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Tip for Tank Makers...


DiverJohn

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HI Guys & girls, dunno if this is relevant, and i have never tried to make a tank myself, but...

Guy was installing my new shower today and sprayed the silicon with a weak solution of dishwashing liquid + water, before wiping with a rag to clean off the excess silicon.

Have absolutly NO idea if this would work on tanks, but the silicon on my shower looks very tidy!!! Oh and wipes of the fingers easy too.

HTH

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Mmmm.. Have to admit.. I lick my finger also.. but to get a nice even bead of silicone up the seams I use the cap from a felt tipped pen.

Just use the "open" end and place it at a sharpish angle and draw it gently along the seam.

Result... Perfect smooth even finish :)

Bill.

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i usually just run my finger over it - but by the time i get around to that point my fingers are already covered in silicone which probably helps them not stick. as long as you start at the bottom and work up and over the edge you don't leave any fingerprints...

either that or i am just a greasy 'lil bugger... you decide ;)

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  • 1 month later...
  • 1 month later...

Tip from hubby....

spraying it with just water alone, before running your finger on it will work for that smooth finnish,(ice block sticks for those who like clean hands) because silicone will not adhere to wet surfaces.

no need for any soap or oil.

cheers

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I have edited my post as requested but still agree with what my husband has said about Acidic cure silcone.

He is a qualified Glazier, and really knows his stuff.

Acidic cure silicone contains Acetone (excuse the spelling if it's wrong), the same stuff you get in cheap nail polish remover, the same stuffthey won't use on false nails as it can cause the plastic to burn\melt.

Now in my opinion, and it is just my opinion, i would not exactly like to burn\melt my fishies skin, or in a less extreme manor, make them sick, by exposing them to such a harsh acidic chemical.

But like i said, this is just my opinion, based on a Glaziers information.

Cheers

And hey, no harm, no foul.

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Kewl Krissie, no penalty shoot out.

I got my information from a fishtank maker from Levin years ago.

He was a valued member of the FNZAS, now deceased, but his explaination was that of experience with fish dying in tanks made from Neautral Cure but not of Acetic Cure.

All the top tank makers that I know of use the acetic cure also.

It could be that the silicone that killed the fish had anti mould in it as well.

Alan 104

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I have edited my post as requested but still agree with what my husband has said about Acidic cure silcone.

He is a qualified Glazier, and really knows his stuff.

Acidic cure silicone contains Acetone (excuse the spelling if it's wrong), the same stuff you get in cheap nail polish remover, the same stuffthey won't use on false nails as it can cause the plastic to burn\melt.

Now in my opinion, and it is just my opinion, i would not exactly like to burn\melt my fishies skin, or in a less extreme manor, make them sick, by exposing them to such a harsh acidic chemical.

But like i said, this is just my opinion, based on a Glaziers information.

Cheers

And hey, no harm, no foul.

I repaired a tank a while ago, tried 3 times using neutral cure and the tank leaked every time when I tested it, as soon as I used acidic cure it worked fine. The neutral cure just doesn't stick to the glass well. Also in my marine tanks that are a lot more sensitive to chemicals I have put still wet acidic cured silicon into the tank and let it cure under water, this has been for sealing bulkheads, putting in overflow etc. Has never caused a problem to the fish or corals.

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Acetone is toxic, but it evaporates very easily and completely. I'm not sure if you're right if it's in acid cure silicone, I don't know. You don't usually use silicone in a full tank anyway, you give it time to cure for at least a few days and by then there wouldn't be any acetone left.

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Are you sure it gives off acetone. I think it gives off acetic acid which is quite different and is a weak organic acid and is refered to as vinegar by the cook. That is why it is called acid cure. Acetone is not an acid. Acetic acid is produced naturally by a bacteria from ethanol which is the active ingredient in your rum and coke, or from the fermentation of sugar by yeast.

