Learning to Build An Amplifier Cabinet…Down the Wood-Working Rabbit-Hole I Go…

[BigDaddy23]

The pyramids are super handy for all sorts IMO.

One other thing you can do with the oil finish is to wet sand it in with 400grit wet and dry paper then wipe across the grain with a cloth. This creates a slurry which fills the grain/pores. I do an initial wipe on coat and let it dry then commence the wet sanding with the subsequent 2 coats. With each of these 2 coats, let it dry and do it again then give it a light sand with 600 grit before a final, light wipe on coat. You'll get a smooth glassy finish like this. Oil finishes are great and super easy to repair.

I can only echo what someone else said above about the 'tactile' nature of this type of finish...it really enhances the wood and says 'come and touch me.'

 

[Crowe Baaah]

The pyramids are super handy for all sorts IMO.

One other thing you can do with the oil finish is to wet sand it in with 400grit wet and dry paper then wipe across the grain with a cloth.

Did some reading/watching on this and I have a question for you after seeing some different approaches. Are you applying your finish, letting it dry, and then wet sanding with mineral oil as your lubricant? I also saw a different approach (in a number of guitar-making videos) where true oil was applied and then fine grit sand paper was used while the application was still wet to smooth.

I think the plan I have settled on is to (first test on a scrap and):

- Water pop grain to 400 grit as described by Powdog

- Apply 2-3 thin coats of minwax tung oil finish (12-24h drying time, perhaps wet sand between coats pending answer to above)

- Add spar urethane to Minwax TOF per "Rudy's Mixture" in video and apply 2 coats with light sand b/t per video instructions.

 

[ievans]

You apply the oil finish and use it as the lubricant while you wet sand.

But you don’t need to do that with poplar. No grain or pores in poplar.

The easiest oil finish available now is an oil/wax finish. Osmo, Rubio, etc. Apply, wait a bit, wipe off. If it looks good, you’re done, just let it dry for a day.

 

[Crowe Baaah]

You apply the oil finish and use it as the lubricant while you wet sand.

But you don’t need to do that with poplar. No grain or pores in poplar.

The easiest oil finish available now is an oil/wax finish. Osmo, Rubio, etc. Apply, wait a bit, wipe off. If it looks good, you’re done, just let it dry for a day.

Thanks for weighing in. Was looking at the Rubio also...maybe that is just the simplest thing to do. Basically all I am looking for is some "okay if you put your beer on this by accident" protection.

 

[ievans]

Rubio or Osmo will do that. A second coat on top might help.

If you use an oil finish, lay out the rags you used flat on something that won’t catch fire, and let them dry.

 

[Doughboy55]

I could learn to woodwork without use of aforementioned power tools

If you haven’t seen this film, watch it. Master carpenter, homestead in the Alaskan wilderness from scratch, with only hand tools. Incredible story.

Alone in the Wilderness, the story of Dick Proenneke, by Bob Swerer Productions

 

[BigDaddy23]

Wet sand using the same finish as the lubricant after the first coat dries. Let that “slurry’ dry and then repeat by wet sanding the next coat in but this time, wiping it off. Moving up through 600 -> 800grit in the last couple coats will get you a lovely finished surface like this. There’s always something that benefits from the light filling in the surface of the wood that comes from this method - particularly the end grain areas where your dovetail pins are and on the round overs.

As I mentioned before, this is so easy to repair with a drop of the oil if something damages it and I’ve even managed to steam dents out through it before.

 

[Crowe Baaah]

God bless you guys for hand holding me through basic woodshop 101 finishing techniques. It is a little bit reminiscent of my first TDPRI thread when you all courageously hand-held me through a diagnosis/repair filter-cap/choke retrofit to silence the SE-hum of a boutique amp I had acquired on the cheap.

