Sanding+TruOil issues

Hello folks. I wanted to consult with you about some problems I am having with my first kit. I have sanded it with 320 and 600 for results that seemed "even enough" to me, other than some points where the grain exits the wood outwards and I couldn't really sand. I have never done this before and have probably made some mistake.

Here is an example:
Attachment 25775

If it is hard to see, there are some spots, areas with scratches and matte look in relation to the rest of the body. This is after 4 coats of TruOil, whereas I waited 24 hours between the 1st and 2nd, and 12 hours between each additional coat.

Can this be fixed? Is it supposed to be like this? Can I sand at this point or will I have to redo the entire thing? Do more coats fix this?

Any tips will be appreciated.

Hi and welcome. I'm doing my first Tru-Oil guitar at the moment, but I know that you are going to be applying many more coats of Tru-Oil to get a really good finish. The first few coats are going to sink well in, especially if you haven't applied a sanding sealer first. So it''s going to look rough and patchy.

I'd wait a day to allow any more sinkage to occur and the TO to harden a bit more, then give it a sand down and then apply more TO. For a flat shiny finish, you are going to need lots of coats of Tru-Oil, as each coat is very thin. Many of those you will mainly sand off again if you want a flat glossy finish, as you will be using the first load of coats just as fillers for the grain, so that you end up with a flat surface.

The Tru-Oil coats after that then go to form the protective layer. Even then, you'll need to sand back flat before you can polish it up to a good shine.

Hi peace, to me it looks like some glue still left on there and the scratches are in the end grain under the clear coating.

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Originally Posted by Simon Barden

Hi and welcome. I'm doing my first Tru-Oil guitar at the moment, but I know that you are going to be applying many more coats of Tru-Oil to get a really good finish. The first few coats are going to sink well in, especially if you haven't applied a sanding sealer first. So it''s going to look rough and patchy.

I'd wait a day to allow any more sinkage to occur and the TO to harden a bit more, then give it a sand down and then apply more TO. For a flat shiny finish, you are going to need lots of coats of Tru-Oil, as each coat is very thin. Many of those you will mainly sand off again if you want a flat glossy finish, as you will be using the first load of coats just as fillers for the grain, so that you end up with a flat surface.

The Tru-Oil coats after that then go to form the protective layer. Even then, you'll need to sand back flat before you can polish it up to a good shine.

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Okay, this is encouraging. So the next step is to let it sit for two more days and then sand again? Then I have a few followup questions:

1. The top of this kit is plywood, and it seems to be already rejecting the oil I put on it. Does this mean it is ready for sanding? How do I know the top and sides are?

2. How do I sand the grainy parts? I am asking you to explain this to me like I'm an idiot. I take a 320 grit and sand, and the surface stays just as rough as it was. What am I doing wrong?

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Originally Posted by Adam Barnes

Hi peace, to me it looks like some glue still left on there and the scratches are in the end grain under the clear coating.

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That's... yeah that's actually very possible. So to get rid of it I need to get like a milimeter off the wood, right? I guess I'll give up on it.

What kit is it? One of the thinline Tele kits? The ply tops are normally pretty smooth and used closed-grain wood, so it won't take too much Tru-Oil before you start to build up layers on top of the base layers.you might want to stop on the top and get the sides and back up to a similar condition

To smooth the end grain, you'll need to go a lot rougher than 320 grit. I'd start with some 80 grit and then work your way up.

If its a glue patch, you could try scratching with a small wire brush -
https://2ecffd01e1ab3e9383f0-07db7b9...0fec897e97.jpg

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Originally Posted by Simon Barden

What kit is it? One of the thinline Tele kits? The ply tops are normally pretty smooth and used closed-grain wood, so it won't take too much Tru-Oil before you start to build up layers on top of the base layers.you might want to stop on the top and get the sides and back up to a similar condition

To smooth the end grain, you'll need to go a lot rougher than 320 grit. I'd start with some 80 grit and then work your way up.

