Let's talk about finish sanding

[Kirkll]

After you got your riser roughed out and shaped, i'm curious what graduations of sand paper you guys use getting down to the finish product?

I use 36 grit on my edge sander, and spindle sander to get my shape, as well as a 36 grit disc on a die grinder to rough shape my radius shelf. Then i go to 80 grit next on my palm sander to get the scratches out, and then hit it with a sanding sealer. At this stage i'm just looking for wiggles or defects in the shaping process, and getting things looking smooth.

Then i drop down to 120 grit and sand the whole riser again, and hit it with my lacquer sanding sealer again. Now i'm looking for 80 grit sanding marks that i missed. i may do this second process several times before i'm happy, and then start the hand sanding process. I start out with 120... seal it again... then 150.... seal it again, then finish up with 180- 220 grit. By this time i'm mostly just sanding the sealer flush again and filling grain. This has worked well for me for a long time.

My problem is.... Recently i have had a hard time finding 120 grit sanding disks at my local supplier, and had to settle for 150.  Going from 80 to 150 is too big of jump and i use a LOT more sand paper doing this.......   I am just curious on how you guys are going about it? ....    Kirk

[Mad Max]

I use 36 grit on my edge sander to get  Back and belly and both sides to shape, then 60 grit and then 220 all on the edge sander.
Rasp to round over everything, 102 grit wrapped around a 6" ruler to take the high spots off and 220 again on the ruler (3/4" x 6" .050  stainless steel ruler), Then I start looking for scratches.
Some times I use a razor blade to scrape

[Flem]

After rough shaping, I start at 100, 150, 220, 320 if the wood has open pores, plus filler, 400 if not.

[Appalachian Hillbilly]

80, 120,220, 320 on palm sander..

120 is a good workhorse that does not leave as many swirlmarks, but I can only find it about half the time I go to buy it. So I have been buying it whenever I find it.

[Kirkll]

80, 120,220, 320 on palm sander..

120 is a good workhorse that does not leave as many swirlmarks, but I can only find it about half the time I go to buy it. So I have been buying it whenever I find it.

How's that leg doing bro?

[OldRawhide42]

Mill as much as I can. 60 and 80 grit to shape . Flap sander with 80 grit. 120 buy hand. Spray finish to seal .
 220 buy hand.

[B-JS]

I used 40 at the edge sander for a long time.
Tried 60 some weeks ago and will stay with it.

The edge sander is used for shaping Risers and limbs.
After that, i use 80 on the orbital to finish shaping and get rid of marks from the 40/60.
Then 120.
If i use my flat tough finish thats IT.
If i use a smooth glossy finish, i sand with 240 after this

[Appalachian Hillbilly]

80, 120,220, 320 on palm sander..

120 is a good workhorse that does not leave as many swirlmarks, but I can only find it about half the time I go to buy it. So I have been buying it whenever I find it.

How's that leg doing bro?

Trying to stay off of it. Swelling is slowly going down. Going to have some very large sections that we hope dry up instead of turning into a blister. See the doc Monday.  I want to avoid skin grafts if st all possible.

Killing me to be this inactive when I have so much to do!  Getting it too heel properly could be the difference from being out a month to several months though!.

[Mad Max]

I hope you can still make  it to the Classic

[Flem]

Damn Hillbilly, I sure hope you don't need skin grafts either. Is there anything topical that you can put on your skin that will keep it nourished, or is that a no no right now?

[Kirkll]

80, 120,220, 320 on palm sander..

120 is a good workhorse that does not leave as many swirlmarks, but I can only find it about half the time I go to buy it. So I have been buying it whenever I find it.

How's that leg doing bro?

Trying to stay off of it. Swelling is slowly going down. Going to have some very large sections that we hope dry up instead of turning into a blister. See the doc Monday.  I want to avoid skin grafts if st all possible.

Killing me to be this inactive when I have so much to do!  Getting it too heel properly could be the difference from being out a month to several months though!.

I hear ya brother....Gotta be patient.

  I blew out my knee a couple weeks ago and have something floating around in there that locks up now and then. I been hobbling around using a cane for a couple weeks now. Went to two different doctors that were trying to tell me i just have arthritis. I called bull pucky on both of them, and finally got through to an orthoperiodic surgeon to get an MRI done. (still waiting on that).. Trust me.... I know what arthritis is, and this knee thing is not the issue.....

