Some test results in. I smeared a little of what was left on my applicator (a hotel key-card) onto a paper towel to give an idea of the amount of color lift.
With the first coat it seemed comparable, with maybe a slight edge to the shellac. This was consistent with every application. Shellac side did a bit better on color lift, but not dramatically different. In both cases color lift was manageable.
Both boards were stained with 90% General finishes Dye Stain + 10% General Finishes High Performance Top Coat. Each received 3 coats of stain applied with a foam brush. After 72 hours the top of the board on the right got one coat of 1lb shellac, and the bottom got two coats. They were left to dry an additional 24 before grain filling. Each board received 4 coats of Aqua Coat clear grain filler. applied with a hotel key card.
Looking at the two sample boards, there is not a lot of difference. Certainly not much that shows up in the pic. There are some subtle differences. Subtle enough that I am not sure how real they are. It seems to me that the shellac may have lightened the color just a bit..but if that's true, why can't I tell the difference between one and two coats? With the first couple of coats, it seemed to me that the surface of the non-shellac board felt a bit rougher. I scuff sanded in-between each coat very lightly with 220. It could be that a bit more of the grain filler soaked in to the non-shellac board. I thought that I might need an extra coat of grain filler on the non-shellac board, but by coat four the two boards seem pretty comparable. On a bass body I would do at least one more, and maybe more, coats to make sure the pores were as closed as possible before top coating.
I think you'd be safe doing it either with or without shellac. The shellac may have colored the wood a little, but you'd need the boards side by side to be sure. Shellac may reduce the color pull by a little, but not by much. What you can't see in the pic is that the shellac board is slightly shinier than the stain only board. The latter is sort of mottled or shiny depending where you look. But when I look at the dull spots, they look exactly like a piece I stained that has no filler. The shine is coming either from the filler or from the the shellac, so that may be a difference without a distinction.
So the results of my tests don't give much guidance. If you like to seal with shellac, it won't hurt to do so. If you don't want to use shellac that seems fine. I am not even sure how I am going to proceed, let alone how to advise anyone else.
The only solid finding from my experiments today was serendipitous. The shellac I had left over darkened at test piece of maple I cut from the headstock rather nicely. So, I have made up another 4oz batch that I will surely use on something...
Last edited by fender3x; 10-02-2021 at 10:46 AM.
I'd be interested in seeing Aquacoat on bare timber (like a traditional grain filler) sanded flat then stained. Aquacoat says it can be done that way.
A similar process can be done with shellac as well. (The slurry method I regularly bang on about)
Good effort with the testing too. Keeping track of what's what can do your head in! (at least my head anyway!)
Thanks for reporting.
Making the world a better place; one guitar at a time...
I had a test board like that from an early test, but don't know what I did with it. If I can find it I'll post it.
Probably also worth noting that the dyestain I am using is not exactly like powder dye. It has a little bit of binding agent in it. The added top coat should help it adhere. That said, looking at them in the sunlight this morning I decided I would probably use a coat of shellac in an abundance of caution.
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Here's what it looks like when yo use AquaCoat first, then stain:
Comparing it to the prior attempt: Upper left--stain then AquaCoat, upper right--stain then shellac then AquaCoat, bottom--AquaCoat then stain. All three have three coats of stain (although the manufacturer recommends just one or two).
It's clear that the stain-first is darker. In the pics it looks like the AquaCoat-first board is just stained lighter. In reality it looks mottled. I tried to capture this with a closeup with mixed results...
In real life it looks like there are places where the stain did not really penetrate at all, and other places where it penetrated deeply. This is not necessarily bad, if what you are going for is road worn.
I did not take a pic of my original test, but I did that with AquaCoat first the pure General Finishes Dye Stain (no 10% top coat added). What I remember is that the results were similar, and maybe a tad worse. It could be that the added top coat helped the dye stick to the mottled places so it was not quite as bad. Or it could be that I don't remember perfectly.
I don't have the materials to test this, but I suspect that the AquaCoat-first approach would work fine with a commercial stain or with a gel stain. I don't think I would recommend using it with a deep-penetrating water based dye stain though.
Added a coat of shellac on top of the stain. Next stop, pore filling with Aqua Coat.
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Thanks for the info in your previous post. I appreciate your effort into the research. Beneficial to all.
Doesn't look like it quite lives up to the manufacturer's option of pre-stain application.
Making the world a better place; one guitar at a time...
Not with dye stain, anyway. The stain MFG and users on the internet have mostly suggested using it Aqua Coat over not under.
Here's a vid from the Aqua Coat people. They're also using the same kind of dye stain that I used.
https://www.youtube.com/watch?v=HzRai_1oTic
I have now completed the grain fill. What you seen the pic, in the order of application is three coats of stain, then 3 coats of 1lb shellac, with 4 coats of grain filler on top. 5 coats of grain filler in a few places. may even use a little more as things progress if I see anywhere that it is needed. I don't think the shellac changed the color much, but three coats almost (but not quite) eliminated color lift using the grain filler. In a couple of places i used a little of the red stain with the Aqua Coat to enhance a couple of lighter areas. Mostly I just used it clear, however.
Comments about applying the filler first and then the stain got me to refer back to where I heard about Aqua Coat in the first place: Simon's SG builds: https://www.buildyourownguitar.com.a...t=10423&page=3
He got impressive results attempting a similar color after using the gran fill first, then the spirt based dye stain. As bad as my test results were using water based dye stain, his were good using spirt based stain. Simon used the the transparent grain filler the way most people seem to use opaque filler, and in fact he dyed his filler black.
Aqua Coat does not really feel like any filler I have used before. It feels more like a kind of a gel top coat that you put on with a credit card rather than a brush or pad. As it dries it is in places flat and in others glossy. In consistency it is somewhere between gell and teeny tiny tapioca balls. In the third and fourth coats there were places where it looked a bit cloudy after being worked in, but when it dries it is absolutely transparent, without any yellowing. This stuff "feels" like it is somewhere between a clear coat and a grain filler. The mfg says that it requires at least three coats of top coat to seal, but it is enough like top coat that I have been able to use it for very small top coat repairs. Once sanded and polished it is so transparent that I can't find the repair I did on a maple neck with it.
Now that I have it, I would definitely use it to fill under a solid color, and would be tempted to try it with a non-dye type stain. I am not sure I could justify the expense to buy it new though, unless I wanted it to go over a color.