Thread sealant

[awreed]

Thoughts on thread sealant that have been troubling me lately.

Two different thread sealants. Loctite 592 for fuel fittings, oil and coolant lines, brake and steering fittings. Permatex high temp. for extreme temps and vibrations.

The first direction on the Loctite package orders: "Clean and dry parts using Loctite Klean 'N Prime Activator", suggesting that this thread sealant NEEDS an activator in order to work properly, yet I have not found Klean 'N Prime on any store shelves yet.

The first direction on the Permatex package suggests: "For best results, clean parts with Permatex Surface Prep activator". To me this means that the Permatex product is anaerobic and will cure on it's own once exposed to the environment and does not necessarily need an activator. This was not my experience. The first time I used it, it seemed to cure fully to a hard substance. The second time I used it the sealant stayed tacky and wet and I had multiple oil leaks at each fitting. I also have yet to find the Permatex activator on any store shelves.

So question time. I know I can find the two activators online- already ordered. If at least one of the activators is necessary for the sealant to cure properly, why isn't it 1) packaged with the sealant, or 2) offered on the store shelves as a complementary product (i.e. peanut butter and jelly, tooth paste and tooth brushes)? Bondo needs an activator to make it cure, and the activator is always packaged with the main product. JB weld has two parts that are always sold as a packaged deal. Coffee machines need filters, which are packaged separately but sold right next to the machines. So why doesn't Loctite or Permatex do the same?

[busman78]

If it was an auto parts store you bought the sealant at they should be able to order the activator for you. According to the manufacturer for proper adhesion and curing you need the cleaner activator.

As for me I know of nothing on a VW that requires a high temp sealer, but just for fun the 592 for example, that costs about $4 for a small tube but $14 for a can of cleaner activator, it had better screw the fitting together for me and open my can of soda at that price. The Napa near me lists both in stock.

[awreed]

On my Bus I have a remote oil cooler, thermostat, oil filter, and a case tapped for full flow, so there are 8 pipe thread fittings that will not seal without some sort of thread sealant.

[Cusser]

Loctite was our sister company, and makes good quality products. I would follow their instructions for best results.

[busman78]

I did not negate the use of sealant, just the high temperature plus the requirement for activator since there are dozens of threads, thousands of suggestions encompassing hundreds of different thread sealants that do not require an activator on this site.

[awreed]

[Cusser]

[raygreenwood]

The activator....is about 90% acetone.

Virtually all of the anaerobic thread sealants .....made by any company.....list BEST RESULTS....when using an "activator" or pre-prep or pre-clean.....using a product that is acetone based.

Of course they are going to tell you to THEIR product....so they can sell you something.

However....it is absolutely true that acetone generally makes the product work better.

Do you know why? For two reasons.

1. Because these are ANEROBIC sealants. They only work their best in the absence of oxygen. If you have excessive moisture in the air that is in and around the threads....it contains oxygen and can make the bond weaker. Acetone is a co-solvent with water. It absorbs water into itself and will pull it off the surface as it flashes off.

2. Some of these products are formulated....to actually use acetone as a true activator or catalyst.

So they tell you to scrub the threads with an acetone based activator.....flash off the excess quick and apply the threadlocker and screw them together quickly. The fumes alone can catalyze the product.

The anerobic activator they are describing...if you read the msds sheet.... is almost all acetone but also contains an ingredient .....to slow down the evaporation....as well as be a catalyst. So they most likely want you to put them together slightly wet. Ray

[busman78]

I prefer liquid teflon to tape, but you can use both at the same time, there are also different grades/thickness of tape, try one for natural gas, can't remember the color, even the paste is different, petroleum is petroleum. Cheaper than activator.

[KTPhil]

[busman78]

Gee thanks, but carbonated caramel colored chemical infused diet drink is the only thing in my can, man.

Thought hit me, since the continual leak is with pipe threads is there a chance the case got tapped with NPS (straight) and the fittings are NPT (tapered), for if that happened it will leak forever, you will need straight pipe fittings with o-ring or gasket to seal.

[awreed]

Ray Greenwood, thank you, man. That was exactly what I was thinking and hoping someone would confirm. Acetone is exactly what I used to clean the male and female threads, but I did not mate the fittings together right away. It was probably more like a couple days or a week.
I do kinda like the idea of the teflon tape, though. A few people in the other threads really hated on it, but what the hell, right? If it works it works, and I'll never know unless I try. Is the teflon tape fuel resistant? Can I use it on the outlet valve threads on my new aftermarket gas tank?

[raygreenwood]

[Cusser]

[raygreenwood]

[busman78]

White - Usually single density for up to 3/8" fittings
Yellow - Double density, 1/2" and up fittings, called "gas" tape but still PTFE
Pink - Triple density, 1/2" and up fittings

The above are all PTFE just different density, all good for WOG,

[raygreenwood]

[busman78]

I left out the green tape, it is for oxygen applications, and the Gray tape is for stainless steel, just what we need, more selections.

[carlos_magnum]

Based on my experience, teflon tape is a hit or miss. Loctite is a good alternative.

[heimlich]

What are you planning on using red Loctite for? That stuff doesn't come off.
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