Primer on top of SKS Stonegaurd (water based)

[Jonny042]

I've sprayed most of the underside of my tub with Water based SKS stonegaurd and the directions on the bottle say it must be primed before painting.

Would a urethane primer mixed as a wet-on-wet sealer be most apropriate? Top coat is single stage urethane.

I would think adhesion between the paint and primer may be an issue if it's not applied wet-on-wet, as its going to be impossible to sand the primer (due to the texture of the SKS).

Thanks in advance, Jon

[962porsche]

primers are a filler type product and most are not meant to go wet on wet .
they do have some primers you can mix as a sealer and then it can be used wet on wet .
your best is to use a wet on wet sealer not a primer .
the big question is why do you want to paint over a chip guard .
once you spray paint over it you now have something that will chip and get sandblasted .

[Jonny042]

I don't think using SKS and then painting it is anything unusual. Seeing as how that's what they do at the factory?

The instructions say to use a primer before painting. But don't specify anything further.

[962porsche]

your talking about a porsche ? on the underside of the car they are not painted it's just chip guard .
the only place they put paint is on the rockers and that is over chip guard .
the paint you see in the wheel houses is just overspray they do not try and get paint coverage there it just ends up there from spraying the top side .

[962porsche]

this is just chip guard not paint over it if you need to match the color you tint the chip guard to match the OE color .

[Jonny042]

Well if my car looked like that I wouldn't have any questions would I I'd just leave it alone!

Open the trunk or engine compartment of any 911 and you'll find a full wet coat of paint on top of most the stoneguard. Also, my car must have been painted on a monday because it has a full wet coat over at least 3/4" of the pan (not to mention the rockers, spoiler, etc. which clearly aren't beige.).

The best match (according to many) for the factory product is SKS and it's available in any colour you want as long as it's black.

So, what we are left dealing with if you make the choice to use it, is.... PAINTING IT. Like it says on the bottle.... "paintable". And it says to use "primer".

So seeing as how I have already made the choice to use SKS, and it's black, and I'm going to paint it, can anyone help with my question?

I'll repeat it - is a urethane primer mixed as a wet-on-wet sealer the best choice for painting SKS?

[962porsche]

ok well 1st off smart ass you didn't state one word about the underside of the hood rockers or valance panel .
instead of getting your back up and trying your best to be a total ass you may want to think about taking some advice from some one that has restored countless porsches of the last 40 years and that worked for porsches coatings dept.
1st you picked the wrong chip guard you should have gone with u-pols chip guard and bought the white color then tinted it to match the underside of the chassis .
you also do this if your restoring your fuel tank .
as for painting over SKS as SKS is made by U-pol again you picked the wrong crap .
you as i stated if you have a primer you can mix as a sealer ( you said primer and not a dam thing about sealer or if you can mix the primer you have as a sealer ) then you would mix it as a sealer and spray one but no more then two coats of its going wet on wet after it flashes off you then would go to top coat .
as you repeat it ! the answer is NO it's not the best but it will work .
try reading your TDS they tell you every thing you need to know .
fyi wurth doesn't make products they take other peoples products and put there own name on them .

[kevin930t]

Fyi wurth is comming out with a grey and possibly a white in the next couple of months,for there sks stoneguard.

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[Dpmulvan]

Listen to 962 he knows what he's talking about and you don't.

[kevin930t]

Who are you talking too

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[Jonny042]

Originally Posted by 962porsche

this is just chip guard not paint over it if you need to match the color you tint the chip guard to match the OE color .

Are you saying that car is original? Because I have 3 911s, all original paint, and none of them have so little paint on the pan.

[Jonny042]

Originally Posted by 962porsche

as for painting over SKS as SKS is made by U-pol again you picked the wrong crap .

You can tell what's in these products by looking at the SDS, and I can't see Gravitex has anything in common with any of the Wurth products.

Plenty of people are using SKS, I can't get behind your assertion that it's "the wrong crap".

[Jonny042]

Originally Posted by kevin930t

Who are you talking too

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I have no idea who he's talking about. I certainly know what I'm talking about, and you seem to, too..... great news about being able to get "the wrong crap" in different colors!!

Mind you I've only been building cars, airplanes, and motorcycles for 30 years so WTF do I know. All those other idiots using SKS should be banned from the paint and bodywork forum don't you think?

I thought my original question was pretty simple. How it degraded into this crap shoot is beyond me. For what it's worth, I sprayed the primer mixed as a wet-on-wet sealer and it seems to work perfect. I did make sure I gave it plenty of time to flash off before topcoating, but it covered up nice and gave a nice finish, overall it's dimpled, but not too dimpled, and has a nice gloss. Just like an over-restored hot rod should look

[962porsche]

Originally Posted by kevin930t

Who are you talking too

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he is not talking about you .

[962porsche]

this is just getting funnier by the minute !
i feel real bad for you ! you are so pissed off about the info you asked about . but going back and editing out and changing it as you keep doing doesn't fit the question you asked about your 1986 carrera .
but the answers are still all the same .
fyi
you are still confused on a number of things . a TDS is not the same as a SDS .
TDS technical data sheet
SDS safety data sheet
no you would not find anything in the uses of a product in a SDS .
30 years of restoring aircraft bikes and cars you should know the difference . quick go back and edit that to make your self right .

sorry your knowledge of the 911's must be 2nd to none as you own 3 and i only own one 1986 carrera right own the other 11 porsches i own at this time and the two other 1986 911's i owned in the past in no way make me as smart as a god like your self .

your knowledge is so great yet you don't know how to prep stone / chip guard for primer sealer or painting yet you know you picked the right product . you must have read the wurth sales brochure and saw it said porsche on there . so you and all the other users must be 100% right they got the right crap . and you did if you wanted black but they OE color is not black .
as for texture you can match that with just about any chip guard on the market . that you do with the gun .

as for you car having the oe finish and it covering 2/3's of the undercarriage ? that would shock the hell out of me as the way porsches are paint at the factory it can't happen even on a monday LOL .
i could get into who and why with 8 by 10 colored glossies but with you and showing you photos of the painting production line and how they are painted from when i worked there is pointless .

