question about finishing a panel

[jason harris]

Hello everyone, I have searched around a bit but not found exactly the answer that I am after.

I was making myself a stereo rack and a few friends have shown interest and want me to make them one as well. I see the opportunity to get a new tool cheap, subsidised by my friends :o


I have made a mock up of what I want to do. So far I have glued the panels together and used a ROS to sand down the panel where they didnt align exactly due to glueing. I have a bit of a dodgy wrist so I don't like lots of sanding this way.

My question is.. Will I get an acceptable finish by sending the shelves straight through a drum sander after glueing? Is there another better or standard practice for finishing a shelf after glueing?

Hopefully it can be as simple as glueing and sending through the sander but I would prefer to do it properly if this is not the case.

Any help will be appreciated. I also want to stain or coat afterwards.

Here is a small mockup of what I am doing, the lengths could go as wide as 1.5m. The metal is aluminium done on the lathe.

http://homepage.mac.com/jason.jane/temp/rack.JPG

Thanks,
Jason

[Jim Becker]

Jason, welcome to SMC.

I personally do not consider, nor use, my drum sander as a "finish" sander. I use it for leveling a workpiece, etc., almost never changing from the 100 grit media, but continue my finish sanding with a random orbital sander. (ROS) In my case, that's a Festool 150/3. Some folks do use their drum sanders for finer sanding...and there is no problem with that if they get the results they are looking for.

What is most important is that you do not have any scratch marks from the abrasives on your workpiece before you move into the finishing steps. They will very quickly become visible, even to the most uneducated eyes. This is one reason I don't use my drum sander as a finish sander...there is only one direction that the abrasives move across the surface and that means the scratch patterns, even as they get finer, are regular and not random. The more random the scratch patterns, the more they disappear.

BTW, it's important to clean the work surface before each abrasive grit change to insure that stray particles of the coarser abrasives don't "linger" and add nasty scratches when you are using finer abrasives.

[jason harris]

Thanks Jim, I see your ROS is a lot larger than mine and probably doesnt put the strain on your wrist as much as mine so I will look around town at the possibility of a better ROS to suit me.

Another question now pops in to mind. I have seen in some posts that people put the panel through a thicknesser after glueing. If additional sanding after using a drum sander is required then is a thicknesser followed by thr ROS a better option? or is there no real advantage over one another.

I am sure a thicknesser would be a lot less dusty - of the fine kind.

Thanks
Jason

[Ted Calver]

Jason,
Welcome to the Creek. I agree with Jim on the use of the drum sander and I really like the the rack design. It has nice clean lines, probably no worries about heat build up from components, and looks very stackable. Nice job!
Ted

[Brent Harral]

Jason, if you take the time to mill (face joint/plane) and start with flat boards, jointing a *perfect* 90 degree edge and glueing up to keep all flat (using Bessey type clamps and/or cauls), you can get away with some light scraping and minimal use of a ROS. You can certainly load some finer grit paper on a drum sander, but a typical drum sanded finish is not ready for the finish room :eek: If your panel is "flat" i.e. flat enough, I'd run the panel through a planer with SHARP knives if it has the capacity for the width, and follow with some light sanding with a ROS.

If that's only a mock up of what your doing, the real deal is sure going to be nice. Good luck.

[jason harris]

Thanks for the feedback guys. I don't deal with a lot of wood so I dont have a jointer or thicknesser at this stage. I get my wood dressed to dimension from a local supplier.

This type of project is new to me because I have usually made things out of panel eg ply/mdf etc.

I know I can take more care to glue the wood which will minimise the little edges.

I just need to get it right if people are going to pay me for it :)

Thanks,
Jason

[Joe Chritz]

Your supplier may be able to glue and surface the panels for you for a small fee. One of the local places I get my wood from will do it fairly cheap.

If you have a drum sander though using that to smooth the surface and then hitting it with a ROS is probably the best way to go. If you have a medical problem with your wrist check with something like the festool line. Ergonomics on them is supposed to be the best of all. They are expensive but still cheaper than a new wrist and they very well from what every says. My poor public servant salary is going to have to stay with a hand me down PC 333 for a while longer.

Cool looking design. Metal working is a love of mine as well.

Joe

[Jim Becker]

You will need to sand and/or scrap anything after you mill it with a thickness planer, etc. The cutting action actually creates "scallops" as the blades whirl around. It may "look" smooth, but it's not. Your finish will only be as good as your preparation... ;)

[jason harris]

Well thanks for the replies guys.

My summary is that I need to invest in a good ROS. Mine is a small makita which is meant to be used in the palm of one hand, hence why it hurts the wrist after a while when doing larger surfaces.

Second is to make up some jigs so that I can try to glue the panels together as evenly and flat as possible. If this works out well then the ROS is all I will need.

If it doesnt work as well as I would like then I think I may follow up with a drum sander to do the initial sand followed by ROS.

Thanks for the advice so far.
Jason