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It's the HBB-5 semihollow bass. Top is plywood, the rest is normal wood, 3 pieces. I have only now learned about the term "end grain". Gonna try. On the neck too - only the very edge of the headstock has this problem, obviously, and its color is much darker after the 4 layers.

I will stop with the top, that's a great tip. Backside is okish, but sides are awful. Gonna try re-sanding. But I will leave it for a week to solidify, first. By the way, is there any particularly good way to sand this endgrain? Cuz "with the grain" is obviously irrelevant.

Thank you for bringing more hope into this. I considered just slapping it together sloppily and hanging it on the wall or something.

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Originally Posted by Brendan

If its a glue patch, you could try scratching with a small wire brush

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Interesting thought. Is it too late if I already have tru oil on? And will it sand off?

Sometimes you have to take a step back to then move forwards. I'm doing it all the time. Yes, TO will sand off. You've either got to just add loads of TO coats, so that it's thick enough to sand back to a flat surface over rough grain, or else you get the wood really smooth first before applying any TO, so that you have to apply fewer coats of TO. Most people here end up putting around 30 coats of TO on, with sandings every 4-5 coats or so.

Towards the end, you can thin the TO with turps about 50/50, so it's a bit more liquid and doesn't leave so many ridges in the finish when wiping it on. It obviously goes on a bit thinner as well, so wait until you've done the main building-up with the full strength TO.

How are you applying the Tru-Oil?

The method I use was shown to me by a gunsmith a long time ago and he had been using it for much longer than that.

You will need the body or neck sanded to where you want it.
Tack cloth
Jersey cloth (t-shirt material) preferably new stuff rather than an old t-shirt as it will have more body.
Tru-Oil.
XXXX Grade Steel Wool.

After sanding I use a tack cloth to remove dust, then get a damp cloth and rub over the sanded surface. This will make loose wood fibres stand up.

These are then sanded off and a tack cloth used again.

Now using a folded square of jersey (t-shirt material) place it over the neck of the T/O bottle and briefly invert the bottle to get a small amount on the cloth.

Start to rub the oil onto the a small patch of the timber in a swirling motion, keep going until you feel resistance. The T/O will sort of get slightly tacky.

Put some more T/O on the cloth and do the same for an adjacent area. Try not to overlap too much.

Repeat until the whole area is covered. Hang the body or neck in a dust free place and leave it alone for a few days. Now take the used cloth and submerge it in a bucket of water and leave it there. Tru-Oil soaked cloth has been known to spontaneously combust - I've never seen but I know people who have.

Do a second and third coat in the same manner.

Lightly rub with the XXXX steel wool. Wipe down and run over with the tack cloth to catch and bits and any steel wool fibres.

Do your fourth coat. Now you can probably start applying coats a bit more often even six or eight hours apart if it is not cold or if it is very low humidity.

Keep applying coats until you are happy with the finish. Every four or five coats knock it back with a very light going over with the steel wool.

I have done well over 30 coats on rifle stocks.

By the way, leave the usd cloths in the water for a couple of days then dry them out in the sun before turfing them out.

Now here is something that a lot of guitar forums seem to miss about Tru-Oil. It is a rifle stock coating. Which means it is hardy and resilient to water, grime and sweat. As a rifle stock coating it is not really designed to be glossy and slippery, Satin-Gloss with grip is probably what it is best described as.

It is not a guitar coating which means super slippery and glossy it ain't.

Don't rush it, enjoy the cathartic release of sitting in the man-cave rubbing your wood. Patience is the secret.

Dont give up peace, its not easy to make a guitar but playing a guitar that you made is very rewarding 2 steps forward 1 step back

Thank you so much, fellas. I enjoy the process, but it is twice as much fun when I know it can actually succeed.

Now for 30 coats I am starting to wonder how many bottles I will need. I have the 3oz one and another one coming (hopefully) in the mail. I get the feeling I need 5 of those?

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Originally Posted by Rabbitz

How are you applying the Tru-Oil?

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Actually I applied it with broad strokes, since I got the feeling it is best to start drying up and becoming tacky altogether. All the luthiers I saw on youtube did it like that. If I can do it per area it will be much easier.

