Official Luthiers Forum!

I am a first time builder (warming up on a ukulele before my first guitar) and I am planning to french polish my uke.  My question is if I  want to  pore fill can I use standard epoxy (e.g. West System 3 which I already have from boat building) or do a need to use  a '5 min' product like epoxy (don't  know if  you can get it in New Zealand)

Can I just brush on a thin layer to the back and sides and then sand it back?

Is there a simpler way to pore fill?

Thanks for your help.  This forum is an inspiration for a new builder.

Hi Rich,
           I can't comment on West system as I havent used it , but a lot of others do. ( I think) they use the 206 hardner , but I maybe wrong there .
I , and heaps of others , have had a great result with Z-poxy FINISHING RESIN .. I pore fill and sand back twice. Some sand back to wood , others leave some z-poxy and go over it one last time with Z-poxy and alochol (meths) mixed 50/50 , applied with a ball of cloth. This evens out any colour variation should you sand through a patch. I apply the first two coats with a credit card ( at least the're good for something ).

I think you're probably meaning Araldite 5 minute epoxy. I used that once ,,,,,,,, and I say ONCE. It doesnt sand very well . ( clogs the paper ) Your only chance is to use a scraper to level it.

You asked if there were an easier ways to porefil ? . I maybe wrong here , but I would say Z-poxy takes the prize as being the easiest . Others may disagree on that . There are of course many other ways to fill . The Milbourne tutorial explains using pumise when french polishing to fill the grain. You could also try egg whites or oil based commercial fillers .

I think one has to resign one's self to the fact that pore filling is always going to be a bit of a chore . The quality of the final finish will reflect how well you filled the pores !

As you can see , I too am a Kiwi . I'm from the Mainland ( Dunedin ) . Been in Aus. for about 25 years now . Where are you situated ?

Regards and cheers , Craig Lawrence

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CRAIG LAWRENCE of AUSTRALIA
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Rich, yes a lot of us use the West System. I use the 206 hardener, because it is the most clear hardener that West System makes.

I apply it with a thin plastic applicator that I bought at a boat building store and then sand back after 24 hours. Usually twice but I if it needs another coat then so be it. I will also go back with a dilute solution to ensure even colour. You want to fill the pores, while leaving as little epoxy on as possible, and make sure all of the wood is covered.

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David White, Toronto

"All my favourite singers can't sing."

Simple answer is you do not want a quick set epoxy IMOP.

If familiar with epoxy systems you will know a fast set epoxy is more brittle than a slower set epoxies. You will also know that the viscosity of faster setting epoxies is higher than slower setting. This can lead to bridging.(not filling but capping the pore. this will lead to srink back.)

Also quick set epoxies tend to be more trouble to sand and load your paper quicker

But all this said if you do as you should and sand all the epoxy off except that in the pores Then rag wash with a 60% epoxy 40% alcohol or 50%/50% mix after sanding back, a quick set would work. But due to quick set times means you have to make more batches and smaller batches.

I too use Zpoxy Finishing Resin. It is formulated to be a finishing coat on fiberglass models like large RC airplanes and boats. I dries slowly, the box states 3 hours but this is the set-up not the cure out. It needs 24 hours or more to cure out.

Rich:

I just did my first pore fill, with West Systems, and yes, I used 206...BUT, only because I didn't have 205 at the time. The guy I've been working with has used 205 for years, and it doesn't set fast enough for there to be any issues at all. His finishes are amazing.

If you like, shoot me a PM and I'll give you a "list" version of how I (we) did it. It's so simple, even a cav...uh, I can do it.

Bill

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Eagles may soar, but weasels don't get sucked into jet engines.

Rich-
You've gotten excellent advice here- not much I can add.
WEST and a plastic squeegee do a great job.
One small quibble and point of info:
If you are around boats and can access the 207 WEST hardener, that is the clearest hardener they make. I'm not sure it's available in the small size containers, though, as it is a finishing resin formulated for clearcoat finishing on canoes,kayaks and wood-finish boats. It also uses a different mixing ratio than the 205/206 family.
In the very thin epoxy layers we use on instruments, I don't think you will notice any clarity differences between the various WEST products. Adding thickeners (don't!) will affect the clarity.
Cheers
John

Thanks everyone for your advise.  I have West 207 because I used it to clear finish a kayak.  Sounds like it will do the job well.

Whoops, John is right. The 207 is the clearest one, and I use that not the 206.

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David White, Toronto

"All my favourite singers can't sing."

Basically I hate Z-poxy.It seems I always need 2 full coats and a 50/50 wash coat.I complain everytime I mess with it.But you know what ,it does the job.
                James

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James W Bolan
Nashville Tennessee