Yet another grain fill thread.

[Colt W. Knight]

Hello Everyone. A common question that keeps popping up is, "What do I use to grain fill my wood, Do I need to grain fill, and How do I grain fill?"

1. Do I need to grain fill?

Grain filling is a fine finishing technique. Open pore wood like Ash and Mohoghany have grain with larger voids in the surface. If you want a flat, wet glass finish, you have to fill these voids(pores) with something. If you do not, your finish will have a textured appearence following the grain.

2. What do I use to grain fill?

There are lots of techniques to grain fill wood, and lots of commercially available fillers.

- Pumice Technique - Often used in french polishing. Search French Polish
- Slurry technique - wet sanding with a sealer or clear coat. Often used in oil based finishes.
- CA Glue - Often used on figured woods.
- Epoxy - Common method, Zpoxy is a typical product.
- Water Based Fillers - Timbermate
- Solvent based fillers - Behlens Pore O Pac
- Apply sealer, sand flush, repeat until the grain is all level.

Which solution is the best?

Depends. They are all time consuming, and they are all fairly easy to do. Some fillers are expensive like solvent based fillers, and some require special application procedures like pumicing. Some are flat out messy, like the epoxy and CA glue method. Some have nasty fumes like solvent based, CA GLue, epoxy, slurry, and sealer, while some have not odors or fumes like water based.

Which you choose to use is up to you, and which one you like better is completely dependant on how you like to approach the situation.

3. How do I grain fill?

Solvent Based Grain Filler - Behlens Pore O Pac

Apply Sealer, Sand flush repeat

- The above link also illustrates proper prep work and procedure for applying a spray on sealer.

The remainder of this thread will focus on another grain filling technique.

[Colt W. Knight]

Another common question I hear a lot, is where can I buy grain filler locally? Or, what is available at Lowes and Home Depot?

Something I have read about for the last 4-5 years is the use of Wall Joint Compound or drywall mud as a grain filler. I have been wanting to try it for a while now, but I have been extremely hesitant. Well I finally tried it, and this thread is a tutorial on how I use Wall Joint Compound as a filler.

1. The body needs to be finish sanded and properly sealed. See above link for proper steps.

This is an Obeche tele body. I built this using a 1 piece blank from eBay member Ohlar.


Step 2. Mix Wall Joint Compound, water, and dye to the consistancy of viscous mucous.





Step 3. I add a heaping spoonful to the back, and massage it deep into the wood pores.









You really want to work that stuff in there. If you massage it enough, it will start to get really thick and almost slighty gritty feeling.

[Colt W. Knight]

Then let that guy dry some. Don't let it dry out completely, but give it a few minutes of sit time.



Then take a scraper( these 96 cent putty knives work great) and remove the excess grain filler.

[Colt W. Knight]

Then just repeat on the front and back.

After the filler has dried thoroughly, you can sand away the excess using a sanding block and 220 grit paper.











Here is some Ash filled in the same manner.



After this whole process has been completed, I will spray another sealer coat.

[Colt W. Knight]

Important things to keep in mind.

1. If you let the filler sit too long before scraping off excess, you will have to sand it all away.

2. Scrapers can be sharp, so be careful, especially around corners. You don't want to gouge wood.

3. Don't sand agressively. If you sand agressively, you can sand away all the filler you just applied.

4. Allow the filler to dry thoroughly before sanding, and make sure its dry before applying the second coat of sealer. You don't want it to dry and shrink after sanding, and you don't want to trap moisture in your sealer coat.

[Colt W. Knight]

How would I compare Wall Joint Compound to commercially avialable solvent based sealers?

- It is cheap, readily available, and cheap to color because you can use RIT tee shirt dye or transtint.

- Dries Quickly

- No solvents to deal with

- Involves more sanding than solvent based fillers, and is a little messier than solvent based fillers.

[telemaster1953]

great thread colt, thanks.

[RollingLedZep]

This is a really good thread. It would be really cool to see you do one for each step, like the sanding sealer, paint, and clear coat. I think that would help out lots of people building.

