Balsa and Routers?

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Kruegon

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Is this even worth attempting or would it be a colossal waste of time?
 

GregGleason

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Balsa isn't a wood that handles power tools all that well, at least in my experience. IMHO, lasers would be better.

Perhaps smaller bits (like a 1/16" or less) might work on balsa.

What are you trying to do with a router that you can't do with a hobby knife?

Greg
 

Kruegon

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Well my beveling skills are non existent. I was considering backing the balsa with a board and using a deep angle router bit to put the base bevel on it and then work it deeper from there.
 

OverTheTop

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I have successfully used a carving bit mounted onto a flex drive shaft, attached to a Dremel, as a toolpost grinder on my lathe. Results were surprisingly good.

18.JPG 26.JPG 33.JPG


Not sure how well it would work for fins though...
 

Kruegon

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Oh. Turning services. Yeah. I'm talking bevels for fins.
 

GregGleason

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I think for balsa you are better off making a fixed angle sanding jig.

Maybe like this?

[YOUTUBE]6qXcicv0QJw[/YOUTUBE]

Greg
 

Kruegon

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Have you considered a Great Planes sander block?
They have them in 5.5", 11", 22" and others...
I actually have. But not having used one, I've been skeptical. Not of the quality, but of my skills. It's still high on the list but I'm exploring other options before I settle in and start destroying fins lol.
 

Kruegon

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I think for balsa you are better off making a fixed angle sanding jig.

Maybe like this?

[YOUTUBE]6qXcicv0QJw[/YOUTUBE]

Greg
I'll have to watch that one and see. I thought about fixed angle set ups, but you'd need one for each individual rocket's fins. They all have different thickness of fins and different angles. Still may end up being the only viable option for the bevel impaired.
 

Nytrunner

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There's a nifty dremel attachment that Forever_metal posted on my BroncBuster II thread in Mid-power.

It takes 1/64 at a pass, which makes me think it may be gentle enough for balsa.
 

Kruegon

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I'll check that one too. I have several builds coming up that require beveling for proper finishing.
 

Incongruent

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I'll check that one too. I have several builds coming up that require beveling for proper finishing.
Masking tape. Masking tape prevents over-sanding. Mask off the boundaries and use a sanding block, tell us how it goes (use scrap balsa to make a practice fin).

For the edge, you can use medium CA applied by Q tip and thick sharpie marker to increase visibility. The glue should also aid adhesion if you mask it.
 

Kruegon

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What grit do you use? 320 seems like it would cut through the tape.
 

Incongruent

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What grit do you use? 320 seems like it would cut through the tape.
220. 320 and 400 to finish up. The fins are then papered, beveled edge sealed with CA, and sanded with 400. Note that the 220 I used is the red "3M pro grade precision" stuff, which seems to have a different texture compared to the wet/dry black sandpaper, like the binder goes over the grit as well rather than just underneath. Not quite sure how to describe it. It does clean easier though, and the sheet is thicker. Also, I dry sanded.

Photos are of my Mercury Redstone that I need to work on sometime. They took ~ 30 mins each to sand, so a total of 2 hours or so. Papering goes quick in relation. The knife edge is achieved through the papering and CA, the paper is folded (and strengthened with CA) to extend the rather blunt wood edge out a little and the sanding rounds it (kind of like an ogive) into a sharp edge . I crease the paper beforehand at the edge (not so hard to distort the paper, but enough to help make the edge more distinct. The transition from the bevel to the flat surface of the fin is much less prominent, unfortunately.

Tell me if anything is unclear or you want to double check. Also remember that I'm by no means an expert. (If my build quality hasn't made that clear.)

IMG_2546.jpg


IMG_2545.jpg


IMG_2544.jpg
 

Micromeister

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Incongruent is right on here:
Plain old masking tape makes a wonderful sanding stop for Beveling and Airfoiling Balsa and Basswood. Competitiion flyer have used this technique for decades to create true airfoils on Glider Wings and Helicopter Rotors. It's even simplier creating very level bevels. All thats needed is a good level surface and a sanding block.
A sheet of Plate Glass makes a wonderful sanding base.

1a_12in x 24in x .75in. Plate Glass & D-F masking tape_01-28-09.jpg


a_5 Glass plates .125in to .75in_01-28-09.JPG
 

Lowpuller

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OH MY GOSH!!!!

Incongruent and Micro actually agreed on something!!

Here here go community!!!
 

Kruegon

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Incongruent is right on here:
Plain old masking tape makes a wonderful sanding stop for Beveling and Airfoiling Balsa and Basswood. Competitiion flyer have used this technique for decades to create true airfoils on Glider Wings and Helicopter Rotors. It's even simplier creating very level bevels. All thats needed is a good level surface and a sanding block.
A sheet of Plate Glass makes a wonderful sanding base.
Ok, Micro doesn't get to comment. That boy bevels fins in his sleep. Correction. He bevels tiny fins in his sleep. He is not allowed to make me look bad lol.
 

heada

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Treat the balsa with thin CA and it'll get rock hard. You can then use standard power tools on it.

-Aaron
 

Kruegon

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Treat the balsa with thin CA and it'll get rock hard. You can then use standard power tools on it.

-Aaron
That's a good idea. How much weight does it add?

And that brings up another question. CA vs Wood Hardner. Pros and cons?
 

heada

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That's a good idea. How much weight does it add?

And that brings up another question. CA vs Wood Hardner. Pros and cons?
It adds minimal weight but you can test it out ahead of time with a fine digital scale and some scrap balsa.

I use thin CA as it is the consistency of water, can cure instantly (with accelerator) and can be used on paper shrouds as well.

-Aaron
 

cxm

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Get a Harbor Freight belt sander...one that goes on the bench...for $50 and it will bevel your fins quickly and easily, and you will find a million other uses for it too.
 

Lowpuller

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Incongruent.......well stated 😀😀😀😀😀🤡🤡
 

Incongruent

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It adds minimal weight but you can test it out ahead of time with a fine digital scale and some scrap balsa.

I use thin CA as it is the consistency of water, can cure instantly (with accelerator) and can be used on paper shrouds as well.

-Aaron
I use thin CA to strengthen balsa as well, but according to Apogee, wood hardener is better since it soaks through the balsa rather than just stiffening the surface. I might try medium CA since it doesn't run as easily as thin and gets sanded smooth anyways but I've misplaced my bottle again.

I would advise against using CA on paper shrouds since (in my experience) it makes paper brittle, though depending on the position of the shroud that might not matter much.
 
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