Scraping pine (grain problems)

[Joe Fabbri]

Hey guys,

I've been making some custom crown molding for a set of exterior pediments. I decided to use simple pine, since I didn't want to spend big bucks, and I figured it would be better than poplar anyway. I cut the coves and angles on the table saw, and the fillet, and I've been working on smoothing them out. I've run into more problems than I thought I would, though. I can't seem to get the grain patterns out of the wood. I made a set of custom scrapers from some old sawzall blades, to match the crown patterns. But it seems the scrapers are just bouncing over the grain lines.

I then tried some sand paper (60 and 100 grit), and I thought I had it pretty good, so I decided to put a thin coat of paint on it, in order to see all the little imperfection, before mitering and putting the crowns up. Some boards that had pretty tight grain came fine, nice and smooth. But others are really showing lines here and there.

Am I going to ever get these out of the wood, or is fresh white pine very problematic in this regard? I'm guessing that a hard wood wouldn't give you these bumpy grain spots, right?

It seems my only options are to chuck the pieces or try to sand and use a filler to smooth out the grain lines. The filler though might be a mess when it comes to keeping the edges crisp.

Any advice is appreciated.

Thanks,

Joe

[glenn bradley]

Pine (and other softwoods) can be problematic. You are easliy removing the softer material and "bouncing over the grain lines" of harder material that is present in pine. For painting (and scraping or sanding) poplar would have been my preferred choice between the two. A long sanding block with the reverse profile would be a good bet at sanding to a smoother surface on the pine as the load is distributed and matching in profile. Even if you get the surface you are after, a really good primer will be a must. Its easy for me to say because I'm not buying the material but, from your description I would be tempted to chalk it up and try again with a different material. Just my .02.

[Joe Fabbri]

Hi Glen,

Thanks for the response. Yeah, you really learn these things the hard way sometimes. I'm new to scrapers, and new to making moldings, so I figured that the softer pine would be easier, not to mention that here in New York the poplar is the last thing anyone wants to use outside. So I went with the pine.

I'd hate to start over with a different material, since poplar is the only other reasonable choice for me and since about half of the trim in pine came out pretty decent. Like I said, where the grain was tight, the pieces are pretty smooth, especially for dormer trim, about 20 ft away.

Maybe I'll give it a go with a tighter grained piece of pine. Only one of the boards so far is really rough. I made them in short pieces (3 feet), which was easier for me to run through the table saw, so replacing one or two is not the end of the world.

I might also try carefully block planing out the high spots of harder wood in the pine. On the convex portion of the trim, that might be fairly easy to do. For the concave portions, well I could try sanding it out more with a dowel, which I did before. This time, I'll skip the scraper and just sand entirely.

[Bruce Haugen]

While pine machines well, it doesn't scrape worth a hoot. Poplar would be a better choice - it's slightly harder and has more uniform grain.

[Joe Fabbri]

If I try to redo it in pine (a better selected board), would it be better then to skip the scraping entirely, and go at it with only sandpaper?

I'd rather not use poplar outside if I can avoid it.

Do you think I would have avoided these problem entirely if I hadn't attempted to scrape at all?

[Bruce Haugen]

yes to both. The problem, as Glenn explained, is that there is a lot of differential hardness between late and early wood in pine. The early grows fast and is a lot softer, and the late wood is slower growth and much harder. Your scraper is digging into the early, softer wood and more or less skips the late wood.

Sanding is the solution. Sandpaper is a tool, too. Don't be afraid to use it.

[Joe Fabbri]

Thanks a lot for the advice guys, I appreciate it.

I'm going to see if the high spots of hard wood will sand out. I'll use a dowel, and maybe cut a cove on a 2x4 and try to work the convex portion of the molding. Maybe the pieces can still be saved. But, if that doesn't work, then I'll start on another piece of pine using only sandpaper to finish it. I'll let you know how it turns out.

Thanks again.

Joe

[john brenton]

You may want to try the "Select Pine" they may sell in the borg. Home Depot usually carries it in my area. It's imported from Sweden or something, and it's a very uniform pine...it almost seems synthetic. It's not (as far as I know), but it's a cheapER (it ain't all that cheap) alternative.

[Prashun Patel]

IMHO, I think yr overthinking this. Pine can be painted just fine.

You'll have to sand up to a higher grit, like 150 or 180.