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Originally Posted by Simon Barden

Towards the end, you can thin the TO with turps about 50/50, so it's a bit more liquid and doesn't leave so many ridges in the finish when wiping it on.

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I actually like the ridges, as long as they're relatively even across the body. In fact, I have been ogling my Corvette ever since I started the process - the finish is amazing, with the grain alternating between smooth and striped, and it feels awesome.

After 10 / 12 coats i start using a 50 /50 mix so one bottle should be enough my first bottle did 3 guitars the 2nd did 1.5 guitars all depends on the how much the timber sucks it in

I'd say one 8 oz. bottle should do one guitar, especially if the last 1/3 ends up diluted. Keep cleaning round the screw part of the bottle, as over time you get small dried bits of Tru-Oil on there, and it's easy to pick them up with the applicator cloth and transfer them to the finish.

Attachment 25788 true oil po,ished with meguiars scratch x used 3/4 of a small bottle

Hi Peace, looks like machine marks were not fully sanded off and are now trapped under the initial layers of Tru Oil. If it bothers you the only way to fix is strip back to bare wood and give it a solid workout with 120 & 240 grit. A lot of newbies make the mistake of getting a smooth feel and moving up through the fine sandpaper grits without realising there could be cross-grain machine marks that have a habit of showing up once tops coats start being applied.

1 x 3oz bottle of Tru Oil will cover at least one guitar & neck with somewhere between 20 - 40 coats, either full strength or diluted 50:50 with turps. Having used TO mostly on all my builds, these days would tend to do about 6 full strength then do light 1200 W & D wet sand. For the next 8 coats would run with 50:50 mix and then do another wet sand, maybe using 1500 grit. About now there should some depth happening and hopefully no obvious overlapping of subsequent coats which tend to look a bit like runs trapped way down below the surface. Periodic wet sanding is the best way to prevent this from happening. At this point it becomes a bit subjective but to bring it home it is best to revert back to full strength and wet sand with 1500 to 2000 every 2nd coat.

Somewhere past 20 coats could be a good idea to do a serious 2000 grit wet sand followed up with all the micro mesh pads, all the way up to 12,000 grit. Inspect things very closely and if it looks good all over, start using the Meguiars cutting compound. On my latest build I have been using Brasso as it takes less effort but can strip lots off and therefore very easy to burn through in places, which has happened a few times thus requiring delicate touch up layers added to the affected areas. Patience is the key and if you stick to the plan and go the distance things will turn out looking like a piece of timber dipped in glass. My build #5 took a lot of time and has 40+ coats. Latest build has plenty of coats and didn't keep track of how many but it should turn out better than the last one. You learn new tricks and techniques on each & every build.

Hope some of this helps and wish you luck.

Cheers, Waz

Edit: There are so many different ways shown on YT to apply this stuff which makes things confusing. Rubbing on until things become tacky may not work out the best as whilst that helps to blend things into prior coats it does not help with promoting a smoother shiny surface. Wiping on all over with a 50mm x 50mm square of an old T shirt folded over a few times and leaving slightly wet works better. Old T shirts have been washed to death and therefore have less fibres to get caught up in the coat being applied.

Well said waz

Well now the advice is getting kind of contradictive, so I will try asking specific questions:

1. What is "tack cloth"? I might've missed this step last time and maybe that's the problem.

2. How do I "wet sand"? With the oil itself?

3. What do I dilute the oil with? Turpentine?

4. If I need to sand off some oil to fix a spot, do I need to sand everything off? How to get it up to the same layer amount?

Thanks yaall

Tack cloth is a cloth that is impregnated with a slightly sticky compound. It is designed to be 'tacky' but doesn't leave residue.

It is specifically designed to dedust surfaces.

Most paint places and possibly BGSFOS will have them.

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Originally Posted by Peace_less

Well now the advice is getting kind of contradictive, so I will try asking specific questions:

1. What is "tack cloth"? I might've missed this step last time and maybe that's the problem.

2. How do I "wet sand"? With the oil itself?

3. What do I dilute the oil with? Turpentine?

4. If I need to sand off some oil to fix a spot, do I need to sand everything off? How to get it up to the same layer amount?

