Guide Coat

[jackson]

Originally Posted by cableguy0

The issue with the primer is that you might end up sanding off a whole lot more than needed just to see results. Results with guide coat are practically instant.

that makes sense

[_Ogre]

Originally Posted by kcsa75

I use whatever I have lying around. Usually a half-empty can of Krylon that the Mrs. bought for some project around the house.

same here: pink, green, puce.... what ever half can laying around with a partially clear nozzle
if the nozzle is half plugged and sprays sideways or in a stream, just move the can faster

[MARTINSR]

Originally Posted by _Ogre

same here: pink, green, puce.... what ever half can laying around with a partially clear nozzle
if the nozzle is half plugged and sprays sideways or in a stream, just move the can faster

Try the dry guidecoat, you will never go back!

Brian

[kxmotox247]

Is the dry guidecoat only for dry sanding? How does the wetsanding not just wash off the dry guidecoat?

[_Ogre]

Originally Posted by MARTINSR

Try the dry guidecoat, you will never go back!

Brian

i am actually hoping never to do body work again

[cableguy0]

Originally Posted by kxmotox247

Is the dry guidecoat only for dry sanding? How does the wetsanding not just wash off the dry guidecoat?

You wouldn't be wet sanding at the point where your worried about guide coat and filling dips and valleys. Your still removing a good amount of material and wet sanding is not the way to do that. Guide coat is for when your block sanding large areas. Wet sanding is your final step which you should be well past needing a guide coat.

[MARTINSR]

Originally Posted by cableguy0

You wouldn't be wet sanding at the point where your worried about guide coat and filling dips and valleys. Your still removing a good amount of material and wet sanding is not the way to do that. Guide coat is for when your block sanding large areas. Wet sanding is your final step which you should be well past needing a guide coat.

Great answer, that is it in a nut shell, you want the guide coat so you can CUT it flat. By the time you get to wet sanding you aren't doing it to remove a lot of material like blocking, you have already done all that. The wet sanding is the final sanding you do where you are simply removing some slightly coarser sand scratches, that is ALL you should be doing at that point.

This being said, I have never done it but I think you can still use it and it will work to find sand scratches you need to sand out.

I need to do a little test to find out as I said I have never used it while wet sanding.

Brian

[lowdownstar]

I have been using high build primer on my truck and the dry 3m guide coat and found that they both work great but for me i've had to block sand the parts like four or even five times because every time i do it, i was still finding low spots. Is this normal?

thanks Ray

[cableguy0]

Originally Posted by lowdownstar

I have been using high build primer on my truck and the dry 3m guide coat and found that they both work great but for me i've had to block sand the parts like four or even five times because every time i do it, i was still finding low spots. Is this normal?

thanks Ray

Yup. If you want your paint to be glass its a really long process. If it was fun it wouldn't be called body WORK. Block sanding properly is an extremely long process. It was no big deal to have 100 hours in just block sanding a vehicle. Were talking show quality but still over 100 hours wasnt unusual.

[lowdownstar]

thanks now i don't feel stupid for doing it, cableguy....

I don't really mine the work i just want it to look good when done...

Thanks again

[cableguy0]

Originally Posted by lowdownstar

thanks now i don't feel stupid for doing it, cableguy....

I don't really mine the work i just want it to look good when done...

Thanks again

You might feel stupid right now for "wasting" all that time. When the paint is laid down and looks 10 feet thick you will suddenly realize it wasn't a waste to do all that sanding. Painters get all the credit for paint looking good. 95% of it is the guy before the painter than spent the hours upon hours sanding and prep work. Prep work makes the paint job.

[lowdownstar]

Thanks for the kind words cableguy, i can't wait to see how it comes out, i need to start a build thread...

Ray

[Kim57]

Originally Posted by lowdownstar

Thanks for the kind words cableguy, i can't wait to see how it comes out, i need to start a build thread...

Ray

Yes you do then you'll be an inspiration to those of us that need a little motivation once in a while.
I just ordered some slick sand and a new gun just to shoot it so I'll be into the block sanding also.
Kim

[kxmotox247]

Originally Posted by MARTINSR

Great answer, that is it in a nut shell, you want the guide coat so you can CUT it flat. By the time you get to wet sanding you aren't doing it to remove a lot of material like blocking, you have already done all that. The wet sanding is the final sanding you do where you are simply removing some slightly coarser sand scratches, that is ALL you should be doing at that point.

This being said, I have never done it but I think you can still use it and it will work to find sand scratches you need to sand out.

I need to do a little test to find out as I said I have never used it while wet sanding.

