Starting out in guitar building - There will be questions!

BillDL · August 2023

It takes a bit of practice to get into a good swing and dressing the fret ends with a safe-edged triangular file, but once you have the knack it becomes a much less laborious task. I keep meaning to buy one of those slim straight concave files that are simlar to crowning files but are intended to make it quicker and easier to do the bulk of the rounding off by just dipping them over the edges of the frets inline with the fret, but I think I can do just as good a job with my old triangular files and it doesn't take me too long. I often do this while watching TV, because it's mostly a feel thing rather than being visually demanding.

SteveF · August 2023

Interesting. I used a triangular crowning file for the crowning, but a straight safe edged file for the fret ends like in this video:

I wasn't a fan of the concave crowning file I tried.

SteveF · August 2023

I'm quickly learning that there are a million ways to do all of this stuff

SteveF · August 2023

Well I wish I’d seen this before cutting my body out with a jigsaw - genius.

https://youtube.com/shorts/-W7rmLAXClo?si=9699MoaYuEpkWJTS

BillDL · August 2023

I need a new jigsaw, but I only realised this as I was roughing out my last body. The mechanism that grips the blade and then supports it has become looser over the years and ends up steering off-vertical even when the saw is held down hard to the flat surface. I'm glad I left a little bit extra outside the pencil mark so I could square it up. That's a clever jig in the video.

SteveF · September 2023

So, finishing queries. I have watched a couple of different approaches to finishing using nitro aerosols. The question I have surrounds pore filling (which I assume is broadly the same as when grain filling is referred to?)

@SteveRobinson has some great posts and videos on his site and I notice he uses Rustins grain filler, then sanding sealer, then primer, colour and finally clear. He does say that some woods don't need filling.

The Stewmac video series below, the chaps use epoxy to pore fill, then vinyl sealer (presumably similar to sanding sealer) and then colour and clear.

Opinions? I am using poplar/tulipwood for the body so I am not sure what is required in terms of filler?

Thanks as always

WezV · September 2023

Poplar can be very thirsty, so needs a good sealer coat. It doesn't have open pores, so doesn't need grainfiller.

SteveF · September 2023

Wonderful

Thanks Wez

For future reference - any view on rustins/epoxy/something else? I would never have thought to use epoxy - I'd have assumed it would create a plasticky coating that wouldn't be good for paint but they get a fantastic result in that series.

SteveRobinson · September 2023

I'm finishing a poplar body at the moment, no grain/pore filling required but there were several knots that needed attention. It's going to be a solid colour so I used my white primer which allowed me to easily see any imperfections. I filled them with Squadron white putty which is easy to use, dries quickly and sands really smooth. After that I applied another coat of primer before the colour goes on.

SteveF · September 2023

Thanks Steve

I have some of your primer too

I will check over for any dents/knots that need sorting and I have some Rustins 2 part filler I can use for that, then your sanding sealer, primer, LPB colour and clear gloss. Still got to sort out my ferrule block first, but certainly fast approaching the stage of finishing.

SteveF · September 2023

General question that's popped up for future reference rather than this build:

When dimensioning parts, how close do you go to the final desired dimension and how much do you leave for sanding etc. e.g. if you wanted a 45mm body and you thickness the blank, I assume you wouldn't go all the way to 45mm with the router/thicknesser but would leave a small allowance to be taken away when rough and finish sanding so as not to end up smaller than the final dimension in the end? Is there a rule of thumb?

WezV · September 2023

As a very rough concept, what sanding takes away, finishing adds back.

Also, how crucial is body thickness? If it ends up 44 or 46mm will it matter?

BillDL · September 2023

SteveF said:

..... Is there a rule of thumb?

Yes, make sure to move it to the side when using sharp, pointy or dull-thuddy hand and power tools

TTony · September 2023

SteveF said:

Is there a rule of thumb?

Stop just before you go too far.

And what Wez said.

Unless you're trying to make vintage replicas to within fractions of a mm, body thickness isn't a critical dimension.

