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Need guidance using Zpoxy on a mahogany build

Posted: Sun Jan 27, 2013 10:23 am
by jeffrodite
I am at that stage where the woodworking screeches to a halt and the finish begins. So I turn to all of u for guidance. My body is sanded, so is pore filler my next step? I will be using zpoxy finishing resin. May sound like a stupid question, but does the entire box get done? I have read up on both yes and no, and this is the point where the wealth of info becomes a logjam in my brain.

Re: Need guidance using Zpoxy on a mahogany build

Posted: Sun Jan 27, 2013 11:34 am
by Ben-Had
Most top wood does not need pore filling because it's closed pore e.g. spruce.

Re: Need guidance using Zpoxy on a mahogany build

Posted: Sun Jan 27, 2013 11:44 am
by jeffrodite
Thanks. So pore fill then seal?

Re: Need guidance using Zpoxy on a mahogany build

Posted: Sun Jan 27, 2013 2:09 pm
by Darryl Young
First, make sure you have level sanded really well. It's difficult if this is your first time as if you are like me, you aren't sure what to look for. Basically, any low spots won't be sanded so they will appear "dull" compared to the spots around it.

I'm about to fill the pores of the wood on my Cuban Mahogany build. Earlier I had sprayed the top with Damar (similar to shellac) and it gave the top a bit of a darker, yellowish tint. I was about to pore fill the sides and I realized the top wasn't sanded perfectly flat with the edge of the binding/purfling......so I decided to level sand the top before starting the pore fill. I sanded with 220g and there were 3 low spots on the sound board where the sandpaper wasn't making contact. these spots were darker (from the previously Damar application) so it really stood out where I had a low spot. So I had to work extra hard (and remove a bit more of the top thickness than I really wanted to) to sand the areas around these low spots down where they were level with the low spots. The darker color was a good visual.

The sides need to be level from top edge to back edge. I use a 2" PVC pipe to sand the waist. It is wrapped in cork and sandpaper on top of the cork. If you pay close attention, you can tell if the sandpaper is making contact all the way across the side. If not, keep sanding.......but pay attention to your technique. You can keep sanding wrong so the side doesn't sand flat. It's very difficult for me but you have to sand with almost no pressure.

As mentioned before, don't put pore filler on the top (unless the top is a hardwood like mahogany). Most tops are spruce/cedar/redwood and don't have pores that need filled. You don't want to add any weight to the top that is unneccessary so don't put epoxy on it. If you want to tint the top you can using other techniques. SealKote is shellac that has a bit of an amber tint and it's plenty for my taste.

Todd STock has videos on YouTube about applying Z-Poxy as a pore filler. I think his name on Y.T. is MDLuthier or something like that. I watched his video, practised on scrap, and did a decent job on my first one.

I'm going to try warming the z-poxy for the first coat so it's a bit thinner and hopefully gets down in the pores easier. I used 3 coats on the Indian Rosewood. I'm hoping (not sure) I can get by with 2 coats on the Cuban Mahogany but if it takes 3, no problem.

Re: Need guidance using Zpoxy on a mahogany build

Posted: Sun Jan 27, 2013 2:36 pm
by jeffrodite
Thanks man. I really appreciate the explanation. My sides/back have been sanded flush w the binding, and scraped w my carruth to fine tune it. I do want to tint the top a bit so sealkote it is, after getting everything nice and smooth. I've done woodworking my whole life, guitars are just a TAD bit diffurnt.

Re: Need guidance using Zpoxy on a mahogany build

Posted: Sun Jan 27, 2013 2:40 pm
by johnnparchem
Darryl Young wrote:First, make sure you have level sanded really well. It's difficult if this is your first time as if you are like me, you aren't sure what to look for. Basically, any low spots won't be sanded so they will appear "dull" compared to the spots around it. ...
A minor correction to Darryl's note The low spots will be shiny as the sand paper dulls the finish. But to Darryl's point make sure every thing is level before you move on. Or you will have a hard time sanding and leveling your finish.

Re: Need guidance using Zpoxy on a mahogany build

Posted: Sun Jan 27, 2013 4:24 pm
by Darryl Young
Yes, thanks! I said it backwards......so good catch.
johnnparchem wrote:
Darryl Young wrote:First, make sure you have level sanded really well. It's difficult if this is your first time as if you are like me, you aren't sure what to look for. Basically, any low spots won't be sanded so they will appear "dull" compared to the spots around it. ...
A minor correction to Darryl's note The low spots will be shiny as the sand paper dulls the finish. But to Darryl's point make sure every thing is level before you move on. Or you will have a hard time sanding and leveling your finish.

Re: Need guidance using Zpoxy on a mahogany build

Posted: Tue Jan 29, 2013 6:44 pm
by Kevin Sjostrand
See what happens Darryl when you say it when walking backwards!!

This Zpozy thing. I used Devcon and it worked great, but I had issues under the finish later. Has ANYONE that has used Zpoxy had issues at the wood surface under the finish down the road? If not, I'm going to try it at some point as I do like the clear fillers, especially on the light colored woods.

Kevin

Re: Need guidance using Zpoxy on a mahogany build

Posted: Tue Jan 29, 2013 6:54 pm
by Darryl Young
Kevin, Zpoxy has an amber tint so gives the wood some warmth. You may or may not want this so beware.

One thing you'll probably notice is that Zpoxy is easier to sand than a regular epoxy.

Re: Need guidance using Zpoxy on a mahogany build

Posted: Tue Jan 29, 2013 8:47 pm
by B. Howard
Kevin Sjostrand wrote:See what happens Darryl when you say it when walking backwards!!

This Zpozy thing. I used Devcon and it worked great, but I had issues under the finish later. Has ANYONE that has used Zpoxy had issues at the wood surface under the finish down the road? If not, I'm going to try it at some point as I do like the clear fillers, especially on the light colored woods.

Kevin
Some people will always have issues......A lot of folks blame the materials they used when in fact it was a mistake in the prep work that caused the film failure. And as mentioned, Z poxy is not clear. System 3 SB112 is optically clearer but still not really water white either.