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Finishing Cherry Blotching Problem

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Forum topic by Hewy posted 12-27-2014 06:42 PM 1182 views 1 time favorited 11 replies Add to Favorites Watch
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Hewy

26 posts in 2154 days


12-27-2014 06:42 PM

I’m building a project from cherry wood. I want to finish it with clear wipe on poly. I do not plan
to use any stain on this. I’m in the process of selecting the wood that I will be using for this project.
I wipe each board with mineral spirits so I can see the color and grain before I glue the boards together.
The problem is that I can see the blotching in the wood already with only the mineral spirits. I think
this blotching will be there when I use the final finish. If I use a sealer coat like the one from Charles Neil or a shellac seal coat and don’t stain it won’t the blotching still show like it does with the mineral spirits? Any ideas would be helpful.

Thank you,
Hewy



11 replies so far

View Grandpa's profile

Grandpa

3256 posts in 2142 days


#1 posted 12-27-2014 06:50 PM

I was taught to use sanding sealer then a top coat. It takes care of the blotching for me. This is one of those things where you can ask 11 people and get 12 opinions. Charles Neil products and methods are top shelf too.

View bondogaposis's profile

bondogaposis

4036 posts in 1818 days


#2 posted 12-27-2014 07:32 PM

Zinsser Seal Coat, then top coat, should work well. Blotching is much more noticeable when you stain. As always experiment on scrap.

-- Bondo Gaposis

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,

2387 posts in 3014 days


#3 posted 12-27-2014 07:36 PM

U can use a pre cat ML Campbell lacquer with no seal coat and achieve excellent results with no need for a conditioner. The finish will be very hard and durable.

-- .

View pjones46's profile

pjones46

986 posts in 2110 days


#4 posted 12-27-2014 08:52 PM

Fist off, one man’s blotchiness is another man’s figure.

Secondly, getting samples before hand is key to getting what you want.

You can spray a light thinned coat of clear Water based lacquer on the project. Wait for it to dry and then carefully sand with 220-320 so as not to break through the coating. Clean the surface to remove any dusts and repeat the spraying process once more to include the sanding and cleaning. Then you can apply your finish. Water based lacquers are very clear.

Some water based lacquers are thin enough out of the can, but, should you have a high solid water based lacquer it should be thinned so it will soak into the surface fibers.

You can also thin your clear wipe on poly and try the same process but you must work very quickly.

Again, try your process on scrap to perfect it to your visual end result standards, and make sure the samples are big enough.

-- Respectfully, Paul

View iminmyshop's profile

iminmyshop

259 posts in 1461 days


#5 posted 12-27-2014 09:59 PM

Cherry is notorious for blotching.
- Test for the likelihood of blotching by applying denatured alcohol. Blotch prone areas will look much darker. If the alcohol test is fine, just sand to a greater degree than usual – 400 grit and apply your finish.
- If the alcohol test shows a likelihood of blotching then stop sanding at 180 grit. Then coat with a 1 lb cut of dewaxed shellac as a seal coat. Zinsser Dewaxed Sealcoat cut 50% with denatured alcohol works very well.
- After it dries, sand it lightly with 320 grit sandpaper.
- Apply whatever finish you like.

View AlaskaGuy's profile

AlaskaGuy

2406 posts in 1776 days


#6 posted 12-27-2014 11:05 PM

http://www.thewoodwhisperer.com/articles/blotch-control-to-rule-them-all/

Everywhere you go on the Internet people say Charles Neil blotch control works great.

-- Alaskan's for Global warming!

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pjones46

986 posts in 2110 days


#7 posted 12-27-2014 11:26 PM

Make your own Blotch Control if thats the way you want to go. Try all of the ways on scrap to get your desired results.

You might want to read Bob Flexner's article also as he is one of the top finishers in the country.

-- Respectfully, Paul

View pintodeluxe's profile

pintodeluxe

4859 posts in 2280 days


#8 posted 12-27-2014 11:50 PM

Thin Bullseye Seal Coat 50/50 with denatured alcohol. Use that as your anti-blotch sealer. Then topcoat it with full strength shellac, or topcoat of your choice. It works amazingly well to control blotching.
If I am staining a project I increase the ratio to 3 parts denatured alcohol to 2 parts Seal Coat. However with a project that will not be stained, use a 50/50 mix.
Good luck.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View Minorhero's profile

Minorhero

372 posts in 2072 days


#9 posted 12-28-2014 12:48 AM

If you want to use a wipe on poly then select a scrap piece of cherry and check if for blotching as you have been doing. If you see blotching with mineral spirits then you have a good test piece. Next apply a coat of your wipe on poly. I pretty much gurantee you will see blotching. Allow it to dry as per instructions and if it needs sanding etc then follow the instructions in that regard. Then apply a second coat.

Chances are VERY good your blotching issues will disappear with the second coat.

I had concerns about blotching with Arm-R-Seal satin. I saw a lot of blotching the first time I used it on cherry. But by the second coat the blotching issues were almost completely gone, by the third coat they were completely gone and it was a non-issue. I have since asked around and heard the same from a lot of people. Cherry absorbs finishes unevenly. Hence the blotching. But by applying multiple coats you take care of that problem.

Good luck.

View Hewy's profile

Hewy

26 posts in 2154 days


#10 posted 12-28-2014 03:06 AM

Thank you all for your input. There are several good ideas here.
I will try some of these on a test piece to see what works the best.

Hewy

View Dave G's profile

Dave G

303 posts in 1515 days


#11 posted 12-28-2014 03:18 AM

Just one comment before you declare victory or failure, in case you haven’t noticed this already: In 5 years that cherry will look nothing like it does now. At least for me, no matter how I finish it. For me it gets much darker and a lot of the imperfections will fade into the darkness.

It’s one of the really cool things about cherry.

The comment may ease any last minute worries you have. Not sure if there is a finish that keeps that from happening. (I think wood needs to breath so you wouldn’t want it completely sealed off from oxygen.)

-- Dave, New England - “We are made to persist. that's how we find out who we are.” ― Tobias Wolff

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