The Blotchies - RC Groups
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Jul 22, 2017, 10:05 PM
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Brynmr's Avatar
Discussion

The Blotchies


How do you keep dark blotchies from showing up on the covered balsa. Even when not pressing I still get discolorations. Not so bad here on the tail but more pronounced on my wing.
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Jul 23, 2017, 09:31 AM
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aymodeler's Avatar
Some people like to see the wood-grain show through, but I am not one of them, so I have fought the "blotchies" myself. Of course, it depends on the covering film you are using and the color. Heavier films like Monokote tend to hide better. Lighter films and certain colors, like yellow, tend to show through.

On one build, I misted a light coat of white primer over the entire airplane before covering. It worked well at keeping the wood grain hidden, but it did add a bit of weight.

On another project where I was covering with yellow film, I mixed up a small amount of acrylic paint (tan, white, and tiny drop of red) to match the balsa and brushed it only over dark knots or streaks that would otherwise flash through. This also worked well and the weight penalty was negligible.
Last edited by aymodeler; Jul 23, 2017 at 09:40 AM. Reason: typo
Jul 23, 2017, 01:30 PM
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Brynmr's Avatar
Quote:
Originally Posted by aymodeler
Some people like to see the wood-grain show through, but I am not one of them, so I have fought the "blotchies" myself. Of course, it depends on the covering film you are using and the color. Heavier films like Monokote tend to hide better. Lighter films and certain colors, like yellow, tend to show through.

On one build, I misted a light coat of white primer over the entire airplane before covering. It worked well at keeping the wood grain hidden, but it did add a bit of weight.

On another project where I was covering with yellow film, I mixed up a small amount of acrylic paint (tan, white, and tiny drop of red) to match the balsa and brushed it only over dark knots or streaks that would otherwise flash through. This also worked well and the weight penalty was negligible.
I like the grain and want it to show through. I'm just trying to lessen the uneven coloring as in this image of my wing. I mean it's not a deal breaker or anything. I can live with it but I've seen much better covering jobs where the coloring is even all over. I like the trans white (tail image)- no problem there but the red is tricky.
Sep 07, 2017, 06:16 PM
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I used thinned speckle then lighted sanded smooth the applied Zinsser Clear Aerosol Shellac. This will fill the grain and the wood will not show. Light sand the Shellac.
DO NOT USE THE NEW DAP SPECKLE WORTHLESS GET OTHER BRAND OLD PHOTO
Ken
Last edited by Ken Smith; Sep 09, 2017 at 07:39 AM. Reason: Photos
Sep 08, 2017, 08:47 AM
ARFs Are Me
TomCrump's Avatar
[QUOTE=Ken Smith;38244167
DO NOT USE THE NEW DAP SPECKLE WORTHLESS GET OTHER BRAND OLD PHOTO
Ken[/QUOTE]


What is it that you don't like about DAP spackle ? It works well, for me.
Sep 09, 2017, 07:38 AM
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Quote:
Originally Posted by TomCrump
What is it that you don't like about DAP spackle ? It works well, for me.
The old Dap was fantastic but the new stuff never really dries and when you try to sand it, it will ball up
Do a Goggle there are complaints about it all over the web

Ken
Sep 09, 2017, 07:50 AM
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TomCrump's Avatar
Quote:
Originally Posted by Ken Smith
The old Dap was fantastic but the new stuff never really dries and when you try to sand it, it will ball up
Do a Goggle there are complaints about it all over the web

Ken
Complaints don't equate to knowledge.

I have noticed the formulation change, too, and I've read the complaints. If you let the stuff dry overnight, and then sand, the product works well.


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