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Post by rivergirl on Jul 16, 2012 18:37:51 GMT
am so loving this build !! the workmanship is amazing
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Post by pistolpete on Jul 16, 2012 21:33:22 GMT
@ rivergirl thank you, would never expect praise like that, just bodging my way through as best I can  turkey good mini spotting! Took me 6 years to get that one something like, still plenty to do on it but needed a break hence the oven. I've got a 1293cc supercharged home built engine under the bonnet  certainly not your every day engine. Plenty of grin factor! Took a look at the dome tonight and the mortar is still a little wet, the weight of the tarp has put load on the top course too and push some of them down into the dome a little. Not much but they have sagged. More worrying though are 2 cracks which go from course 4 down to course 2, just as you said they have gone where the bricks are stacked direct onto of each other. I'm damn annoyed at that as we pondered butting a 1/4 brick in to help push the course around a bit so the bricks would be off set from the course below but I read on somewhere that the "key stone" for a course should/could be hidden out of view near the entrance. Bloody annoyed I put looks in front of stability. Smoothed off the mortar in the cracks (still very soft in some) and re-bedded the few bricks on the top course which needed slight attention, rest of the courses are ok. Basically I don't think the mortar has set too much on the top course, we did this one in the evening so it didn't have the sun on it drying it out like the first bucket did plus Dad did the top course and I wonder if he didn't fill the gaps between the bricks as much as I did (I managed to push a lot of the mortar into the gaps tonight with one of my wedged). Lessons learnt. Should I strip down a course and off set the bricks to avoid the "H" problem or just leave it and hope the mortar will hold it once set (and avoid any further "H" moments from now on)? |
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Post by cannyfradock on Jul 17, 2012 9:09:45 GMT
Pete Nobody likes taking their work down, but Turkey's comment on the bricks that are stacked one on top of another.....and you saying that it's already cracking might just push me to relay the last 2 courses. To give you a better idea of "bond" here's a pic of Charlie's dome. Don't be put off by his neat work....my dome's are nowhere near this standard, but it does show clearly the 1/4 and 3/4 bricks he has used to "keep bond....  What is more of a concern is that you are using the ready-made fire-cement for the complete build. Please check on the pot....or ask Liam if this fire cement can be used so thick. Normally the stuff in the pot is only good for 3 to 5mm max. Please don't start to panic. It won't affect what you have done, but if the larger joints at the rear of the dome are still soft......you may have to scrape them out (at the rear ) and re-point with homebrew. I mention this now as IF the fire-cement is not suitable for large joints the top of the dome will be really difficult to build. The "keystone" is the uppermost brick in a vaulted or arched structure. Terry p.s.....Check your PM (private messages)....I'll send you my telephone number just in case you want to give me a call. |
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Post by turkey on Jul 17, 2012 9:48:56 GMT
btw if you check even in Charlies build there are a few H joints, its not always possible to avoid, if you do get one then I would start the course above over that joint to make sure there is the best possible bond either side holding it in, once the dome is complete with keystone it should be fairly well fused. The lowest rings are probably the most stable and able to take this but anything by the opening arch might need to be checked as this will take additional force.
Its hard to see them all from the build shots as some look perfectly offset and others don't and I think some are actually right but the angle of the shot makes them look aligned when they are in fact perfectly spaced. Looking back over it looks like the only ones that line up are the last 3 say on the left hand side? (perhaps these are easy to get to?)
btw for the engine is that some Suzuki swift 3 cylinder type jobbie? I always thought a 16v mini would be a good conversion, a lighter engine, 5 speed gearbox and better reliability.