Thanks yaall

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Point 1 has already been addressed however you may need to visit a lrge reputable paint or hardware store.

Point 2 relates to wet sanding with water to cut back some of the finish which helps next coats go down better.

Damn phone won't let me see the rest of your post so will respond across a few posts.

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Point 3. Mineral turpentine seems to be best stuff to use for diluting whilst still retaining most of Tru Oil's properties.

Point 4. Presume this relates to the deep scratches or machine marks under the finish? Sanding back to bare timber should probably be done all over rather than in sections as it would be very hard to hide large spot repairs and touch ups.


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Should add that i have also applied Tru Oil with 1200, 1500 & 2000 grit paper which helps to smooth things as you go but it doesn't take much for things build up in funky ways that are hard to rectify once many, many layers hsve been done.

Method outlined before is simplest and best way to go, particularly for anyone new to this process.

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Alright, I feel like I am getting somewhere with this.

First off, I now realize my mistake with sanding. I didn't understand what "tack cloth" was and thus failed to fix spots with endgrain, as they got filled with wood dust.

Second, it is not important to me to fix all the stains, but I do want the thing to be evenly smooth. So I will try sanding down the rough spots and continue from there.

So far, maybe due to not using filler, I could see the wood responding to the oil only on the top, which means I probably didn't build anything up. So I will wait to next weekend for it all to solidify, then start sanding down with 80 to see what happens.

Since the back is pretty good I would consider sanding down the sides all the way to bare wood, but I am worried about the binding. It is about 1 mm thick and thus can be eaten away if not careful.

In any case, this build will not be perfect and I will not try to make it as such.

The binding is pretty tough, I wouldn't worry about it too much. It can take a lot of sanding and scraping (if you are cleaning paint or stain off it) and still look as it did before.

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Originally Posted by Simon Barden

The binding is pretty tough, I wouldn't worry about it too much. It can take a lot of sanding and scraping (if you are cleaning paint or stain off it) and still look as it did before.

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I have already sanded some of the binding off in the neck pocket area and around its edges, so we either have a different definition of "tough", or I got gorilla hands. Probably both.

But sharp change of subject, I've read in one of your diaries that you can use alcohol to see glue marks in advance. I probably should do this next time. Is there a professional term for "white spirits"?

Where in the world are you? It's a turpentine substitute, used for cleaning wet paintbrushes, (but not a dedicated brush cleaner for cleaning dried paint off brushes). You can use turpentine, but it's about twice the price, if not more, though it smells a lot nicer. It's just that it doesn't cause the wood fibres to swell as water does.

We have two kinds of turpentine here, one of them synthetic. I guess that's the stuff.

And I am in Israel. Imagine the challenges I face - have to translate yaalls handiman lingo to proper English, then to Hebrew, then to Hebrew Handiman Lingo (tm).

Took me a while to find "Tack Cloth" here.

Oh and feast your eyes on the drying rack I just cobbled together after yall's comments made me realize I have weeks to go still and I need my table clear.

Attachment 25796

Nice drying rack.

I have to tidy up from time to time and lose my workbench as well, so I sympathise.

If you are worried about damaging the binding whilst sanding try using some high quality painters masking tape to cover it so that the sandpaper can attack that before going too far through. The masking tape will also give you a border to work with and once most of the heavy sanding has been done simply remove for the final light higher grade grit sanding.

With some of the end grain it does take a lot of work to get really smooth and sometimes you need to sand with the direction of machine marks to take them off and once that has been accomplished you revert back to sanding in the direction of the grain to remove any cross grain scratches introduced from sanding.

Quite often that end grain around where bottom strap button would be located is very stubborn and you may have to do your best and then decide if will be good enough. Always wipe down with something wet, whether you use water, methylated spirts, Turps, whatever to get an idea of how things will look once coats of finish are applied.

Cheers, Waz

Just a quick note to say that I've found this a really useful thread, thanks all!