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Hi all,

I am no kind of luthier: in fact I am only now contemplating assembling a guitar for the first time, and having spent the last couple of weeks researching techniques for the kind of finish I want, I know only that I am still far from sure how to go about it.

I'll be buying an unfinished, rear-routed S body - budget dictates that the neck will have to wait a couple of months, which will at least force me to take my time with the body - probably in ash or maybe alder. I want a natural finish, hence the rear-routing.

So far I understand that I need to do a lot of sanding with progressively finer grit paper. I have learned that grain-filling is an option, bordering on compulsory for an ash body which can often have a wide or rough grain. I am quite tempted by some of the techniques I have seen to highlight the grain or make it pop. And I would like as smooth a finish as possible, so probably will want to avoid any kind of glossing or varnishing. I have read all kinds of conflicting opinions about Tru Oil, Tung Oil, Linseed Oil, etc. I have come across the occasional mention of wax.

I'd be most grateful for any kind of advice (or indeed any necessary corrections to any part of the above), but ideally what I'd hope to nail down is a specific order of events.

In particular, do I need to fill the grain in between sandings, or should I sand, clean, sand, clean, sand, clean etc, and only apply grain filler at the end? Or should I apply it first?

If I want to highlight the grain but without bringing any artificial colour to it, what are some good products to use? Would highlighting the grain necessitate any alteration to the order of sanding and filling? Would this product be in addition to or instead of the grain filler?

Once the sanding and filling is complete, is there anything else I would need to do before moving on to the oiling? For example, I have seen a number of references to staining, but I think I'm right that wood that has been stained need to be varnished, yes?

I have read that ash is a comparatively porous wood. Does this make it a less or more promising candidate for an oil finish than alder?

Finally, is there any mileage in applying wax?

Sorry that these are very noob questions. I was digging around the forum trying to find if they have been answered before, but to little avail.

Thanks in advance.

Rich

Hi, Rich. These are all very good questions and they indicate that you're giving a lot of very careful thought to all of this. I can give you some general opinions on your options, but you'll get other advice, too, so you should weigh all of the advice before plunging in.

In general, I believe ash or any other open pored wood should be pore-filled. There are many ways to do this and many products that can be used. If I were doing it, I'd carefully sand to about 220 grit and then I'd pore fill. I'd wait a couple of days to let the filler really harden up and then I'd examine everything to see if the filler had shrunk in the process of curing. Most likely, it would have, so I'd go all over it again with another pass of filler and then I'd wait once again.

Closed pore woods, like maple or cherry, don't need to be filled. I believe that ash, walnut, mahogany, oak, rosewood, or any open pored wood should be filled. However, some people like the open pored look, so you might decide not to fill the pores.

If I were going to stain the wood, I'd mix the stain with my filler, but I'm probably a little different in that regard. However, I would NOT stain before filling, because the stain is likely to go into those open pores as if they were soda straws and cause ugly dark lines all over the instrument. You'll hear about other methods and finishing schedules, so consider them all.

The oil finishes you mention can be applied over stain and they are very forgiving and easy to use. IF you go that route, just apply lots of thin coats instead of a few heavy coats. You could think of products like Tru Oil as wiping, oil based varnishes.
I've used Tru Oil and tung oil on different projects and like them both. Be very, very careful with any rags you use during an oil process. Lay them flat on your shop or garage floor until you can dispose of them. Don't stack them or wad them up--that could lead to spontaneous combustion.

Now, here's the very best advice I can give you: Get some scraps of ash and your proposed neck wood, too. Before doing anything on your guitar, experiment on the scraps. This applies to filling, dying or staining, sealing, varnishing, oiling, shellacing, lacquering or any finish method you use. Get as many scraps as you can so that you can experiment with all the different methods and suggestions you're about to receive.

Best of luck. When you come to a hurdle, just come back to the forum. Folks will help you.

Patrick

Thanks for the reply and advice Patrick. Thanks to your post I've discovered that I should really be talking about pore-filling . I would like a very smooth surface on the finished guitar so on the strength of what you say I would think I will definitely do this one way or another. Would adding stain to the filler be one method of highlighting the grain? And when you say not to stain before filling, do you mean fill once without the stain, or simply not to apply stain before the fill?

