RTV Sealant Cure Time

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I put in anew thermostat on my small block chevy, and on the back of the RTV sealant tube it says that it dries in 1 hour and fully cures in 24 hours.

I think that the 24 hour time is probably for room temperature which is like 70 degrees.

I put the stuff on at 5 p.m. and it was tacky at 7 p.m.

I checked it at 10 p.m. and it was dry to the touch, the temperature in the garage is about 40 degrees, should I let it cure for 48 hours.

I am wondering if I took a hair dryer or a heat lamp that maybe it would help the RTV cure faster.

Any ideas would be appreciated.
 
i used blue rtv silicon to seal a blow off valve on my SRT-4. i let it cure maybe 2 hours, then took it for a drive. the blow off valve also mounted onto the compressor side of the turbo, which by the way gets very hot when driving, especially with spirited driving. i never had a problem with boost leaks there however, so letting it sit and cure for just a little while must have worked. now in your case, you're dealing with water... we used rtv at work to seal hydraulic tanks and then we filled them very soon thereafter. never had a problem with leaks there either. i wouldn't wait past a day, it should be all nice and cured by then
 
The heat lamp is a good idea. I have done this quite a bit. RTV (Room Temperature Vulcanization) not being a smart [censored] just throwing that out there as alot of people dont realize that is what its short for. You are correct on the temp. Its not to particular unless its cold like your current situation.

Next time look into a much better product made by Permatex. Its called the RIGHT STUFF. It sets up in one minute and works better than RTV. I swear by the stuff. In the meantime looks like the heating lamp is your answer.
cheers3.gif
 
not to much! i just let it set up for 2hours in the summer and put it back together. now if i had to get it done fast then i use a gasket and coat it with rtv and let it set up 15min and slap it back together.
 
On a thermostat I use a gasket and the Permatex Super Tack spray (I think that's the name), its red and tacky, sprays on like spray paint. I put it together let it sit while I clean up and put the tools away, then fill the system start the car and I'm GTG. They've never leaked with that stuff. If I were using RTV sealant in the winter I'd use a small heat lamp and give it about 2 hours then add the coolant.
 
Originally Posted By: -Clayton-
Did you use a gasket as well?


My thermostat housing is a Mr. Gasket and it is made out of aluminum and it has a O-ring seal.

I called them up and they said not to use a gasket, I had a few gaskets in my toolbox but they did not fit, meaning the gasket was hitting the o-ring. I tried to cut an old gasket to make it fit, but it did not work.

I have a 195 thermostat in there now because of the cold weather, and I may go back to the 180 in the summer. I have heard of some type of gasket that you make yourself, of I may just use the Permatex Right Stuff or what demarpaint has said.
 
IIRC my Buick Century had an O ring and I don't think I used anything but the O ring, it didn't leak. As a side note, I got rid of that car in the mid 90's so I could be mistaken. I was under the opinion that nothing should be used with an "O" ring. Hopefully someone else will chime in. My current fleet all use gaskets with the T-Stat.
 
Originally Posted By: demarpaint
IIRC my Buick Century had an O ring and I don't think I used anything but the O ring, it didn't leak. As a side note, I got rid of that car in the mid 90's so I could be mistaken. I was under the opinion that nothing should be used with an "O" ring. Hopefully someone else will chime in. My current fleet all use gaskets with the T-Stat.


I even found a Mr. Gasket thermostat gasket on the net that said it was not for an o-ring seal on a thermostat housing.

The sealant has now been on there for 16 hours, should I just let it sit and cure since it may be too late for the heat lamp. As of 5 p.m. today it will be 24 hours, do I take it for a drive tonite or just wait until tommorow.
 
At this point the heat lamp won't hurt, I'd put it on for about 2 hours fill it and drive it. I've never waited 24 hours on anything, and I'm positive a shop wouldn't wait either.
 
You should be OK. The O-Ring is doing or should be doing the bulk of the sealing. If it needs sealant, something else is wrong.
On a side note; Everybody I knew including myself that tried a Mr gasket T-Stat housing leaked, due to warpage. This was back in the '70's when they used a gasket. Once checked, they were seriously warped. A little file work and a surface plate fixed them.
RTV cures by absorbing humidity from the air.

RTV-1 (One-component systems)

RTV-1 hardens directly under the action of atmospheric humidity. The curing process begins on the outer surface and progresses through to its core. The product is packed in airtight cartridges and is either in a fluid or paste form. RTV-1 silicone has good adhesion, elasticity and durability characteristics. The Shore A hardness can be varied between 18 and 60. Elongation at break can range from 150% up to 700%. They have excellent ageing resistance due to superior resistance to UV radiation and weathering. Industrial RTV-1 products are referred to as CAFs.
 
Leave the 195 in there. If you need max cooling, either one will be open all the way anyway.
You can use RTV with an 'O' ring gasket, BTW.
 
Thanks for the responses, this thermostat housing is very thick polished aluminum, so I do not think that I will be worrying about any warpage.

This housing is much thicker than my old thermostat housing, with a 180 stat in there before the old thermostat housings temp measured with an infrared gun was like 180 degrees.

This new thermostat housing's temp with the same thermostat is like 110 degrees, I think the lower reading is because of the thickness of the aluminum.

I am also thinking that the 195 thermostat will burn off any condensation or harmful emmissions better than the 180 thermostat.
 
My dad swears by using silicone in the summer heat and by letting it dry for the full 24 hours. (starting it at 7am to let it cure). He says using this method had never caused a leak since on all the units he has sealed. He has done a lot of work on the notorious leaking 2.5 Litre 4cyl Chrysler engines from the K-Cars. These were bad for leaking rocker covers.
 
Originally Posted By: StevieC
My dad swears by using silicone in the summer heat and by letting it dry for the full 24 hours. (starting it at 7am to let it cure). He says using this method had never caused a leak since on all the units he has sealed. He has done a lot of work on the notorious leaking 2.5 Litre 4cyl Chrysler engines from the K-Cars. These were bad for leaking rocker covers.


StevieC is here, now wheres Mori.

I am going to let the silicone cure 42 hours since my Dad lent the heat lamp to his friend, so I will take the car out tommorow around noon.

I did let the silicone cure for 24 hours the last time, but I added the anti-freeze 2 hours later, this time I will not be adding the coolant until I go to drive it, I do not need any anti-freeze messing up the silicone before it cures.
 
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