Stabilising surface of wood to carve into.

[Wal]

Hi all.

I'm doing a few test cuts where I'm carving simple letter-forms into Ziricote using a 0.5mm end mill and cutting to a depth of 0.75mm before filling the resulting channels with glue/resin to make them legible.

Here's an example:

As luck would have it - that was a reasonably successful effort, but on smaller typography where there are tiny islands of wood (like the inside of the A) - or long sharp corners (M's N's etc.) there's a constant danger of tear-out, which is what happened here:

(Point of a cocktail stick for reference :lol: )

There's a brief video of the cutting process here:

YouTube link

If this were a one or two-off object I'd probably cut as normal (expecting a bit of tear-out) fill any resultant tear-out with a resin mixed with dust particles from the wood, and then re-cut the repaired sections relying on the resin to hold everything together.

The problem is that if the project goes ahead I'll need to make around 60 off, in batches, where I can't really afford the time to have my router sat doing nothing whilst I fill the problem areas and allow the resin to cure in situ before re-cutting.

So - Is there an elegant/clever way to stabilise the surface of the wood (up to a depth of 1mm) to eliminate this kind of tear-out? I've heard of Cactus Juice et al - but when I've seen it used in the past (from where I was standing) it appeared to be a waste of time - furthermore, it's not recommended for close-grained or oily woods - Ziricote falls into both of those categories..! - maybe it's close grained nature means that I'm asking the impossible and just need to bite the bullet when the time comes and repair what needs repairing...

Thanks for reading this far - any suggestions..?

Wal.

 

[Trevanion]

You could try painting the surface with wood hardener, not 100% it would work for what you're doing but it definitely hardens up the surface of softer woods and rot.

A pointed mill instead of a square one would help quite a bit, but not sure you'd find one that's 1/2mm in size.

Have you tried putting some tape like masking tape over it before cutting? sometimes that's enough to stop tearout.

 

[Wal]

Thanks Trevanion

>Have you tried putting some tape like masking tape over it before cutting? sometimes that's enough to stop tearout.

I may give that a go - but I reckon with this size of cutter the adhesive on the tape and the way the flutes will clog may be an issue - ie. pushing un-cleared debris against weak spots.

>A pointed mill instead of a square one would help quite a bit, but not sure you'd find one that's 1/2mm in size.

Hmm - you've given me an idea there. I can get hold of 0.5mm diameter ball-nose end-mills - they'd help to minimise tear-out from the base of the cut by giving thinner sections a wider stance - wouldn't make much difference to tear-out occurring halfway up the wall of the cut, though. Probably worth using a micro ball-nose as a matter of course for this kind of cut, though.

EDIT - found this too:

Might be worth a punt - not sure how wide the taper would be at 0.75mm from the tip...

Ta.

Wal.

 

[profchris]

A couple of wiped on coats of shellac helps when I'm cutting binding channels on musical instruments. It only penetrates a fraction of a mm but seems enough to keep the surface intact, and thus resist splintering below the surface.

I only use hand tools, but luthiers with powered routers have written that shellac helps them when doing this.

 

[Lons]

I'd second the hardener or shellac. I stabilised some punky basswood years ago that I was hand carving, as it was in the round I needed to do it several times as the carving progressed deeper but it turned firewood into usable timber though only hand tools used.

Not sure about the masking tape but always worth a go. I've done quite a lot of "window method" marquetry and tried sellotape, masking tape, brown paper tape etc and all can tear off the fibres if not very careful.

 

[Droogs]

First wipe down with acetone and then flood with Very thin ca glue would do the trick

 

[Wal]

Thanks guys, plenty of options to get going with there.

If I were to use shellac or ca glue, would either of these support a sealing finish? It's probably all a question of chemistry and compatibility, but should I expect a bit of discolouring in the areas of grain that hold the stabilising medium?

Wal.

 

[AJB Temple]

When I used to do inlays in guitars, where I was using a router, I used thermoadhesive tracing paper. You iron it on, and it peels off. It's used in the tailoring and embroidery field. It's not super sticky but it's not messy either. I never found that tape worked. In my case I drew or printed the patterns onto the paper.

