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Building Tips and technical articles. => Paint and finishing => Topic started by: Dennis Toth on May 26, 2019, 07:17:49 AM

Title: 3M Dry Guide Coat for sanding
Post by: Dennis Toth on May 26, 2019, 07:17:49 AM
Guys,
I was channel surfing and came across a car paint show that showed the surface prep to fine small scratches and imperfections. They used a product called "3M Dry Guide Coat". If you google this you will see YouTube videos showing how this is used. From what I can see it works like using Silver base to find problem areas in the substrate material before color.

Anyone try this? Seems this would work with any type of blocking coat to find flaws. Since it is dry should be easier than sanding silver.


Best,  DennisT
Title: Re: 3M Dry Guide Coat for sanding
Post by: Chancey Chorney on May 26, 2019, 08:46:43 PM
While I have not used it anytime recently, I have used it a lot in the past when I worked in a dealership. Very nice product. Sanded very easily and did not clog up sandpaper like rattle can or basecoat guide coat. The other bonus is when using the applicator sponge, you get a very good full coverage of it, and can make it lighter or darker by using a second or so coat.
Title: Re: 3M Dry Guide Coat for sanding
Post by: Randy Powell on May 28, 2019, 03:58:35 PM
Could cause a weight issues.
Title: Re: 3M Dry Guide Coat for sanding
Post by: Avaiojet on May 28, 2019, 04:02:18 PM
You don't need a "silver base" before color.

A "primer base" is all that's necessary, you just have to learn how to work sanding out primer.

Title: Re: 3M Dry Guide Coat for sanding
Post by: Mike Haverly on May 28, 2019, 04:42:45 PM
Could cause a weight issues.

It's a guide coat and practically gone when completed.  Also, lght.  I've used it, too expensive for my taste.
Title: Re: 3M Dry Guide Coat for sanding
Post by: Randy Powell on May 29, 2019, 03:42:25 PM
OK. I've used guide coats. I'm getting to where I want to put the least amount of paint on the plane possible.
Title: Re: 3M Dry Guide Coat for sanding
Post by: Dennis Toth on May 30, 2019, 02:15:00 PM
Randy,
Have you used the silver base coat method and how does the guide coat compare work wise, time wise and weight wise? Seems the dry guide coat should be less in all categories?

Charles,
I understand that you can do it with just the primer but you have to develop the skill over many ships. The silver is a time tested way to see how flawed the surface is for those that do one ship every few years. Seems the guide coat might be fast and lighter for the average Joe.

Best,    DennisT
Title: Re: 3M Dry Guide Coat for sanding
Post by: Avaiojet on May 30, 2019, 03:11:33 PM
Den,

I wish I could agree, and some may agree with you. Someone said it's "all opinions."

What will you fix the imperfections with, more silver paint? I don't think so.

If your a diehard front row guy you'll probably use a two part putty, even a two part primer for that matter.

One light from one direction, then move the light.

I have 1.75 glasses. If your eyes are bad, go to 2. Brings the surface in close.

I used a really nice white primer on some of the last models I've finished. Look at my old Builds.  LL~ I'm out of the Build business.

You saw the ARGO 2, but the ARGO is finished a tad better.

Go with the primer. Find and fix all the imperfections as best you can with a good grade putty. Then load on the actual color.

That'll get knocked down again with 600 or so anyway. The model should be nice by then.

The "Jet"  ;D

Title: Re: 3M Dry Guide Coat for sanding
Post by: Dennis Toth on May 30, 2019, 07:45:55 PM
I agree that you can do it with the primer/light candle method. The idea is that with the dry guide coat approach you can see the flaws, sand them down till the guide coat is gone then clean off the surface and light candle (as you suggest) to check. If you sand through, you add spot primer and go through the process again. With the silver process you apply silver, look in horror at the surface, fill any bad hanger rashes sand the surface to get almost all of the silver it off (candling as you go). Then clean the surface and add a full coat of silver, light candle (looks a bit better). Sand the silver off again, clean, candle spot spray any areas that have minor flaws left. At this point you can usually do a final sanding, apply block coat (either white primer or Diana Cream dope). At this point you are ready for color.

This is a tried and true method that many front row fliers have used. It is lots of work and time consuming but does work. My question for those that have used the dry guide coat does it get as good finish as the silver method and is it quicker.

Lots of ways to get this done, your way works fine the ARGO 2 has a great finish. I just want to see what other options are out there.

Best,    DennisT
Title: Re: 3M Dry Guide Coat for sanding
Post by: Brett Buck on May 30, 2019, 08:50:23 PM
I understand that you can do it with just the primer but you have to develop the skill over many ships.

   And/or not care how much it weighs. If you just pile on primer, you can solve any problem, but it can be insanely heavy. The silver or other guide and blocking coat is there to save weight by allowing you to fix the flaws with minimal extra primer or filler, and to make the surface an even color with a high-coverage paint (like silver or gray) so you don't have to make translucent color above it completely opaque.

    Of course, this is not a consideration for static display modelers.

  The problem I have seen people have with silver dope is that while it covers and blocks incredibly well, it also tends to have the adhesion properties of teflon. Gray covers just as well, and subsequent coats stick to it OK, but doesn't show flaws to be corrected as well.

     I have toyed with using silver epoxy as a blocking and reveal coat (since adhesion is never an issue), but the regular colors cover well enough that I don't think it's necessary. I do apply the red (which is about the most translucent color with poor coverage) over the white base coat, instead of back-masking it.

    Brett