filler

The caulk is probably better but I use drywall compound.

Spackle

I agree with Brian that caulk will probably give you more grip.  I used lightweight spackle, but the kerfs in the Homabed I used were a little smaller than yours, so it wasn't as much of an issue.

Homasote Curved Roadbed Filler

I, too, used Homabed and filled the kerfs with drywall joint compound. I did not try caulk, but I suspect it might be a little messy and difficult to produce a uniformly smooth surface and bevel.

Dante 

P.S. Have you painted that roadbed (Homasote isn't blue)? Probably better to wait until you've finished filling the kerfs and forming the bevels.

"I’m thinking caulk would be

"I’m thinking caulk would be the best for flexibility and it would provide some grip for spikes (albeit minimal), but I’m interested in other ideas. '

What do you plan to glue the ties with? I'd select a filler that is compatible with the glue so the ties don't pop off. Thin layer of caulk for tie glue over caulked filled kerfs should work but it would take a lot of caulk to make the roadbed slopes on each side.  I'd also look into just leaving the kerfs and filling them during ballasting with loose material. The roadbed slopes on each side can be made from plaster without needing to fill the kerfs on top. On my last O scale layout I made the side slopes from foam cut with a hot wire to an angular cross section then glued on after the ties were installed, it was light and easy to work with. A lot depends on what you have to work with tool wise and material availability?  ...DaveB

Glue and slope

I plan to use wood glue.

I was planning on using a simple angled wood jig to form the slope when ballasting. 

"I plan to use wood glue.  I

"I plan to use wood glue.

I was planning on using a simple angled wood jig to form the slope when ballasting."

Ok, so I'd check the filler on a short section to see if the wood glue sticks to it before doing the whole layout. Something like "Fixall" might work with yellow carpenter's wood glue but I'd check first to make sure. It will be hard to fill all the saw kerfs without getting the filler on the tie gluing surface so you don't want to use something that has the be sanded totally off to get the glue to stick.  The reason I was suggesting a filler for the slopes is to save ballast, filling in under the ballast with something cheaper like plaster, foam, or wood is a common method....DaveB

You could try...

You could use Durham's Water Putty.  Mix a thin soup for the top, and a thicker batter for the slopes.  With a little practice, its easy to get a smooth, even texture (I use cheap plastic putty knives).  It sticks to just about anything and it loves wood glue.

Available at Walmart, Amazon, etc.

http://waterputty.com/

Wood glue

Scott, I'd experiment with that before you commit.  Wood glue dries harder than Elmer's white glue, and you've got me wondering if you could drive spikes through even a thin layer.  If you had a low-lying area on the roadbed where the wood glue pooled up just a bit, and if that happened to line up with where you had to drive a spike, I'm not confident you could.

Glue test

Already did the test, Joe, and spikes push through the glue fine. But, I may go with white glue because as you mentioned the wood glue is a lot harder and if I had to do some repair it could turn into a nightmare of destruction.

The ballast glue will hold everything in place, so...

Hi Scott:

If you're planning to ballast relatively soon after laying track, then I don't think it really matters what you use to fill the kerfs. The ballast and glue (I like diluted Weld-Bond for gluing down scenery materials like ballast) will lock everything together really well - including locking the spikes to the ties.

So I would go with something that's easy to apply, like spackle.

In S scale, my ties are slightly (36%?) thicker than yours, but I use the stainless steel proto-sized spikes from Proto:87 Stores, and they don't even break through the bottom of the ties. And yet, everything is held together nice and tight. The spikes hold just fine while I'm building and testing track - and hold even better once the diluted Weld-Bond soaks into everything.

Cheers!

- Trevor

"You could use Durham's Water

"You could use Durham's Water Putty.  Mix a thin soup for the top, and a thicker batter for the slopes.  With a little practice, its easy to get a smooth, even texture (I use cheap plastic putty knives).  It sticks to just about anything and it loves wood glue."

   I can second the use of Durham's as a filler, it's quite similar to the Fixall product.  I couldn't recall gluing wood to it so I'm glad to hear that works fine. Once the track is spiked the ties/glue joint  wouldn't be a problem but during construction you don't want to have a ties popping off when you are sanding their tops fair. The other thing you might want to check before going too far is lay a bit of hand laid then a bit of flextrack and see which looks best, unless you are modeling a very old or very small line without tie plates it might look better and be a lot easier to use flextrack.....DaveB

No need to re-invent the wheel

when it comes to individual ties on Homasote. On my current layout, I used Homabed yellow-glued to the sub-roadbed, then applied drywall mud to fill the kerfs and fill in any irregularities in the surface of the Homabed. Somewhat of a Hobson's choice, but I'd stilI rather sand drywall mud as opposed to sanding Homasote inside. I usually hold the sanding block in one hand and the shopvac nozzle in the other. I used a thin layer of carpenter's glue (spread with a putty knife) to hold the ties. I find a 6" putty knife (O-scale, YMMV) is a good tool for smoothing out the drywall mud on top of the Homasote. This is basically the way it was described in MR nearly 50 years ago!

