seeking advice - sanding solid oak and oak plywood

[Dave Tesch]

i'm knee deep in a project and using material i have not used before - oak plywood. i've used the solid oak before but the plywood is new to me. i'm building trapezoid boxes and using solid oak 1" for ripping edge bands.

usually when i do this i use pine and make each piece oversize, then sand it to final shape. this is quite fast and doable with pine but is unfeasable with oak i am finding. i spent 2 hours on two edges today, at this rate i will be done in time for my funeral. the edges i worked on today were solid oak edge banded to oak plywood and oversized approx 3/16" in width so that each side overlapped approx 3/32". i used 80 grit on an ROS to ballpark the edges and then 220 on the ros to finalize it. i used 4 pieces of 220 paper in the ros on approx 60" of edge. i am hoping this makes sense.

i think i need to cut the boards closer to the final shape but i am a little scared to do that due to the fact that being a trapezoid the pieces need some wiggle room. yesterday i spent 4 hours fussing with the miters to get the outsides to close tight, and this throws all the edges off.

i wouldnt mind the sanding if i werent using oak plywood - i am really scared of plowing through that thin veneer so i have been very careful not do (i have not used the belt sander).

if this box were a cube i wouldnt be having this issue, but being a mitered trapezoid i am having difficulty with the entire box a little in flux during the fitting stage. the plywood sands quick, but the solid oak doesnt.

i'm planning on stain/varnish or poly and not paint so i am trying not to damage the material (which is over $100 so far, an expensive box for a guy who usually uses pine)

[Phil Phelps]

Dave, I hope I'm understanding this correctly. I'm in the display business and have done several of what I think you are describing. I don't understand the oversize portion, however. You build a box, any shape, from plywood. All mitered corners and the outside/inside is all, in this case, oak. Now you need to edge band it to look solid. If this is the case, you either use veneer tape or thin oak strips. If I use the oak strips, I'll let them extend over by about a 1/32". When dry I'd flush trim with a router. Hand sand with a 220 grit block.

[Andrew Nemeth]

+1 on flush trimming with a router.

[Dave Tesch]

i'd love to flush trim with a router but the angle is not 90 degrees. in this case it is 105 degrees.

[David Prince]

If it is as I think you are explaining, your edge band is thicker than just a thin band. I have done some edge bands that are 3/4 or even more (kinda like a bread-board edge treatment). Plywood does have some variation to it, so I do leave it a bit oversized when I attach it, but I usually use a planer or a jointer to get it as close as I dare before I attach it. From there I will use a ROS and put the pressure on the solid portion. (the belt sander is too hard to control when you are on an edge like that.) If you hold the ROS level, it won't sand the plywood veneer until you are right on it. That is when you proceed cautiously so that you don't go through the veneer. Don't let anything lower than 150 grit hit the plywood. If you get the piece close to begin with, your sanding is minimal.

If I am not getting this, try to explain your project in a bit more detail. It is kinda vague. A better description may get you better answers.

[David Prince]

I re-read your post again. I think you can get the pieces closer to 1/16 or less oversized and leave 1/32 or less on each side. Say your plywood is .71 then you can get your oak strips to .72 or .73. That will save you a ton of sanding. I recommend a $10 digital caliper from HF to mic it in so that you are super close in comparison to the plywood. I would use biscuits to join the edge and this will also help you line up the edge band. Cut your banding long and sneak up on your cut line to cut it to an exact fit as you dry fit it together. Sand with 80 on the oak edge to get it close, then 150 to get it even. After that, just a quick hit with 220 to shine it up. I have done it several times, but you can sand through the veneer if you stay on the plywood too long. If you go through the veneer, you will be in a glue line and that won't take stain. Your only option then is to use paints and an artist brush to faux finish the sand-through spot to match the other or to make a new board. good luck and it isn't difficult.

[Steve Griffin]

Hi Dave,
If I understand your situation, it sounds like you may just be set up for one of those jobs which takes a pile of sandpaper and patience.