Unfortunately ya gotta jump through all the hoops before anyone will ever listen to you..... I had one doc say i probably needed physical therapy...... I cordially invited him to go pound sand up his arse, and found a different doc.  Mobility isn't a problem at all, nor do i have any pain..... until that loose piece goes into the joint..... This is messing with my fishing time here....

I wish you the best....

Kirk

[katalyzt]

This is good stuff guys. After milling I use a variety of sanders like drill drums and Rotex rotary sander using 80 grit.  I work some files and cabinet makers rasps into there and for some of the milling.  I love shaping with a rasp but you have to be careful as it can tear at accents and chip glass.  But oh so satisfying for curves. After that it's hand sanding with 120, 180, 220, and sometimes 320.  I'm still working on my finishing process but I'll be trying Thunderbird for the first time here on the next bow so we'll see how that goes.

I think I should and will be incorporating some sanding sealer into the process.

So how about limb lams? I'm currently leaving them at 60 from grinding them on the drum sander (although in the past I think I've done a set or two at 120) because I'm terrified of de-lamination.

Sending good vibes your way Hillbilly.  It's rough not being able to not move about and do what you want. But you're right, put the time in now to hopefully heal quicker and not be dealing with it as long. 

[Kirkll]

So how about limb lams? I'm currently leaving them at 60 from grinding them on the drum sander (although in the past I think I've done a set or two at 120) because I'm terrified of de-lamination.

The rougher the better for lamination. I mill all my lams including veneers with 36-40 grit. I used to run the veneers back through with 80 grit, but.... there was no noticeable difference under the clear glass, and 80 grit eats more veneers than 40 grit.

If you think about it, it makes sense.  a flat surface line 1.75' long has a glue surface of 1.75".  A 36 grit or 40 grit has deeper ridges going up and down that fit into each other in the press and probably has closer to 2" of gluing surface making the bond much stronger using epoxy.     Kirk

[Flem]

More than one school of thought when it comes to coarseness of finish and epoxy viscosity.
Sanding wood lams to 150grit and using non thixotropic epoxy, makes for a tight flexible joint.
Epoxy is going to be the least flexible and heaviest component of any laminated bow.
The thick glue/coarse surface protocol is a left over from the old days when the only adhesives available were Resicronal and other filled glues.

[Kirkll]

More than one school of thought when it comes to coarseness of finish and epoxy viscosity.
Sanding wood lams to 150grit and using non thixotropic epoxy, makes for a tight flexible joint.
Epoxy is going to be the least flexible and heaviest component of any laminated bow.
The thick glue/coarse surface protocol is a left over from the old days when the only adhesives available were Resicronal and other filled glues.

 EA 40 is the most common glue used in laminated bows today. Using a decent press system like an air hose is quite common too, and most of the excess glue squeezes out using as little as 30# air pressure, but most commonly use 50-60# pressure. But I know some outfits have gone to low viscosity Huntsman epoxy. Maybe using finer grit on low viscosity glue would be better.... 

 But saying that using fine grit sand paper with epoxy is going to lighten the mass weight of a limb is kind of a stretch don't ya think?. ...   I don't think this is old school thinking about extended glue surface using rough grit with EA 40. i've been doing it this way for 15 years now, and know a lot of other bowyers that have too.      Kirk

[mmattockx]

The rougher the better for lamination.

Not necessarily, that depends entirely on the adhesive requirements. Most adhesive manufacturers will publish the preferred surface finish, joint gap and other joint conditions to maximize success with their glue. Look at websites and read data sheets to get the best info on how to use your particular glue.


Mark

[Kirkll]

Agreed Mark..... But i'm talking EA 40 with bow laminations. Nothing else. Please read my previous post.   Kirk

[Flem]

There are many published scientific papers on surface bonding coarseness. This subject has come up before.
Here is one that addresses aluminum to wood and wood to wood bonding.

https://appliedadhesionscience.springeropen.com/track/pdf/10.1186/s40563-015-0050-4.pdf

Weight wise, not going to be noticeable. But still a fatter glue line is going to be heavier, less flexible and weaker.
Will it be a problem? No, it's just one small detail. On the other hand, what if you take all the little imperceptible details, that individually look benign and look at them cumulatively?

[Mad Max]

EA-40 spec. sheet say's for bow laminating 120 grit

[Buemaker]

E