SEM Rust-Shield

[Ferrino]

I'm looking for a durable satin black paint that I can apply both direct-to-metal and as a topcoat and have seen this product is popular here. I'd like to apply it directly to bare metal around the front of the chassis, but also to stripped/blasted parts that I am not having powder-coated (small brackets etc) and maybe also alloy wheels and fuel tank. I have a few questions:

1. The technical data sheet says it should only be applied to ferrous metal. Does this mean it is not suitable as a DTM for alloy wheels and aluminum parts? Or does it mean I would need a primer between the Rust-Shield and the non-ferrous metal?

2. Will this coating (with hardener) be durable enough to paint the engine bay? I would hope to just degrease and scuff the existing engine bay surface, rather than taking down to the bare metal.

3. If I use the "flat black" with hardener (8:1), will I get a level of gloss comparable to black powder-coat (you know, the standard black used for chassis parts etc)? That is the level of sheen I am aiming for (what is that, maybe a 50% gloss?). They also sell "black" and "gloss black", so it's confusing what the finish of the hardened product will be.

4. Can I just use a urethane reducer if it needs some thinning? i.e. the same reducer I'd use for a acrylic urethane topcoat.

5. Do you think this product is durable/good enough to paint stripped/blasted window frames/trim? Or will the UV break it down?

Thanks!

[962porsche]

this is the TDS I have a little out of date but should be the same as a up to date one .
it states it's formulated for ferrous metals so being designed for that it's recommended for it .
It will still have good adhesion to aluminum but what it will not do is offer corrosion protection for aluminum .
if you would need that you would want to spray a coat of epoxy down 1st .
this I will do from time to time but most times I do not .

we build allot of aerodynamic products for race cars like the front under tray in the photo we use rust-shield right over the bare well sanded aluminum .
it has never given us a problem in any way .



this motor is out of my endurance race car the hole motor was painted with rust shield .
all the aluminum on the motor like the valve covers and intake are over bare aluminum .
the motor has seen more 4, 6, 12 and 24 hour events on it then I can remember . every thing is holding up good .

you can not use the rust shield over plastic things like bumpers and composite materials .

[Ferrino]

Thanks! So can I just use the same urethane-grade reducer I use for base/clear with this?

[962porsche]

why do you need to reduce it ???

the mix is 8 parts rust-shield to 1 part hardener .
if you use flat black and then add the hardener it will change it to a semi gloss .
the semi gloss will look like the black on the valve cover and the covered with dust underside panel .

it's a very good match to the OE black they have on the parts and pieces .

[Ferrino]

Thanks. I've ordered the flat black and hardener. I was thinking that for small parts and one-offs it might be easier to just use a Preval sprayer and that would require some reducer.

[962porsche]

with the preval you will have to use some reducer . a 8-1 to 1/2 enamel reducer will do the trick .
enamel reducer is best to use but you could use the urethane reducer .
the problem with the urethane is it will make the black more of a flat shade then a semi gloss .

[Ferrino]

Thanks. I wasn't sure what the difference between enamel and urethane reducer was.

[962porsche]

the rust-shield is of enamel base so you would really want to keep the reducer the same .
you shouldn't use a enamel reducer in a urethane product but you can to a point used urethane reducer in a enamel based product .
all a reducer does is reduce a product so it can be sprayed and atomize correctly .
all reducers evaporate off in the end .
a urethane reducer is a higher/faster exploring product were a enamel reducer is a medium exploring product . so what that means is because the enamel is not as aggressive it will not break down urethanes .

sorry a simple question was such a long ass answer .

[Ferrino]

Thanks again. Another question - if you stripped the whole of the front of the 911 down to bare metal and then had a choice of applying Rust-Shield or epoxy primer direct-to-metal, which would you go for?

[962porsche]

great question !
but there is more then one answer to it .
if your looking to restore the car as it came from Porsche then I would not do that !
but you can do it !

we are restoring a very old Beetle and as the car has new floors and rockers we are spraying black RS on the floors , rockers and in the trunk area .
as the floors in the car should be black we will mask off the floors and then paint over the RS with 22 line in the trunk area and the inner rockers .

so you can do it you bet your life you can !
it does have good rust protection and if your going over some little areas of body filler it will work for that too .
how ever on big areas of filler you would not want to use it over that .
the reason is it will shrink in more then a real primer will .

[jrsully]

Another related RS question for 962, do they make RS in a SPRAY CAN that can used straight away for a degreased/cleaned engine area.? Looking to just respray over the original blacked out area on a 71T (will powerwash and degrease area as indicated) do they make a shade that is reasonably close.? Thx for your help

[962porsche]

SEM used to offer RS in spray cans but I think they discontinued it years ago .

I have used flat black RS mixed 8 to 1 on things like the targa bars and it's pretty much a dead nuts match for it's gloss .
I would not use the RS for a concourse resto's as it's not the same type of coating Porsche used but texture and shade of gloss are the same as OE.

[Ferrino]

Another quickie: the tech sheet calls for a HVLP tip of 1.6-1.8. If I wanted to shoot out of a smaller detail HVLP gun (which seem to have much smaller tips in the 0.6-1.0 range) for smaller parts/areas, would I just need to reduce a little? Thanks.

[962porsche]

yes you will have to reduce it about the same as if your using a preval .