Beginner Needs Help

[ultrazone5150]

Hey there,

Im a long time guitar player whos just getting into some beginner building and finishing. If I buy a body thats already been sealed and i want to apply a laquer finish, how many coats do I need apply and how much sanding between coats is necessary? Once the lacquer is correctly applied, do I need to sand the final coat? Do i have to apply some sort of clear coat? Does the finish need buffed? I was going to use KTM water based lacquer? ANY HELP U GUYS COULD OFFER WOULD BE MUCH APPRECIATED!!!!

[j. pierce]

I used the KTM-9 stuff with my father's spray gun with really nice results. Some people say it doesn't harden as much as other stuff, I don't know; I can say the guitar I did last year has taken a lot less finish damage than most of my guitars (retail ones) do in a year. I'm not the best judge of telling how hard a finish is though.

One thing with the KTM-9 is that you'll have to use some sort of grain fill coat on any porous wood. I did a maple neck through with mahogany wings and a rosewood headstock. I neglected this step, and the rosewood finished up nice and glossy, the maple got a nice satin sheen that with enough elbow grease glossed up. With the mahogany, I went through an entire can of KTM-9 applying coats trying to get things smooth - The best I could do was a mostly-smooth semi gloss finish; think halfway between those faded, pore-showing finishes on those new issue LP junior doublecuts and a regular guitar finish. Without the filler this stuff just keeps soaking into the wood, although you mentioned you did a sealer coat, this would probably alleviate a lot of this, but if you want a gloss finish, the grain fill is probably still a good idea.

(yeah, I made a lot of stupid mistakes on my first guitar, not realizing there where great places like this to turn to for information and questions.)

System 3 Epoxy filler is the stuff recommended under KTM-9, and it works quite well and is fairly easy to apply, but you really need to get the mix right or the stuff either sets to this incredibly rock hard mess you can't sand at all, or doesn't set at all and stays malleable forever. This is why I neglected the filler in the aforementioned project - I ended up having to beltsand a bad fill job off the whole the guitar, (one side too hard the other necer set) and then re-stain it. I decided I'd rather have a satin finish anyway, so I jumped into the spraying to see what I could get.

I've done some experimenting on scrap since, and I think the finish would be much more durable with the epoxy layer underneath, and also looks nicer. Make sure you get the epoxy layer real thin (you really only want it in the pores) because sanding it is a pain. It's hard to sand around the edges without sanding through it, be careful there. A cloth wet with alchohol while applying helps smooth down the corners without taking the epoxy too much out of the pores around the corners.

in my practice, sanding down the epoxy with 400 grit paper tends to leave the epoxy a little cloudy, even after cleaning off all the sanding residue, however once it gets wet with finish it turns clear again. I don't know why this is. It had me a bit confused.

I did my finish job in two days, spraying a bunch of coats one day, and then sanding with 600 grit the next day before spraying another bunch of coats. (I don't remember how many I sprayed. It was a lot.) I probably didn't sand enough on my guitar. Then again, on properly grain-filled practice pieces since then, it didn't take much sanding at all. Just to level things out. I only did a cursory sanding with 1000 grit and 2000 grit paper before jumping into polishing with the practice pieces I've been doing. The guitar I decided I liked the way it looked and left it as is. (That thing is an ugly dog and weighs a ton, but it's a good sound . . . sitting down. In the studio, where no one can see it.)

As far as KTM-9 finishes go, you can find most all the info you need at the LMI page and the stuff linked of them:

LMI Product description for System 3 Epoxy Filler, some good instructions/FAQ

LMI Description page for KTM-9, some info

LMI instructions for KTM-9

Another set of KTM-9 instructions

(those links are from my bookmarks file, they're showing up good for me, but I might have had them cached; regardless, if you look up KTM-9 on LMI's page, you can find all the info you need linked from there. I believe there where a few discussions here about it if you use the search function)

I'm sure other people will pipe up with more info for other finishes, this is really the only finish I really have experience with in the guitar realm, (only gotten to the finishing stage on a guitar that one time, although I've been practicing with this stuff in anticipation of my current project actually finishing) but since you mentioned KTM-9, I thought I'd toss in what bits of info I have.