Okay, now to the shop 101 hand-holding. I’m on my fourth coat of Minwax Tung Oil Finish (MTOF) on a test-poplar scrap. To prep the wood, I water-popped to 400 grit. I know there is varying opinion on how best to apply the MTOF (saturate-and-let-sit x 15m, then wipe off, versus thin coat), but I am opting for thin coats of finish with a sponge applicator. After the first coat dried, I attempted a wet-sand with 400 grit paper and let the slurry dry. I am fairly certain a blew it at this step, as this left behind a fair bit of streaking that has not fully come out after a 320 dry sand, another application of finish, and now a 600 grit light orbital sand (after the first wet-sand with MTOF attempt, I am now applying a light coat with sponge applicator and wiping off with a lint-free rag immediately after).

On the plus side, with 4 coats in, the surface is quite smooth and developing a bit of a sheen. I noticed that the end-grain took the finish quite a bit more readily on the last application (after the 600 grit dry sand) which I take to indicate that the fibers are getting less thirsty.

I think the wet sand is a bridge too far for my skill level, so I think I’ll leave that out of the process for now and stick with the dry sand. Question on the streaks (which I can only see in the right light): are they likely to disappear with further sanding/application? Obviously this is just a test piece, but I want to determine if I need to practice on another piece to perfect the process before working on the cab itself?

 

[CUINOZINKS]

Dang Crowe what a killer journey you are on. Been away for a while and am glad to see this post. I’m impressed with your dedication for the old school building techniques. Inspires me to build another amp and cab. Great job man. Can’t wait to see what you do next. Will stay tuned…..

 

[BigDaddy23]

That's looking pretty darn good! Those sanding marks will be more apparent with dry sanding than wet sanding as the former tends to be more aggressive. Stick with it - wet sand with 600 or 800 grit then wipe across the grain with each coat. You can then do a final coat with a cloth and a small amount of oil. You can then buff that final coat if you like. It will look great once done.

 

[Crowe Baaah]

That's looking pretty darn good! Those sanding marks will be more apparent with dry sanding than wet sanding as the former tends to be more aggressive. Stick with it - wet sand with 600 or 800 grit then wipe across the grain with each coat. You can then do a final coat with a cloth and a small amount of oil. You can then buff that final coat if you like. It will look great once done.

Will do, thank for the encouragement!

 

[Crowe Baaah]

Dang Crowe what a killer journey you are on. Been away for a while and am glad to see this post. I’m impressed with your dedication for the old school building techniques. Inspires me to build another amp and cab. Great job man. Can’t wait to see what you do next. Will stay tuned…..

Thanks for that! It’s been a lot of fun to work with hand tools. There has been a few milliliters of blood from a surprising number of small cuts, a decent amount of sweat during the humid summer, but fortunately no tears (yet), and hopefully it stays that way!

 

[Crowe Baaah]

Ok, I believe I’ve moved from scratches to streaks, which I take to be a good sign. The streaking was actually difficult to capture on photo but is more readily seen with obliquely incident light. Below I’m testing half the board (left) with wet sanding with 1500 grit and horizontal wiping, and, on the right, dry sanding with an orbital sander in the direction of the grain, followed by wipe on and wipe off with the grain.

I am gently wiping off and in the horizontal sections, it’s almost like the pressure from my fingers leads to more removal in four spots creating the streaks. Should I be really wiping it off more aggressively?

Otherwise, really happy with it and I think I am more or less done (with practice, and ready for the cab itself) i if I can get the streaks out.

 

[BigDaddy23]

You can sometimes get marks like that from the paper getting clogged too....the finer grits are more prone to this if the previous coat has not completely cured. On the last couple coats you can go with circular wiping - that will give you an idea if what you are experiencing is from the linear wiping. You should need considerably less oil on the last coats too which makes that a bit easier to manage in an even way.

