30"/760mm Scotland Pompeii

[jms]

Re: 30"/760mm Scotland Pompeii

I'm not sure I understand your comment "more thermal mass considering I'm not using vermicrete" ??? Vermicrete is an insulator (not a great insulator but an OK insulator - your CalSil board is much better). Therefore it plays no role in the thermal mass of your oven. It's fine to have a bit more mass in the floor - it will take slightly longer to saturate it with heat but that shouldn't be an issue.


My only comment based on your drawing is that your arch appears to be a little too far forward. That is going to cause some weird gaps in your dome-arch transition near at the top of the arch. I wish that I had built my inner arch about an inch or two further back. In my opinion it is easier to fix transition issues when the dome is too far back rather than too far forward - unless you can design it perfectly before you start like some of the pro's on this site!

I remember reading a post some time ago about how vermicrete wasn't a perfect insulator that it did add some mass to the oven. It probably doesn't matter.

The sketchup arch isn't 100%. I was trying to use it to pre-plan cuts but it was just adding to my confusion because of the way the program deals with intersecting objects.

[UtahBeehiver]

Re: 30"/760mm Scotland Pompeii

the taper arch process takes a while to grasp but well worth the effort. Look at Gianni Focaccia's thread. I also documented the tapered arch process too. A lot of new builders are doing tapered arches. Give a yell if i can help.

[Bookemdanno]

Re: 30"/760mm Scotland Pompeii

You can visualise it a whole lot more when you actually get to that section in the real world of bricks, mortar, dust and sore fingers!

Nice start!

[mrchipster]

Re: 30"/760mm Scotland Pompeii

the taper arch process takes a while to grasp but well worth the effort. Look at Gianni Focaccia's thread. I also documented the tapered arch process too. A lot of new builders are doing tapered arches. Give a yell if i can help.

I second this technique, I used it on my oven and it worked very well. I think it provides the strongest and cleanest dome to arch transition available. It does take a little time to wrap your head around what is happening to the brick shapes but once you understand it it makes total sense.

Two things to remember regarding this type of arch, place your dome bricks next to the arch first on each course, they are the most difficult to cut properly and adjustments can be made to mating bricks to get the dome back int perfect position on the next few bricks if needed.

Second using a IT to build this type of arch is very helpful so think about building one.

[EddiePJ]

Re: 30"/760mm Scotland Pompeii

I could have cut up an old brick paver to use as chairs, but it didn't occur to me until just after I had poured it

A better solution if you don't have any steel or concrete chairs, is simply to cut a few short lengths of plastic soil or waste pipe and use that. You can even cut your own seating grooves into it, and structurally it makes a better job than broken bricks, as the pipe will also be filled with concrete.

[jms]

Re: 30"/760mm Scotland Pompeii

I've had a bunch of fun trying to source a brick saw.

They just don't seem to be widely available in the UK. No hardware store sells anything like the Harbor Freight saw which US people can get. I went to all my local tool hire places, most had never had anyone request one before, let alone have one in stock. Two places did have them on their system, one of them had a saw available 350miles away and the cost to courier it here would have wiped out their profit on the rental. The other place had two saws locally, one which was burned out and wouldn't be fixed for a month, the other was on an indeterminate length rental and could be out for just as long. To buy one new online is at least ?600/~$1000.

So I looked for second hand masonry saws locally and found one on ebay not too far away for ?300, hoping I could sell it on afterwards. 1.5hr journey each way, not too bad, we won the auction and went to pick it up yesterday. Looks like it did in the description, obviously well used but not terrible, the seller (a used construction goods reseller, 100% good ebay reputation) couldn't be there but it was at his parents house so they greeted us, nice people. Took it home and left it until this afternoon.

Turned it on without a blade in, motor seems to work fine (it was shown working like this in a video in the description), so does the water pump. Must be all well then? Screwed the blade into place and turned it on. Ouch. When the motor gets to full speed there is the most horrible earbursting loud whistle. When turned off (quickly) the blade took a long time to come to a stop, and the entire motor mounting did a bit of wobbling. After this I checked it with a spirit level and the entire motor mount is off angle by a couple of degrees from the base, and due to this the cutting tray gap doesn't line up with the blade.

At first I thought the whistle might be because of the type of blade, but I found a youtube video of a similar saw using the same brand of blade, sans blood curdling whistle.

NORTON CLIPPER JUNIOR MASONRY SAW BRICK BLOCK STONE TILE SAW - YouTube

If it was just the off-angle I could deal with it by compensating with my cuts. But I have no idea what is up with the whistle. Does anyone here know?

The seller is going to be in my town tomorrow (wed) anyway so has said he will come around and have a look. But I don't know what I can really expect him to do, his listing said no returns and the description is pretty water tight from his perspective. Argh just another in the list of everything that could go wrong, going wrong.

