V-cut saw blade?

[PA strawbale]

I have a wish for a saw blade and I do not know if it exists. My project-- bending baseboard to match the radius (6"+/-) of the wall at the doorways in our strawbale house. I would like to use the standard pine baseboard I use on the rest of the house. Pine does not bend well via steaming. I have tried one bend by making numerous cuts almost the whole way through. This bends okay, but it leaves the kerf-width visible. This would need to be filled in one form or another, which is less than ideal as can be seen in the sloppy attempt in the photo. I am dreaming of a blade (for table or chop saw) that would go from about an 1/8" kerf 3/4" in from the outside of the blade to a point at the edge/tip of the blade. When bending it would simply close the gap completely. One would space the cuts according to the desired radius of the bend. Does any such thing exist?! 

[Coop]

Darn, and your  kerfs couldn’t have been more evenly placed. My only thought would be to fill in the gaps with some kind of wood filler and paint the top edge the same as the wall. Assuming you want to keep the face natural? 

[krtwood]

The teeth would break if they came to that sharp of a point.  What you can do instead of kerf bending is a bent lamination.  Build up multiple layers equal in thickness to what you left when you cut the kerfs.

[rainjer]

Try using a circular saw blade on you table saw. They have a smaller kerf. Also try going a little deeper on your cut. Put masking tape on the outside surface you at the bend.

[wtnhighlander]

A V-shaped kerf might be achieved with a veining bit in a router table. Check into the V-bits used for carving script letters on a CNC machine.

https://www.toolstoday.com/v-14008-ams-159.html?glCountry=US&glCurrency=USD&ne_ppc_id=1701009076&gclid=Cj0KCQjwlvT8BRDeARIsAACRFiVRj3eJ7stv8bRjjST1FDGIB-zIWxjDQa70vwmBC-cu95PB8sjB1tIaAq0KEALw_wcB

[Mark J]

Didn't @pkinneb solve a similar problem with his basement project.

[Chestnut]

I think bent lamination is your ticket here. If you can find pine that hasn't been kiln dried that may help a lot.

Or segments. Cut the curve into 5 segments and smooth the curve. So basically what your doing but cut through and glue back together.

This leaves me wondering why pine? Are you painting? If you are you might be able to find plastic and heat bend that.

[Tom King]

The wall corner would have to be a perfect arc for a perfect cut to work.  Not going to happen in the real world.

[gee-dub]

Flexible molding is available in several profiles.

 

https://www.trimster.com/flexible_moldings?gclid=Cj0KCQjwufn8BRCwARIsAKzP6970t3vHzCUQ7exU2Y1iS0PhSO3C2bK0jLm_EajoQfkLqO03B0euwb4aArHQEALw_wcB

[drzaius]

1 hour ago, Tom King said:

The wall corner would have to be a perfect arc for a perfect cut to work.  Not going to happen in the real world.

This is the rub. The blade would need exactly the right angle, the spacing would have to be precise, and even then if the curve wasn't prefectly uniform, it wouldn't work. Bent lamination is the way to go if you don't want to just paint the baseboard.

My house has those 1/2" radius corner beads on the drywall, which presented a challenge for the baseboards. I don't like the look of bulky corner blocks, which is the most common method dealing with it. The baseboards are milled from 3/4" x 6" MDF with a 1/4" pine shoe molding, all painted. MDF does not like to bend, even with kerf cuts, and you can imagine what happens if you try to steam it.

I was able to make it work by using an ultra thin kerf circular saw blade to make about a million cuts almost all the way through the MDF. The cuts were then packed with Bondo & quickly formed around the corner on the wall & nailed in place. Then when the Bondo set, lots of filing & sanding to make it all look good. The same method was used on the pine shoe. The pieces were extremely fragile until I got them on the wall & the Bondo was set.

[pkinneb]

As suggested by others I used the Flexible trim and it worked great in my basement. If I hadn't done that I would have gone with bent lamination.

[PA strawbale]

Thanks for all your interest and responses! Some of my thoughts below. I've also added another photo to show the wall and baseboard.

Coop - I did use some cheap wood filler on the kerfs in the top photo. I'm guessing a better wood putty would give a better look. Neither the base board or wall is painted and I would like to stick with that. The wall is simply the plaster that was put directly on the straw bales. We prefer this natural look.

krtwood - I think you are right on the the saw teeth breaking if they were so fine pointed. It was wishful thinking on my part. I will think more about your laminate idea. I would first need to figure out how to cut them and then how to glue them. I think that could only be done in place because the curve is not consistent.

rainjer - I wasn't aware circular saw blades have a smaller kerf. Thanks. I am not sure how going deeper on the cut would help with my challenge, although it would probably comply more readily to an inconsistent curve.

wtnhighlander - At first I liked this suggestion, but even with the pointiest bit, 18°, it would only take 5 cuts to get to my 90° corner which would make it too angular. I have over 30 cuts on the one above.

Mark J - I started looking at pkinneb's Basement Project thread but got side-tracked with the climbing stories there! I need to spend more time on it to find the right page of that long thread.

Chestnut - Still not sure on the details on the laminating. How would the non-kiln dried help my situation? Segments, maybe, but would probably need many more than 5, also because of the top view. Not painting. No plastic, sorry!

