Damn open pores

[JJohansen]

I swear the finishing gods are trying to drive me insane.

I pore filled my last batch of ukuleles as usual- four applications of west systems epoxy 207 sanded back. To my critical eye under good light I absolutely thought I’d done a complete fill.
Yesterday I applied the first four building coats. Cardinal Lacquer, reduced 60/40 with 5% retarder.

Today I go to level, and I’ve got way more open pores than I expected. I wet sanded with 320, and still had many bright blips where the damn pores weren’t filled. Burned through on one back trying to get rid of them.

I’m completely a novice as far as finishing goes and I’m wondering if this is normal? Perhaps the next building costs will fill up the low pores enough to be levelled? Or- strip off the lacquer and try again?

 

[sequoia]

Just a guess, but what you might have seen was what is called "significant shrinkage" in that the epoxy shrunk back by the time you started your finishing.

As to striping off and going back, that might help getting to a level sand, or you could hope to fill the hopefully by now shallower pores... I feel your pain.

 

[Red Cliff]

I swear the finishing gods are trying to drive me insane.

I pore filled my last batch of ukuleles as usual- four applications of west systems epoxy 207 sanded back. To my critical eye under good light I absolutely thought I’d done a complete fill.
Yesterday I applied the first four building coats. Cardinal Lacquer, reduced 60/40 with 5% retarder.

Today I go to level, and I’ve got way more open pores than I expected. I wet sanded with 320, and still had many bright blips where the damn pores weren’t filled. Burned through on one back trying to get rid of them.

I’m completely a novice as far as finishing goes and I’m wondering if this is normal? Perhaps the next building costs will fill up the low pores enough to be levelled? Or- strip off the lacquer and try again?

I don't use epoxy for pore fill. To be honest I prefer the none-flat look with some pores - looks more like wood to me.

However I do use epoxy for other things. I think West Systems epoxy doesn't reach complete cure until up to 4 days. Up until then it could shrink. So maybe you needed to wait longer between epoxy applications?

 

[Pegasus Guitars]

Josh- I don't use epoxy, so can't help much. Curious though where you got the Cardinal? I tried it once, but the cost of bringing it in was off the charts. I use Stew-Mac or Sherwin williams now.

 

[JJohansen]

Josh- I don't use epoxy, so can't help much. Curious though where you got the Cardinal? I tried it once, but the cost of bringing it in was off the charts. I use Stew-Mac or Sherwin williams now.

Hey Bob, I ordered it through Allied, shipped in with USPS. I’ve always pore filled with epoxy, and then farmed out the spraying. Half my problem is that I don’t know what is normal at each stage of the process- maybe it’s totally normal to have a smattering of low pores that will eventually get filled up as the costs build…. Anyways, I just bought the Jeff Jewitt finishing course online so maybe I’ll learn eventually 😂

 

[Pegasus Guitars]

Josh- Thanks. I did not know Allied shipped finishes here. I have been spraying lacquer for 50 years and still have not got a plan that works everytime. I see on the web that many builders seem to have a system that is reliable, but every finish seems to present some issues for me. For me, there is nothing normal about finishes. And, we have the additional problems with high humidity. Builders who fill with superglue seem to have a lot of success. With experience though, you learn to see problems before they get too bad. Trying to level a poor pore fill with lacquer is a long road home.Even after it looks level, the lacquer will shrink back and the pores will show later. The best filler I ever used was the old fashioned Naptha based stuff. Basically Naptha and dirt! Problem with it was that it had to be colored and matching the color to a widely varying wood like koa can be difficult. I'm using waterbase now. Not very good, but it does work. Fairly labor intensive. I know exactly what you ae going through and wish I could give you some help. Good luck!-Bob

 

[sequoia]

Trying to level a poor pore fill with lacquer is a long road home.

You got that right. You layer until the cows come home (and they are always late) and just when you think you got level, something shows. From what I understand, serious luthiery shops send their instruments out to specialty shops who only do highly technical instrument finishing and have the proper facilities to do it. Basically they don't even mess with finishing. I get why.

 

[Moore Bettah Ukuleles]

I swear the finishing gods are trying to drive me insane.

I pore filled my last batch of ukuleles as usual- four applications of west systems epoxy 207 sanded back. To my critical eye under good light I absolutely thought I’d done a complete fill.
Yesterday I applied the first four building coats. Cardinal Lacquer, reduced 60/40 with 5% retarder.

Today I go to level, and I’ve got way more open pores than I expected. I wet sanded with 320, and still had many bright blips where the damn pores weren’t filled. Burned through on one back trying to get rid of them.

I’m completely a novice as far as finishing goes and I’m wondering if this is normal? Perhaps the next building costs will fill up the low pores enough to be levelled? Or- strip off the lacquer and try again?

