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Two questions...shellac and mineral oil (2 separate issues on a project)

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Forum topic by BB1 posted 03-04-2018 12:21 PM 1983 views 0 times favorited 16 replies Add to Favorites Watch
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BB1

1167 posts in 964 days


03-04-2018 12:21 PM

I am continuing to work on a “frame” for a small cutting board and two small bowls; thinking of it as a cheese or veggie cutting area and then the bowls to hold crackers or a spread. I’m used mineral oil for the board (Howards Cutting Board Oil) -have applied about 5-6 coats. This was my first attempt at an end grain cutting board and I have a couple spots that aren’t as smooth as needed and tend to look “dry” – I had tried to level the top with a router but don’t think I was fully successful in getting it smooth. Any suggestions on salvaging this would be appreviated.

Setup for router to level the board

Dry spots on cutting board

General plan:

For the “frame” in which the board and bowls will fit, I decided to try some Zinsser Bulls Eye shellac. Here comes a series of mistakes. I didn’t try it on a scrap piece and a put on way too thick of a coat. That resulted in a sticky mess. Spent a good amount of time sanding to remove that -most of it appears gone. I know I cannot put polyurethane over the top of that can shellac (according to the instructions on the can) so thought I would try some spray shellac that I have used before.

It is ok, but would like to add some protection with a coat or two of General Finishes High Performance. It is my understanding that the spray shellac is a sealer that would allow for another finish to be applied on top. Is this correct?

Learned a lot with this project but then stumbled with mistakes on the homestretch. Finishing is still an area that I need to learn, and take my time.

Thanks for any insights.


16 replies so far

View Fred Hargis's profile

Fred Hargis

5068 posts in 2609 days


#1 posted 03-04-2018 12:39 PM

There isn’t (IMHO) a perfectly straight answer to your question. Urethane resins do not adhere as well as, well, almost anything else…that’s why you have to scuff sand them between coats in most applications. Then when you apply that to shellac which has a natural wax in it, it compounds the problem. But that’s not a given, many folks have done this inadvertently and it worked out OK. Also consider that when you apply one coat of shellac to another, the new application will dissolve into the previous one, forming essentially one coat. In the case of putting dewaxed shellac on top of natural shellac, that dissolving may bring some of the wax to the surface of the coat, and cause the adhesion problems (with urethane). That’s why the Zinnser does a CYA and declare that you not use the urethane over the shellac. Some waterborne finishes (which are more acrylic than urethane) also have adhesion problems with natural shellac. This very long winded answer is to explain the possibilities…....but in case it goes wrong, it may help explain it. If it were me, I’d go ahead and try to apply the GF HP, if that was my plan.

-- Our village hasn't lost it's idiot, he was elected to congress.

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BB1

1167 posts in 964 days


#2 posted 03-04-2018 02:08 PM

Fred – thank you for the insights. I’m starting to think that I may best just leave it as is with the two coats of spray on shellac. The “disaster” with my too thick coat of brush-on was yesterday. Examining the tray again in the morning light, well, I think I’m ok with it. I spent a lot of time on the construction and would hate to scrap it at this point.

I am pretty much a weekend woodworker and my downfall is to get in a “rush” mindset when I get to the final stage of finishing. I am getting some better at that as I have started to use our front unused living room as a finishing area. This allows me to add coats to projects as I have time…but then I revert back to my “get it done today” as I did with this tray, and frustrate myself! Another lesson learned.

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OSU55

1831 posts in 2106 days


#3 posted 03-04-2018 02:27 PM

The only rattle can Zinnser shellac Ive seen is waxed – all of the dewaxed has been in paint cans. If you keep alcohol and ammonia based products (many kitchen cleaners have ammonia) away the shellc should hold up fairly well. A property of shellac is it “burns in”, mixing with previous coats, and is easily repairable in the future.

Finishing is at least 1/3 of a project – design, build, finish. Give finishing 1/3 of your time and effort. Make finishing part of the design phase – adapt the design to accomodate finishing. Most of the time it means creating access to areas for sanding, spraying, brushing, etc.

