How best to stain prior to shellac?

[Kalimna]

Greetings folks,
As some of you may have read on my ukulele WIP, I plan to finish using French polish. However, for the second instrument (being completed a couple of steps behind the first one) I would like to up the finishing ante by adding in a colour to the (blonde) shellac in the form of a stain. The stains I have are the rainbow coloured tester pack of Chestnut Spirit Stain.
As is always the advice, I tried out a sample on some maple offcut, using a couple of different colours and another panel with a base coat-then-sanded-back application of black stain (to 'pop' the grain) prior to colour.
Having left the stain to dry overnight, I wiped on a thin shellac coat (premixed, but otherwise similar to the home-dissolved shellac I plan to use for the actual finishing), only to find the stain was lifting and being wiped along with the shellac.
Should I have expected this?
What would be the best way to avoid this, given that I want to use the French polish method?
Should I apply a sealer after the stain coats/washes? If so, would an acrylic based sealer be better, and would the shellac 'stick' to it?

As always, thanks for any help offered,

Cheers,
Adam S

 

[RogerS]

.....
Should I have expected this?

Yes but I too got caught out. It's because you are using the same solvent for both. General advice is to use acrylic and shellac for one or the other but not both.

What would be the best way to avoid this, given that I want to use the French polish method?
Should I apply a sealer after the stain coats/washes? If so, would an acrylic based sealer be better, and would the shellac 'stick' to it?

As always, thanks for any help offered,

Cheers,
Adam S

I can't advise re acryiic based sealers or stains as I have found a way that lets me use solvent stains together with French polishing. I bought one of these from Axminster

http://www.axminster.co.uk/axminster-sg ... uch-up-gun

and use it to spray a light mist coat of diluted shellac over the stain. It dries very quickly and seals the stain. Then proceed with FP but don;t get carried away too quickly in the early stages otherwise you will redissolve everything and be back at square one.

Now having said that you're going to find people saying that you should have a dedicated spray booth/blah/blah/blah but I only ever do relatively small stuff and very infrequently so don't consider this to be a problem. I do use a spray mask. Any overspray consider it a boon as it gently falls on your cast-iron surfaces thus giving them a coat of anti-rust :wink:

One tip that Sgian Dubh (richard) told me was that if you are working with wood that has a lot of cross-grain mixed in (flame mahogany, for example) then a light wash coat prior to staining will prevent over-absorption of the stain in the cross-grain.

 

[marcros]

I have never French polished, just brushed it on. However, I would be nervous of the mist coat if you are new to French polishing- it wouldn't take much to burn through it and get to the stain.

I would use a water based dye. If you have the opportunity to get some, transtint are very good but you will need to import them or find somebody who is going to the USA.

 

[Terry Smart]

Can't fault any of Roger's comments, an alternative to the spray gun would be an aerosol sealer.

Traditionally french polishers would have used an oil based (naphtha) stain and there would have been no problem, but these stains have very poor fade resistance and can take an age to dry.

There should be no problem with the shellac adhering to the acrylic sealer, as always try a test piece first.

 

[Kalimna]

Thanks for the advice folks.
re:the spray gun - at some point in the future I may invest in some spray gear (particular to do lacquer), but for now I am going to keep it as hands-on as I can. As far as using a wash coat to reduce cross-grain spread of the stain, I think it is the opposite (sort of) that I am after, as the maple has a fairly tight ripple/curl figure to it that I wish to accentuate with the initial black dye. Thanks for the advice though

re:transtint - I shall look into that as I have come across it in a couple of youtubes regarding guitar finishing.

I think, then, that for now I shall go with the acrylic sealer and then FP on top. It seems the least likely to cause problems for a beginner.

Cheers all,
Adam

 

[Newbie_Neil]

Hi Adam,

I think, then, that for now I shall go with the acrylic sealer and then FP on top. It seems the least likely to cause problems for a beginner.

It's probably a bit late now but, if you wanted to spend some money, you could have a training day in Glasgow on French Polishing March 7th.

Neil