gap filling + bursting

[swarfrat]

I have some gaps which weren't nearly as noticeable until I stained the sides of my guitar black. I tried filling them with wood filler, but they're shallow and it didn't really stick well. When I sanded most of the putty pulled out. I'm bursting the edges black to hide this, but I need to build it up to the same level as the surface. (It's lam top glued onto a base. I originally built it as one piece, then router planed the top 1/4" off, and glued another top in its place.  The gap is where I didn't QUITE go deep enough and picked up a previously imperceptible bit of the old roundover.)

The sides are black but the top is dye + clear. It is currently stained, hoping I'd get some bridging but alas no. So the stain on it now is probably presenting some adhesion difficulties. Whats my best option?  (You can see a bit of the edge on the inside of the horn in the shot with the bridges, and on the butt top side in the other one.)

Also - the finish is shellac. Since the body is so small - I don't have a lot of room for a wide sweeping burst. But I still need to make a nice transition from black edges to clear. I figured that the template I used to route it plus an inch or two of spacing above might make a good mask for spraying the edge transition. But since the current finish is shellac - I'm not sure what I find in a rattle can that will go down on it.

 

[Cagey]

You're in kind of a bad place, I think. For those kinds of surface defects, grain filler isn't thick enough and wood filler/putty is too thick. Having a finish on it isn't helping. At the risk of pouring salt in a wound: surface prep is everything!

All is not lost, though. Rather than fill it, sand it away. Since it's on the outline, you don't have dimensional issues. It appears that the areas that need attention are a solid color, so refinishing the blemishes that sanding would create will be easy. Grain fill after sanding and before any new finish.

 

[swarfrat]

What about spackle / bondo / PVA glue / CA glue ? My orbital sander is a single speed and a bit hard to control on small surfaces. I figure the stain is going to have to come off before anything will stick. 

Too bad the toy budget is shot this month already. An oscillating spindle sander might be just the ticket. I already want it for templates. 

 

[Cagey]

I think you may still have the too thick/too thin problem with those materials, although thin is not necessarily a Bad Thing if you can do multiple passes to build with. I was trying to avoid that. But, even grain filler will work if you have the time and wanna work. Fill it, sand it back, fill it, sand it back, repeat until you have a flat surface. This is often necessary even with flat surfaces on some woods such as Mahogany or Ash.

I share your desire for an oscillating spindle sander. The little buggers are surprisingly expensive, though. What I've been doing in the meantime is using my drill press with these sanding drums...

They're just the opposite - surprisingly inexpensive. That set is $20 from Rockler.

 

[swarfrat]

This little puppy actually beats the Horrible Freight version by $40 and about 2.5x the power. I figure their power rating inflated by similar amounts.

http://www.amazon.com/WEN-6510-Oscillating-Spindle-Sander/dp/B00LPFIPPQ/ref=sr_1_2?ie=UTF8&qid=1459265206&sr=8-2&keywords=spindle+sander

 

[Cagey]

Wow. I had much higher prices in mind. I may have to snatch one of those babies up. That looks like just the ticket for 99% of what I need it for.

 

[swarfrat]

Yeah, the Rigid Oscillating Edge sander looks awesome for this kind of work - it's basically an oscillating belt sander with different sized rollers - so it's like getting a belt and two drum sanders at once. At $200 I suppose it's reasonable for what you're getting, but it still doesn't fit inside the "Honey, look what I found today!" price.

https://www.ridgid.com/us/en/oscillating-edge-belt-spindle-sander

 

[swarfrat]

Also - I figured the table on the spindle sander would be a HUGE help in keeping the edges nicely controlled. The problem I have with a high torque orbital sander in my hands trying to sand a 1.5" wide face.

 

[Cagey]

Damn. Now I gotta have one of those! What a handy tool! Plus, you get a lot more surface for workpieces to ride on that's also angle-adjustable. You can see it at work in this video...

[youtube]yyuhK2FESzE[/youtube]

I understand about the wife thing. Fortunately for me, I no longer have that particular hurdle to jump  :laughing7:

 

[swarfrat]

Ordered that OSS in the first link. With Amazon prime getting it here in 2 days - that helped decide.

 

[Cagey]

Good for you! Gotta love a new tool!  I'm sure it'll not only help with the current issue, but come in real handy a lot down the road.

 

[swarfrat]

Someone at work recommended Durham's Rock Hard Water Putty. Which after looking around appears to basically be Bondo relabeled. Since I have a new toy coming - I think I'll leave it be until I turn it all to dust, but I'll keep it in mind.

 

[bagman67]

Please accept this admonition in the spirit of positive criticism:


When that spindle sander comes in, please oh please do plenty of practicing with some scrap to get your feel for what it's likely to do to the guitar body.  It looks to me as though you have changed directions a number of times, with a healthy ration of slipups along the way - and in response you have improvised solutions which then engendered more problems.  I say this without any intent to be insulting, but just as an observation. 


You are nearly at the finish line, and as I see this new power tool getting ready to take center stage, it occurs to me you could just as easily destroy this project as solve the problem you are out to fix.  I am eager to see this bass wind up in your little guy's hands, and I have the feeling that the frustration of another cock-up might take some of the joy out of this experience for both of you.


Just my opinion, and worth what you paid for it.

 

[swarfrat]

Point taken. Worst comes to worst - I have the original body for the interim, a body template, and a neck pocket template. I certainly hope this doesn't happen - if only I suspect it'd take me about 1/5 of the time to do it over again from scratch as it did the first time.

 

[pabloman]

The Rigid unit is a great piece. I've had mine for a couple of years now. It's super versatile. I've made a couple of sleds and fences for it. You can do a whole lot with it.

 

[swarfrat]

Nice video on spindle sanders. I really like his fence for straight edges (of which I have a few)
http://www.finewoodworking.com/tool-guide/video/spindle-sander-basics.aspx

 

[swarfrat]

I made a fence for the 1.5" drum, tried it out on some scrap. The key as in the video, is light strokes, use a straight edge, and keep it moving. I'm pretty happy with the results so far. Honestly, this is one of those tools - when you get one you'll ask yourself how you did without it.  I'd say it's essential for anyone doing router template based work.  I got em all but one that seems to be deeper than I really want to sand off. But it should also fill easier than the others.