[Jonny042]

I never meant to come across as a know-it-all. I'm not going to pretend to know everything, and yes I am sure you know a lot more than I do, and in particular about Porsches, and paint and bodywork. Your contributions to this forum are appreciated by us all.

The decisions that led me to using black SKS were made a long time ago and I believe them to be valid ones. As a result of these choices I am now faced with covering up the black with body color. That's what my original question was about (and has not changed).

In retrospect, my reply to your original response should have been this:

"Thank you, yes, I have a primer product that can be mixed a few ways, including as a wet on wet sealer. I will give it a try and let you know how it works out."

My smart-ass response was not wise or in the spirit of this forum and I apologize that it led us down this unfortunate path. Sometimes I need to take a step back and realize we are all here because we have interests and passions in common - were we having this conversation face to face in a body shop or a club meeting or in a bar over a beer it be a lot easier to find common ground and smooth over differences. I am sure we both have a lot to offer.

So, again - thanks for contributing a useful answer to my question. I apologize if I reacted poorly to one portion of the response when I should have been thankful, instead, for the input you provided.

[Dpmulvan]

So you've built cars,motorcycles and airplanes for 35 years. I guess you must have sub' all the paint work out. If you want a colored chip guard why not buy white and tint it with acrylic enamel?

[Iciclehead]

Originally Posted by Dpmulvan

So you've built cars,motorcycles and airplanes for 35 years. I guess you must have sub' all the paint work out. If you want a colored chip guard why not buy white and tint it with acrylic enamel?

I have no real knowledge in this space, but am getting close to the point where I need to reapply chipguard on my '89 project. I just don't know how to tint the chipguard, seeing as it is water based and the acrylics are not. Suppliers (to date) don't seem to know....

My previous restoration, I just did the chip guard on the underside, let it cure, then cleaned it well and sprayed top coat on it (speed yellow in my case). Only real issue has been that a couple of places have had the colour chip off and when I applied the finish, it took a lot of yellow to cover the dark grey of the Sikkens chipguard I was using.

Probably should have sprayed a base coat of white and then the yellow on retroflection..

Dennis

[962porsche]

JON it takes two .
i tend to just say it as i feel i'm willing to help any one with there projects .

ok so your looking to paint the underside of your car as you know i feel this is one of the biggest mistakes for a number of reasons . the biggest is no matter how or what you do over time down the road you will have the painted finish sandblast to hell .

i have had a few customers ask us to do this and this so far is the best way we have found .
we are going to get right back to the tinted chip guard but you would tint it to closely match the color of the paint color your looking to use . by doing this when the finish does get scratched , chipped and sand blasted you would not see a big difference in the colors from the top coat to the chip guard .
then you would also want to pick a sealer you can also tint to match the top coat color .
when it comes to the top coating you want to use a flex additive as you would use for rubber bumpers . this will add to the impact protection . it's not a cure all never to get damage on the finish but it's a big help .
as we all know the undercarriage takes the biggest beating from sandblasting of road debris .

prep becomes very important when your looking to paint the undercarriage .
spray your stone/chip guard then let it dry . i wouldn't try wet on wet from stone guard to top coats .
once the chip guard is dry sand it with a red pad . an easy way to sand some thing the size of the chassis is to use a DA sander with a hook and loop pad on it .
the red pad with stick to the hook and loop pad because the hooks grad the red pad .
this will get into the nooks of the chip guards texture and not sand the tops of the texture as sand paper will .
with an old pair of scissors you can cut the red pads round to match the DA backing pad .
once you sand every bit of the area blow the area off and clean with a prepaint cleaner .
from this point you can go wet on wet .

as i'm sure you can guess i think it's a very big mistake to paint the under side of the car like this unless you are only going to show the car and trailer it .
this is not to say i don't think it should ever be done i finished a deuce coupe not long ago and i painted the underside of it the same pearl color as the top side . the big difference is the owner is not really going to drive this car . we did all the suspension in chrome and the frame is a gloss black . as we can guess he is not going to drive this car . it's nothing more then a trailer queen ( now how sad is that ? )
porsche's are made to be driven take our loved 86 carrera's don't know about you all but i like that car should it not be driven ?
OMG NO !!!!! even my car with low miles and in very good shape it's meant to be driven and get driven .
it is such a drivers car ! think about its a exotic car you can take to work with great every day road manners and yet take the same car to the track and whoop up on bigger cars .

i have seen more times then i can remember people painting the undersides of there car or spraying rubberized undercoating on them .
any one ever trying to clean it off will tell you the hell job it is many times i have found it easier to fix it we would just end up stripping the chip/stone guard right off the car and just replace it (the chip guard ) .
when we do replace it we use the white chip guard and tint it to match the old 3M product that was used .

i maybe should have stated this from the start ????
you would have a better understanding of what i'm trying to get across and why i feel it's a very bad idea .

[962porsche]

if you really want to match stone/chip guard to a 10 point concourse for want the car has this it the type of gun you would use .
this type of gun you can adjust the texture from almost flat to more then twice the texture a porsche has .

i also have the lemix chip guard gun that also works great . the key is to buy a gun that you can adjust the spray pattern and droplet size .
the lower cost none adjustable guns are pretty useless .