Finishing by hand...what to use?

gratay · Post by **gratay** » Mon Sep 22, 2008 3:10 pm

thanks kim..do you buy sheets or use the soft touch pads?
I found this guy in australia...has anyone bought from him?
http://www.activeabrasives.com.au/home. ... n=0&page=3

I don't know if thats a good price or not..

Kim · Post by **Kim** » Mon Sep 22, 2008 3:52 pm

gratay wrote:thanks kim..do you buy sheets or use the soft touch pads?
I found this guy in australia...has anyone bought from him?
http://www.activeabrasives.com.au/home. ... n=0&page=3

I don't know if thats a good price or not..

Grant

I buy the 6" x 3" sheets, others prefer the pads. I have a firm foam block and get good wear from a sheet. A tip with this stuff is to not rub too fast and hard, the heat will cause the cloth to glaze and it shortens the life dramatically.

As for price, the guy you link to seems fairly reasonable especially when you consider that when I first started using MM about 4 years ago, a local company quoted me around $50au for one "polishing" kit. I thought at that price this kit would be something special like the one micro mesh does for airplane windshield repairs which includes all the grits a liquid polishing compounds and foam backing blocks etc.

This polishing kit was special all right, when I enquired it turn out to be only 5 sheet being the 3600, 4000, 6000, 8000 and 12000 grits, if you wanted the 1500, 1800, 2400, and 3200 grits that was another kit called the "preparation" kit and they want another $30au for that,,,,I of course told them to go and make love.

Cheers

Kim

gratay · Post by **gratay** » Tue Oct 28, 2008 9:37 am

finished prepping the guitar for finishing and making my bridge....although I've read that to get a good finish result with tru-oil you should get the bare wood to a natural gloss ..so i might continue with finer grits.

anyway
Just about to start the finish and have been doing a lot of reading about how to go about it..

I've decided on Z-poxy and tru-oil and I'm wondering about a few things that maybe some of you could shed some light on.?

I was thinking of just using a washcoat of 50/50 Z-poxy/DA on the soundboard rather than shellac ..only reason really is I already have the Z-poxy.
Would there be any reason to not use the Z-poxy on the soundboard..?
I know it doesn't need the pores filled but
I feel maybe its a good idea seeing as the tru-oil may dampen without some sort of sealer under it.?
what do you guys think?

also does anyone know where to get DA..? is it anything like shellite or mineral spirit? or can I thin a Z-poxy washcoat with anything else.

cheers grant

Paul B · Post by **Paul B** » Tue Oct 28, 2008 10:48 am

DA is just denatured alcohol, is it not? Metho.

hilo_kawika · Post by **hilo_kawika** » Tue Oct 28, 2008 11:24 am

I have French polished about 20 instruments. It's a beautiful finish and in principle straightforward to apply. And it looks more and more beautiful as you put more of it on. So much for the good news.

From a business standpoint, this stuff is a nightmare. It takes forever for it to harden (that is to the point where a velour lining in a case won't make little holes in it) and about 5% of my customers have something in their perspiration which reacts with and removes the shellac, causing warantee nightmares. I had three instruments go back and forth to Japan twice for this reason.

So I've switched to Tru-oil which seems to have its own issues...

Those whom the gods would destroy they first cause to perfect finishing.

aloha,

Dave Hurd

kiwigeo · Post by **kiwigeo** » Tue Oct 28, 2008 11:35 am

Grant what youre after is technical grade or IMS meths. The stuff you get from Mitre 10 is denatured and contains a certain amount of water. The IMS stuff doesnt have the water in it and isnt denatured. I get mine from a furniture restoration joint here in Adelaide.

IMS grade meths discussed at length here:

http://www.woodworkforums.com.au/showth ... 41&t=51789

jeffhigh · Post by **jeffhigh** » Tue Oct 28, 2008 11:53 am

Gratay,
If you are going to tru-oil the soundboard, I would recommend the Birchwood casey "Sealer and Filler" as the prime coat.
Stops too much absorbtion/ colouring.
Was able to scrape back to clear wood for the bridge very easily too.
Jeff

sebastiaan56 · Post by **sebastiaan56** » Tue Oct 28, 2008 12:14 pm

Paul B wrote:DA is just denatured alcohol, is it not? Metho.

