Doing a Proper Masked Binding

[Gemcutter]

I'm a noob, so before ruining my quilted Tele I'm practicing putting dye on a maple board. I rounded one corner and got it all sanded down with a radius matching that on the Tele body. I masked the edge and figured I was all ready to go. After applying the water-based dye I noted that I got a significant amount of bleed under the tape. I'm using 1/4" Scotch 06301 (as recommended somewhere in the forum) and I'm not getting the desired result. I cleaned the wood with naphtha and let it dry before taping. I used a plastic pen to push down on the tape for a good seal...still have the bleed.

Any tips and tricks will be very welcome.

 

[Cagey]

All wood is fibrous, so depending on the species its wicking ability ranges from that of newsprint to photo stock. What you need to do is seal it. That'll knock most of its wicking ability back, assuming you've grain-filled it (if necessary).

Masking tape is good for most finishing materials because of the finish's viscosity, which is high relative to dyes. Dyes are microscopically thin, so they tend to sneak in anywhere they can. You need essentially an alcohol-tight seal between the wood and the mask to hold back dye, which means the wood surface has to be very smooth and the mask has to be thin and close. That doesn't occur naturally, hence the need for at least a sealer, if not a filler, and some reasonable sanding. 320 grit is usually good enough.

 

[Gemcutter]

Sealer...interesting. I was under the impression that with a maple top, no sealer was necessary, and that it really shouldn't be used if applying a water based dye. So just to be very clear - on maple: sand, apply a sanding sealer, sand again (or not?) covering both the wood I want to dye, and the wood I will mask to prevent dying...then mask and dye.

Again, I'm a noob, so I'm sorry for asking questions that are silly for those who have been finishing for a while, but I really appreciate the wisdom.

 

[Cagey]

Whether or not you seal Maple sorta has to do with what you're trying to accomplish. Maple often doesn't take dye evenly, so sealing it assures an even take-up. You're basically dying the sealer. But, if you're trying to bring out the grain like you would with a quilted/curly piece, then you sometimes dye it dry because you're going to sand most of it off and only leave the absorbed bits. But, those are general guidelines - I've had it both fail and work out well either way.

Also, you have to keep in mind the difference between sealing, sanding sealer, and grain fill. The latter two are rarely needed with Maple.

Think of sealing as waterproofing. Sanding sealer does the same thing, but has some fill ability for finer grains. Grain fill is for aggressive filling like you'd need for Mahogany, Ash, etc. Usually if the wood is coarse enough to require grain filling, it needs to be sealed first to prevent filler shrinkage.

The critical thing for keeping dye from bleeding under your mask is to make the wood non-absorbent, and have a good seal between the mask and the wood. Sealing ends the absorbancy issue, and the proper finish prep and masking tape/film makes for a good seal at their contact point.

Surface prep is everything for a glamour finish, so sand it first to get rid of gross defects, seal it, polish that off and seal it again. Then, mask it and dye the body. Do whatever you have to to get happy with the appearance of the dye, remove the mask, and start shooting clear until hell won't have it.

Sealer is nothing special; it's usually just a thinner version of your topcoats. A 50/50 mix can be used as a "wash coat" or sealer.

 

[Gemcutter]

Exactly the info I needed. Thanks Cagey. I'm off to see what I can do to some other pieces of sacrificial maple boards as I learn the right technique for my quilted Tele.

 

[Cagey]

Finish work is laborious and time-consuming. Practice makes perfect, and saves you a lotta grief. I'm glad to hear you're terrorizing a sacrificial board rather than a body. You'll be much happier in the end.

 

[Gemcutter]

A quick tour of the PRS factory (https://youtu.be/BpeWQ1taxaY) finds that they apply the stain, and then they go back to the router to put on the faux binding edge. Well, those of us without the CNC machines may opt for a little different technique such as that used by Big D Guitars - he makes it look easy. (https://youtu.be/JWInVZUYdhs) It appears as though the water based dye doesn't even try to stick to the sanding sealer. Time to offer up some low grade maple in the name of practice!

 

[stratamania]

@gemcutter, it doesn't say that they take it back to the CNC machine. It goes back to the finish guys to cut the binding. At that stage they have already invested a lot of time in sanding and prep, putting it back in a CNC would in all likelihood put them back several steps.

Now it doesn't say how exactly they do it, but I suspect they are using a technique similar to this video that you can also try.

[youtube]TNbsZsSabPs[/youtube]

 

[Cagey]

That only works with actual binding. He's trying to do a masked binding, like Warmoth does on some of their bodies. There's no actual binding there.

 

[Gemcutter]

I tried a bit of sanding sealer on a portion of a maple board, the water based dye lays right on top of it and won't penetrate. Having done that, there's no doubt in my mind that Big D Guitar's method of applying the lacquer sealer to the faux binding area is the way to go. Any color that may end up on top of the sealed wood can be carefully scraped or sanded off.

[youtube]JWInVZUYdhs[/youtube]

 

[dmraco]

Here was my process, I taped the side off and hand rubbed the first dye....then sanded back.  As Cagey stated there can be some seepage.  I had a small spot and sanded it clean.  I was also very careful not to saturate the rag.

To put on the amber you can either spray or hand apply with rag.  I used dye in denatured alcohol and apples the color being very careful on the edges.  Again making sure the rag is not completely soaked really help. 

I then shot a poly top coat.  I guess the process depend on how you will be applying the finish.  If you are spraying the color or makes things easier.  The use of a sealer really helps too.

Good luck.

 

[stratamania]

That only works with actual binding. He's trying to do a masked binding, like Warmoth does on some of their bodies. There's no actual binding there.

I realise that but then what are PRS cutting ?

 

[bagman67]

I would guess (speculating here) that "cutting" may very well be shorthand for "razor scraping and/or sanding."  I'd be surprised if they take a router to the edge of a freshly dyed body.

 

[Cagey]

If you're referring to the video a few posts back, they're not cutting anything. They tape off to produce a faux binding. The guy mentions "cutting in the binding" early on in the video, but it's a slang term painters use for doing trimwork.

 

[stratamania]

Cutting in within painting (decorating) is using a brush for example to do the corners of a wall or edge prior to using something like a roller.  So does cutting in have a different definition in the US ? Because in that PRS video, the top is already stained and it mentions that it's then going back to have the binding cut in.  So it seems to mean something and if it was masking it would be a little late at that stage.

 

[Cagey]

I think you may be taking his words a little too literally.

 

[stratamania]

Yes Cagey, I suspect we may be.

But of course that's the thing with language, without context or background to what is being done, it could mean several things.

Perhaps we need a forum member to get a job at PRS to find out what they are up to.  :icon_biggrin:

 

[Pelagaard]

You might also want to look into the liquid masking tape that Kuro (I think) mentioned using in several of his builds.

 

[Gemcutter]

[youtube]eC3muvR8s-4[/youtube]

At 4:40, the PRS technician tells you what they mean when they say "cut the binding".

 

[stratamania]

@gemcutter, well done on finding that video.

So in summary,


PRS mask off the mahogany back up to where it meets the maple top.
They do not mask off the side of the maple which becomes the "binding"
The top is carefully stained.
Then the "cut in" is done with sandpaper to accentuate the join of the stained top to that of the "binding"

Easy when you just write it out. Those finish guys are doing this a lot and are skilful in what they do. Definitely worth spending time on scrap as practice.

Anyone know what kind of stains PRS use in terms of water or alcohol based ?