View dhazelton's profile

dhazelton

2789 posts in 2413 days


#4 posted 03-04-2018 02:28 PM

When you say your shellac was a sticky mess that tells me your shellac might be old – shellac usually dries in a matter of minutes.

I think your cutting board looks great. Dry spots means the grain is really sucking up the finish and you just need to keep oiling it.

I’m not a fan of ‘first a sanding sealer and then an oil coat and then 5 coats of this 50 dollar a quart finish sprayed and then hand rubbed with two coats of an acrylic this and that and then a tinted lacquer…..’ If I’m going to varnish something I just varnish it, maybe with a stain first if I need to change it’s color. I usually use shellac with light sandings between and a final polish with 0000 steel wool and paste wax. It’s fast, simple and always works.

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BB1

1167 posts in 964 days


#5 posted 03-04-2018 03:10 PM

Yes, I’m learning, at times the hard way, that finishing is part of the process. When I first got into woodworking I tried to convince my husband that he would enjoy taking care of the finishing. That didn’t work…especially when he got a lathe and started turning his own projects! :)


The only rattle can Zinnser shellac Ive seen is waxed – all of the dewaxed has been in paint cans. If you keep alcohol and ammonia based products (many kitchen cleaners have ammonia) away the shellc should hold up fairly well. A property of shellac is it “burns in”, mixing with previous coats, and is easily repairable in the future.

Finishing is at least 1/3 of a project – design, build, finish. Give finishing 1/3 of your time and effort. Make finishing part of the design phase – adapt the design to accomodate finishing. Most of the time it means creating access to areas for sanding, spraying, brushing, etc.

- OSU55


When you say your shellac was a sticky mess that tells me your shellac might be old – shellac usually dries in a matter of minutes.

I think your cutting board looks great. Dry spots means the grain is really sucking up the finish and you just need to keep oiling it.

I m not a fan of first a sanding sealer and then an oil coat and then 5 coats of this 50 dollar a quart finish sprayed and then hand rubbed with two coats of an acrylic this and that and then a tinted lacquer….. If I m going to varnish something I just varnish it, maybe with a stain first if I need to change it s color. I usually use shellac with light sandings between and a final polish with 0000 steel wool and paste wax. It s fast, simple and always works.

- dhazelton


It was a brand new can. I don’t blame the product – I put it on WAY too heavy. Plus, not sure where the humidity was as I applied it outside.

With regard to the wax -what brand do you use? I think I have some Johnsons paste wax that I use on my table saw top and jigs.

View johnstoneb's profile

johnstoneb

2999 posts in 2289 days


#6 posted 03-04-2018 03:26 PM

You can’t put shellac on too thick it will run off and or cause runs in the finish if too thick but it will not stop it from drying, having a sticky mess because shellac supposedly didn’t dry tells me you have other problems. The solvent in shellac is alcohol it evaporates quickly and completely. High humidity may slow evaporation down a little sticky shellac after overnight says you have other problems. I use shellac both waxed and dewaxed extensively and the only problem I have when I put it on too heavy is runs and a two hour dry instead of 30 minutes to an hour.

-- Bruce, Boise, ID

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Aj2

1654 posts in 1914 days


#7 posted 03-04-2018 03:36 PM

I’m late with this tip. Next time you have a shellac blunder just soak a clean shop rag in denatured Alcohol. It wipes up much easier then sanding. Wear gloves and give yourself plenty of good air to breathe.
This is a good way to fill pores.

-- Aj

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BB1

1167 posts in 964 days


#8 posted 03-04-2018 06:12 PM

Likely I did not wait long enough for that thick coat to dry. I think I knew I had an error with a thick coat and so after an hour I started to remove it. So just compounded my initial error.
Lesson learned :)


You can t put shellac on too thick it will run off and or cause runs in the finish if too thick but it will not stop it from drying, having a sticky mess because shellac supposedly didn t dry tells me you have other problems. The solvent in shellac is alcohol it evaporates quickly and completely. High humidity may slow evaporation down a little sticky shellac after overnight says you have other problems. I use shellac both waxed and dewaxed extensively and the only problem I have when I put it on too heavy is runs and a two hour dry instead of 30 minutes to an hour.