If you are trying to make vintage replicas, you'll probably find that dimensions of one example differs by more than a few fractions of a mm from another example!

SteveF · September 2023

Thanks all, makes sense. I guess body blank was a poor example - I was more thinking about things that are more specific e.g neck thickness at the nut etc. The guidance about finishing basically replacing what is sanded away helps though.

SteveF · September 2023

Getting there. Brief pause to cobble together a spray station and we're away. Body is all sanded and first coat of sanding sealer is on (picture is before that happened).

Image: https://tfb-user-images.eu-central-1.linodeobjects.com/da4846ae0d58ed0bebf7404caf1f47710b526763d984bef14c

SteveF · September 2023

Sigh.

A temperature drop and a rainy day (presumably, at least from what I can gather from googling) and there’s white patches in my clear coat. Any advice? (Beyond don’t spray on a cold, rainy day - I got that now)

davros · September 2023

Are you spraying nitro? I tend to use MGT nitro and it has anti-bloom thinners in it. Otherwise, a light sand and spray another coat in better weather should release it.

WezV · September 2023

Do a light sand now, spray a light coat on a dry day

SteveF · September 2023

Yes it’s MGT nitro clear gloss over LPB.

I’ve brought it in from the garage to the house to see if it releases when properly dry but it’s been in a couple of hours now and it’s no better - worse if anything.

If it doesn’t improve I’ll wait for a better day and try as you suggest. Dry sand with 600 do the trick?

SteveF · September 2023

Presumably sand until all the white has gone?

WezV · September 2023

Yeah, or even a hard rub with a cloth now... just something to break the surface enough for the moisture to release. Success will depend on how deep the moisture is

SteveRobinson · September 2023

Another light coat should fix it.

WezV · September 2023

SteveF said:

Presumably sand until all the white has gone?

Not necessarily.... it needs to come out, it can be quite deep.

If sanding or a rub down now doesn't clear it, the next coat should, if sprayed light

SteveF · September 2023

Cloth didn’t seem to do too much but a quick rub over with some 600 seemed to sort it I think. It’s supposed to be dry tomorrow afternoon so I’ll give it a light coat then and see how it goes.

SteveF · September 2023

Well, first attempt at wet sanding was disastrous. I think some of it was actually down to my prep not being quite as good as I had perhaps thought. I have a couple of areas where I sanded right through to the primer and some patchy areas that I think is where I have gone through the clear to the colour and therefore there are lighter areas where it's just colour and darker areas where there is some clear still.

Count to ten. Learning process. I think I'm going to go ahead and finish for now and then I think I'll try and respray when I do the next one.

SteveF · October 2023

Managed to sand through completely at the edge here:

Image: https://tfb-user-images.eu-central-1.linodeobjects.com/9a2c72c5bda6fe8c9eaca8857268a4d65b24bbb660bc1147fa

And again here. I think as the light patches appeared I thought they were low spots, so kept sanding. I actually think it's where I had gone through the clear and into the colour coat, so the light patches are where there is colour only. Keep sanding til the low spots disappear... whoops.

Image: https://tfb-user-images.eu-central-1.linodeobjects.com/64a876473d6c44b76368bcab02bda3ee0b9bf4384656a7322f

On the plus side, I kind of like how my heel looks.

Image: https://tfb-user-images.eu-central-1.linodeobjects.com/198cf258a91bbdaf07745c0961b1d52cc822c0cd62b2e5614b

Image: https://tfb-user-images.eu-central-1.linodeobjects.com/2858bd8ddd69e0f66cb3d5e0db93a54bb6d212c84171ffcfaf

More patchiness. Again where I think I have gone through the clear. Also near the ferrule block rout, I had some kind of high spot I think.

