Print Through

[Fletch170]

After getting my 17 out in the sun to pour the stringers, I notived the hull sides have a good amount of print through, I am planning on laying a good amount of primer and sanding after each coat, then hitting the hull with 3 coats of paint. I will be using interlux brightside for paint, and prekote for primer.

Will the layers of primer and sanding make the appearance of print through less noticable?

[gran398]

Yes. You can build it up so there is absolutely no print through if you like.

We have four coats of gel so far....no print through.

[Capt. Bob]

Hey,
For us DAs, how about a pic of "print through".

It's nice to learn something new.

Thanks.

[Fletch170]

http://www.boatdesign.net/forums/fiberg ... 36526.html

Here is a few.

Not sure what causes it, you usually see it on cheap boats....not.....that.,..mine..is...cheap? Yea. it's a pile of S*it.

[LilRichard]

I'm no expert, but I believe it's cause by resin shrinkage over time (or obviously not enough mat over roving).  

I had some and just hit it with a no shrink filler - sanded - and primed/painted.  Gelcoat may work, but remember, Gel can shrink as well over time.

[Fletch170]

I've seen a lot of it on brand new boats with dark hull sides. Regardless, it looks terrible and I hope the paint covers it. Someone told me it happens when the glass is laid up too quickly, when the glass backing had not fully kicked, this maintaining some flex...when the roven woven is laid down, and rolled out, it shows. I'm not sure if that's correct.

[gran398]

Reckon its the same across the board, the dark sides just show it easier.

[dburr]

Print through...

When glass is laid properly there is JUST enough resin to make the bond.. The strength of the system is from the glass fibers not the stuff it is laid in.  If enough resin is added to prevent the weave from showing before the glass bonds to the surface it lays on, the glass will float making the whole show weak because the resin will form a layer between it and the surface.  To prevent float, just the "right" amount has to be added.  Thick base gels over 20 mils used to be the order of the day to prevent this..

Now, why you get it through the gel coat is a mystery, it leads me to beleave that the gel was not thick "enough" (maybe shot at Friday afternoon at 14:59 instead of Wednesday at 08:00)..  Needles to say if you prime with high build you will be just fine...

[wingtime]

I was looking at my 200XF today and noticed a bit of "print" thru.  Not bad since you have to look at it just right to see it.  I think today with biaxial and other modern weaves it should be less prevalent than the massive woven roven used back in the day.  I'll ask Roadasprin what was the old causes of it.  dburr is right about layups being resin rich are weak.

[pbustle]

Print Through can be a result of a post cure as well as poor layup techniques and it should be a concern if you are going to use a dark color to paint your 170.  You can use enough high build primer to block sand the print through out of it, but if you have post cure go on after paint it may show up again.  Its always a warning that shoudl be given to people who paint a dark color because you have not changed how your Hull absorbs sunlight and UV rays.

Give it a good coat of high build, block sand it smooth, primer it again adn then paint and you shouldnt see the current print through you are seeing.

[Fletch170]

Should not be a problem, the hull sides will be ice blue, so It should hide a lot of the inperfections.....I hope.

What is the best method for block sanding? I'm glad you mentioned that, because I was going to use my oribital sander. I was going to use a sanding block on the transom to get it nice and flat. You suggest doing the same on thehull sides?

[gman 82 aquasport]

I had sort of the same problem on the hulls sides of my 19-6 when I got it, while sanding, prepping for paint (above the water line) I had some lines show up. I used flairing mix to cover it over, mixed a little up after sanding down with 60 grit and gave it a skim coat, less the 1/16 inch thick, let it harden and then sanded with 120 grit then 320. Afterwards you couldn't tell where it was if you didn't know where it was before.. I'm not a bodyman by no means, but if you take your time you can make it as smooth as  you want. primed it over with prekoat and painted with brightsides paint...looks fine now :)

[gman 82 aquasport]

Add-on.... if you are going to block sand the sides(large flat areas) use a long board, about 18-24 inches will do fine, you can wrap them with sand paper and using long stokes along the side it will tend to keep it smooth and not have as many waves in it. I only use an orbital for knocking down the bit stuff or for the first sanding, I'm not good enough with one the finish sand with it :( , so I block sand for finishing.. :pirat:
Napa usually sells sand paper that will fit long boards..

[wingtime]

Here is one option for a long board.  You should be able to find them locally at any body shop supply house.
http://www.jamestowndistributors.com/userportal/show_product.do?pid=2&familyName=3M+Marine+Hookit+Fairing+Longboards+4-1%2F2+inches+wide+x+30+inches+long

[gman 82 aquasport]

The link that wingtime sent is a good one, my long board looks a lot like the flexible one, I've had mine about 10 years... they work real good