- johnstoneb


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BB1

1167 posts in 964 days


#9 posted 03-04-2018 06:13 PM

Thanks -good for future refetence.


I m late with this tip. Next time you have a shellac blunder just soak a clean shop rag in denatured Alcohol. It wipes up much easier then sanding. Wear gloves and give yourself plenty of good air to breathe.
This is a good way to fill pores.

- Aj2


View jdh122's profile

jdh122

1033 posts in 2934 days


#10 posted 03-04-2018 08:34 PM

I bet the shellac was too old. That’s the only reason I can think of that would explain it not drying. Even unopened in the can it slowly goes bad. I don’t think that applying it too thick would explain your problem. Test some of your shellac on a test piece before going back to your project in case that’s the issue.
Personally I find it much easier to pad it on than brush it – take more coats, but less problems with runs, brush marks etc. But people who are better than me with a brush can do it.

-- Jeremy, in the Acadian forests

View Mike54Ohio's profile

Mike54Ohio

175 posts in 594 days


#11 posted 03-04-2018 09:07 PM

If you take that big box store can of Zinssers and mix the shellac with a 1:1 ratio of DNA (denatured alcohol) for application I think you will find it much easier to work with.

When you use the thinned version, you have cut the mix to roughly what is referred to as a 1 lb cut of shellac. Take an old t-shirt rag and cut a piece off and then fold and roll it into a cylinder. Wet the edge of the rag in the shellac and just smoothly wipe in even strokes the length of the piece, overlapping the next stroke with the previous and work your way over the surface.

By the time you get to the other end the first pass will have dried enough to add another layer. Working like this you can probably apply 4 or 5 passes for your first coat. When the finish feels like it is pulling against the cloth on application you know that your 1st coat is probably thick enough.

Let that sit for about 10 to 15 minutes and the DNA will have flashed off already and your finish is dry to the touch.

If you want you can lightly sand with a 0000 pad between coats to even out the surfaces. You are not building a finish layer but sealing the pores of the wood.

if you by de-waxed sanding sealer shellac then you have no concerns about compatibility with other finishes.
The shellac can be waxed after you are happy with the finish if you like or left as is.

your project is nicely executed and as others have stated the finishing of that hard work is as or more important than the construction phase. Patience is mandatory here and we all have struggled with that in finishing up a project.

With practice, the lightbulb will go off on shellac application and you will find it a very easy finish to apply once you get the hang of it.

-- It's only a dumb question if you ignore the correct answer

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BB1

1167 posts in 964 days


#12 posted 03-04-2018 09:27 PM

jdh122 – I think the likely culprit was my impatience rather than the product. Will see about improving my technique in the future!

Mike 54 Ohio – thank you so much for the information and encouragement. Won’t abandon trying the shellac again in the future. I appreciate the suggestions on improving my chances of success (that “lightbulb” moment!).

View dhazelton's profile

dhazelton

2789 posts in 2413 days


#13 posted 03-04-2018 10:25 PM

Humidity will effect it, yes.

Yes – Johnson’s Paste Wax, Butcher’s Wax, anything.

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BB1

1167 posts in 964 days


#14 posted 03-04-2018 11:45 PM

Thanks … will do a test run with some wax.

My husband has some of the Howard Feed-N-Wax…would there be any concerns with that over shellac? Looks like it would be ok from what I have read.


Humidity will effect it, yes.

Yes – Johnson s Paste Wax, Butcher s Wax, anything.

- dhazelton


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dhazelton

2789 posts in 2413 days


#15 posted 03-05-2018 12:56 PM

Not if the shellac is dry, it should be fine.

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