A couple thoughts though--can you assemble with more precision somehow so as to not have that large 3/32 bit of oak to sand away?

If I did need to remove that much wood to get to the plywood, I'd be tempted to get it down to say 1/32 with a sharp block plane.

Also, I hope you are using some intermediate grits from 80 to 220. Sanding out 80 grit, or even 100 grit scratches requires a pile of 220 paper and time. I agree with the earlier comment that 150 is coarse as I'd go once you are touching plywood.

Once you get close to the plywood, I like to work in good lighting, keep the sander flat, and keep it moving. Maybe even lower RPM's when you are getting close. I also swear by 6" ROS, as they get more work done in the same time and are easier to keep flat.

hope it goes well. Post some pictures if we are not giving good advice.

-Steve

[johnny means]

I like to use a card scraper for work that delicate. They are fast and precise.

[Dave Tesch]

i'm sorry i was not more clear. maybe a pic will help:



the two angled bands were what gave me so much grief - i left that entire panel wide and sanded it flush; it took forever. i did plan the project on paper but no matter how much trig i did i just wasnt confident until i actually fit the piece. i'm just used to working this way with pine as its easier to make a panel smaller than bigger when in doubt.

there are braces that go inside to help me assemble it so i can cut the panel smaller next time, it just didnt dawn on me until after i had glue it together that i should have spent more time fitting the panel better.

i honestly dont do so much of this level of finish type work, i mostly do paint grade woek. this is not my first 'fancy job' but it is my first trapezoid where i am showing my work (no bondo or edge plies)

[Joe Watson]

i'd love to flush trim with a router but the angle is not 90 degrees. in this case it is 105 degrees.

Can you rip a scrap plank and clamp it to the box and then use a flush trimmer, riding the router on the "scrap plank jig" ?
Or scrap plant jig and a couple pieces of tape on the box, ride the trimmers bearing on the tape to "rough" it closer (to make for less sanding) and then sand finish ?

Just some ideas.

_

[Dave Tesch]

Can you rip a scrap plank and clamp it to the box and then use a flush trimmer, riding the router on the "scrap plank jig" ?
Or scrap plant jig and a couple pieces of tape on the box, ride the trimmers bearing on the tape to "rough" it closer (to make for less sanding) and then sand finish ?

Just some ideas.



_

that sounds really dangerous if i owned a plane i would have tried that i think, but i dont own one. i think that with the internal brace/jig i'm going to have to learn to trust a more exact panel.

[Phil Phelps]

Dave, I can't enlarge the photos to see more clearly. I'm on an old Mac. The bottom pic seems to show joinery of two angles, but the top photo appears to be a single angle that exposes one edge of the plywood. You should have two angles joined together to form a knife sharp edge. To finish off the ends, I would use "iron on" oak veneer tape and trim at the same angles as the joint. In other words, the tape would be a trapezoid. You could even veneer the four peices before assembly. The only difficulty here is the set up to make perfect cuts on the plywood for your joints.

[Dave Tesch]

i though about doing a miter like that, i thought about it a long time and even drew it up and made a cutsheet for those pieces. in the end i decided the likelihood of me getting two perfect 37.5 degree angles on the correct width panel was slim. it is a possibility, it just wasnt in the works for this project.

forgive the poor zoom






but there arent any plies showing - before assembly the two parallel sides had edge bands added - the large piece has 1/4" thick bands and the smaller piece had 9/16" thick which was trimmed down, angle cut and finally sanded down to about 5/16" thick after gluing the panel to the box.

i have one more of these boxes in this project so i am hoping the mistakes i learned from this i wont repeat.

[Jay Jeffery]

How well tuned is your table saw?
If you had a decent dado blade you might cut an angled rabbet that would allow the 2 pieces to nest without the need for a band. If it doesn't work out perfectly, glue them together, then rip a slot for a small band that will be easier to sand.

I've never done this myself though so this is purely theoretical idea.

[Mike Barney Sr]

How about a trim router with a tilt base for the angles?