Need to sand a Flame Maple top back to bare wood - need help

[Dano]

This is my first rodeo doing this and I would appreciate some advice from some of you guys who have a lot of experience in finishing / refinishing.  I was finishing a new Flame Maple body with dye and Polyurethane on top.  The dying process went well, but I ended up messing up the finish when I tried to polish. 

I have sanded back to bare wood (or close to it) using a random orbital sander with 240 grit paper.  That is the lowest grit I currently have.  I have reached a point where there is still just a little stain left and the flame pattern is visible in some places on the body but is nondescript in other places.  It just does not have the nice continuous flame pattern that it did prior to the screw up.

I have ordered some lower grit sandpaper and I was thinking I would try to take more wood off with a rougher grit in hopes of getting back down to the original flame pattern.  Please let me know if this is the way to go or if I should be doing something else.

I will post pics to show what i am looking at.  Thanks in advance to anyone who can be of any help.

 

[Dano]

Here are a couple of pics showing the flame maple prior to my messing up the finish.  The other pic is what it looks like after I sanded it down.  The flame maple pattern is not present all across the body like it was before.  Instead, some areas are washed out looking with no distinct pattern.

Thanks again for any help you can give me!

 

[AirCap]

First of all - STOP SANDING!

What "mistake" did you make that needed to be rectified?

 

[Toulouse_Tuhles]

First, don't be dismayed at the flame, it will return.  Once you start to sand with the grain using a sanding block.... and re-stain.  The flame is not skin deep, but the REFLECTION of the wood fiber is disrupted with orbital sanding, so its surface reflection is also disrupted.

 

[Dano]

First of all - STOP SANDING!

What "mistake" did you make that needed to be rectified?

I used Minwax "Fast Drying" Polyurethane.  I put 4 coats on according to the directions on the can.  The finish looked pretty good but not quite as shiny as professional finishes.  I watched a ton of YouTube videos and saw one guy shine his finish up with 2000 grit on and orbital sander, then buff with automotive polish.  I proceeded to give that a try.  I started with the 2000 grit and it just smudged beyond repair.  I think I put the polyurethane on too thick.  I seem to recall one of the videos recommending to cut the poly 50/50 with thinner, but I cannot find the video now.  I watched so many videos and read so many forum posts that I lost it.  Minwax makes a "wipe on" polyurethane and I guess it is a thinner mixture.  Most of the videos I saw were done with that product.  When I purchased the product that I used, I was unaware of any difference.  As I said, this is my first attempt at finishing with anything other than Tru-Oil.  I may just go that route once I get this cleaned up.

 

[Dano]

First, don't be dismayed at the flame, it will return.  Once you start to sand with the grain using a sanding block.... and re-stain.  The flame is not skin deep, but the REFLECTION of the wood fiber is disrupted with orbital sanding, so its surface reflection is also disrupted.

Thanks Toulouse!  I appreciate the comment.

What you are saying makes sense because on the edge of the body you can see the flame going all of the way through the Maple top.

I have not sanded all that much with the orbital sander thus far.  As you can see from the pic I posted, there is still quite a bit of dye showing.  One YouTube video on refinishing said to start with a course grit (80 grit) and take it to bare wood, but that was on a painted guitar.  You are suggesting that I have gone far enough with the orbital, and to just block sand with the grain?  The Maple top is really thick but I don't want to take off any more than necessary.

I will give that a try. 

Again, thanks!

 

[Cagey]

Poly doesn't "dry", it cures, and that takes time. Much more than you'd think. It's why Warmoth quotes 8-10 weeks for finished bodies. The thing probably gets finished the same day it's prepped, but it has to sit long enough for the material to get good and hard, or it won't polish as nice as it could. Even though it dries rather than cures, lacquer does the same thing. Seems counterintuitive because to the touch, either one feels bone dry pretty fast, especially lacquer.