Image: https://tfb-user-images.eu-central-1.linodeobjects.com/810b187f2daa6944c98fe23db87ff78921be2f46b2ef097239

A few factors at play here I think. Preparation first of all. I don't think I had sanded nearly as well as I thought I had. Also, poplar seems to be REALLY soft and dings up easily, so more care required in general. Obviously second is my lack of experience with wet sanding. I thought I was being safe by starting at 800, but it was still really easy to go through. I think too much pressure perhaps was a factor too. The large area of sand through on the upper front section was the first area I did. I reduced the pressure after that and it seemed to help a bit.

I figured I would carry on and see what I could get the "good" bits looking like. I did 800, 1200, 1500, then used some autosol and then t-cut and it seems to have come up ok. Not sure if I should have gone even higher with the sandpaper first? I also think I will need some kind of buffer to get much better shine.

I think I am going to get the guitar built, nut cut and see how it plays and then move on to the next project for now. It will need a refinish, but I need to work out how I am going to do my spraying going forward first. My makeshift spray area worked fine for keeping direct spray off everything that it should have, but the garage with no extraction is not ideal - There was a thin film of blue dust over EVERYTHING in there as it had obviously just been in the air. I'm going to still be wiping that off stuff come Christmas!

I'm going to have to do it outside or get some kind of pop up spray booth or something. Having hit October in Glasgow, I don't think I will get string of suitable days to do it for about 6+ months though.

BillDL · October 2023

That's a shame Steve. I had a similar disappointment with a guitar I just finished a few weeks ago, but that was down to the dye continually separating into creamy streaks and being unable to achieve a consistent opacity and shade. I made the best of it and sanded it back to a kind of "beach washed" finish and it came out OK. You're right about the weather though. Even if you managed to install a powerful enough extractor fan and an improvised filter, the air from now until Spring is likely to be either too humid or too cold (condensation) for any guarantee of a decent finish.

I used to have to spray paint industrial machine components and finished parts in an open fronted booth. All they used was relatively cheap double-layer concertina paper filters similar to these that are really just a baffle with offset holes in the front and rear layers to trap the particulates:

https://spcb.co.uk/products/cardboard-spray-booth-filters

You could probably knock up a small booth frame from ordinary lengths of pine and just make a "lip" around the open area for the filter to sit in. The area behind with the extractor fan needs to be enclosed and vented to the outside air though. You could use plastic, aluminium of galvanised flexi-piping for that. You would need a fairly strong fan behind the filter, but I think you could easily get by with a large diameter domestic pedestal fan running at full speed. You would obviously have to be well aware of the potential of a spark from switches or the motor when you are dealing with volatile solvent fumes. A guy down the road from me fixes up motorbikes and has to spray paint them. He has an old and fairly wide perspex half circle shower enclosure that he modified into a spray booth in his Marley lock-up garage, and he uses those paper baffle filters and a large fan ducted through a corrugated flexible drainage pipe.

SteveF · October 2023

Thanks Bill. It is disappointing, but I am fairly sanguine about it. This is my first build and I fully expected there to be some learning experiences. I had expected to have made half a dozen bodies and necks by now

I will work out what to do with the spray booth at some stage. I see plenty of people who seem to get decent results by doing it outside, so it might just be that I need to wait on some decent weather - I am struggling for space as it is. As long as I can get a full day's spraying in without rain etc, then I should be ok. If I have to have gaps between each spraying day it's not the end of the world.

It will come. I am confident that I can learn from the errors and get better as I go on. As long as I have a playable guitar at the end of the first build then I have met my aim (and surpassed my expectations!

)

TTony · October 2023

I remember my early builds, and thinking that I was almost there when I'd finished the woodwork part.

Then I realised that it can take 5x (or more) as long to get the finishing done!

One "experience" was with a no-longer used stain-based finishing kit that didn't turn out how I wanted, so I decided to strip and re-do. But the stain had penetrated into the wood. I ended up taking 1mm off the thickness of the body (with my surfacing bit in the router) to get back to bare wood to be able to start again ...

Finishing is a definite skill!

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Starting out in guitar building - There will be questions!

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