Jump to content

Custom Guitar Build - First time build


Recommended Posts

Wipe-on poly: I was also looking at wipe-on poly’s and found that the chemical ingredients don’t mention that they contain urethane. They seem to list a bunch of thinners. See below the ingredients for Minwax and Watco’s wipe on poly. Not sure what I’m missing here. 

Watco:

FF960A82-9B4B-43FD-AF5E-B981C809F033.thumb.png.9531062471b6bb6c9eca7dc5d440a286.png

Minwax:

7BEEE570-3FF8-453C-84F0-2A503791D925.thumb.png.7ba855e6c86473b5203b98d0a9f9530f.png

Link to comment
Share on other sites

I've used Minwax wipe-on poly before, both the satin and gloss varieties. They both work well and are easy to apply with a clean, soft lint-free rag. The trick to it is more about working out how best to apply the finish so that it doesn't leave behind streak marks or runs.

Is there a reason why you're specifically interested in urethane?

  • Like 1
Link to comment
Share on other sites

6 minutes ago, curtisa said:

Is there a reason why you're specifically interested in urethane?

So I assumed that urethane would be required to make the product polyurethane, but I couldn’t spot it in the ingredient list for these products. Unlike these two, the PU finish I bought locally says that it contains Urethan Alkyd Resin (see pictured below). 
 

62959A6A-CB56-4245-9AF3-762A5F340926.thumb.jpeg.6b132b186d152e8e7843393cec98df2b.jpeg


My objective was to use danish oil to get a nice colour into the wood and penetrative protection, and then apply poly over it to get more protection and a glossier top coat. I’ve now applied 4 coats of Danish and was planning to move on to Poly or a mix of danish and Poly for the top coat.

This is my first wood working project and I have no experience in these matters. Hence the many questions!

Link to comment
Share on other sites

4 hours ago, Armaan said:

the chemical ingredients don’t mention that they contain urethane.

As you said they list a bunch of thinners or vapourizing agents making the product dry faster. Looking closely the percentages they don't come even closely to 100%. Does that mean that the main ingredient isn't harmful so it need not be listed? The Berger stuff tells that the main ingredient is Urethane Alkyd Resin and as it shows in the table it has no CAS registry number (which is for quickly identifying chemicals worldwide). It looks like Watco and Berger contain more of the "real thing" than Minwax. Thinners like Mineral Turpentine are very cheap so I guess Minwax makes a good profit with their ready mixed stuff!

Here's some info about making your own wipe-on poly:

As you see, the "secret formula" is even simpler than the Danish Oil!

  • Like 1
Link to comment
Share on other sites

26 minutes ago, Bizman62 said:

It looks like Watco and Berger contain more of the "real thing" than Minwax. Thinners like Mineral Turpentine are very cheap so I guess Minwax makes a good profit with their ready mixed stuff!

Seems to be the case. I’m planning to thin the Berger Poly with mineral spirits and give it a go. Let’s see how it turns out. 

Btw I was watching this exact video this morning! Plus some videos by Highline guitars and Brad Asgove - I usually find their videos to be quite informative. 

Link to comment
Share on other sites

3 hours ago, Armaan said:

This is my first wood working project and I have no experience in these matters. Hence the many questions!

Understood. If it were me undertaking a first-time project I'd probably just choose a product based on the directions on the can, rather than try to blend my own mixture by combining different products. At a basic level that means if you want to try a wipe-on poly, buy a tin of pre-mixed wipe-on poly. If the directions indicate it can be thinned with a particular product, then only use that thinning agent. Keep things simple for starters. 

  • Like 1
Link to comment
Share on other sites

Also, just to be sure, I could just use turpentine to thin the Berger poly right instead of mineral spirits? I believe these are interchangeable solvents/thinners?

The Berger ingredients list “mineral turpentine oil” as an ingredient which I understand is the same as mineral spirits. 

Link to comment
Share on other sites

Mineral spirits is a generic catch-all term to describe a broad range of petro-chemicals and solvents. It means different things to different people in different countries, so it's not necessarily safe to assume that a bottle of something labelled as 'mineral spirits' you can get from the hardware store is the same thing Berger, Minwax or Watco state can be used to thin their products, particularly if those products are imported from different places.