[Colt W. Knight]

Originally Posted by RollingLedZep

This is a really good thread. It would be really cool to see you do one for each step, like the sanding sealer, paint, and clear coat. I think that would help out lots of people building.

Its a longer thread, but I have laid out just about all of that information from finish sanding to buffing in this thread.

How I approach a Nitrocellulose Lacquer Finish.

[Rockdog]

You are a gentleman and a scholar, Colt. Thank you!

[Colt W. Knight]

Originally Posted by Rockdog

You are a gentleman and a scholar, Colt. Thank you!

I'll let you know about the scholarly part after I finish my Ph.D. interviews.

[adirondak5]

Hi Colt , great thread as usual . What is your take on that Obeche , I've been curious about that since Ohlar started listing it.

[Colt W. Knight]

Originally Posted by adirondak5

Hi Colt , great thread as usual . What is your take on that Obeche , I've been curious about that since Ohlar started listing it.

I can not attest to the tonal quality yet because I have not finished any obeche guitars, but Obeche is extremly lightweight. The stuff I recieved from Ohlar is Extremely clear grained. One blank is quartersawn. The wood itself looks like blonde mohoghany, and has a smell like a cross between Ash and Limba. I bet you could stain the obeche a reddish brown, and no one could tell the difference from it and mohoghany. It works like pine, super soft, and the grain is prone to raising. Filling the grain on Obeche is easier than Ash. The darker/deeper grain on Ash is tough to fill. The structure of the grain is tougher to fill. Obeche's grain is pretty straight forward, and the filler just falls into place.

[SSO720]

Colt,
Another great thread, as usual. Have you ever grain filled with the Timbermate product and if so, how do you think this compares with it? another quick question on the finishing. I know that you use S-W vinyl sealer and the lacquer. I have been unable to develop a source for it here but have found PPG/Pittsburg products of a similar nature. Have you ever used the PPG product?

[Colt W. Knight]

Originally Posted by SSO720

Colt,
Another great thread, as usual. Have you ever grain filled with the Timbermate product and if so, how do you think this compares with it? another quick question on the finishing. I know that you use S-W vinyl sealer and the lacquer. I have been unable to develop a source for it here but have found PPG/Pittsburg products of a similar nature. Have you ever used the PPG product?

Timbermate is a good a product, and it comes precolored.I also believe the particle size is smaller on timbermate, so it can get into the aggressive grain of ash a little better. You can actually thin and apply this wall joint compound the same way as that Timbermate. It would probably be less messy. For my money though, I would opt for Wall Joint compound or Behlens Pore O Pac before timbermate. JMO.

I have never heard of Pittsburg Products/PPG before, but I would be willing to bet its probably a good product.

[Colt W. Knight]

To add some more information to this thread.

I filled three bodies. 1 Ash strat, 1 obeche tele, and 1 ash tele.

I used a power sander to sand away the compound on the strat, and block sanded the teles.

Before I sprayed the teles, I wiped one down with naptha, and the other I blowed off with air.

The naptha wiped away quite a bit of filler, so I wouldn't recommend wiping down the bodies to remove dust. Just blow them off with some air.

[Colt W. Knight]

I gave these guys a healthy coat of vinyl today.





I went a little agressive on sealer this afternoon. I guess I was just in that sort of mood.

[adirondak5]

Originally Posted by Colt W. Knight

I gave these guys a healthy coat of vinyl today.

This is the Obeche Colt ? That is pretty cool looking .

[Colt W. Knight]

Originally Posted by adirondak5

This is the Obeche Colt ? That is pretty cool looking .

Yup, Obeche. I like dark grain filler, and I got a feeling the grain is going to show through that seafoam green I mixed up like a charm!

[adirondak5]

Originally Posted by Colt W. Knight

Yup, Obeche. I like dark grain filler, and I got a feeling the grain is going to show through that seafoam green I mixed up like a charm!

Seafoam , wow , my favorite color , that will look great , post some pics of it when you are done. I really like the looks of that Obeche .