Cheers,

R

Hi Rich - let me add some suggestions. First, here is a good flow chart of the basic steps for finishing

http://www.stewmac.com/How-To/Online_Re ... edule.html

You will be skipping the second staining step if you want to stay with natural wood color. The chart then splits with porous wood (including ash) on the left - non porous like most of the other electric guitar body woods on the right. There are a variety of pore filling materials that luthiers use - common ones include a paste material that can also have stain in it, CA glue (which is a hassle) and my favorite, thin epoxy which also has the advantage of soaking into the grain at different rates and doing a very good job of highlighting or "popping" the grain. I have used a product called Zpoxy on koa, maple and mahogany and really like the results (I did a comparison test on scraps of koa using paste, CA and Zpoxy and the latter was by far the best).

If you don't have to pore fill (woods on the right) then light stains can be wiped on the wood and sanded or wiped off to highlight the grain - this is the way old Gibson guitars and mandolins from the 30's were done. Seems to work well on most woods - I've used it on maple to bring out the figure. The darker the stain the more dramatic, but you will loose that natural look to the wood. Get some scraps similar to your body and experiment on them.

Lots of people use wiping oils - I frankly never have. Many of the oil finishes that I see just don't have the sparkle of a sprayed lacquer finish - I think you can get it with many very thin coats, lots of drying time and then your final polish. I spray everything that I do, I now use so called "water born" lacquers which are non toxic and safe, but my first guitars were done with rattle can spray lacquer (available from StewMac) - if you wear a respirator and shoot outside that an option to consider.

This is Spanish cedar, a type of mahogany, that has been pore filled and "popped" with Zpoxy and has a dozen coats or so of water born lacquer - no other stains, fillers, sealers etc. This is during finishing - the lacquer is on but it hasn't been buffed



Here is the same body before so you can see the effects of the epoxy

Thanks Freeman - the flowchart looks useful. I should add that in addition to actually wanting to end up with a smooth natural finish, I also have a one-year-old boy running around and I don't really have anywhere - like a shed - where I would feel happy spraying chemicals around, even the waterborne lacquers, or leaving the body to dry in between coats. That's a nice top tho .

So let's say I follow the flowchart and prepare the wood down to 220. I could then stain the wood. I've read that I could then sand again with a coarser grit (150?) which would remove the stain from the surface wood but not from the grain, which would also help the highlighting. Is this right or advisable? Obviously I would then sand again at 220. Would that be compatible with subsequent pore-filling?

And presumably if I weren't going to use any kind of lacquer I should skip the sanding sealer step and go straight to the oils?

It does occur to me that the reviews of Z-poxy all point to its waterproofing. Would this mean that I couldn't use oil to finish if I'd pore-filled with Z-poxy? Surely the oil would not be able to penetrate into the wood? Or is the point, as with the stain technique I mentioned, to sand off the pore-filler from all surface parts and just leave it in the grain?

Thanks again. I really want to have a very clear idea of what I'm going to do before I do it as I have never worked any kind of wood before (well, I made a wooden cat in sillhouette once in CDT (what I think most people here call Shop) when I was ten. But that was longer ago than I care to remember and I just bunged some varnish on the bare wood).

R

Not sure what techniques you are referring to but usually a stain or dye is used in combination with sanding to highlight figure in the wood. As you seem to be new to wood finishing in general and guitar finishing in particular I would advise maybe you let this technique go until you become a bit more experienced. You will have more than enough to worry about in just getting a good looking finish the first time out.



Well a well done high gloss instrument finish is as smooth as it gets.....I notice you are leaning towards oil finishes but think you should maybe consider a spray can finish as an option too. You can buy decent quality lacquers in a spray can from Stew mac, Behlin, Re-ranch just to name a few. Be aware that traditional pore filling methods often don't work well with oil type finishes and slurry filling ash will be a long and tedious affair. Of the 3 oils you list tung oil would be my choice.