Most metho has 5% water in it, check the label. Dunno why, maybe for flammability reasons? I buy 100% from a car finishing supplies place in Penrith. $15 for 1L can, cheaper than Vodka!

jeffhigh · Post by **jeffhigh** » Tue Oct 28, 2008 12:49 pm

You can finish completely with oil too

http://www.ukulelecosmos.com/phpBB2/vie ... php?t=8120

Using the slurry sanding method for pore fill.

This guy used danish oil for the basecoats but I have used tru-oil with a few drops of turps to keep it wet.

Craig · Post by **Craig** » Tue Oct 28, 2008 1:58 pm

I think I'm correct in saying 100% Alcohol will absorb water from the atmosphere once it's opened anyways. Meths from the store is 95% which is what the 100% stuff ends up . Could our resident scientist, Paul confirm this ?

Paul B · Post by **Paul B** » Tue Oct 28, 2008 2:06 pm

It has about 5% water in it because ethanol forms an azeotrope with water at around 95%:5%. It can't be distilled to a higher purity than that.

If you buy 100% Ethanol it means they had to break the azeotrope, usually using Benzene, so I wouldn't go drinking it as it will generally still have around 5ppm of Benzene in it. Benzene causes blood disorders, leukemia, and other cancers. Also, 100% Ethanol doesn't taste very nice, don't ask me how I know

Chem student parties...sheesh

If you leave the bottle of 100% Ethanol open for very long - or just keep opening and closing the bottle during general use, it will quickly absorb water from the atmosphere until it re-attains the 95:5 ratio.

In the laboratory to keep ethanol dry we have to add molecular sieve (a granular drying agent) or it doesn't stay at 100% for very long.

There, more than you ever wanted to know about Ethanol.

sebastiaan56 · Post by **sebastiaan56** » Tue Oct 28, 2008 3:33 pm

Thanks Paul,

So for those who have a tin of this stuff maturing in the cellar any suggestions to improve the shelf life? and is this why my G&T seems to get more insipid as a empty the glass?

Paul B · Post by **Paul B** » Tue Oct 28, 2008 4:59 pm

Another interesting thing about Ethanol; if you take 100ml of water and 100ml of ethanol, and add them together, the combined volume will be less than 200ml. It has to do with how the molecules pack together. Pretty cool huh?

Ok, now I'm just being a geek.

kiwigeo · Post by **kiwigeo** » Tue Oct 28, 2008 6:11 pm

Keep the cap on the bottle and dont stock pile the stuff. I buy a couple of bottles at a time and if the bottle doesnt get cracked after a few months it gets relegated to window cleaning duty.

If as Paul says the stuff has benzene in it then keep it off your hands. Ive been merrily french polishing with bare hands for a couple of years now.

sebastiaan56 wrote:Thanks Paul,

So for those who have a tin of this stuff maturing in the cellar any suggestions to improve the shelf life? and is this why my G&T seems to get more insipid as a empty the glass?

Paul B · Post by **Paul B** » Tue Oct 28, 2008 7:25 pm

Another thing to do (we buy 20L drums of 100% Ethanol for the lab) is to use a "working bottle". You just decant what you expect you'll need for a specific task into your working bottle and leave your main supply untouched as much as you can, keeps it fresher longer.

Oh, and Martin, not a lot of Benzene in it, just around about the time weighted PEL (permissible exposure limit), bad news if you drink the stuff all the time, but I wouldn't worry about getting it on your hands occasionally.

gratay · Post by **gratay** » Tue Oct 28, 2008 8:20 pm

thanks for all the info guys..
I've googling my eyes cross and the 100%IMS methylated spirit isn't easy to come across.

I found these guys ..who say they're product is 100% ...There is an outlet near me so I'll go and see them tomorrow..
here's a link for anyone else looking

http://www.haymespaint.com.au/haymes/main.php?c=471

Here's a quote from Ubeaut courtisey of the link Martin posted. Thanks for that.

