Thread: Bowl sanding mandrels for violin contours ?

Hi Donny, McJing Tools online have them.
Cheers

I think you are making a mistake.

I'v just spent two days carving in yellow cedar which is also soft with distinct differences in hardness between early and late wood.

I suspect that the "deep-ish grain lines" you have in the top is where your sanding has preferentially excavated the soft early wood. I strongly suspect that in attempting to do a sanded Tru-oil® finish you will only make the grain lines worse.
Based on what I've experienced over the past two days, I suggest you scrape the harder wood down to the level of the early wood and apply a film finish like shellac

Originally Posted by ian

I think you are making a mistake.

I'v just spend two days carving in yellow cedar which is also soft with distinct differences in hardness between early and late wood.

I suspect that the "deep-ish grain lines" you have in the top is where your sanding has preferentially excavated the soft early wood. I strongly suspect that in attempting to do a sanded Tru-oil® finish you will only make the grain lines worse.
Based on what I've experienced over the past two days, I suggest you scrape the harder wood down to the level of the early wood and apply a film finish like shellac

Thanks again Ian. I understand the part about the excavated soft wood, and its quite pronounced. Like tram tracks.

Before I started this thread today I was doing what you've recommended using a scraper in heavier 'tracked 'places , and 360 grit alum oxide paper on a stiff sponge all over, being careful not to exert much hand pressure. Its much better, but there a few places where the tracks are deeper than I'd like to try to scrap/sand back level. Just a thing about taking off too much wood, but may have to.

So, I thought if I could fill the tracks with truoil and spruce dust, and have a film of the same over the level areas (rest of the violin), that the tracks would blend and be hidden?

You're saying that will not be so ? Is that because the initial coats of oil slurry will absorb differently where there is more oil and spruce dust laid on (in the tracks) and much less of that mixture on the higher level areas adjacent?

Id like to understand this before I attempt a new way for me of coating the violin . And I have to stain it too as you have previously advised me about. Thank you again.

Based on my experience over the past 2 days, I'm thinking that attempting to fill the "tracks" with a mixture of spruce dust and oil will result in the tracks becoming deeper as the softer early wood will be the source of the dust you are trying to generate.

I think that if you want to fill the "tracks" you will need to use a grain filler.
Some years ago, I used this Wattyl Craftsman Grain Filler
I'm not sure who currently stocks the product

Attacking a violin with any sort of power sander is asking for trouble, if you even slightly change the thickness or profile in any way the instrument will be ruined

Originally Posted by ian

Based on my experience over the past 2 days, I'm thinking that attempting to fill the "tracks" with a mixture of spruce dust and oil will result in the tracks becoming deeper as the softer early wood will be the source of the dust you are trying to generate.

I think that if you want to fill the "tracks" you will need to use a grain filler.
Some years ago, I used this Wattyl Craftsman Grain Filler
I'm not sure who currently stocks the product

OK I can see the problem, which comes from the semi-soft sanding pad on the drill touching into the top of the softer wood, even with light pressure applied. Hmm.
I could try this sanding kit (photo below) from Mc Jing Tools (supplier recommended by Mace above - thankyou) which may act as a block sander of the contours down to level, and I will look into the grain filler you recommend.

I might seem to be overthinking this, but with it having taken me 3 days to get the violin back to bare wood, I don't want to get it (surface prep) wrong, and then with getting the staining even, and the 'whatever' clearcoat on nice too !

Ive just made email contact with Wattyl. The Craftsman product sounds good, although you cant sand it back. It must self level (?). And you can add tint to it from their range.

Ive also asked them if I go that way, could I use Stylwood (clearcoat) over it (spray) as I have some on the shelf, and I also mentioned Rediseal (sanding sealer) which I also have, and both are Wattyl products. I forgot I had both ! LOL.

The Wattyl grain filler I've used doesn't self level. It has to be worked into the pores (your "train tracks") with the excess wiped off before kit dries.
Using it is a fair amount of work, but years ago I saw a guitar with a Douglas Fir top that had been grain filled and then clear finished. It was spectacular.