Large area refinisning

[wptski]

First off, a wood worker I’m not!

I have six birch veneer interior doors that are pushing sixty years old, I’m removing the finish by sanding because I’m doing it in an empty room(hardwood floor is covered with plastic to the ceiling) so I don’t want to mesh with chemicals.

They are standard 30”x 80” so that’s 16.6 sq/ft or 1.5 sq/m which is a large area.  I started off with a DeWalt 5” orbital but ended up with a Festool RO 125.  I did have big box store discs from 60-120 grit so punched new hole, not a problem since I’m a retired mechanic from the auto industry and have a shim die/punch set.  I ordered Rubin 2 150-220 with the RO 125 but bought some 40 grit Granat locally.

I noticed how much better the Rubin 2 was at the start of the pass and the previous pass at 120 grit appeared darker.  Here’s the issue that difference gradually faded the further I got along.  Since I can’t reach across the entire width and keep the RO 125 flat so when the end of the pass reaches the starting point, it’s dark meets light.  The disc is still cutting are my pencil marks are removed but it’s more of a polishing action than cutting, I think.

How would/does this affect my final finish of water based poly which I plan to spray using a HVLP turbine system?  Do I just have to use 2, 3, 4, etc. discs per side?

All Festool sanding videos only show demos on small wood areas and nothing like this.

 

[nclemmons]

A photo would help, but it sounds like you are wearing down the grit on the paper as you progress on a door.  I think you will see a difference in the color under the water based poly.

If you want to go natural, I'd try to finish sand with a fresh sheet of paper once you have removed the old finish.  I use Rubin and Granat and change the discs more frequently as I approach the final finish.

Can you share some photos?

neil

 

[sancho57]

Perhaps it's your choice of sand paper. Festool has a link for the various types and grades of sand paper for different types of sanding. A brilliant or spaniel might be a better choice for you.
http://www.festoolusa.com/abrasives

 

[wptski]

A photo would help, but it sounds like you are wearing down the grit on the paper as you progress on a door.  I think you will see a difference in the color under the water based poly.

If you want to go natural, I'd try to finish sand with a fresh sheet of paper once you have removed the old finish.  I use Rubin and Granat and change the discs more frequently as I approach the final finish.

Can you share some photos?

neil

Okay, here it is and I started this pass from the right hand corner.  I couldn't preview an attachment of it but I think this is bigger and easier to see.  I noticed that the Rubin 2 disc had a lot of sawdust clinging to it, something I didn't have previously and it did vacuum right off.  I was thinking of making a quick pass with a fresh disc.

These doors are in no way flat either, lots of woop de doos in them.  I first thought that the veneer was one thick veneer but found out that it was a three layer.  I was going to flatten them out in Rotex mode.  Yep, burned right through the first layer.    Good thing is on the backside of a normally open door near the hinged edge!

 

[monstrol]

Go with granat, various grits. More up front in cost but will last longer. Just my 2 cents.

 

[wptski]

Go with granat, various grits. More up front in cost but will last longer. Just my 2 cents.

Yeah that's what the Festool selection tool showed which was after my purchases.tool suggests.  Rubin 2 is for wood so once the finish is removed which was with Granat 40 grits isn't it just wood?? 

If I had it to do all over again, I'd go with Granat.

 

[tiralie]

Since I can’t reach across the entire width and keep the RO 125 flat so when the end of the pass reaches the starting point, it’s dark meets light. 

Rubin and Rubin 2 is not great at removing old finish. It can be done but the pads clog up quickly and you do get little or no abrasion. If you can get some old stock of 100, 120 or even 150 Crystal which has been discontinued you will see better results faster. If Cristal is not available, Granat is your next best paper to use.

How would/does this affect my final finish of water based poly which I plan to spray using a HVLP turbine system? 

You will see a lot of crap (swirls, burnishing etc.) once the poly is on. If the doors are not hanging in a very conspicuous place should be OK but otherwise a bit more attention to detail will help.
I would try to get a complete final sanding across the door keeping the sander even. The best way to do this is to get on your hands and knees and sand from the top to the bottom of the door and then back across the opposite way.

Do I just have to use 2, 3, 4, etc. discs per side?

If you can't get some Cristal or Granat that's what it'll take. I think Rubin really sucks for removing old finish. Once you get a majority of the old finish off it's good.

All Festool sanding videos only show demos on small wood areas and nothing like this.

Apply the same principles, just get your body and arms over the work.
Tim

 

[wptski]

Rubin and Rubin 2 is not great at removing old finish. It can be done but the pads clog up quickly and you do get little or no abrasion. If you can get some old stock of 100, 120 or even 150 Crystal which has been discontinued you will see better results faster. If Cristal is not available, Granat is your next best paper to use.

You will see a lot of crap (swirls, burnishing etc.) once the poly is on. If the doors are not hanging in a very conspicuous place should be OK but otherwise a bit more attention to detail will help.

I would try to get a complete final sanding across the door keeping the sander even. The best way to do this is to get on your hands and knees and sand from the top to the bottom of the door and then back across the opposite way.

If you can't get some Cristal or Granat that's what it'll take. I think Rubin really sucks for removing old finish. Once you get a majority of the old finish off it's good.

Apply the same principles, just get your body and arms over the work.
Tim

The first pass was with 40 grit Granat, 60-120 grit was stuff from Lowes, 150-220 grit is Rubin 2 and the picture is from 150 grit.  I'll just have change discs more frequently.

Thanks for the replies!