Just a thought, maybe you’re sanding back too much, especially on your initial coats. On my first pore filler coat I’m just really knocking back the dust nibs and raised grain. I think what happens in many cases is that people sand fill coats too aggressively and keep exposing new pores that weren’t there before. It’s the final, in my case third, coat that I except to be close to perfect. If by chance I’ve sanded down to bare wood I fill that area again. I consider the final pore filling coat to be the first of my finish coats.
But I’m using ca glue as a filler. I’m an impatient and lazy builder. I find it very fast, easy and consider it to be an excellent pore filler with no shrink back. But it’s Pretty unforgiving and there’s a learning curve. It’s not for everyone (as Bob can tell you). I have a handout if you’re interested.

 

[Kelali Kev]

Just a thought, maybe you’re sanding back too much, especially on your initial coats. On my first pore filler coat I’m just really knocking back the dust nibs and raised grain. I think what happens in many cases is that people sand fill coats too aggressively and keep exposing new pores that weren’t there before. It’s the final, in my case third, coat that I except to be close to perfect. If by chance I’ve sanded down to bare wood I fill that area again. I consider the final pore filling coat to be the first of my finish coats.
But I’m using ca glue as a filler. I’m an impatient and lazy builder. I find it very fast, easy and consider it to be an excellent pore filler with no shrink back. But it’s Pretty unforgiving and there’s a learning curve. It’s not for everyone (as Bob can tell you). I have a handout if you’re interested.

I have used Chuck's handout on ca pore filling and have had great results. The pore filling handout helps you get a good understanding of how to use the ca, and where to purchase it in quantity. I am not shooting for completely smooth though and want some pores to show. I used zpoxy previously, but this is faster and easier, and makes a great base for a nice lacquer finish.

 

[JJohansen]

Just a thought, maybe you’re sanding back too much, especially on your initial coats. On my first pore filler coat I’m just really knocking back the dust nibs and raised grain. I think what happens in many cases is that people sand fill coats too aggressively and keep exposing new pores that weren’t there before. It’s the final, in my case third, coat that I except to be close to perfect. If by chance I’ve sanded down to bare wood I fill that area again. I consider the final pore filling coat to be the first of my finish coats.
But I’m using ca glue as a filler. I’m an impatient and lazy builder. I find it very fast, easy and consider it to be an excellent pore filler with no shrink back. But it’s Pretty unforgiving and there’s a learning curve. It’s not for everyone (as Bob can tell you). I have a handout if you’re interested.

Just a thought, maybe you’re sanding back too much, especially on your initial coats. On my first pore filler coat I’m just really knocking back the dust nibs and raised grain. I think what happens in many cases is that people sand fill coats too aggressively and keep exposing new pores that weren’t there before. It’s the final, in my case third, coat that I except to be close to perfect. If by chance I’ve sanded down to bare wood I fill that area again. I consider the final pore filling coat to be the first of my finish coats.
But I’m using ca glue as a filler. I’m an impatient and lazy builder. I find it very fast, easy and consider it to be an excellent pore filler with no shrink back. But it’s Pretty unforgiving and there’s a learning curve. It’s not for everyone (as Bob can tell you). I have a handout if you’re interested.

Hey Chuck, I very well think that might be my problem. I'm power sanding with 320 after each coat and It very well may be that I'm just opening new pores. The kick in the pants is that I go over every inch of the damn thing with a magnifying glass and can't see any pores that look open. Regardless, I stripped off the finish and had a go with medium CA applied with a gloved finger. I'd absolutely appreciate that handout!

 

[Moore Bettah Ukuleles]

I power sand my fill coats too, 220 On a medium setting. Success with that really depends on the backing pad you are using and a light touch. For that stage I use a very soft pad (Festool). You probably can’t see the infilled pores because they are packed with dust.

‘Here;s my email address if you want the handout: moorebettahukes@aol.com

 

[Kekani]

All different roads, in the same direction. I use the 207 as well, but you must be patient, like a week, at least.

Once I started scraping back the epoxy (and ca, when I did that process) with a razor blade, sandthrough became less of an issue, and provides a nice base for the next coat of epoxy. I pay a lot of attention to pore filling, and it’s never enough.

 

[JJohansen]

Chuck very kindly gave his protocol for using CA glue. Using bounty brand paper towels absolutely made a difference. The only modification that I made was tucking a 2” square of 1/8” Teflon into the folded paper towel applicator. This gave me a much more even coat as the straight edge of the Teflon insert helped evenly distribute the CA glue.

By far the biggest change in my approach is thinking of the grain fill as an initial base layer of “finish”, not as something to be sanded off.

All I can say is I’ve been working with wood professionally in some form or another my entire life, and making a dinky ukulele at a high standard is absolutely the most challenging.

 

[TheDudeAbides]

Last one I used Aqua Coat(believe it came from LMII) with good results. Did 2 coats with a light sand between.

I've only used it once but it worked well on Sapele.