Top quality wood finishing

[Simpo Two]

I'm building (trying to build) a museum-quality model boat which will be finished in gloss sapele mahogany with brass fittings. It will look amazing, but only if I can get the finish spot on.

The mahogany planking (6x1mm strips) is complete and whilst it looks great so far, the grain is quite open and needs sealing - preferably a sealer with some 'thickness' to fill minor gaps too. After sanding and when the surface is good enough, I'll use aerosol varnish to finish.

Normally I'd use shellac based sanding sealer, but I've seen cellulose based sealer too: https://www.amazon.co.uk/dp/B005Q8567I/?coliid=I2E...

Has anyone used this, and if so would it be better or worse than shellac based? Can't afford any mistakes!

[Big Al.]

Just a suggestion, this thread may be better suited in the Scale Models forum some pretty savvy guys in there.

[scottydoesntknow]

Pics man! Where are the pics

[Aluminati]

scottydoesntknow said:

Pics man! Where are the pics

+1

[singlecoil]

You should use a mahogany grain filler first. Then the cellulose sanding sealer and finally cellulose gloss spray, which after it's hardened (couple of weeks indoors) you can flat with fine grade W&D used wet with a little bit of soap in the water (maybe start with 600 and work you way up to 1500) and then polish with polishing compound.

[mikeiow]

Big Al. said:

Just a suggestion, this thread may be better suited in the Scale Models forum some pretty savvy guys in there.

We have a scale models forum? Cool!
My ‘skills’ would bring Cuprinol or a bit of Osmo to the table.....he’s right, better off in the right forum

[Simpo Two]

Thanks guys - I'll try to take some decent photos soon and post them.

Like any wooden model, especially scratch-built, you start with a theoretical maximum score of 100%, and the challenge is to try not to lose too many before you finish...!

[Evangelion]

When I had to grain fill a guitar body recently I used Johnson's Klear (yep, still got some!). Naturally, being water-thin it needed lots of coats. After a quick sand down I sprayed the top coat on (ordinary aerosol from Halfords) and the finish ended up so good it didn't even need polishing.

I'm going to try french polishing the next one though.

[singlecoil]

Solid grain filler works better, Rustins make it in various colours.

[Simpo Two]

Thanks - I'm a bit wary of grain filler because if the shade isn't totally perfect it says 'Hey look at me I'm grain filler!' afterwards.

The shellac-based sanding sealer has a bit of thickness to it but I'm not sure about the cellulose one. I might be better off sticking to what I know... because if I wreck it it will wrecked...

[singlecoil]

Simpo Two said:

Thanks - I'm a bit wary of grain filler because if the shade isn't totally perfect it says 'Hey look at me I'm grain filler!' afterwards.

No, it doesn't.

[Simpo Two]

singlecoil said:

No, it doesn't.

Well it looks like I shall have to use some. I have a small tin of Rustin's mahogany-flavoured grain filler but it's 10+ years old and really stodgy with a layer of liquid on top; I can barely push a spatula in. It would be pretty impossible to make it malleable enough to use. Do I need a new tin or is there a better make on the market? There are also few tiny areas, like where the gunwales join on that will need a little bit of filling, less than 1mm. Presume it's OK for that too? (Normally I'd just press on but it's taken a lot of hard work to get this far and I really don't want to mess it up!)

[CypSIdders]

I've used Osmo, water based, wood filler for grain filling sapele!
Mix up a bit with some water until you get a thick, creamy, consistency, apply it across the grain, pushing it in with a flexible spreader, I used an old credit card. It dries fairly quickly and sands easily!

[singlecoil]

Osmo stuff is good, I didn't know they did a grain filler as well.

I don't know how well any grain filler would do on a 1mm gap. Usually the best way to deal with gaps that are too large is, if you can't get a perfect match, which is almost certain, then go with a darker filler rather than a light one. If you can get an even gap all the way along then even with a black filler it will look as if it's meant to be there.

[Simpo Two]

Thanks for the info.

Is it this one? https://www.osmouk.com/sitechaptern.cfm?bookid=Pro...

If so it looks like it will fill gaps too... 250ml is called 'putty', 100ml is 'paste', though what the difference is is not explained...

[Murph7355]

Simpo Two said:

Thanks for the info.

Is it this one? https://www.osmouk.com/sitechaptern.cfm?bookid=Pro...

If so it looks like it will fill gaps too... 250ml is called 'putty', 100ml is 'paste', though what the difference is is not explained...

One is in grammes and the other millilitres. I would guess one is "diluted".

I would also think this:

"250g does not shrink or fall out (suitable for ceilings)
250g can easily be sanded at any time after drying"

might give clues as to what the 100ml isn't as good at...?

Osmo make very good products - have only used it on a building but their oils are superb.

[Simpo Two]

Murph7355 said:

One is in grammes and the other millilitres. I would guess one is "diluted".

I would also think this:

"250g does not shrink or fall out (suitable for ceilings)
250g can easily be sanded at any time after drying"

might give clues as to what the 100ml isn't as good at...?

Thanks Murph, good detective work!

It's a pity the website doesn't make this clear or explain the difference. They don't even call the paste grain filler! I might get both, paste for filling grain and the putty for the bigger gaps - that will save making a mess and possibly getting it the wrong consistency.

Edited by Simpo Two on Friday 1st November 10:53

[Simpo Two]

Just to finish this thread - the Osmo paste arrived but it was too pink for sapele mahogany. It was also clear that if I was going to cover the boat 100% with grain filler it I'd be sanding it for about a year. So today I wandered into my local ironmongers and gambled £4 on a tube of Ronseal 'Dark' multipurpose wood filler. It works well. The most obvious cracks are filled and the minute ones can stay for character.

I want to seal the wood before spraying aerosol varnish, so have set up some test pieces with sanding sealer (which I'm familiar with from woodturning) and will see how the aerosol goes on top. And then it will be into the Spraying Booth (well OK a spare bedroom with the radiator on) and then... hopefully a wonder will emerge!