CVRT hull sealant

[Grasshopper]

While doing some work on the Scorpion project, I noticed that some kind of sealant has been used on components that bolt directly to the hull ie stub axles/final drives. Anybody any idea what it might be? It's a kind of sandy colour and does not seem to be a silicon type sealant but may have once been a liquid/paste.

 

Vince

[sirhc]

Vince,

 

It should be JC5a jointing compound, but that's expensive as it's used in aerospace. I've been using Red Hermetite instead as it's cheaper. You will find a mix of both on CVRTs.

 

Chris

[Richard Farrant]

While doing some work on the Scorpion project, I noticed that some kind of sealant has been used on components that bolt directly to the hull ie stub axles/final drives. Anybody any idea what it might be? It's a kind of sandy colour and does not seem to be a silicon type sealant but may have once been a liquid/paste.

 

Vince

 

Hi Vince,

 

It was a thick paste / paint of a yellowish colour and I think, made by International Marine Paints for dissimilar metals, ie steel to alloy, to stop corrosion.

 

If Clive Elliott reads this, he may be able to give you the full description.

[fv1609]

Probably H1/8030-99-220-2495 or H1/8030-99-224-7400

[Richard Farrant]

Probably H1/8030-99-220-2495 or H1/8030-99-224-7400

 

What is the description for those numbers, Clive?

[sirhc]

8030-99-220-2495 is JC5A

8030-99-224-7400 is a Dry Moly Paste

[fv1609]

What is the description for those numbers, Clive?

 

Sealing compound by Desoto Europe & Matra BAE Dynamics also used by Thorn EMI & Pilkington.

 

The full details should be in COSA H1(b) Abrasives, Industrial Chemicals etc Unfortunately the edition I have is missing the last few pages:-(

[Richard Farrant]

8030-99-220-2495 is JC5A

8030-99-224-7400 is a Dry Moly Paste

 

Oh... then it would originally have been the JC5A I reckon as that is a zinc chromate paste and fits the description of what we used.

[sirhc]

Richard,

 

I have just put some Messier dampers on my Sabre, the mod instruction states to use JC5A. However the dampers had both the yellow stuff and the red stuff on them, so I guess they used whatever they had to hand. It also seems they didn't quite follow the instructions on my vehicle, the rear mounting holes were not deep enough for the bolts specified in the mod instruction and one of the holes is a few mm out! :argh:

 

Chris

[Richard Farrant]

It also seems they didn't quite follow the instructions on my vehicle, the rear mounting holes were not deep enough for the bolts specified in the mod instruction and one of the holes is a few mm out! :argh:

 

 

 

Chris, you cannot get the staff nowadays...........and standards have slipped.

 

Not like that in the old days

[Grasshopper]

Been looking at the ROCOL website, lots of interesting stuff but couldn't find JC5A or Dry Moly paste (using the number Clive gave) on there. It would be nice to get a price on the correct stuff if i can find it.

[Richard Farrant]

Been looking at the ROCOL website, lots of interesting stuff but couldn't find JC5A or Dry Moly paste (using the number Clive gave) on there. It would be nice to get a price on the correct stuff if i can find it.

 

Vince,

 

It is basically a zinc chromate paste and may be available in marine or yachting suppliers. As I said, the one supplied though the army which we used way back on Fox and CVR(T), was a standard International Marine Paints product.

[Grasshopper]

I have found that JC5A is rather expensive (as Chris pointed out), but found a product called Duralac DTD 369B appears to do the same job and is cheaper. It seems that Duralac hardens with time whereas JC5A will remain paste-like. This should not be a problem on the CVRT hull componants.

 

http://www.intek-uk.com/Duralac%20TDS.pdf

 

http://www.lasaero.com/site/products/article?id=P002OHHP1

Edited October 9, 2009 by Grasshopper

[alant]

The Duralac will do the job but does harden and can require a little effort to remove parts stuck on with it. In the light aviation world it is known as Yak Sh*t.

Suppliers are LAS and Skycraft at Spalding.

Alan

[Timinder]

When I did a bit of resto work on Spitfires we used something similar to JC5, but it was known in the workshop as "monkey sp**k" I guess 'cos you wouldn't want to get either on your hands

[malyutkaman]

Don't know if it will help but I work on Eurocopter AS 350's and they call out for loads of the zinc chromate paste. The brand name (in the US?) for the junk is "Mastinox" more commonly known as nastynox. Comes in small tubes and a little goes a long way. Really good stuff, no dissimilar metal corrosion problems and stays paste-like forever.

Hope this helps,

Rich

[Grasshopper]

Thanks everybody for the help. I have a couple of options now! Found Mastinox here:

 

http://secure.silmid.com:80/ENG/product/__MA6856K160__/SEAG/Sealants/Mastinox%20Jointing%20Compounds/MASTINOX%206856K%20160ML%20SEMCO%20BMS3%2d27%20MIL%2dP%2d8116C

 

The parts I am fitting should not have to be removed again, so I may go with the Duralac.

Edited October 9, 2009 by Grasshopper

[Tugger]

It sounds like you're sorted for it now, but we use Duralac (yes...with the boats...again) when putting dissimilar metals together especially masts, where there are stainless fittings attatched to an ally mast, if it wasnt for this the mast would soon corrode and fall over... not an ideal occurance.

 

The riggers on site use nothing else which would imply that as an anti corrosion solution it's probably the best available to them.

[Grasshopper]

Thanks for that. Decided to go with the Mastinox in the end as it can be applied using a squeezy gun.