 

[Seamas]

I would do any of the fine sanding of the finish (after it cures) by hand-- and work up to the 2000 grit, starting with 400 or 600. I'd do wet sanding, and definitely wipe the body clean before going up a grade.

 

[Dano]

Poly doesn't "dry", it cures, and that takes time. Much more than you'd think. It's why Warmoth quotes 8-10 weeks for finished bodies. The thing probably gets finished the same day it's prepped, but it has to sit long enough for the material to get good and hard, or it won't polish as nice as it could. Even though it dries rather than cures, lacquer does the same thing. Seems counterintuitive because to the touch, either one feels bone dry pretty fast, especially lacquer.

Thank you very much Cagey. 

I am going to give this another try with the Minwax "Fast Dry" Polyurethane. 

How many coats would you recommend? 

Is there any need to cut it 50% with thinner like I saw or read by one user of the product? 

I put it on last time with a foam brush.  Is that the best way to go?

I assume I need to put the coats on as thin as possible.

I will plan on getting the poly on and let it cure for a month or so before I mess with the polishing.  The advice I got was to start off with a 2000 grit sandpaper on a random orbital sander, then buff with automotive polish, then wax.  Would you recommend that approach?  Maybe given my past "success story" I might want to stick to hand sanding?

I know this is a lot of questions but that demonstrates my total lack of knowledge of the process.  I have always thought that getting Warmoth to finish the body was WAY more cost effective but I saw this beautiful body on eBay and it had the Flame Maple on both the front and back.  So, I figured I would go ahead and give it a shot.

I am building this for my 15 year old grandson, so perfection is not a deal breaker, I just want it to be the best I can do for him.

I very much appreciate you taking the time to help out a beginner!

Dan

 

[Dano]

I would do any of the fine sanding of the finish (after it cures) by hand-- and work up to the 2000 grit, starting with 400 or 600. I'd do wet sanding, and definitely wipe the body clean before going up a grade.

Thanks Semas,

Your post came in while I was replying to Cagey's.  You have answered a couple of my questions and I do appreciate that.  With the help of you guys, I will get this thing done.

Appreciate the help!

 

[Cagey]

From what I remember of doing wipe-on poly, the stuff doesn't like to be "worked", so a good result kinda depends on a smooth, fast application with a good, wet applicator. Otherwise, you get stroke marks that are difficult to get rid of. You don't want to depend on finish sanding/polishing to get a good surface like you do with lacquer. You may end up with multiple coats just to get it right, not because the end results require it. Also means you don't want to deliberately apply it "thin" or sparingly like you would with the various "oil" finishes that benefit from repeatedly curing/building. You need to find that proper applicator loading that will get a wet finish on, but not so heavy that it wants to run/sag. Ideally, it would be a one-coat deal, but you probably can't do that with wipe-on going around the inside curves/corners you see on bodies. I'd suggest finding something with an irregular shape to practice on to get your material handling mojo in good shape.

 

[Dano]

From what I remember of doing wipe-on poly, the stuff doesn't like to be "worked", so a good result kinda depends on a smooth, fast application with a good, wet applicator. Otherwise, you get stroke marks that are difficult to get rid of. You don't want to depend on finish sanding/polishing to get a good surface like you do with lacquer. You may end up with multiple coats just to get it right, not because the end results require it. Also means you don't want to deliberately apply it "thin" or sparingly like you would with the various "oil" finishes that benefit from repeatedly curing/building. You need to find that proper applicator loading that will get a wet finish on, but not so heavy that it wants to run/sag. Ideally, it would be a one-coat deal, but you probably can't do that with wipe-on going around the inside curves/corners you see on bodies. I'd suggest finding something with an irregular shape to practice on to get your material handling mojo in good shape.

Thanks a bunch!  I sure do appreciate you taking the time...  I will give it my best shot...

 

[Cagey]

Of course, some of that depends on the manufacturer as well. Everybody has their own formulation to satisfy different consumers/applications, so handling characteristics will change from one brand to another. All the more reason to practice.