How difficult would it be to modify the standard Hitachi barrel into an EPS grit barrel? I sure safety issues would be the biggest concern.
My ideas: remove blades; fill in gaps with silicone so the barrel is round again; sand this down (with the barrel spinning against some sandpaper) so the barrel is round again ; once smooth & round remove from planer; cover with epoxy and roll through a suitable loose grit mixture (tungsten carbide perhaps).
Epoxy might be a better choice for filling the grooves on the barrel. Maybe the grooves don’t even have to be flush… they might leave an escape route for cuttings? Carbide grit is available pretty cheap and just might work with epoxy for your grit barrel. Definitely wear eye protection in case pieces start flying off. You might be able to slide a sanding drum over you exisiting blade? Not sure of the size you need but here is a link to the type of thing I’m talking about…
In fact, a sanding drum cover somewhat larger so you’d have the same cutting diameter as the edges of your planer cutters, mebbe a section of inner tube or something like that to provide traction and such between the existing barrel and the drum cover.
The problems with silicone are two-fold: it may or may not bond to the aluminum of the barrel itself, and if it does it’ll likely move some under centripetal force…and that could give problems with a questionable bond to the epoxy.
Now, howzabout a middle ground, one that would be cheap and easy to implement?
Take your worst set of cutters, rough sand the bevelled edges and dip them first in an epoxy, then in silicon carbide grit. Let it go off and set 'em in place While this won’t be grit over 360 degrees of rotation, it’ll be a good ‘proof of concept’ to see if the epoxy and grit setup works. Then, you can go from there.
how bout the pleskunas grit blades for the Hi tachi? at the foamese site? Hmmmmmmmmmmmm?.. ambrose…aren’t tools fantastic you can dream ///>>>while pounding a peg with a rock
When I ordered my grit drum for the Hitachi from Fiberglass Hawaii I was offered an inexpensive alternative. Dave said that they also offered “tungsten carbide grit blades”. Seems that they were blade blanks bonded with the same material as the grit drum, slip them in instead of the regulars for a good alternative when working with EPS.
Both personal safety and wrecking your planer may be valid concerns here. The drum turns at about 12K+ RPM and things can fly off with some deadly velocity (I’ve seen it happen). Also, grit drums get very hot regardless of the planer type. The Hitachi is notorious for having the bearings melt into the plastic housing even using just the cutter drum. The “grit blades” that Tomas mentioned might be an easier and safer alternative to a home-brew drum.
I hate grinding through eps with a planer. How about using a hot wire? I cut the foil and rail bands with one. Eliminates a lot of that eps foam dust which seems to stick to everything.
you must not try to fill the gap, that is extremely dangerous, and there is no need as the “speed” bridges the gaps.
any kind of grit glued on with epoxy will work for a while (carborundum, carbide, diamonds) but only on foam, the stringer will make it disappear very fast due to the friction heat. the technique is used in the sheet metal industry on several sanding and polishing tools.
you might be able to use high quality sandpaper (with cloth backing) and use the existing blade clamps to hold it in, in any case you should watch for imbalance and always wear safety glasses when working with power tools.
I made the experience that shapers who bought the sanding dum used it less and less till it was forgotten as the advantages are not that great and the same effect can be achieved with the normal blades and the right technique and adjusted working speed.
I use a 50-grit disc on a 4.5" angle grinder on EPS. Works great, if you don’t mind dust. I also tried a homemade hot-wire cutter on my most recent board, but still had to grind because I was afraid to get too close to my plan with the wire which creeps around in the foam a little. You could also use heavy grit on an angle sander with a soft pad. That way, you’d get variable speed. That’s what Mike Eaton uses to shape his paddleboards out of EPS…
Some kind of applied sanding grit or sleeve etc. may work but these planers turn at really high RPMs.You may want to slow down the RPMs by purchasing a Speed Control Box.They cost around $35 and work great.I use them on routers and disc grinders that don’t have factory variable speed. RB
I made the experience that shapers who bought the sanding drum used it less and less till it was forgotten as the advantages are not that great and the same effect can be achieved with the normal blades and the right technique and adjusted working speed.
Exactly, it’s all about technique. Taking your time with the proper technique can result in a board that is almost completely shaped. Dragging the planer backwards over the blank results in the chatter gouges that are such pain to sand out. Also, cutting too fast can cause the chunking out that we all hate so much, especially when you have dull blades. Shaping at an even speed and concentrating on forward passes, with no dragging cuts… with sharp blades, your tool should yield desirable results. Also, for the truly ballsy you can attempt to learn how to use an angle sander (2500 rpm Milwaukie) with a soft or really soft pad (custom made) and a light grit paper, somewhere around 120-220 grit. I have also seen sanding screen used, but have never tried it. I personally have tried using sanders many times, but I have never gotten confident with one. Though I do know a couple of shapers, specifically one of my fellow employees at Arrow that can take a board to 220 screen with the sander. Then all thats left is the turning of the rails with the screen. But I have never seen it done consistently on longboards, it seems easier to do on shortboards because you don’t really have to hold the sander steady while you walk. You can stand in one place while you do sweeping passes with the tool. The grit drums seem to leave a rougher finish, sorta like as if you had just shaped the board with a wire brush- ick! The plane leaves nice clean cuts- good! -Carl
For roughing with a grinder, I use a 24 grit disk on a hard disk at 3500 RPMs. This cuts very fast and true. Leaves a bit rough but this is just for roughing only. Also some of the higher density EPS foams, lighter sandpaper can melt the foam surface. 24 won’t. For the rough I first get the stringer shaped to close and then move out from there. It’s important to rev the machine up to RPMs and then let off and enter the blank while gliding and then turn the power back on. This makes entry much smoother. Takes a bit of practice to get it just right. On rails cut the bands the same as you would a planer. Again entering on the glide is WAY important. I use a soft pad with 40 or 50 grit at 1500 RPMs after that and then sandpaper and a block.
Yeah, Gregs got it right, I was only talking about finish work before, but you can rough with a grinder, I only use the method on shorboard noses, works great. Haven’t ever gotten around to shaping a whole board that way though. -Carl
Carl, there is a shaper across the hall from me who triggers his planer on and off about a gazillion times a minute, it drives me crazy to hear it. His cuts come out with a velvet texture, too bad the engineers who designed the planer don’t now it is supposed to run at X RPM. He must think it is a variable speed.