Tom King - They definitely aren't perfect arcs. The cuts would need to be spaced accordingly, but I think that pointed-bit idea is out.

gee-dub - Thanks, but not considering plastic.

drzaius - Sounds like you found a good solution for your 1/2" radius. Still pondering the details on laminating.

pkinneb - That looks nice, and it will save me looking through that long thread!

Everything is pointing toward laminating. Anyone do something similar with pine? I'd be glad to hear the description and see photos.  Thanks again to everyone!
 

[drzaius]

You will never, ever find a filler, no matter how good, that won't look like filler, so forget that plan.

For laminating the curved pieces, cut the pine into thin strips, maybe 1/8" (might take some trial & error), & a little wider than the final baseboard width. Using the actual curved wall as a form, apply glue to the strips & clamp the assembled lamination against the curve until the glue is dry. Remove the piece & trim to width & thickness, sand it, and install permanently. A glued scarf joint would work well to connect it to the straight baseboards.

I will strongly encourage you to reconsider the choice not to apply any kind of finish (walls and baseboard). If you like the unfinished look, there are clear, flat, water borne finishes that will look like there is no finish at all. It will protect the wood from dirt & grime that will accumulate with every touch, sweeping, and especially washing. Left unfinished, the walls & baseboards will shortly be a filthy, unhygienic mess. 

[Chestnut]

54 minutes ago, PA strawbale said:

Still not sure on the details on the laminating. How would the non-kiln dried help my situation?

So you take a board and cut think pieces 1/16-1/8" thick. Take the pieces and put glue in between them and bend them around a form. Luckily you have the perfect form for this, you wall. I'd cut the laminations and just use your wall as a form.

Here is an example. If you do a search for bent lamination you'll get a lot of results.

For the air dried vs kiln dried. A lot of pine lumber is kiln dried quickly which changes the properties of the wood making it much more brittle. Air dried lumber can bend to a MUCH tighter radius. The radius you have pictured looks tight for even bent laimination using kiln dried lumber. Sourcing something air dried would go a long way. That or segments.

On the segments you wouldn't leave them angular. The segments would get glued togehter and then sanded to form a curve.

[PA strawbale]

Thanks again.
For clarification, I did water-base polyurethane the base board. And full disclosure-- we built the house in 2002 / 2003. The baseboard and walls still look great. Covid and in-between jobs has given me time to work on projects that should have been completed years ago!

How to clamp to those corners will be interesting.

[Chestnut]

If you have some heavy objects I'd use those and just brace it. It doesn't need to be clamped for a long period of time. How is the trim attached to the wall? will you be nailing it? There may be some spring back with bent lamination so some sort of fastening will be required.

[BillyJack]

If I don't have access to wiggle board I either use the radial arm saw to make enough kerfs, take several pieces of 1/8  mdf and wrap to get close to the thickness then apply a 1/8 piece mdf oak,etc. This is what I will do on my poker table build. I will apply Masonite to the needed thickness,using the planer I will plane a piece of 3/4 mdg sapele down to 1/8 and glue in place I will do the same if I change my mind and make a walnut table...

 

[curlyoak]

Due to imperfect corners a lot of fill work is needed. That means to trick the eye best is to paint so you can cover the fill. Laminating would be the best for natural. I would keep the thickness around 1/16". Maybe a fart skin more. Non heart, straight grain would be easier.

[PA strawbale]

1 hour ago, Chestnut said:

If you have some heavy objects I'd use those and just brace it. It doesn't need to be clamped for a long period of time. How is the trim attached to the wall? will you be nailing it? There may be some spring back with bent lamination so some sort of fastening will be required.

Mostly attached with a brad nailer. Some Tapcons.

[krtwood]

For clamping I would probably screw some boards with a notch at the bottom into the wall framing and then use wedges to tighten the glue up against the wall.

[BillyJack]

3-4 oak 1/8 thick is really a tight bend. Can you prop 2×4's against alternation walls to form the bend. It would have to be glued or nailed till it dried. Pull it clean it and apply it. 

[PA strawbale]

19 minutes ago, krtwood said:

For clamping I would probably screw some boards with a notch at the bottom into the wall framing and then use wedges to tighten the glue up against the wall.

Except that my walls are basically an inch of cement-based plaster sprayed into/on the strawbales.

[PA strawbale]

3 minutes ago, BillyJack said:

3-4 oak 1/8 thick is really a tight bend. Can you prop 2×4's against alternation walls to form the bend. It would have to be glued or nailed till it dried. Pull it clean it and apply it. 

The outside end of the curved wall is the easiest part to "clamp," since I can wedge a board in between that and the other side of the doorway. For the other end I could use long 2x4's to brace from the other side of the room. I'll likely need other pressure points around the curve and will need to figure that out.

[wtnhighlander]

If using the wall as your bending form, remember to place wax paper, plastic wrap, etc... between the mess and the wall, or it will all stick together.

Another consideration: polyurathane glue ( original Gorrila Glue type ) cures in the presence of moisture, not air / oxygen. You can make the 'layer cake' of thin strips and this glue in a safe location, then totally encapsulate the stack in stretch wrap before applying it to the 'form', to elimate glue on the wall or floor. Remember to dampen each strip before applying the glue.