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How to sand and finish tight corners?

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Forum topic by Carloz posted 10-15-2017 07:54 PM 1115 views 0 times favorited 4 replies Add to Favorites Watch
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Carloz

973 posts in 428 days


10-15-2017 07:54 PM

I made 8 raised panel mitered doors with profile stiles and rails to match the existing kitchen cabinets? I have a hard time sanding the joints. I tried oscillating tool whick kind of works but the tips of the trianglular sanding paper wear off after one corner. Manual sanding with sanding foam pads misses the corners, so does regular sandpaper. I tried my Dremel with different attachments but it makes more mess than no sanding at all.
The second question: How to stain in the corners? I use water based dye and it is not forgiving to moving the staining pad across the grain (especially that I am using Charles Neils conditioner) and either stile or the rail would have to be stained that way. I cannot use a spraygun as I already wiped on the dye on the panels and do not want a different look.


4 replies so far

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OSU55

1424 posts in 1826 days


#1 posted 10-16-2017 04:15 AM

I prep all the RP parts before assembly due to your issues stated. For dying, I use a stain base with some open time, more than just water, so issues like yours dont occur.

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Carloz

973 posts in 428 days


#2 posted 10-16-2017 08:40 AM

Thanks for the hint with slow drying stain. General Finishes sells some drying retardant i will give it a try. As for preparing before the assembly it does not always work. Like in this case it is very difficult to align the parts perfectly. They inevitably flow during glue up so the sanding is necessary. Even if they stayed perfectly aligned you still need to clean the glue traces.

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JBrow

1274 posts in 757 days


#3 posted 10-16-2017 11:51 AM

Carloz,

Since I rarely use dyes or stains, I am of no help. When I apply a film top coat to project corners, I find a build-up of excess polyurethane pools occurs in those inside corners. In fact sometimes I try to pool a little finish in the inside corners to get good coverage. The pools are then removed by a light wipe or blot with a clean paper towel immediately after application and before the finish tacks. It works ok, although a wipe-on finish may be a better approach but the finishing rag may have to be wrapped around a chisel to coat the inside corners. I do not spray on finishes but would think these inside corners would come out nice when a spray-on finish is applied.

Sanding inside corners is a challenge for me also. Some things I have done are to 1) Wrap a piece of sand paper (4-1/2” x 5-1/2”) in a tight cylinder. The stiffness seems to allow greater pressure to be applied at the end the cylinder thus allowing the sandpaper to bite a little better. 2) A sharp chisel can sometimes work when pulled to scrape the wood. 3) When sanding two pieces that form a ninety degree angle, I sand a past the joint line. This introduces some cross-grain scratches on the adjoining piece. Once the joint is flush, those cross grain scratches are removed with patience and sanding up to the joint line on the second perpendicular piece. 4) Finger pressure applied to the very edge of a folded but flat piece sandpaper can help apply pressure fairly close to a joint line or transitions in a profile.

I normally cut a full sheet of sandpaper (9” x” 11”) into four equal pieces. I then fold one of these pieces with two folds to form a folded 3-layer piece of sand paper. This affords the sandpaper some stiffness, while leaving it flexible enough to follow contours. Since sanding contoured corners is so difficult, ensuring the sandpaper is fresh and cutting well can save some time.

Dealing with glue squeeze out in these tough-to-sand places is difficult so cleaning any squeeze-out after the PVA glue has skimmed over (after about 15 minutes in the clamps) can leave little, if any, cured glue to sand away later. A chisel can be used to scrape skimmed-over glue off the work pieces.

If the glue is allowed to rest until tacky before bringing the joint together, the tendency of parts sliding around when clamped can be reduced. But then on the end grain of those mitered joints may require a second very light coat of glue after the first coat has tacked. The end grain can soak up some of the initially applied glue.

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Rich

1980 posts in 426 days


#4 posted 10-16-2017 02:37 PM

There are a number of ways to limit the slippage when gluing up mitered corners. The most important is to use a clamp made for the purpose with corner blocks that push them into alignment. There are several different brands that use different designs, but all of them serve that purpose. Do a search for “picture frame clamp” to see some different options.

You can also add some table salt to the glue to give it some friction. Not so much that it keeps the joint from closing up, but enough to give it some grip. Finally, drive two thin brads into one face and clip it off nearly flush with the surface. The main downside to this method is that the boards won’t self-align in the clamps, so you have to get them pretty much perfect before you add pressure.

-- No matter how much you push the envelope, it'll still be stationery.

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