  • Like 1
Link to comment
Share on other sites

2 minutes ago, curtisa said:

Understood. If it were me undertaking a first-time project I'd probably just choose a product based on the directions on the can, rather than try to blend my own mixture by combining different products. At a basic level that means if you want to try a wipe-on poly, buy a tin of pre-mixed wipe-on poly. If the directions indicate it can be thinned with a particular product, then only use that thinning agent. Keep things simple for starters. 

This makes sense and I’ve tried to follow this as far as possible. But unfortunately, if I were to try to buy wipe on poly in India, it would cost me over 10 times as much as the Berger poly I bought 😂 

Difficult to find properly stocked hardware stores and to find people who know the answers to the questions I’m asking. Which is why this thread gets such a steady supply...

Link to comment
Share on other sites

In that case I'd be guided by whatever the manufacturer says their product can be thinned with and the ratios to which they can be mixed, rather than try and guess. Check with them first - maybe printed on the tin, the product page on their website or send them an email. Deciphering the MSDS can be a bit hit and miss, and that's not what an MSDS is really meant for anyway.

  • Like 1
Link to comment
Share on other sites

The manufacturers often recommend to use a minimum amount of thinner. However, that's not stone carved as this article (which has been referred to in the PG tutorials as well) tells: https://www.popularwoodworking.com/finishing/you-can-add-all-the-thinner-you-want/

In my understanding "Mineral Turpentine Oil" is the same stuff that's on the video where it says "Mineral Spirits" on the can, There's also "Pine Turpentine (Oil)" which can be used instead - actually the word "Turpentine" originally comes from Greek "Terebinthine" which means "Resin" that's sourced from living trees. Pine Turpentine is a side product of cellulose industry.

Mineral Turpentine acts and can be used similarly to Pine Turps which is why they can carry the same name. However as it has a low flash point it should not be used to thin linen oil paints because of the autoignition feature of linen oil.

The Berger GP Thinner is just that, 100% MTO (Mineral Turpentine Oil).

The Wikipedia article shows some interesting CAS codes when compared to the MSD sheets: https://en.wikipedia.org/wiki/White_spirit

 

  • Like 1
Link to comment
Share on other sites

1 hour ago, curtisa said:

In that case I'd be guided by whatever the manufacturer says their product can be thinned with and the ratios to which they can be mixed, rather than try and guess.

A local dealer said it would be fine. Checking with the company as well. 

Link to comment
Share on other sites

@Bizman62 I agree with what you’re saying. It should not matter how much thinner you use, as its purpose is only to thin the poly and will evaporate after application. I guess more thinner would simply mean more coats are needed to achieve the same build up. 

I’ve got artists turpentine, which appears to be the pine turpentine you mentioned. 

Let me give it a go🤞

Link to comment
Share on other sites

@Bizman62 The solution for drilling the holes in the knobs worked well. Made two pieces of wood with triangular cut outs to hold the knob in place in the vise, rounded them off with sandpaper to fit the curve of the knob and placed a piece of wood below them to keep it stable in the vise. The Brad point drill bit kept the hole straight and I used the dentist drill to expand the holes to the right size. The knobs can now be pressed on to the pots. 

E9AD1112-5AC5-4D6B-BEE6-FC6078FD4F14.thumb.jpeg.bc102ddb888ec5b942c2667c7540694a.jpeg829182EE-3110-41FD-AB1E-C6EE3FA6E13A.thumb.jpeg.efdb458aa5b89e2d221fecb22d680332.jpeg

  • Like 2
Link to comment
Share on other sites

@Bizman62 @curtisa So the poly mixed well with the turpentine and applied nicely to my offcut. I’ve now applied two coats to the guitar, which dried quite quickly - around 2-3 hours. I left it to dry overnight to be safe anyway. The mix was around 60/40 of poly/turpentine. I sanded between the coats using 2000 grit sandpaper (I should have probably used 600?). 

For the final coats, Im planning on thinning it further - maybe 40/60, to try and get a smooth finish. The current mix applies easily with a rag, but I feel a thinner mix will form a nice even surface easier. Does that make sense?

Btw I tried using 0000 steel wool to sand and it left strands everywhere! So I moved to sandpaper. 

  • Like 1
Link to comment
Share on other sites

Now that's good news to start the morning with! Those knobs really are pretty and now that you've got them drilled they're also useful.

I guess sandpaper is a better choice as steel wool tends to wear and leave tiny bits of steel everywhere which can make the surface look dirty - even more if they start to rust due to humid weather or such! If 2000 grit levels the surface without scratches it's a good grit, there's no stone carved rules. What works with you is good.