[ultrazone5150]

I used the KTM-9 stuff with my father's spray gun with really nice results.  Some people say it doesn't harden as much as other stuff, I don't know; I can say the guitar I did last year has taken a lot less finish damage than most of my guitars (retail ones) do in a year.  I'm not the best judge of telling how hard a finish is though.

One thing with the KTM-9 is that you'll have to use some sort of grain fill coat on any porous wood.  I did a maple neck through with mahogany wings and a rosewood headstock.  I neglected this step, and the rosewood finished up nice and glossy, the maple got a nice satin sheen that with enough elbow grease glossed up. With the mahogany, I went through an entire can of KTM-9 applying coats trying to get things smooth - The best I could do was a mostly-smooth semi gloss finish; think halfway between those faded, pore-showing finishes on those new issue LP junior doublecuts and a regular guitar finish.  Without the filler this stuff just keeps soaking into the wood, although you mentioned you did a sealer coat, this would probably alleviate a lot of this, but if you want a gloss finish, the grain fill is probably still a good idea. 

(yeah, I made a lot of stupid mistakes on my first guitar, not realizing there where great places like this to turn to for information and questions.) 

System 3 Epoxy filler is the stuff recommended under KTM-9, and it works quite well and is fairly easy to apply, but you really need to get the mix right or the stuff either sets to this incredibly rock hard mess you can't sand at all, or doesn't set at all and stays malleable forever.  This is why I neglected the filler in the aforementioned project - I ended up having to beltsand a bad fill job off the whole the guitar, (one side too hard the other necer set) and then re-stain it.  I decided I'd rather have a satin finish anyway, so I jumped into the spraying to see what I could get. 

I've done some experimenting on scrap since, and I think the finish would be much more durable with the epoxy layer underneath, and also looks nicer.  Make sure you get the epoxy layer real thin (you really only want it in the pores) because sanding it is a pain.  It's hard to sand around the edges without sanding through it, be careful there.  A cloth wet with alchohol while applying helps smooth down the corners without taking the epoxy too much out of the pores around the corners.

in my practice, sanding down the epoxy with 400 grit paper tends to leave the epoxy a little cloudy, even after cleaning off all the sanding residue, however once it gets wet with finish it turns clear again.  I don't know why this is.  It had me a bit confused. 

I did my finish job in two days, spraying a bunch of coats one day, and then sanding with 600 grit the next day before spraying another bunch of coats.  (I don't remember how many I sprayed.  It was a lot.)  I probably didn't sand enough on my guitar.  Then again, on properly grain-filled practice pieces since then, it didn't take much sanding at all.  Just to level things out.  I only did a cursory sanding with 1000 grit and 2000 grit paper before jumping into polishing with the practice pieces I've been doing.  The guitar I decided I liked the way it looked and left it as is.  (That thing is an ugly dog and weighs a ton, but it's a good sound . . . sitting down.  In the studio, where no one can see it.)

As far as KTM-9 finishes go, you can find most all the info you need at the LMI page and the stuff linked of them:

LMI Product description for System 3 Epoxy Filler, some good instructions/FAQ

LMI Description page for KTM-9, some info

LMI instructions for KTM-9

Another set of KTM-9 instructions

(those links are from my bookmarks file, they're showing up good for me, but I might have had them cached; regardless, if you look up KTM-9 on LMI's page, you can find all the info you need linked from there.  I believe there where a few discussions here about it if you use the search function)

I'm sure other people will pipe up with more info for other finishes, this is really the only finish I really have experience with in the guitar realm, (only gotten to the finishing stage on a guitar that one time, although I've been practicing with this stuff in anticipation of my current project actually finishing) but since you mentioned KTM-9, I thought I'd toss in what bits of info I have.

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