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UV-Cured Polyester Finishing Schedule
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Author:  scottsailors [ Thu Jun 07, 2012 3:54 pm ]
Post subject:  UV-Cured Polyester Finishing Schedule
A number of luthiers and hobby-builders have asked me, recently, to post a suggested finishing schedule for use with the UV-cured polyester finish. We use the products manufactured by Simtec Coatings. We are always striving to improve both the process and the result, but following is our understanding of Simtec's recommended finishing schedule for use with their products. In addition to this information, you can go to our blog at http://www.ClearCreekGuitarFinishing.net to view posts on Equipment and Tools; Finishing Products; and Solvents, Viscosities, and Application Temperatures. Here's the schedule:

* Mix two-part insulator in a one-to-one ratio

* Spray insulator using a 1.0mm nozzle at psi recommended by sprayer manufacturer

* Allow insulator to cure overnight

* Thoroughly scuff insulator with a Scotch-Brite pad

* Apply first coat of pore filler

* UV cure

* Sand level being careful not to sand back into the wood

* Clean the surface

* Repeat the pore filling process until level

* Thin topcoat to original viscosity of new material (if necessary)

* Spray 3 coats of topcoat, 20 to 30 minutes apart, using a 1.2mm nozzle at psi recommended by sprayer manufacturer

* After third coat, allow to gas-off for 20 to 30 minutes before UV curing

* UV cure

* Scuff finish thoroughly for a mechanical bond with the next 3-coat application

* Spray 3 coats of topcoat, 20 minutes apart, using a 1.2mm nozzle at psi recommended by sprayer manufacturer

* After third coat, allow to gas-off for 20 to 30 minutes before UV curing

* UV cure

* Final sanding, buffing, and polishing

*400, 600, 800, 1000, 1200, 1500, 2500, 3000 sandpapers

*Buff on 16” Domet wheel using the X-Fine polishing compound

*Polish using Perfect-It 3000 Swirl Mark Remover with foam buffing pad on a drill (moisten with water)



Final material thickness should be 3 to 5 mils.
Author:  CharlieT [ Thu Jun 07, 2012 6:07 pm ]
Post subject:  Re: UV-Cured Polyester Finishing Schedule
Thanks for the information Scott! Very generous of you to share it. Does Simtec Coatings sell direct or through distributors?
Author:  scottsailors [ Fri Jun 08, 2012 7:35 am ]
Post subject:  Re: UV-Cured Polyester Finishing Schedule
CharlieT wrote:
Thanks for the information Scott! Very generous of you to share it. Does Simtec Coatings sell direct or through distributors?


They do sell direct. To purchase minimum quantities, however, costs a little over $200, and the shelf-life is pretty short.
Author:  Robert Renick [ Fri Jun 08, 2012 8:54 am ]
Post subject:  Re: UV-Cured Polyester Finishing Schedule
Thanks for posting this information, I look forward to getting into UV cure products, this will get me there sooner. Much appreciated.
Rob
Author:  Pat Hawley [ Fri Jun 08, 2012 2:43 pm ]
Post subject:  Re: UV-Cured Polyester Finishing Schedule
Thanks for the info Scott.

Can you tell me if you ever have any issues with curing your pore filler? I've been using the stuff from cureuv.com and I've pretty much given up on the uv cured pore filler and am now doing the pore fill with epoxy instead. What I think is my challenge is that the light does not penetrate into the pores sufficiently to cure the filler and also possibly oxygen inhibition with the very thin coating on the surface of the wood. The result is uncured stuff that bleeds from the pores forever. The same thing happens if I don't use the pore filler i.e. just the top coat on top of the insulator.

The epoxy pore fill works as a first step but it's a workaround that I feel should not be necessary.

Thanks,
Pat
Author:  woody b [ Sat Jun 09, 2012 9:36 am ]
Post subject:  Re: UV-Cured Polyester Finishing Schedule
Pat, Simtec uses a catalyzed isolator/sealer, even with a UV cured top coat. The sealer is applied before the filler. Weren't your problems with a UV cured sealer? IMHO you need something to seal and lock the pores before using any kind of UV cured coating. The UV can't get into the pores, so the sealer doesn't get cured.

I talked to Simtec about (catalyzed) finishes, and was going to give them a try, but decided to go with Axon. I can pick up Axon products at the plant and save on haz-mat shipping charges. I do believe Simtec products are top good products.


I've said this in a bunch of threads. Most finishes (especially Polyester) are dangerous, reguardless of how they're cured. Educate yourself on the proper safety equipment and practices. UV lights can be dangerous without proper precautions to
The "safe", and more cost effective choice for most small volume builders would be to send their guitars to someone like Scott, Joe White, or Tony Ferguson for finishing. If I didn't already have a shop and equipment for finishing motorcycle frames, tanks, and racing mower parts I'd send my finishes out.
Author:  Pat Hawley [ Sat Jun 09, 2012 11:09 am ]
Post subject:  Re: UV-Cured Polyester Finishing Schedule
Woody, the isolator/sealer that comes with the cureuv.com set up dries relatively quickly in air so I don't believe it is the problem. The problems occur on wood with deep pores after I have applied either the pore filler or topcoat that need to be cured with the light.

Pat
Author:  woody b [ Sat Jun 09, 2012 2:05 pm ]
Post subject:  Re: UV-Cured Polyester Finishing Schedule
Pat Hawley wrote:
Woody, the isolator/sealer that comes with the cureuv.com set up dries relatively quickly in air so I don't believe it is the problem. The problems occur on wood with deep pores after I have applied either the pore filler or topcoat that need to be cured with the light.

Pat


One of the jobs of a insolator/sealer is to "lock" the pores. "White pore" can be a problem (even with catalyzed finishes) if the pores aren't "locked". I suspect the problems you've had, (as well as Stuart?) were either because the sealer didn't properly cure, or because of some other type of sealer problem. I don't recall the specific species you had problems with, but perhaps I could send you a piece with Axon sealer on it. It would be easier to ship (especially across the border) than some sealer.
Author:  Pat Hawley [ Sat Jun 09, 2012 9:21 pm ]
Post subject:  Re: UV-Cured Polyester Finishing Schedule
Woody, thanks very much for the offer to send me a piece of wood with some sealer on it and I would be happy to take you up on it but, at this point, I don't understand what the objective would be. As I've said, the sealer I am using goes bone dry in about 30 minutes and does not need any light to become "cured". The problem is from either uncured pore filler or uncured top coat - I have the problem with both.

I'm not sure what you mean by the expression "lock the pores". Can you expand on that?

Thanks,
Pat
Author:  scottsailors [ Mon Jun 11, 2012 11:05 am ]
Post subject:  Re: UV-Cured Polyester Finishing Schedule
Pat Hawley wrote:
Thanks for the info Scott.

Can you tell me if you ever have any issues with curing your pore filler? I've been using the stuff from cureuv.com and I've pretty much given up on the uv cured pore filler and am now doing the pore fill with epoxy instead. What I think is my challenge is that the light does not penetrate into the pores sufficiently to cure the filler and also possibly oxygen inhibition with the very thin coating on the surface of the wood. The result is uncured stuff that bleeds from the pores forever. The same thing happens if I don't use the pore filler i.e. just the top coat on top of the insulator.

The epoxy pore fill works as a first step but it's a workaround that I feel should not be necessary.

Thanks,
Pat


Pat -

We've not had any issues with curing the Simtec UV-cure pore filler. We've not used the products from cureUV.com. Sorry I don't have more definitive information for you.
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