Colourfastness #2: One Month Check-in, .... some surprises

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Blog entry by shipwright posted 01-02-2018 12:42 AM 4202 reads 1 time favorited 16 comments Add to Favorites Watch
« Part 1: A Little Experiment ... Part 2 of Colourfastness series Part 3: Two Months in the Sunshine »

Its been a month since I put my test panel out in the Az (winter) sun and there have been some changes and a couple of surprises.

1) Almost all of the bare wood has faded.
2) The shellac alone seems to be the finish that is out of step.
3) The Amaranth (Purpleheart) is ….. AMAZING!
4) The Cherry is a surprise too.

This is the original, before picture.

Here is today’s. Sorry it’s upside down vs the above pic.
The Amaranth is second from the top.
The Cherry is second from the bottom.
Both are similar in most of the tests but very different in shellac alone.

Here is a close up of the Amaranth with only shellac.
Out in the sun it appears to be lit from within. ... spectacular …. and red!

So far the other three finishes seem to be about the same.

Until next check- in….


-- Paul M ..............If God wanted us to have fiberglass boats he would have given us fibreglass trees.

16 comments so far

View Jerry's profile


2573 posts in 1581 days

#1 posted 01-02-2018 02:26 AM

Interesting, Paul, so are you concluding that the shellac is not only protecting the color but helping to enhance it?

The old ways , I’m beginning to see, are very often the best. For example, hide glue, I’ve gone completely over to hide glue in my most recent projects.

I suspect there are many reasons shellac has been so popular for so long.

Thanks for sharing!

-- There are good ships and there are wood ships, the ships that sail the sea, but the best ships are friendships and may they always be.

View drewpy's profile


783 posts in 1290 days

#2 posted 01-02-2018 02:41 AM

Thanks for round #2. Shellac seems to be protecting well. I agree with Jerry, it might be enhancing it as well.

-- Drew -- "The greatest wealth is health".

View MontanaBob's profile


826 posts in 2617 days

#3 posted 01-02-2018 03:40 AM

That is very interesting…Look forward to the outcome of the test… Thanks..

View madburg's profile


197 posts in 776 days

#4 posted 01-02-2018 05:00 AM

Thanks for the update. Interesting results particularly the shellac. As the test is outside as opposed to inside the test panel has direct exposure to UV. So, I wonder what effect this is having. I guess you wouldn’t normally use shellac as an ‘outside’ finish anyhow. Do any of the finishes act as a block to UV I wonder, and following on from this, is the UV affecting the wood or the actual coating …......................? Look forward to the next post Paul.

-- Madburg WA

View Woodknack's profile


11311 posts in 2313 days

#5 posted 01-02-2018 06:03 AM

It’ll be integrating to see what happens after a few more months.

-- Rick M,

View Druid's profile


1735 posts in 2728 days

#6 posted 01-02-2018 06:26 AM

Watching with interest. Thanks for the update Paul.

-- John, British Columbia, Canada

View Sodabowski's profile


2372 posts in 2766 days

#7 posted 01-02-2018 10:42 AM

Surprising indeed, looks like your brand of shellac is either super pure or it contains stuff that really blocked the UV rays.

-- Thomas - Pondering the inclusion of woodworking into physics and chemistry classes...

View stefang's profile


15878 posts in 3267 days

#8 posted 01-02-2018 12:08 PM

Pretty amazing results for the shellac. I would have thought that it would become very brittle and perhaps crack. The epoxy also surprisingly looked very good . In the past I have used expoxy underneath a coat of poly with uv protection and that worked really well.

-- Mike, an American living in Norway.

View shipwright's profile


7937 posts in 2731 days

#9 posted 01-02-2018 02:27 PM

Thanks for the interest.
The shellac is just Zinser from a can. It surprised me as well. To my knowledge it and the epoxy alone are without uv filters. The others, with the Epifanes marine varnish, are the ones that should stand up the best as it is touted to be high in uv filtration.
It is all just an experiment so surprises are good I guess. One thing that is very obvious is that any finish beats the crap out of no finish.
I’ll check again in another month.

-- Paul M ..............If God wanted us to have fiberglass boats he would have given us fibreglass trees.

View htl's profile


3696 posts in 1092 days

#10 posted 01-02-2018 03:32 PM

I don’t know if this helps or not, but I tried.

-- Learn More About Making Wooden Models. An Index Of My Model making Blogs.

View mousejockey's profile


64 posts in 2876 days

#11 posted 01-02-2018 05:55 PM

Consider this. The assumption that the shellac has blocked UV rays is wrong, the new beauty within the wood is damage to the wood that has an interesting effect but will probably continue to degrade over time. Time will tell, but how long?
It doesn’t seem to make sense that companies spend so much time and money on stopping UV rays if it wasn’t a real a problem.


View Jim Jakosh's profile

Jim Jakosh

20169 posts in 3039 days

#12 posted 01-02-2018 06:05 PM

Hi Paul. The sun is rough on wood . The purple heart should get purpler in the sun.
have you tried any Helmsman Poly with the UV inhibitors? I use it but have not conducted a test like this.

Cheers, Jim

-- Jim Jakosh.....Practical Wood Products...........Learn something new every day!! Variety is the Spice of Life!!

View Grumpymike's profile


2221 posts in 2248 days

#13 posted 01-02-2018 06:40 PM

Excellent demo Paul, and I agree that any finish is better than none.
Your comment on the Purple Heart rings true with me as I will mill my pieces and set them outside for a couple of days to “mellow” the color.
Thanks for doing the experiment that many of have been thinking about and procrastinating.

-- Grumpy old guy, and lookin' good Doin' it. ... Surprise Az.

View shipwright's profile


7937 posts in 2731 days

#14 posted 01-02-2018 08:15 PM

Mike, My personal observations of Amaranth (Purpleheart) are that the “bloom” occurs with or without uv, as does the eventual degradation to brown however, in my experience the degradation is much faster with uv exposure.

I’m currently waiting to see how long Canarywood takes to go dark again after cutting. I have some marquetry pieces that are counting on it doing so.

Jim, The varnish I am using is the industry leader in Marine varnish. Lots of uv filters.

Myles, Time will tell. I went in with no expectations other than perhaps to see if the uv filtration helps and if so how much.

htl, Yeah, I tried that too. It just looked too weird to me so I went with the upside down one. Next time I’ll shoot it the same way as I did the first time. Thanks for trying.

-- Paul M ..............If God wanted us to have fiberglass boats he would have given us fibreglass trees.

View CharlieK's profile


548 posts in 3726 days

#15 posted 01-02-2018 11:00 PM

Fantastic Paul. I love these kinds of comparisons.

-- Adjustable Height Workbench Plans

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