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Forum topic by Curtis Calderon posted 11-18-2018 01:44 PM 296 views 0 times favorited 9 replies Add to Favorites Watch
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Curtis Calderon

6 posts in 90 days


11-18-2018 01:44 PM

Hey folks,

I make these wooden instrument cases and have used Epifanes Spar Varnish on them and had no troubles, but was looking to get a harder, longer lasting finish. The biggest issue I fear is cracking in the finish if I use a harder finish from temperature/humidity change. I was considering Behlen Rock Hard, that’s recommended for table tops. The only issue is that the cases are solid wood and will be used in different parts of the country, so let’s say someone has the instrument case in their warm house (or car), then is gonna walk a few blocks to their show and the temp changes from say 73 degrees (indoors) to 40 degrees (or less outdoors) rather quickly, could the Behlens crack? I’ve seen finishes on guitars get dozens of small cracks if you change the temperature too quickly. Any thoughts or experience using a finish that won’t live outdoors, but could possibly be exposed to big changes in temperature or humidity within minutes? Thank you for any advice/help/insight you can give.

Curtis


9 replies so far

View eflanders's profile

eflanders

318 posts in 2054 days


#1 posted 11-18-2018 01:55 PM

You may want to consider a marine epoxy like West Sytems, Raka or others. You will still want to put on 3 coats min. of spar varnish for UV protection even though marine epoxy is supposedly UV stable, but any boat builder will tell you that the varnish is still needed.

View bilyo's profile

bilyo

424 posts in 1306 days


#2 posted 11-18-2018 02:42 PM

Long ago, I played an instrument in a marching band. I know the kind of beating an instrument case can get. I kind of agree with eflanders, but I wonder if you might consider going one step further. Look at the way wood strip canoes are built and finished. I think they cover them with thin fiberglass cloth and a clear gel coat. They look beautiful and are very durable.

I could be wrong, but I don’t think that UV stability needs to be of great concern in this case. I cant imagine that an instrument case will be outdoors long enough to be affected by UV.

Sounds like an interesting project. I would love to see some pictures.

View Fred Hargis's profile

Fred Hargis

5177 posts in 2697 days


#3 posted 11-18-2018 04:54 PM

Spar varnish is softer for a reason. It doesn’t have the same problems with cracking/crazing as harder ones caused by wood movement. When the wood moves and the finish doesn’t, you get cracks. It’s (spar varnish) called a “long oil” varnish….more oil was put into the mix that gets cooked to become varnish, hence the softer film. When I read your post you stated you were having no problems with the Epifanes, then wanted a “harder, longer lasting finish”. Epifanes (and other clear finishes) most often fail because of UV exposure. Without that exposure I would expect Epifanes to last as long as anything else, a good long time. I suspect you’re trying to fix something that isn’t broken. Also keep in mind, harder finishes are more easily scratched than slightly softer ones, so daily wear/tear may be more of a problem.

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

View Curtis Calderon's profile

Curtis Calderon

6 posts in 90 days


#4 posted 11-19-2018 07:15 AM

Thank you for the reply. I’m still looking into this aspect more. It might be a little more time than will be good for me financially as far as the cases go, but longevity is important for sure.


You may want to consider a marine epoxy like West Sytems, Raka or others. You will still want to put on 3 coats min. of spar varnish for UV protection even though marine epoxy is supposedly UV stable, but any boat builder will tell you that the varnish is still needed.

- eflanders


View Curtis Calderon's profile

Curtis Calderon

6 posts in 90 days


#5 posted 11-19-2018 07:19 AM

Thank you for the reply. I’m going to look into this briefly, but as just replied above, it may cut into too much time for me for the profit margin, but if it’s something that could way outlast and be more durable, quality trumps a few bucks for sure.

Let me see if I can figure out how to post a pic or two…


Long ago, I played an instrument in a marching band. I know the kind of beating an instrument case can get. I kind of agree with eflanders, but I wonder if you might consider going one step further. Look at the way wood strip canoes are built and finished. I think they cover them with thin fiberglass cloth and a clear gel coat. They look beautiful and are very durable.

I could be wrong, but I don t think that UV stability needs to be of great concern in this case. I cant imagine that an instrument case will be outdoors long enough to be affected by UV.

Sounds like an interesting project. I would love to see some pictures.

- bilyo


View Curtis Calderon's profile

Curtis Calderon

6 posts in 90 days


#6 posted 11-19-2018 07:24 AM

What’s funny is I’ve read as much as I could about epoxy and then varnish over and several other options and you have a great point. I might trying to find a problem for a solution! I failed to mention in my original post that I was also having a hard time getting a glass finish because I would get more dust specs that I was happy with. I’m gonna build a little room over the next day or two with an exhaust vent and high quality filter, hoping that it can help alleviate this a bit. I think for now, I’ll stick with the epifanes high gloss finish until I can experiment over the next 6-9 months and see if there’s anything else that might be better, but really, since it’s going to be going through a lot of temperature changes and the texting I’ve done over the last couple of years has shown no cracking whatsoever if the epifanes, only seems to scratch a bit easier, but I also only used about 3-4 coats in my test cases. I just need to get to about 7 coats minimum for my commercial cases. Thank you for the advice.


Spar varnish is softer for a reason. It doesn t have the same problems with cracking/crazing as harder ones caused by wood movement. When the wood moves and the finish doesn t, you get cracks. It s (spar varnish) called a “long oil” varnish….more oil was put into the mix that gets cooked to become varnish, hence the softer film. When I read your post you stated you were having no problems with the Epifanes, then wanted a “harder, longer lasting finish”. Epifanes (and other clear finishes) most often fail because of UV exposure. Without that exposure I would expect Epifanes to last as long as anything else, a good long time. I suspect you re trying to fix something that isn t broken. Also keep in mind, harder finishes are more easily scratched than slightly softer ones, so daily wear/tear may be more of a problem.

- Fred Hargis


View Curtis Calderon's profile

Curtis Calderon

6 posts in 90 days


#7 posted 11-19-2018 07:42 AM

I posted some pics real quick of the demo cases I’ve built and tested and different phases of building. I’m still learning a lot but I enjoy it and sell a few here and there but it’s picking up more and more. My drum case picture isn’t a finished picture, just a picture I took along the way for a customer. There are a few spots in the varnish I need to sand down, like having a cheap brush (wasn’t that cheap)) leave a bristle that got by me until I saw it in there dried :( Not a big deal, this was only about the third coat, so I’ll sand down that bump and still add 4 more coats at least. Should look really nice when all is said and done. I try to give clients updates via pictures when I can, so they can see and get even more excited as it gets closer to being done.

Cases

I do apologize if for some reason personal links aren’t allowed. I’m not pushing these for sale here or anything, so it should be fine.


....

I could be wrong, but I don t think that UV stability needs to be of great concern in this case. I cant imagine that an instrument case will be outdoors long enough to be affected by UV.

Sounds like an interesting project. I would love to see some pictures.

- bilyo


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bilyo

424 posts in 1306 days


#8 posted 11-19-2018 02:30 PM

That is some nice work. Thanks

View OSU55's profile

OSU55

1975 posts in 2193 days


#9 posted 11-19-2018 04:09 PM

Since you are doing production work and time is $, perhaps you should consider a water based finish. My recommendation is Target Coatings EM9300, for exterior apps. Faster dry and cure times, but doesnt create the chatoyance of oil based varnish. Shellac or varnish could be used to create chatoyance then the 9300. Only recommend it to reduce time, not that its better.

Luthiers use the em6000 and em9000.

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