 

[Mongo Park]

This is a tricky thing, wet sanding finish.
I think the wood had different densities/ hardness throughout the cabinet. This affects how much the sandpaper removes or doesn’t remove. As the finish becomes more glossy this aspect come into play. The difference in surface smoothness were created earlier with lower grit sandpaper. Harder wood has more uniformity in hardness. I’m not saying you are not paying attention to detail, it is a learning curve as to what detail you are looking for. Sanding like the rest is not just rubbing it around singing a song in your head.
As you do this finish a few time you will get a better fell for how it goes and how the type of wood takes this finish.
For me and this type of wood I would just apply the finish and lightly sand between coats of needed, which it usually does. Very light final coat. This produces a less glossy finish which I am happy with. Less gloss and less noticeable imperfections in the wood. This is just another option of the many ways to finish something.
It’s good to do a few different finishes so you have a variety of go to finishes in your skill set.

 

[Crowe Baaah]

I don’t intend for the cabinet to get this glossy, so I think it is a byproduct of the experiment. Probably the sweet spot is in the 3rd or 4th coat. I think I am going to get it another trial run and work primarily on the sanding technique.

Just want to take a moment to acknowledge that the people on this forum are fantastic, patiently sharing their time and experience. I’m looking forward the opportunity to paying it forward as I gain in experience and knowledge.

 

[ievans]

Having gone through this myself, one of the things that made getting a good finish difficult was reading all the different techniques that vary from person to person and finish to finish and species to species. You’re committed now, but you probably made it more difficult by doing the wet slurry sand on a wood, poplar, that is a little soft, and has closed grain and closed pores. Horses for courses, etc.

An even initial sanding to 220, and then a light 400-600 scuff sand between coats would be all I would do on poplar with tung oil.

 

[Crowe Baaah]

Having gone through this myself, one of the things that made getting a good finish difficult was reading all the different techniques that vary from person to person and finish to finish and species to species. You’re committed now, but you probably made it more difficult by doing the wet slurry sand on a wood, poplar, that is a little soft, and has closed grain and closed pores. Horses for courses, etc.

An even initial sanding to 220, and then a light 400-600 scuff sand between coats would be all I would do on poplar with tung oil.

Thanks for the perspective. Fortunately I'm only committed to this test piece and I intend to do at least one more before getting to the cab itself.

I really want it to be top notch and am willing to be patient to get it there.

 

[King Fan]

@Crowe Baaah , I usually skip over cab threads -- let's say I'm a recovering woodworker. So catching up on your project here was a real pleasure -- you did do the deep dive. Just the workbench alone is a super reward -- be proud.

For the cab finish, let me echo something @Powdog said. After struggling with every finish known to man and every application method, I finally tried rub-on poly. Yes, I sand like he does and then some more -- lots of elbow grease and time and trips to buy sandpaper -- but the hard part for me was always getting clean, smooth, even coats without dry spots, buildup, brush marks, stray bristles, runs, wrinkles, puckers, orange-peel etc -- and most of all the devil's spawn known as dust landing on the wet finish. Rub-on cured all that.

 

[Powdog]

@Crowe Baaah , I usually skip over cab threads -- let's say I'm a recovering woodworker. So catching up on your project here was a real pleasure -- you did do the deep dive. Just the workbench alone is a super reward -- be proud.

For the cab finish, let me echo something @Powdog said. After struggling with every finish known to man and every application method, I finally tried rub-on poly. Yes, I sand like he does and then some more -- lots of elbow grease and time and trips to buy sandpaper -- but the hard part for me was always getting clean, smooth, even coats without dry spots, buildup, brush marks, stray bristles, runs, wrinkles, puckers, orange-peel etc -- and most of all the devil's spawn known as dust landing on the wet finish. Rub-on cured all that.

The last wipe-on poly finish I did was a butcher block top for a kitchen island. It wasn’t gonna be used for food prep of any kind so I used the poly. But I didn’t really rub or wipe. I used a 4” wide foam brush and laid it down with long even strokes going the entire length of the top. I did it early in the morning when it was cool so the brush strokes had time to lay flat before tacking up. Light dry sanding between coats. I use satin finish most of the time, not a high gloss fan.