Hotblast Grate Changes??

Hello everyone! I have a Vogelzang Norseman stove that is basically a hotblast. It shares the same fragile grates as the hotblast. I have burned mine for a year and have been really anal about keeping the ash pan empty and also try to keep a layer of ash on the grates and my grates have still warped quite a bit. I luckily never broke a nub off...yet... I have decided to modify and replace the grates in my stove. I have looked for some replacements for other stoves that might work without too much modification, but I never found anything that I thought would work. I have finally decided on having a custom set of grates made by a small foundry. The grates will basically be the same design as the old grates, but just beefier. I would like to try to use the same grate frames. I am trying to decide what changes should be made to the grates. Here is what I am thinking so far...
1. my grates as measured are only about 1/2" thick. One grate has sagged down and the other has warped up. I'm guessing that a thicker grate would be less likely to warp and sag. I was thinking of the grate being a good 1" thick.

2. The nubs or shaft portions of the grate are also small and I know they have a problem of braking. My shafts are like 5'8" thick right now. I was thinking of at least a 3/4" thick shaft for the replacements.

3. The joint or socket where the two grates connect in the middle seem to have alot of slop. I added shims to my old ones and later a set screw to tighten them up. I was thinking of doing away with this socket type joint and basically having two male round shafts where the grates connect and using a pipe type coupler in which the two shafts would slide into and then connecting them with a couple of pins.

What do you guys think? What are your suggestions? Let me know!
Thanks!
Ben

Hi ,I have a hotblast and I'm surprised you've had the trouble this soon .I've burnt mine for 4 years so far and the only thing I've had to replace is the brick. There are a few different variations I've seen here as far as mods ,mostly with the fire box design .Squaring it up to get a better burn for instance . Do you burn bit or hard ? My stove when new stated that it was designed for bit and I have tried anthracite ,it does burn a little hotter so that may be the problem . For me it was the cost ,they get around $230 per ton for hard and I drive to the mine with a dump trailer and get soft for $100 ,it is a little dirtier but I'd pay myself $130 a ton to deal with it. Another issue is the way it burns ,the bit almost burns like wood once the fire is going good and I don't need to force feed air. I start with hard wood slab to get stack temp and gradually feed coal after I get a good bed going ,after that I feed about a half to 3/4 of a 5 gal bucket let it draw with the ash door open for about 15 min or so ,then close it up . Bud

Bud, I burn bituminous in mine also. I'm from Montana so there isn't any anthracite around here. The Bituminous I have been burning is good coal although. It seems to be fairly hard and burns hot. I'm not really sure why my grates haven't held up either. I figured it was because they are thin and a poor quality cast as I'm extremely careful with the stove. As far as the rest of the stove, I'm happy with it. I feel that for the price I got what I paid for. The bimetalic damper on the load door is sort of a joke, but with coal I don't use it. I just leave it closed. This summer I built an automatic draft for the ash door. It has a 24volt damper motor that opens a flapper door. The damper is controlled with a thermostat upstairs. I've got the damper assembly bolted to the door, but I still need to run the wire from the thermostat yet. I also am in the process of installing a hot water coil to heat or at least preheat our domestic hot water. I will post pictures when I get it all done.
Ben

If you are going to talk to a small foundry, ask them if they can cast your new grates to ASTM A319. I don't know what your grates dimensions are for that stove, but you may wish to go with a class II or class III in that standard. Class II gives you a high temperature resistant casting with tensile strength (at temperature) of about 30,000 psi. The class III gives you about 40,000 psi tensile strength. If the design doesn't need the higher tensile strength, then you would be fine with a class I.

dj

Bvrwolf ,please be carefull with the hot water idea I tried it with swet fittings and almost had a serious issue I changed from that idea to a loop of soft copper and two three way valves with the coil over the stove and I just preheat the water to my hot water tank with ambient heat . I took the original damper out and installed a blower fan over the opening (haven't used it since ) it pulls through the door.

Sorry ,I got cut off in mid thought ,I use the three ways (and soft 3/4 copper) to isolate the loop during the summer ,I know of some who've put a loop in the stove or at least in the housing ,but you'd need a recirculation pump (more headache than I want) . It saves me about $80 per month in l.p. gas for the hot water tank. Next house will be different may just run tubing in the floor and have a loop for domestic in the winter .

Bud wrote:Bvrwolf ,please be carefull with the hot water idea I tried it with swet fittings and almost had a serious issue I changed from that idea to a loop of soft copper and two three way valves with the coil over the stove and I just preheat the water to my hot water tank with ambient heat . I took the original damper out and installed a blower fan over the opening (haven't used it since ) it pulls through the door.

Bud, you say that your copper sweat fittings unsweated or something? Was your coil made of copper pipe and sweated fittings? My hot water coil is a one piece stainless loop that goes inside the firebox. It has ends that stick out of the stove that you hook up to your hot water tank. I plan on using copper pipe and "sweat" type fittings. I would think that your water temperature would have to be over boiling before a "sweated" joint would come apart. Why did you almost have a serious issue?

Ben

I had an air bubble and no circulation of the water