Brian

So you guys don't do any guidecoating when wetsanding? I'm talking about with 600 grit before sealer and base? I understand you guys are using guidecoat when dry sanding to quickly identify highs and lows. I use it there too.
The way was taught was guide coat thru the whole process. The guidecoat when wet sanding isn't so much for leveling but more so for even consistent sanding. And there's always one more scratch or flaw to be found... and it's easier to deal with it at that stage rather than seeing it with shiny base/clear. I'll personally stick with it thru the whole process but will probably try the dry guidecoat sometime to see how it works.

[theastronaut]

I always use guide coat no matter what I'm sanding. Filler, Slick Sand, urethane high build/surfacer, or single stage/clear when cutting/buffing. You can't really see what you're doing without a guide coat.

I guide coat and wetsand my surfacer with 220 to get it completely flat, then re-guide coat and wetsand with 5-600 to get it smooth enough to paint over. Unless your primer lays out as smooth as paint (usually not possible) then 500 won't remove the texture as easily or quickly as 220. 220 knocks it completely flat, even when using a soft pad on rounded parts- something 500 isn't good at especially if it's not a fresh piece of paper.


For single stage or clear, I use a Sharpie marker to highlight all of the edges and body lines so I can see if I'm sanding too close to them. Then I go over and highlight all of the imperfections that I need to sand out. This way you can see exactly how much you're cutting and you can see if you need to be more careful around edges.










Creases on a door that I buffed. Marked them with a sharpie and watched my sanding pattern to avoid cutting through the clear in the crease.






After buffing.





Sharpie works best for the initial color sanding with 1000 grit since dry guide coat won't stick to shiny paint and spray guide coat will clog finer grit paper. After that you can use dry guide coat or use a Sharpie again.

[MARTINSR]

Let me make something clear on the use of a Sharpie.

DON'T EVER, EVER, EVER USE A SHARPIE BEFORE PRIMER, PAINT OR CLEAR.

Just in case I didn't make myself clear.

DON'T EVER, EVER, EVER USE A SHARPIE BEFORE PRIMER PAINT OR CLEAR!!!!!!!!!!

The ink in that Sharpie WILL bleed thru paint like I have never seen anything bleed thru paint in my life. You could write your name on the door and paint SS urethane paint over it and that Sharpie will come thru so clear you would swear someone walked in the booth after the paint dried and wrote on it!

You don't want to use Sharpie for ANYTHING around the car before paint. You can't believe how easy it is to accidently leave some and have it come to bite you in the butt.

If you are experienced and have a good eye for details sure, you can mark stuff for cutting or what not, but you have to be VERY aware of it.

Brian

[theastronaut]

What he said! ^^^^ I should have mentioned that in my first post. I've made the mistake of painting over Sharpie marks and had to start over because it bled through.


It works well for guide coating clear or single stage only AFTER it's painted. And I wouldn't use it on fresh paint either, let it cure for a week or two- the solvent in the pen can soak in and cause the paint to slightly swell or do something weird that leave marks after it's buffed. Use on very dry paint only, not fresh paint! We've had no problems when it's used on PPG paint that's dried for over a week. No promises on what it'll do with other paint.

[lowdownstar]

Originally Posted by Kim57

Yes you do then you'll be an inspiration to those of us that need a little motivation once in a while.
I just ordered some slick sand and a new gun just to shoot it so I'll be into the block sanding also.
Kim

What did you buy for a gun Kim? i just picked up a new commpressor so now i can get myself a good gun and want to buy something better then what i have.

Thanks Ray

[Kim57]

Originally Posted by lowdownstar

What did you buy for a gun Kim? i just picked up a new commpressor so now i can get myself a good gun and want to buy something better then what i have.

Thanks Ray

I bought this one.
Amazon.com: TCP Global? Brand Professional New...
Not sure how good it is but should work for the slick sand as it has an 2.5 nozzle.
Kim

[Hogshooter]

Its amazing how far a thread started about guide coat can go. I have some lacquer primer left from the days of lead and dinosaurs that I like to over reduce and add contrasting basecoat that has been left over from repair jobs. It doesn't clog sandpaper like the aerosol paint will. Dry guide coat will work when wet sanding I like it pretty well, it is very convenient. I would like to add you should never use any kind of ink on the body filler metal or primer, pencil is not so bad just NO ink.

[rgunlock]

Ouch, wish I'd read this particular thread a while back. I've already made a couple of the "NEVER DO THIS" type things on my build, like using a red sharpie to highlight bare metal I need to do work on. Guess I better go back to my build thread and point out my bad ideas.

Very good info here - thanks guys!