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Forum topic by Karda posted 12-09-2019 07:13 AM 491 views 0 times favorited 11 replies Add to Favorites Watch
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Karda

1966 posts in 1160 days


12-09-2019 07:13 AM

bowl finish don’t look good. more frequently than I like I am getting swirl marks in the finish on the inside of my bowls i have done everything I know and it still happens. sometimes I examine my surface closely on the lathe but it isn’t obvious till i take it off. I tried to take a picture of it but it is to subtle and my camera skill are not that good. ny Idea how I can do better.I wipe on cut shellac


11 replies so far

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Jack Lewis

571 posts in 1685 days


#1 posted 12-09-2019 01:53 PM

A steady progression through the grits is the only way. Progress through the grits 80, (up 1 1/2 or 40) 120, (up 60) 180, (up 90) 360. E.i. 1 & 1/2 x’s up each step. Remove the residue from one sanding when you change to a finer grit. If you still have marks after using one grit return to the previous grit until gone, then cotinue.

-- "PLUMBER'S BUTT! Get over it, everybody has one"

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Karda

1966 posts in 1160 days


#2 posted 12-09-2019 04:07 PM

but what about the marks in the finish, that is more of a problem. I can deal with the sanding

View Jack Lewis's profile

Jack Lewis

571 posts in 1685 days


#3 posted 12-09-2019 04:48 PM



but what about the marks in the finish, that is more of a problem. I can deal with the sanding

- Karda


If you have lines in the wood before finishing they will still be there.
Make your last grit the finest and the lines disappear. Also DON”T press the sandpaper real hard on the surface, the grits dig in deeper than you want. If you have lines AFTER the finish, go back and sand off the finish and some more.
Looking back at OP I see you are using shellac, maybe you are continuing to wipe too long and the DNA is evaporating and leaving marks in the soft shellac. Put it on, smooth it and go away!

-- "PLUMBER'S BUTT! Get over it, everybody has one"

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Aj2

2650 posts in 2405 days


#4 posted 12-09-2019 04:52 PM

You might have the shellac too thick. You want very thin coats barely perceptible.

-- Aj

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Nubsnstubs

1662 posts in 2337 days


#5 posted 12-10-2019 12:17 AM

Mike, I think you need to get lathed…...... Jerry (in Tucson)

-- Jerry (in Tucson) www.woodturnerstools.com

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Karda

1966 posts in 1160 days


#6 posted 12-10-2019 12:30 AM

That would be nice but not at my age

View LeeMills's profile

LeeMills

690 posts in 1908 days


#7 posted 12-11-2019 02:39 AM

None of this may help but hopefully something will.
I use a lot of shellac finish myself.
Possibly, you can see the swirls on the exterior; because the interior is not as well lit a little more help may be required. Use a flashlight on the interior and try to shine it parallel to the surface as much as possible. Most ridges or valleys will be easier to see.

I put on the first finish coat heavy. Then I have a jar lid with DNA with 4-0 steel wool. Using the wet steel wool I more or less burnish the finish in. You will probably have to dunk the steel wool several times during the process.

Possibly, wrinkles in the application cloth. I know that with Mylands friction polish (mostly thinned shellac) I get ridges if there are wrinkles. A thicker coat is applied where there are wrinkles and it dries within seconds.
Possible, try OB Shine juice. You can mix just 3 ounces to give it a try. You have the shellac and DNA so you just need a little BLO (boiled linseed oil). I don’t use it alot because I perfer a low gloss but I have never had streaks with it. Maybe the BLO provides a more even flow and a little slower drying time?

If you do try the 4-0 you can keep it in a jar with a little DNA for the next time. Maybe get a half dozen uses from the same 1/2 pad.
Of course a light with just DNA on the inside will show any additional sanding needed before you start with the finish but it sounds the problem is with the finish itself.

-- We cannot solve our problems with the same thinking we used when we created them. Albert Einstein

View Lazyman's profile

Lazyman

4513 posts in 1994 days


#8 posted 12-11-2019 04:01 AM

If it is the shellac that is causing the problem, try thinning it further with DNA and adding BLO to make your own friction finish. You wipe on enough to completely cover the surface and then buff it with the lathe turning at 500+ RPMs using a clean cotton rage to get an amazing glass smooth finish in seconds. The key is that heat from friction evaporates the alcohol and sets the finish.

I currently use Mylands friction finish but if you want to try this and are unsure of the proportions or don’t want to spend a bunch of time experimenting, try these recommendations.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

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Karda

1966 posts in 1160 days


#9 posted 12-11-2019 04:13 AM

thanks lee I will try that, My swirl problem is on the inside especially the bottom. What I do that works is squirt thew shellac in on the moving piece and keep the lathe running for a few minutes. That works but it is messy. I have one I have to do off lathe. How do i do that without streak. I will be doing only the outside, it is a live edge bowl

View moke's profile

moke

1477 posts in 3383 days


#10 posted 12-11-2019 06:04 PM

I had similar issues, the only way I got around it was to buff it…...

-- Mike

View Karda's profile

Karda

1966 posts in 1160 days


#11 posted 12-11-2019 09:31 PM

ok

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