"To test metho for water content take out a little of the meths from the bottle and add a good dollop of mineral turps then shake (the bottle not you). If it stays crystal clear it is fine for shellac, if it goes cloudy (even a little) it contains more than a little water and really isn't suitable for shellac, if it goes milky it has way too much water and is probably only good for cleaning windows."

I will try this test first..

JeffHigh, I was reading about the birchwood casey sealer and have heard its a thickened version of the tru-oil? I'm not sure but if it is would it soak into the soft top...I'm using cedar so I'm wondering if this product is a good idea or not?

Does anyone think a washcoat or full strength of Z-poxy be a good way to go on the top?

cheers thanks a million everyone.

Craig · Post by **Craig** » Tue Oct 28, 2008 8:22 pm

jeffhigh wrote: If you are going to tru-oil the soundboard, I would recommend the Birchwood casey "Sealer and Filler" as the prime coat.
Stops too much absorbtion/ colouring
Jeff

Jeff, where did you get hold of the sealer ? and thanks for the turps tip . I wasn't sure what the solvent was .

Cheers

Bob Connor · Post by **Bob Connor** » Tue Oct 28, 2008 8:36 pm

I get it from Haymes Grant. Make sure you ask for the %100 stuff 'cause they stock both.

kiwigeo · Post by **kiwigeo** » Tue Oct 28, 2008 8:57 pm

Only if you want to pop the grain. You could try using egg whites as a seizing agent as Colin does.

I dont bother with Zpoxy on my spruce tops....I french polish them all the way.

gratay wrote:
Does anyone think a washcoat or full strength of Z-poxy be a good way to go on the top?

cheers thanks a million everyone.

WaddyT · Post by **WaddyT** » Wed Oct 29, 2008 12:33 am

Martin, I think that would be a "sizing" agent. A seizing agent might stop all vibrations!

Sam Price · Post by **Sam Price** » Wed Oct 29, 2008 6:37 am

kiwigeo wrote:Only if you want to pop the grain. You could try using egg whites as a seizing agent as Colin does.

Just a word about egg whites...some egg whites have a bit of tint in them-even when separated properly from the yolk... so test before applying to lighter coloured woods. My Oregon Myrtle OM had to be sanded back after it started looking like it had been sitting in a smoky pub for a year.

kiwigeo · Post by **kiwigeo** » Wed Oct 29, 2008 8:47 am

Sam,

I suspect smokey coloured eggs are a phenomenon perculiar to Wales. I believe foxes are a big problem in Wales and as a result people there often take their chooks with them when they head off down to the local for a pint.

Sam Price wrote:
Just a word about egg whites...some egg whites have a bit of tint in them-even when separated properly from the yolk... so test before applying to lighter coloured woods. My Oregon Myrtle OM had to be sanded back after it started looking like it had been sitting in a smoky pub for a year.

jeffhigh · Post by **jeffhigh** » Wed Oct 29, 2008 9:46 am

I got the "sealer and filler" from these guys

http://www.magnumsports.com.au/product. ... t=0&page=1

Despite having "filler" in the title it is actually quite thin viscosity and clear not at all like the tru oil itself. Can't imagine it filling deep pores readily.
I have used it on lutz spruce, redwood and Celery top pine so far.
Not really needed on the darker hardwoods

sebastiaan56 · Post by **sebastiaan56** » Wed Oct 29, 2008 12:26 pm

Paul B wrote:Another interesting thing about Ethanol; if you take 100ml of water and 100ml of ethanol, and add them together, the combined volume will be less than 200ml. It has to do with how the molecules pack together. Pretty cool huh?

Ok, now I'm just being a geek.

So let me see if I understand this correctly. I order a Gin and Tonic, the gin is 12ml and the tonic 150ml the combined drink is not 162ml?!? I know Gin is only 40% ethanol but I cant help feeling like Im being ripped off. Similarly a CC on ice.......

Now Im just being a wino......

Paul B · Post by **Paul B** » Wed Oct 29, 2008 12:29 pm

Ask for a double, problem solved...

Australian/New Zealand Luthiers Forum

Finishing by hand...what to use?

Who is online