pore filling

[DaveW]

Hi Guys
i see a few posts regarding pore filling ,well probably more than a few on different woodworking and luthier sites and it seems to me that pore filling doing the traditional french polish method or Robbie Obriens modified version seems to be a "no brainer"its clean ,its non toxic,its easy, its everything one could hope for , well I thought,
shellac and the wood your filling
why would anyone do it any other way
maybe someone could explain to me ??
Dave

[simso]

I use UV.

http://www.mirwa.com.au/Painting.html

[Allen]

What product are you using for the fill? Polyester of some sort?

[ozziebluesman]

Hi Dave,

If you use the pumice powder and metho after a few wash coats of shellac that works great but it is labour intensive. I think the main reason it is popular is that it is non toxic and you are able to fill the pores with the right colour match.

Cheers

Alan

[simso]

Hey allen,

Yes the pore fill itself is a polyester

We use it because its clear, takes about 30 seconds to apply and is dry in about 5 seconds after exposure to the UV lights.

Basically, we can go from a rosewood bare to pore filled ready for paint in about 12 minutes.

Awesome stuff, but to setup properly for painting costs between 5 and 10k dependant on what you use

[Allen]

There are some UV cured automotive products that have been available for several years now. Often enough we get a rep wanting to do a demo, but when they start talking about the cost of fitting out a commercial automotive size spray booth with the lamps, your eyes glaze over with the cost. Interestingly enough, the products are the same as the conventionally catalysed ones, since you have to put that catalyst in it when the UV can't hit hit, such as when you are painting inside door jams, engine compartments etc. as part of an overall respray or part there of.

If it's not a trade secret, what product are you using, and how are you levelling it in a few minutes? Whats the top coat?

[DarwinStrings]

I would like to know what sort of lamp they use, sounds like a fair whack of money for what seems to be just high UV lamps. Some high UV lamps (high enough UV so that at close range they will fry you faster than a hot summer day close to the equator) you can pick up second hand from guys who use them for a while then get paranoid and they end up sitting in a corner of their shed from then on.

Jim

[simso]

No trade secrets, the gel comes from a company called cureuv.com. Shipping is obscene as its shipped hazadous

The lights are very intense, we have a full jacket face shield and long heavy welders jacket, the first time we used it, spent about 5 minutes using it directed away from us with no safety gear on and we ended up with sun burns.

You can only use it for pore filling, if you build too much on the surface it will actually crack.

You also have to be super careful around binding, it will dry the binding out and the binding will crack.

Levelling is done with 220 and a palm sander

I think the Uv will get cheaper as it becomes more used by the big guys, I know taylor/prs use it, maton here in australia have just started using it.

We also have uv paint for the top coats, but I still prefer 2 pack and we use infa red lamps for curing those

[DaveW]

Hi Alan
yes I use the pumice and metho ,Im not sure I agree that its labour intensive as its pretty easy
Ive also used Robbie Obriens method of just of just the wood dust (preferably from endgrain)rubbed in with shellac to bind it ,this works well but I prefer the traditional method .
just the conversations here regarding UV put me off it.
Dave

[ernieman]

Hi there,

I use the pumice (or brown ones for darker wood, not sure what its called) method.
I tend to use a little shellac in the rubbing cloth as well, to make the pumice/wood-dust stick into the pores. Always worked for me. It's pretty traditional, but a little labor intensive. You pretty much need a good bit of elbow grease for this
Friends of mine have used "chemical" woodfillers as well, but in the end that still was a lot of work.

[Taffy Evans]

Very timely topic for me as I was in the process of looking at my poor...oops, pore filling methods. One method that I did on some test pieces of NGR and long while ago, was to mix wood dust with model aircraft Dope. I got a great fill, I can't find the test pieces now but I'm going try it again, this time using end grain dust, I had not thought of that. Trouble is its a bit on the nose and precautions need to be taken.

[DarwinStrings]

Interesting Taffy as Dope is just nitro with a acrylic in it, which I have been told by the local paint mobs is what pre-cat lacquer is. Might have to give it a test with Mirotone 3220 to see how easy it is.

Jim

[Taffy Evans]

Yes Jim, that's what I put over it. I think I just found one of the test pieces and it has a mirror smooth finish cant think why I did not use it on a guitar yet.

[simonm]

Current method. Wash coat of shellac. Sandpaper (preferably wet and dry) and alcohol of some kind. Still experimenting.

[kiwigeo]

Current method. Wash coat of shellac. Sandpaper (preferably wet and dry) and alcohol of some kind. Still experimenting.

Simon, I think you'll find your sandpaper will clog up with shellac.

[nnickusa]

I've used a method like Simons's on my two that needed pore filling so far. 3 brushed coats of shellac, wrap an eraser with wet dry 400. Soak very well in metho and rub in circles. Keep dipping the sander in the metho and keep it plenty wet.....No porblems for me so far....

[kiwigeo]

I've used a method like Simons's on my two that needed pore filling so far. 3 brushed coats of shellac, wrap an eraser with wet dry 400. Soak very well in metho and rub in circles. Keep dipping the sander in the metho and keep it plenty wet.....No porblems for me so far....

Glad to hear it works for you guys. I guess if you keep plenty of meths on the paper it serves as a lubricant.

[nnickusa]

I keep a bowl with 1/2 an inch of metho in the bottom, and dip as soon as the paper gets even a tiny bit tacky....

[simonm]

Current method. Wash coat of shellac. Sandpaper (preferably wet and dry) and alcohol of some kind. Still experimenting.

Simon, I think you'll find your sandpaper will clog up with shellac.

Yes, it does to some extent. But overall much easier than with pumice, at least with my level of pumicing skill. I initially tried it out on headstocks with no shellac at all. Just wlth alcohol and sandpaper. Went through a few grades of wet n dry and got a nice shiny finish. Quick coat of shellac afterwards. Very effective. I've done that a good few times.

Relatively recently I decided to try it on b+s which I had shellacked already (3 instruments). Worked better than I expected. Used plain ordinary sandpaper as that was what I had handy. My next step will be to do it without any shellac and see what happens. And yes I used quite a lot of alcohol. Other lubricants have been suggested and I will try these too. However, it will be a while before I get round to doing another. Gotta finish the ones in progress and the day job is pretty bust this year.

[sebastiaan56]

I have a UV coating system for print. It is a great finish, hard, high gloss and very clear, it really brings the colour out of the sheet. It also has serious disadvantages, the smell, the need for a preheat and the risk of burns. My staff use appropriate PPE but there is a real risk of burns to skin, eyeballs etc. that said we coated a few knife handles etc and they look great. Now that UV temperature LEDs are becoming more available this will address the huge energy cost and it will be more widely used.

For instruments and at home I'm a Botecoat kinda guy.

[kiwigeo]

I keep a bowl with 1/2 an inch of metho in the bottom, and dip as soon as the paper gets even a tiny bit tacky....

Something to watch out for when pumicing is overworking rosewoods and other woods that bleed easily. The result can be leached out lighter patches over the back or sides.

The hardest part of pumicing is letting the wood paste build up and harden. If youre quick enough you can "clear" the build up wth the punce but left to harden your only option is then sanding.