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  • 2 weeks later...
Are you sure it gives off acetone. I think it gives off acetic acid

Now, this is not an answer, but I found this conversation very interesting, so I asked my partner his opinion (he works in a paint factory). So if anyone's interested (note, when he refers to "one pack", that is opposed to a two pack polyurethane, which contains isocyanate, so it cures faster and stronger but very toxic):

Well I have no real knowledge about acid cure silicones…. BUT in acid cured paints we use para toluene sulphonic acid, and sulphuric acid in relatively weak concentrations to catalyse the reaction of urea formaldehyde, and amino resins causing them to crosslink and go hard (cure). Solvents of various kinds are used in the formula to give the correct viscosity and flow characteristics and suitable surface dry times but they take no part in the reaction and evaporate at various rates with residual solvent still coming from the film up to a week later. The curing reaction gives off free formaldehyde which in case you were in any doubt is a bad thing and poisonous at high enough levels. Full cure is not achieved until up to a week after application depending on drying conditions but is substantially completed after a few days. Formaldehyde is emitted by the coating in reducing amounts for a long time after application (up to 6 months at times).

The coating always contains some residual acid as it is not entirely consumed in the reaction and this residual acid makes the coating more susceptible to water damage than say a polyurethane coating which cures harder and more completely.

I am guessing that the “acidic cure silicone†is a one pack product and may indeed contain acetone as a solvent to aid in workability. Acetone has a VERY fast evaporation rate and I would imagine it would be free of the product within a day at the most! As the silicone is a one pack (I am assuming here) it would not be highly cured and I would imagine there is very little free acid left in the cured product to kill little fishies or reduce its waterproof properties.

Oh, and he just asked his head chemist:

Just checked with Mark he used to make it at Fosroc It contains glacial acetic acid (quite nasty) in relatively small amounts but is packed under nitrogen to stop it reacting so it is quite reactive. He would imagine that it would have residual acids which may leach out but acetone he agrees would be gone in no time

Hopefully I'm not the only person who finds this interesting! :P

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As I suggested it contains acetic acid that is why it is called acid cure. White vinegar is a solution of about 4% glacial acetic acid in water. Non acid cure RTV is used when in contact with reactive metals such as copper, galvanised iron and zincalume where an acid would be corrosive. As I also suggested, if you read the label it usually has on that if it is suitable for aquaria. I would hate for a members large aquaria to end up in a thin layer on the lounge carpet because someone used the wrong glue.

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i will get hubby to read all this when he gets home, and post his feedback after...

We have built alot of tanks, mostly for ourselves and friends and family, and have only ever used neutral cure.

To date we have had no leaks, with the exception of our big tank, but that was due to a warped stand and you can see the visible 'bow'.

Given silicone has a +\-25% movement rate, i'm not surprised the big one leaked given the state of the stand. (about a 30mm drop in the middle)

Anyhow... as i said, i'll get hubby to read this and get back to you... if he has anything relevant to say... :D

Cheers

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well Hubby read all this and i decided to put his comment here, as promised. I'll just not quote him as i can't really remember his exact words.

His basic opinion to all the above posts is....

'It's their tanks, their fish, their problem.'

(Not in a grumpy way... more like indifference)

Anyhow...

We worked it out, and he has built in the last 8 yrs, roughly 2 - 3 tanks a year. Not one of them has leaked, and had no 'strange' Tank die-offs.

In his experience, there has been no adverse side-effects of using Neutral Cure Silicone, so therefore no reason to not continue using it.

Maybe it has something to do with how he puts the tanks together?

I guess this is just one of those things that comes down to personal choice and his choice has been made.

I personally would prefer to see people saying that 'they believe Acidic cure silicone to be the right one to use', as opposed to 'Only use Acidic Cure, Never use Neutral cure.' as i believe by having tanks made with neutral cure proves the point that it 'will' leak to be false or unfounded.

But i also strongly believe in everyones right to speak thier opinions... so makes no odds to me either way.

Has been interesting though.... right? :wink:

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http://www.selleys.com.au/ARTICLEDOCUMENTS/SIL%20SEAL%20Glass%20Benefits.pdf

People choose particular products based on technical specifications, experiences of others, cost and personal choice. Yes, you are allowed your own opinion, but it should be yours. I dont know about other people but " I'll ask hubby" gets my back up instantly.

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