Paint to show where I have allready sanded

What paint should I use as a "marker" paint? I have spent hours washing down and scrubbing the deck and now I need to sand. This paint will show where I have sanded and not contaminate the area with oil or some other stuff that will cause the 2 part epoxy primer a problem.
Thanks for any help

 

you can use any caned lacquer (black works best). but this should but used at the end of your sanding schedule not the beginning. It'll just slow you down.

GWB, how bout some details, like age, size, color, type of finish (paint or gel)
etc etc.............

 

Thanks for the reply Grady.
I'm using interlux primekote 2 part before prefection top coat. I don't understand why you say I should spray the lacquer after sanding....I need to see what I have not sanded.
The current finish is old gelcoat. Boat is 32 foot long Westsail....I'm doing the deck currently

 

I only say that because from my experience, the texture/color change is quite dramatic on the first cut it's after that it becomes a little hard to see.

But Just use hull markers like stantions and other hardware to go along with your paper changes (you'll find that you use a lot of paper). The reason you won't want to use a guide coat on all cuts is that becomes costly and time consuming. But that's just my opinion, as I said I'm new to this as well.

Take a minute (or hour) to read through some of those other treads there's tons of info there. As well as some really knowledgable folks helping out.

And I sure a painting/preping professional will be along with advice.

 

if your sanding old gel,,,,,the "shine" or "reflection" will tell you where you have already sanded. even old,old,old gel coat has a "shine" to see it,,just sand a spot,,the "shine" will go away,,when you got old paint,, spraying first wont help you a bit,,they "use" that technique to see your orange peel on your primer ,,and when done,,,all you do is spray from like 2 feet away,,and get a few "drops" on the paint.,,,ohhh,,,,red rustoleum is the best to use hehe

 

You can alway's use a pencil drawed lightly across the deck. Is textured, molded nonskid? If you spray you'll have to mask off surfaces you want to keep. More WORK!

 

If you are sanding white top there is a tendency to get "snow blindness" if you are working in the bright sun. That is the only reason to use a spray marker.

 

We use both Texta marker pens scribbled all over the area or printers ink. The ink is very cheap, 1 litre covers an enormous area, it is easily sanded and of course waterproof. You simply put someonto a rag and go mental, but do not use much, you are only after a grey shade, black overall coverage is not needed. All the dents and hollows, pin holes and scratches will be revealed as you fair sand.

We also use it again in the final sanding processes, such as 1200 to 1500wet and dry as it shows any sanding scratches easily.

 

Check with your paint distributor

There is a product used for a guide coat. It is a very fine black dust and has a pad applicator. One just rubs down the surface and the product leaves a gray tint. Sand till its gone and you are in business. Maybe its better for finding pinholes and small scratches than anything else. I think this is a 3M product. With practice and a systematic sanding technique you can dispense with marker coats.

 

Thanks for all the help

 

I just stumbled onto this thread and although its a couple of months old i figure i may as well add mt 2 cents worth.I do like to apply a guide coat before it ever sees sandpaper,i never use paint for this,its way too expensive and slow to apply,i bought a gallon of blue dychem layout fluid from an industrial supply house about 25 years ago and dozens of boats later we still havnt used it up because it is so dark that we dilute it way down with denatured alcohol and then wipe it on with a rag,i do this right after de waxing before any sanding because there is no time when a visual aid isnt helpfull,i like to take care of any issues early in the game and bury any filler deep within the primer.