Then, use a primer. A shellac-based primer like Zinsser BIN is a good choice because it'll also seal the wood against any sap leak, which pine can be prone to over time.

Sand again with 150/180 after the BIN, and then paint with your topcoat. I believe you'll be fine - especially in a crown, where you'll have some distance between the observer and the wood.

Personally, I prefer composite material for exterior crown. It bends better and doesn't open up.

[Patrick Tipton]

FWIW, you can scrape pine just fine, but the scraper has to be tuned just right. I do it with windsor chair seats. When making a scraper, the metal needs to start at a high polish with a nice square edge. Burnish the edge to draw a bit of metal out. Then using a very small angle, roll a very small burr. One or two passes with the burnisher will suffice. If the burr is too large it will break off - not enough and you won't accomplish your task. It is working correctly when you get shavings like a plane set extremely fine. A well tuned scraper will cut fine across grain and end grain, even in softwood like pine.

Regards, Patrick

[Joe Fabbri]

Thanks for the responses, guys.

The pine I got from Home Depot was the clearest stuff they had in regular common. I guess I should have looked into the Select, but I found boards with little to no knots, straight, and decent grain, so I figured it was okay.

As far as the primer goes, I'm using Zinser's oil-based stain killer/primer, as well as shellacking the individual knots first. I'll probably finish with Benjamin Moore brilliant white.

Patrick, I'm also wondering if my problems aren't related to the scrapers I made. They're homemade, from old sawzalls, cut to the shape of the crown itself. I simply used a small round file to burnish the edge. Perhaps in spots I had too much of a burr. Would too much cause it to dig out the soft spots? Or is a heavier burr better for more aggressively hitting the hard spots in the grain?

I got very decent results in some areas. Perhaps when I went to redo the burr at times I made it too heavy or too light, and that changed the results.

Also, I started off using the scraper freehand, but that got tiresome, especially since the scraper is so thin (being from a saw blade). So I switched to putting it in a holder, just an old polyurethane lamb's wool wooden applicator I had laying around. It worked pretty well, and held the scraper tight. It was much easier to use then.

Toward's the end, I took the scraper out and did some freehand. That's the piece that came out worst, but it's also the piece that had the worst grain. So I don't know if it was a mistake to do it freehand or if it was just the board itself.

Will holding it fixed, rather than freehand, make a big difference in terms of jumping over the grain? It seems when the scraper's fixed it functions almost like a scraper plane, right? This would be better, I'd think.

Joe

[Bob Smalser]

Am I going to ever get these out of the wood, or is fresh white pine very problematic in this regard? I'm guessing that a hard wood wouldn't give you these bumpy grain spots, right?



All softwoods are problematic milling crisp detail into the flatsawn face because of the difficulty obtaining clean cuts between soft earlywood and hard latewood.

That's why proper molding stock is...and always has been... vertical grain...and the higher the ring count, the better:

http://pic20.picturetrail.com/VOL12/1104763/18208631/385793690.jpg

This same dynamic also applies to all the...cough...professional tool hacks out there who write page after page on why various Stanleys...particularly combination planes...don't work worth crap. It's rarely the tool, gang, but the idiot behind it, in this circumstance the idiot not understanding that the less mouth the plane has, the tighter and more vertical grain the wood has to be. It's always amazing how far some get without understanding their material.

[Joe Fabbri]

Hey Bob,

Thanks for the reply.

Yeah, I heard that vertical grain should be used, but because of my inexperience, I thought that was merely for the stability of the wood, so that it wouldn't cup. To account for cupping, I oriented the boards to cup in, and stay tight, and I thought that was good enough for flat sawn wood.

Actually I had a few pieces of 1x12 boards that I was going to use originally, in order to cut out the quarter sawn parts out of the edges. But I decided instead get new wood because the old pieces were a bit dented and had nail holes. I guess it would have been much better in the long run, though.

Anyway, I stripped the paint off the pieces, and I made a sanding block the shape of the crown's ogee. I think I got most of the grain high spots down. A few are still slightly detectable when I run my finger over them, but it is very slight and no matter how much sanding they don't seem to go away. Bottom line, I think they're salvageable enough for what I'm doing.

I am, though, making another set of pieces, because one was very rough in terms of the grain and one I cut the molding profile a bit narrow. I'm making these out of vertical grain boards, so hopefully that works out better.

Joe