A thinner mix for the final coats is common practice.

  • Like 1
Link to comment
Share on other sites

How long should I wait after the last coat of poly before I polish with wax?

The poly should air cure within 24 hours, but I understand that it may take longer to fully chemically cure. I’ve seen people online recommending 7 days to 30 days between the poly and wax. Is that overkill? I would think it should be fine to wax after the surface hardens fully.

I’m planning to wait 72 hours. 

Link to comment
Share on other sites

I'd wait for at least for a couple of weeks. Much longer if the conditions are moist! For what I've understood the humidity over there is very high at the moment so I'd wait at least a month, rather longer.

Just so you know, crackling is made by applying another coat (often of another colour or finish) before the base layer has thoroughly dried. It's possible that wax would act similarly on semi-dry poly. If only the wax cracles, that can easily be buffed. But if the wax draws crack lines on the poly, you'd be sorry you didn't wait!

  • Like 1
Link to comment
Share on other sites

8 hours ago, Bizman62 said:

Just so you know, crackling is made by applying another coat (often of another colour or finish) before the base layer has thoroughly dried. It's possible that wax would act similarly on semi-dry poly. If only the wax cracles, that can easily be buffed. But if the wax draws crack lines on the poly, you'd be sorry you didn't wait!

Ah, did not know about crackling. Will wait then. As a test, I applied wax yesterday to a bookmark I made using an offcut from my neck - it has the same number of danish and poly coats on it. It hasn’t cracked overnight, but I’ll wait and watch to be safe. 

Link to comment
Share on other sites

To be honest I don't know if threre'd be any crackling under any circumstances with the finish you've chosen but better safe than sorry. Letting the finished guitar rest a longer period is common practice.

That said, I've seen videos where the Master Luthier applied one or two layers of a Danish/TruOil type finish and waxed it immediately when it was dry. It was a challenge build, he was trying to build a guitar in a given number of hours, hence the rush. A friend who used to work there told that the "built in a day" guitars were then almost totally rebuilt and refinished before they were delivered to a happy winner. Agreed, they were playable and solid at the end of the challenge but they couldn't be delivered as a master built quality instrument before letting the guitar settle down to reveal all potential issues like warping or shrinking - or the finish peeling off.

  • Like 1
Link to comment
Share on other sites

Electricals: First time soldering today. Burnt my fingers with the soldering iron, so that was not fun ... 😂

I followed the wiring diagrams that came with the Seymour Duncan’s and theoretically the wiring should work. I’m one cable short (the bridge ground wire) and will do a test tomorrow once that’s put in. In hindsight, I should’ve made the wiring harness outside the guitar and tested it first, but I’ve already installed the pickups and the jack and soldered it all together. 

Also placed some metal washers between the pots and the body, so that they don’t sit so tall on the front of the guitar. Could that cause noise and require additional grounding?
 

B79734E2-9356-404B-B971-B41B8B3C9923.thumb.jpeg.334258ea45d123f812a9953a9a86ccf2.jpeg5BEC7C81-ADE3-47F7-A537-F7823A4E45AB.thumb.jpeg.3dcaff11a1882e8c731a493e5172c9cd.jpeg

Link to comment
Share on other sites

3 hours ago, Armaan said:

Also placed some metal washers between the pots and the body, so that they don’t sit so tall on the front of the guitar. Could that cause noise and require additional grounding?

No, that shouldn't have any effect at all, noise wise.

SR

  • Like 1
Link to comment
Share on other sites

4 hours ago, Armaan said:

Also placed some metal washers between the pots and the body, so that they don’t sit so tall on the front of the guitar. Could that cause noise and require additional grounding?

What @ScottR said. The washers are metal so it's all metal to metal contact from the copper shield to the pots.

Your wiring looks quite neat, by the way! The solder joints look solid and clean, not bad for a first-timer.

  • Like 1
Link to comment
Share on other sites

10 minutes ago, Bizman62 said:

Your wiring looks quite neat, by the way! The solder joints look solid and clean, not bad for a first-timer.

So a part of this was pre-wired and came with the pots. I’ve had to solder the pickup wires, connection to the jack and the ground wires.

Btw, burnt my other hand a few minutes ago soldering the bridge wire. Fun times ... 😂

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...