[texman]

Re: 30"/760mm Scotland Pompeii

i suspect the noise is from a bearing about to give up. It may also cause the alignment problem-hard to say. If the blade runs true, as you said, adjust your cuts since you have invested in this saw. You will want hearing protection anyway and that will solve the noise problem. the noise you hear now will be nothing to the noise of the blade cutting firebrick. Good hearing and eye protection and cut away. I have been around saws with that noise you mention and a continued blade spin after shutoff-they are made that way. I am just not sure with yours but use it and be safe. There should be some adjustment to get the cutting gap where you need it so you can make full cuts; you will definitely need that. maybe it fell out of the truck and got tweaked?

Texman

[jms]

Re: 30"/760mm Scotland Pompeii

I expected it to be loud, and to have to wear ear protection. But even if the saw was safe its too much. It pierces at the level where I don't think I can rightfully subject my neighbours to it.

[texman]

Re: 30"/760mm Scotland Pompeii

yikes
that is bad. that is a shame. these ovens are hard enough to build without having these kinds of setbacks. If i could get my old saw to you somehow, i would. but i am thinking it would cost prohibitive from Texas to Scotland. Many builders have cut brick with angle grinders and built ovens. Others have used the old hammer and chisel for half bricks and the grinder for the tapers. It can be done. Hope you can figure out the saw problem.

Texman

PS here is the support for a norton clipper (looks like yours) jut down the road from me-maybe they have someone close to you.

HTH

[Bookemdanno]

Re: 30"/760mm Scotland Pompeii

Like Tex says, there are other options.

You can use compound mitre saws with suitable dry cut diamond dics too, so that you can still set your angles and bevels. You just need to match the speed, size and hole size. You can get reducing washers too, if you get a disc that has a larger centre hole than the spindle of your tool.
Look into the Evolution range of tools, as they maufacture Compound Mitre saws and do a diamond disc which is a direct replacement.
These may be better as they also do cut-off saws up to 350mm diameter with diamond blades also. They seem to be dry cut only, and i've not seen them used for firebrick. These saws would only do a straight cut, so you'd have to fashion some sort of jig for angles. Their Youtube video shows them cutting concrete pavers.
Steellearning has uploaded a vid of him cutting soaked firebrick with a diamond disc modified mitre saw.

[mrchipster]

Re: 30"/760mm Scotland Pompeii

I expected it to be loud, and to have to wear ear protection. But even if the saw was safe its too much. It pierces at the level where I don't think I can rightfully subject my neighbours to it.

Bearings are inexpensive & easy to replace (or have pressed off and on). It'll cost under $20 to see if that does it.

Norton uses. Baldor motors which are very common and easy to find bearings for.

It does sound as if the saw was dropped because of the misalignment. And if there are no adjustments on that saw you may be out of luck.

Not sure if this will help but it is a collection of norton owners manuals but not in English, you may be able to find your on here.
Spare parts lists masonry saws - RuhrBaushop.de

[jms]

Re: 30"/760mm Scotland Pompeii

Thanks everyone. Just out of interest I looked for the shipping cost of getting a saw from the US; $1100. Yeah, no thanks

The seller and his dad came around and had a look and agreed about the problems. He has another one which could be in a slightly better condition. He offered to take it away and get the motor looked at, and look into getting the frame straightened. If it can't be fixed and the other one is better they offered to swap them. I mumbled about a refund and they said they'd like to try fixing it first. So they've taken it away and will get in contact with me before the weekend. Probably the best result I could have expected.

Danno; If it comes to it I'll use a dry saw. I'd just really like to avoid the clouds of dust.

I could buy a brand new masonry saw for ~?700, my worry is being able to sell it on afterwards and not make too much of a massive loss.

[jms]

Re: 30"/760mm Scotland Pompeii

So everything has worked out in the end. The seller replaced the original saw with another due to the bent frame. The screeching sound turned out to be just really really bad blade-whistle, confirmed by putting the blade in the second saw, and using a different blade in both which didn't produce the sound. The second saw is newer so its resale value should be higher according to the seller, although he didn't charge me anything extra for the swap.

I've ordered a new blade which shouldn't have any problems due to it being a proper wet-cut blade with a continuous rim. It should get here early this week, and in the meantime I'm going to clean and oil the saw's moving parts because they are all pretty gummed up.

[UtahBeehiver]

Re: 30"/760mm Scotland Pompeii

Glad it worked out, now you can concentrate of dialing in the taper arch process.

[jms]

Re: 30"/760mm Scotland Pompeii

Glad it worked out, now you can concentrate of dialing in the taper arch process.

After looking through the suggested threads again I think I've got a grasp on what I've to do.

I like the saw jig design which you used in your build. Am I correct in thinking it works with the chipster values in the v4 dome spreadsheet calculator?