The exact order of events or "finish schedule" will vary some based on what products you decide to use to build the finish. Sorry there is no really universal answer. So first you should choose a type of finish and then I could be a bit more specific about what steps to take in which order.



This will depend on what type of filler you go with. Will it be epoxy, traditional paste, slurry or something else? A paste filler will usually go on between two coats of sealer a slurry is generally done on bare wood. Bear in mind that the type of filler chosen must be compatible with the rest of your finish products. As I mentioned most oil finishes do not go well with the fillers typically used with lacquers which are more the norm for this and you are limited in those cases to some type of slurry fill.



Not sure how to highlight grain without adding color.....I have seen guys use water to "pop" the grain on oak flooring but all they are doing is actually raising the grain. As floors are not grain filled and cut and buffed to a piano shine the fact the grain has raised is of little consequence there but on a guitar where smooth is needed this I feel would be counterproductive as the raise would need sanded back or filled over. Paste fillers can be used to highlight grain if color selection is made carefully, other than that it is usually done with a dye.



No, stained wood can be oiled but staining must be done prior to any sealing or filling. The first coat of finish or the sealer is the critical step here. It is easy to reactivate the stain with an oil finish and smear it around creating a blotchy looking finish.



Alder will be easier to finish no matter what as it is a closed pore wood and requires no filling. Ash by contrast has large open grain and if a smooth surface is desired will require a good bit of filling.



Forget it on a guitar. Tried that one once a long time ago. It wears away quickly, looks dirty quickly and is difficult to clean and polish and as a bonus leaves the wood contaminated so no other finish will ever stick.

_________________
Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

Finishing is the most difficult part of building, and you've gotten some good advice.
I didn't see any recommendations for French Polish, it's a hand applied shellac finish that doesn't require spray equipment and is nontoxic. Brian can tell you whatever you need to know about FP, our any other finish for that matter.
I've done mostly TruOil finishes, so if you decide to use that, I'll post my schedule.

The most important part of a good finish happens BEFORE you put anything on the wood. Surface preparation is the key to a good finish.

_________________
A man hears what he wants to hear, and disreguards the rest. Paul Simon

Thanks Brian and Rodger. Brian, I appreciate the note of caution you sound regarding grain highlighting . I am well aware that I have zero experience with this sort of thing, and I will definitely be taking the advice I got from both Patrick and Freeman about practising on offcuts. But I refer you to your own signature . I'm looking at spending close to £1000 when all is said and done, so once I've bought the body I'll have plenty of time to practise and research and make sure I get it right before I can afford to buy the neck and hardware.

On the question of "smooth", perhaps it's the wrong word. Probably matte or satin would be better. Perhaps my use of smooth is a result of my only having really experienced low-end gloss or lacquer finishes which can tend to be slightly "sticky". I certainly wouldn't want to end up with anything remotely "glassy". The gloss finish shown here is about as glossy/glassy as I would want to get:

http://www.warmoth.com/Guitar/Body/Fini ... ClearGloss

...but I don't know that I would even want to go that far.

Rodger, please by all means post your schedule for TruOil, and if you have any examples of the result then so much the better . I was under the impression that FP was a technique best suited to acoustic guitars, but I am as ever open to correction. As for preparation, see my comment above: I'll be sanding just to kill time!

Cheers,

R

Here's a pretty good thread about TruOil, with some photos.
viewtopic.php?f=10101&t=43958
another good thread with photos.
viewtopic.php?f=10123&t=44107

Here's one I did with TruOil.

_________________
A man hears what he wants to hear, and disreguards the rest. Paul Simon

Richard, The warmoth link you posted is a full gloss finish. It will definitely have that piano gloss look in person.

As to french polish, it is a suitable finish for any guitar. Or anything made of wood for that matter. But it is a labor intensive process to get right and as far as I know can not be successfully done in anything other than high gloss.

_________________
Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

It's been a while since I used an aniline stain or whatever the current tech is, but if I recall right, you should seal the wood before staining to prevent endgrain from soaking up too much dye and turning too dark, among other reasons, no?

Staining or dyeing needs to be done on bare wood. Proper prep sanding will help keep endgrain from getting too dark.

_________________
Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/