alcohol will do damage to acrylic tanks. You may not notice it immediately, but it starts to dull it and make it look cloudy. I've always just used warm water and lots of towels. It did a good job with no residue and no streaks and the silicone always held just fine with that.

 

[Somethingfishy]

Yup, I would back sleepless up on that one, that is all I have done and it seems to work OK.

 

[loganj]

Silcone

I have seen two sumps and one tank (acrylic) that were put together with silicone come apart. You could use silicone to seal the acrylic after it's glued if there were leaks or you wanted the extra insurance against a leak. YMMV
Logan J

 

[targaboy78]

Ooops, sorry, my bad... I guess I left out some information.

It is an established glass FW tank and I was cutting out some of the silicone that was either loose or "untrustworthy".

I just wanted to prep the area before applying a new bead.

Thanks very much for the input, I'm sure that info will come in handy for my future projects.

 

[loganj]

silicone

Targa,
You have to look over me sometimes , I get carried away. I think you could scrape the area in question clean with a razor blade and just clean it good with water and a scrub pad. Since you won't actually be putting glass together, I think I would skip any solvents. The silicone should stick just fine. The GE 100% pure silicone will work well and comes in tubes that will fit your caulking gun. Just don't get the stuff for bathrooms...make sure it is the clear 100% pure silicone...it's lots cheaper than the stuff at the LFS and is the same thing.
Logan J