Shellac, tinting and the order of battle

[fender3x]

I have a paulownia body. I know that a lot of the world's paulownia supply is grown in AUS, and is used a lot for surfboards in AUS, but there is not a lot on this board about finishing it. Would be grateful to be pointed at any build diaries or finishing threads.

It is very open grained, and what I can find on finishing it says that the grain needs to be filled. I am wondering how to handle it to get a finish that shows the grain. I have seen that some folks seal open grained woods with shellac. But there does not seem to be agreement about whether to seal with shellac first then stain. Others say stain first, then shellac. What I think I understand is that the latter stains deeper, but risks blotching. The former is less prone to blotching, but does not stain as well.

Does shellac blotch? I have seen nothing about this...

I have also seen references to folks who tint their shellac with water or alcohol soluble dyes. Would that be a good alternative to staining? I would like to go for a reddish, burgundy color that shows grain. Could I get that by tinting my blonde shellac? Or by using garnet shellac?

As you can see I am truly clueless ;-)

[JohnH]

I refinished a mandolin once which used shellac as a sealer over the stain, and then an oil finish over the shellac. It came up really well, though it was so long ago I don't remember any particular details. I do know I got all the advice from the Mandolin cafe forum, as I think it's a not uncommon method for finishing those types of instruments. It might be worth doing a search on their forum to see if anything useful pops up?

https://www.mandolincafe.com/forum/f...ers-and-Repair

[EDIT] I just realised it's the mandolin in my profile pic, so you get a bit of an idea how it came up

[fender3x]

Looks nice. Will check out mandolin cafe ;-) Thanks!

[Simon Barden]

Being as you're US based, I'd suggest using Aqua Coat water-based clear grain filler as it should be fairly low cost for you. Water-based, so you can stain it a dark colour with a water-based dye. Use gloves though! Worked well on my GSJ and GSM builds. Sand down again, Repeat at least once until the surface is nice and flat. I'd then use a spirit-based lighter stain over the top of that (for best penetration). I got a nice even highlighted grain stain on the SGs using that method.

[fender3x]

Thanks, Simon. Aqua Coat is on my radar. I really like the outcome you got on the SGs.

[fender3x]

Simon, I am curious why you chose spirit based rather than water based stain?

[Simon Barden]

1. Because Aqua Coat is water-based, so is less likely to remove some of it when applied.
2. Won't raise the grain like water-based stains will, so no extra sanding is required.
3. Spirit-based stains penetrate that bit further into the wood. Only a bit further, but it all helps get a consistent colour.
4. I feel that they are easier to apply without leaving tide-marks. It's a lot easier to blend any small tide-marks back in than with water-based.

I wouldn't use it if I had any curved binding. I don't know if it's just the Chinese stuff the kits use, but anywhere on the binding with any sort of curve, you get tiny stress cracks forming in the plastic. The sharper the curve, the more cracks you get. Straight binding seems to be OK, e.g. binding on a neck. You can't see the cracks with your eyes. But spirit-based stain is thinner and has a lower surface tension than water-based stain, so whilst water-based stain may find and sit at the top of the very largest cracks, this can normally be scraped off. Spirit-based stain will find every single crack and work its way down to the bottom, of the crack which can be 1-2mm deep in places and can't be removed by scraping. Even masking the binding doesn't guarantee that it won't seep in.

[fender3x]

Thanks! Always good to understand the "whys" of the wise ;-)