Jotun 87.... overcoating question

[GRW]

I've got a jacking point & possibly a sill repair on my 2008 Renault Master Mk2 camper conversion.
So after my iffy welding skills get an airing I need to protect the repaired area, plus I'd like to protect other areas of the underside & possibly the outer sills up to & under the side plastic bump strips potentially.
(Van is white so thinking maybe get white Jotun 87??)

I've noted for chassis / underbody that the Hive Mind on here rate Jotun 87 Epoxy. As it can be brushed etc on this sounds the thing for my Camper.

Firstly can I ask if it dries to a smooth finish?
Secondly - it's a "Primer" I understand.... so does it HAVE to be overcoated with another product, or is it OK as-is?
Thirdly - if it does need covering asap... what top coat is suggested (for the ham-fisted non-painter ideally!)

I've never used Epoxy, but it looks like you mix the 2 parts together as per instructions, and paint it onto a prepared surface.

I'm thinking some Dinitrol in the cavities to try & fend off the tin weevil as much & as long as possible.

TIA, G.

 

[Misterg]

Firstly can I ask if it dries to a smooth finish?
Secondly - it's a "Primer" I understand.... so does it HAVE to be overcoated with another product, or is it OK as-is?
Thirdly - if it does need covering asap... what top coat is suggested (for the ham-fisted non-painter ideally!)

I've never used Epoxy, but it looks like you mix the 2 parts together as per instructions, and paint it onto a prepared surface.

I've used the 90, which I believe is very similar. It goes on a bit like thin tar. I couldn't get a smooth finish - lots of brush marks. I intend to roller the next lot to try and get an even texture at least. If I thinned it, I was left with the surface grinning through the brush marks.

It only needs overcoating to protect from UV degradation. I've only used it on the underbody and most of it's got stone-chip over the top.

Yes, stir the big tin, measure some out, add hardener, mix together and apply. Seems to have a decent pot life.

 

[steveo3002]

it dries smooth as in its not 40 grit sandpaper , if brushing it chances are there will be brush marks , it doesnt flow out like a coach paint etc , you can sand smooth any runs or drips , but yeah its an industrial coating not a show car paint

you dont have to overcoat but it will chalk up in sunlight , wont effect its performance but you can use top coat over it , it will accept almost anything

yes mix a small amount and use that , will be going off after a few hours so dont mix more than you need ,i use the little paper drinking cups to knock up a small amount

 

[GRW]

I've used the 90, which I believe is very similar. It goes on a bit like thin tar. I couldn't get a smooth finish - lots of brush marks. I intend to roller the next lot to try and get an even texture at least. If I thinned it, I was left with the surface grinning through the brush marks.

It only needs overcoating to protect from UV degradation. I've only used it on the underbody and most of it's got stone-chip over the top.

Yes, stir the big tin, measure some out, add hardener, mix together and apply. Seems to have a decent pot life.

Thanks for the reply.
I have seen people speak of both 87 & 90.... but I don't know the difference or which one would be the best for my application .
Sounds like both will do the job!

 

[steveo3002]

the number is solids /good stuff content iirc ...might be wrong

 

[GRW]

it dries smooth as in its not 40 grit sandpaper , if brushing it chances are there will be brush marks , it doesnt flow out like a coach paint etc , you can sand smooth any runs or drips , but yeah its an industrial coating not a show car paint

you dont have to overcoat but it will chalk up in sunlight , wont effect its performance but you can use top coat over it , it will accept almost anything

yes mix a small amount and use that , will be going off after a few hours so dont mix more than you need ,i use the little paper drinking cups to knock up a small amount

Thanks. I guessed as it is a 2-pack process (my brain thinks "like Araldite") so once mixed it's "use pretty quickly or it's gone off"

 

[Misterg]

once mixed it's "use pretty quickly or it's gone off"

Yep - you've got a good few hours, though.

On 87 vs 90, this is from the SML site:

Q. How does Jotamastic 90 compare to Jotamastic 87?


A. Jotamastic 90 offers a smoother finish, faster curing, and improved aesthetics while providing the same corrosion protection as Jotamastic 87.

 

[GRW]

Yep - you've got a good few hours, though.

On 87 vs 90, this is from the SML site:

Ooh! Maybe 90 might be better then

 

[steveo3002]

isnt there a zinc one for added protection , i havent used it so cant vouch for it

note theres a winter and summer hardener , the winter one works all year round , the summer one will struggle to go off in cooler temps

 

[Misterg]

isnt there a zinc one for added protection

I don't *think* any of the Jotamastic coatings contain anything that is actively corrosion inhibiting - My understanding is that they rely on being an impermeable layer that sticks like sh*t.

There are versions that contain glass or aluminium flakes, but pretty sure they just act as mechanical barriers / reinforcement.

I think there is a Buzzweld epoxy that contains zinc.

 

[GRW]

I do have some Bilt Hamber Electrox high zinc paint.
No idea if that would be good or bad underneath an Epoxy layer though