 

[Wal]

Just reporting back with some results.

To stabilise I used some Liberon White Polish I've had sat around for a while - I let it stand so that the white sediment settled in the bottle, then used a paint brush to apply it fairly liberally. After drying I gave it a quick buff with some 0000 steel wool (a really smooth surface needed as I use a Stanley blade to push pigmented two part clear epoxy glue down into the channels) and then cut it. I could've just got lucky here, but it seemed to hold up really well with no tear-out to speak of. The R has a small imperfection, but I put that down to not using sufficiently overlapping tool-paths, consequently a little flap of wood remained in the channel. Pretty happy with the results.

Wal.

 

[Suffolkboy]

could you apply West Systems epoxy resin and use a heat gun to thin it and get the wood to take it up? I have done similar with Cedar (which is much more porous than the woods you are using.) The resin goes foamy as you heat it but it dramatically increases how much is absorbed by the wood. You'd need to clean the surface up with fine sandpaper after.

 

[sunnybob]

OK, I'll bite :shock:
What do you do with the finished product? :?:

 

[thetyreman]

I think it's just a test piece sunnybob

 

[custard]

Lovely job, very clean and tidy!

From my small experience working with Ziricote, but my much greater experience of similar timbers like Rosewood and Ebony, I'd suggest any finish isn't really penetrating the surface. So if it's adding stability it's in exactly the same way as laying a layer of masking tape can reduce tear out from a saw cut. Not from penetration as such but more by bonding the surface.

 

[Bm101]

Hi, an internet friend of mine is a knifemaker and he introduced me to this site:
https://www.feinesholz.de/ for blanks. I remember reading on there about stabilised wood that has been pressure treated (I think) with resin.
The stabilised stuff is here:
https://www.feinesholz.de/en/knife-bloc ... ized-wood/
If you click on a particular wood it will give you details on the process.
This link is for Ash Burl included because it describes the process.
https://www.feinesholz.de/en/stabilized ... i0915.html

Hope it helps but I feel you probably know all this already so just in case. It's all quite expensive to buy and to process so won't be much good if you are hoping to prepare it yourself I would guess.
Good luck,very interesting thread. Please feel free to post more if it suits you. I'm fascinated.
Regards
Chris

 

[Wal]

Thanks for your comments guys.

Yep, this is just a test piece using some small ziricote off cuts I have laying around. Hopefully this will turn into making a prototype plinth-type object that makes use of pearl and aluminium wire inlay as well as the resin lettering... and if that's a success then there could be 50 or sixty to make.

The client wants the darkest wood possible. Ebony is just about impossible to get hold of in quantity (say 60 off 100*100*10mm) as is African Blackwood. Wenge is a no from me - haha - I'm dying early as it is..! Ziricote works for me - I thought about using a stain of some sort, but it's not really a viable option as it'll stain the decorative elements along with the wood...

Any other readily available dark wood options out there..? Close grained, oily and water resistant as pre requisite.

Wal.

 

[AJB Temple]

For getting dark wood, you may consider this sacrilege, but old crown green bowls can often be had very cheaply and can be cut up fairly readily with a jig. Old ones are made of lignum vitae and a no.3 size has 124mm diameter. Not sure you would get many 100mm squares out though. The diagonal of the square would be 124, giving sides just over 150mm. So you would get a one at around, 14 and then descending through 10 etc depending on thickness.

 

[MARK.B.]

could you use ebonising spray to darken your wood and then put in the detail before a final polish and buff :?:

 

[Wal]

could you use ebonising spray to darken your wood and then put in the detail before a final polish and buff :?:

Hi Mark. I don't think so, the reason being that once the resin and pearl have been placed I run a surfacer over the lot to clean it up in one pass - I only take about 0.1mm off the top of the wood, but that's probably enough to get rid of anything applied to the surface - especially as the wood is incredibly close grained..!

Wal.

 

[MARK.B.]

Ok,sorry then cant think of anything else.