I have a friend who cuts his roadbed from Homasote the same as you are doing, Scott, and he filets the edges to get a bevel with a mixture of builder's sand and white glue - I'm not sure if he dilutes it, it's about the consistency of spackle compound.

Lowell Dorman (sitting within ear-shot of the Milan branch as I type)

Glue 'n' stuff

I've handlaid a lot of track.  I almost always used Elmer's wood glue for ties in the past, and the glue caused no interference with spiking.  More recently I've tried adhesive caulk and it works great.  Spread it out like glue and it creates a nice, flexible bond.  

I normally haven't done much to the kerfs in Homasote roadbed.  I used the Homabed "hidden track" product for my previous layout as it was much cheaper than the regular roadbed with the beveled edges.  It also was in one piece for the full width and could open some wider kerf slots.  Unless the kerfs interfered with something, I left them and filled during ballasting later.

As for dealing with ballast edges, we hobbyists often make this job harder than it needs to be.  Trying to slop plaster, water putty, or other filler around the roadbed isn't much fun.  I use plain sand for the slope, and the final ballast on top of that, usually all at once as the last step in finishing the scene.

Here's a photo of that earlier layout.  All the mainline roadbed here was Homabed with square edges and the occasional wide kerf.  The ballast took care of everything.

Good points about ballast slope

If I've read Rob Spangler's post correctly, he doesn't bother forming a slope with something else before pouring granular materials (sand followed by ballast). Good point. If you just leave the Homasote roadbed square at the sides, you can then let the ballast material form its own slope (the "Angle of Repose", IIRC). And it'll probably look better than something manufactured.

You can try this of course - pour a little ballast on the roadbed and see what it does. Sweep it off or vacuum it up when done experimenting (it'll be an inconsiderable sum compared to ballasting the whole layout) - or glue it in place.

BTW, I'm enjoying your posts on your layout - keep them coming!

- Trevor

Re: Trevor

Correct.  I allow granular material to form the whole slope.  If I have something with a factory beveled edge underneath, fine, if not, fine.  The sand and ballast form the same finished slope in the end.

 " I allow granular material

" I allow granular material to form the whole slope.  If I have something with a factory beveled edge underneath, fine, if not, fine.  The sand and ballast form the same finished slope in the end"

I've done that using mortar or grout as the under coat.  I placed it dry then sprayed it with a mister bottle than added a thin layer of scale ballast and glue. On one layout  I used gray SP ballast so the mortar blended in pretty well and didn't show thru. On another one I used brown grout to better match  brown ballast. This technique works well if the track is already installed, but if the road bed only is in place it seems to me just about as easy to slope the sides with plaster or other compound and let it dry before adding the track( thicker layers of ballast/sand require more care in the wetting and gluing where plaster dries all the way thru automatically) . Either way one saves a lot of expensive scale ballast by filling in with cheaper material.......DaveB

Thanks everyone…

…for the great input. 

I’m not that concerned about saving ballast material when I build the slopes because my branch layout is small. If I was building a bigger layout I would probably be more concerned about conserving material. 

I think I’ll leave the kerfs open now and if a tie happens to fall right over top of one then I could fill only that specific kerf. 

I’ll also mention (in case anyone’s interested) that the offset kerfs make the roadbed extremely flexible and easy to work with. I haven’t used Homabed with the kerfs on only one side, so I can’t speak to its ease of use, but I’m very pleased with the offset approach. I experimented with several different spacing dimensions and 1 inch between kerfs (on the same side) was the perfect dimension. I also used 1/16 inch blade in the table saw. 

Lowell: if you’re within earshot of the Milan branch I’d love to talk with you. Would you mind contacting me via email? Thanks!

how about paper for paper

Sculptamold mixed slightly thin.   It's a paper product, homasote is a paper product.   They both hold spikes....you can create your ballast profile with it and then feather it out to the flat or use it to start irregular land....you can do anything you want with it.   Some people mix it with latex paint instead of water to pre color it.   a bag of it goes pretty far and is very versatile.

Good idea, Loren

I’ve never used Sculptamold, but I just read some reviews and it seems like it might be a good solution. Can’t hurt to buy a three pound bag and give it a test. 

Thanks much!

"I’ve never used Sculptamold,

"I’ve never used Sculptamold, but I just read some reviews and it seems like it might be a good solution. Can’t hurt to buy a three pound bag and give it a test."

Sculptamold is handy for surfacing foam or other material to build up a texture.  Due to  containing chunks of paper it's a bit grainy so probably not as good as Durham's or Fixall spackle for troweling into saw kerfs.  I'd get a small package of both and see where you can use each to advantage. Last time I bought it Sculptamold cost more than Durhams or Fixall so I'd only use it where it has a clear advantage....DaveB