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Post by pistolpete on Jul 17, 2012 12:35:17 GMT
See you point about having the joints off set. Most are, some are not though and I want to have this right. I'll check it out again tonight and if need be start stripping down the courses to get to the bits that need fixing. The bricks near the left of the door way are the worst. Liam did say it would do when I ordered, its what he used on his but maybe I've mis-understood. I'll give him a ring to confirm. Might have to research homebrew on here some more, where to get fireclay from locally though? Google here I come! turkey engine is a standard Metro lump bored out and rebuilt. Charger is from a modern BMW Mini Cooper, when they build the Cooper S versions first thing they do is upgrade the charger to a bigger version so there are loads of cheap delivery milage chargers floating around (well there was). Clocked 120bhp on the rollers, stopped counting after that |
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Post by pistolpete on Jul 19, 2012 17:05:14 GMT
Ok so time for another update. Its a sorry tale. There are some big old cracks, mainly where I didn't over lap the brick from the course below:    Checked the mortar over again last night (3 nights since I did it) and its still very, very soft once you get through the initial 1mm or 2mm crust. Some of it is crusting better than other (the bottom row for instance which are dong in the blazing sun) but its not ideal.    After talking it through with Liam we've come to the conclusion that it won't do (as it needs heat to cure it which would mean getting a blow torch on every joint enough to get it up to 300C!). Tried that on a small lump (3cm square) and it did "go off" but took be about 5 mintues and when I cracked it it was still soft inside...DOH! Tried to take a brick off and see how easy it was, few quick taps with a hammer handle and off one came, notice the mortar not sticking to the brick and the marks in it where I prodded it to see/show how soft it was underneath. Its just the crust holding a lot of this together at the minute!   Can see the void here too on the top course that my dad missing (to be fair I missed some too further down as you'll see).  Took the top course off hoping that might be it  but then the second looked like it was bad too so gave that a tap and a whole chunk came down, this is the area with the worst cracks and all the "H" joints  In short, don't use the pre-made cement for a pompeii or any brick oven with joints/gaps larger than 5mm. A vaulted oven with angled bricks would do but its homebrew from now on for me. So I started bringing it all down, right back to the floor and we'll start again on saturday with Homebrew (which I pick up tomorrow from Jewsons thanks to the forum account!). One thing I did notice, I put my bricks in a tub of water to try to soak the old mortar off (which sort of worked with some scrubbing). When I put them in the water though they bubbled and hissed, guess its air getting pushed out as the water soaks in? What ever it was its taken the edge off a lot of my bricks as if I've smashed the edges against a wall or something, guessing the bubbling has made some of the brick come away? That or it has reacted with the mortar and water? Anyway, I won't be putting any more in water as a result, not sure how those who say "soak your bricks before cutting" get on? Some plus points from all this set back, I now get to have the fun of building 2 ovens! I'm also going to have a go at the "half solider" route and try a half brick on its side all around the bottom course but on top of the hearth bricks, this should give a good fire area and more strength I hope, will mean the dome has to curve in more earlier but we can handle that now I've had a dry run at it Here is a pic of Jon, me and my little man helping me out who hopefull will be eating pizza from here for many years to come. Another reason it has to be well built, its a lot of weight and I need it strong for when he starts climbing all over it no doubt (the boy that is no Jon)!  Pete |
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Post by cannyfradock on Jul 19, 2012 18:35:38 GMT
Hey Pete....and the gang. You are truly a bunch of Trojans!!!
Reading between the lines you were sent the wrong mortar for a Pompeii build. I also have vertical joints in my Pompeii builds.....but they haven't cracked. It's always best to try and put a half or three quarter in to avoid them, but as someone said.....sometimes it difficult to avoid them. In your case the cracks were caused from shrinkage of the wrong building medium......so glad we sussed that out before you had gone too far.
Looking forward to plan B......keep us informed.
Terry
p.s.....still think that soaking the bricks is a better option when using an angle grinder.
p.p.s....love the picture...
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Post by pete123 on Jul 19, 2012 22:19:15 GMT
Another reason for soaking the bticks is to stop the firebricks sucking the moisture out of the homebrew. I only did mine for 30 seconds or so.
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Post by bookemdanno on Jul 20, 2012 11:58:35 GMT
I'd soak them too. If the bricks pull too much moisture from the mortar, it'll weaken it as the chemical reaction will not get a chance to get going. Like Pete says, 30 seconds dunk or soak the stack with a hose. If its hot, or warm and windy do as Terry did on another build, and keep the work damp. Even put it to bed at night with a damp blanket draped over the work. The longer you can hold off drying out the work the better, IMO. Oh yeah, sorry for your loss! But i do like the philosophy of "hey i get to build another one!" Looking forward to the new dawn. Good Luck! |
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Post by pistolpete on Jul 23, 2012 20:09:42 GMT
Quick update, forgot to upload the pictures at work today so just words for now. The dome is finished! Topped it out Sunday night about 7pm. Homebrew is great to work with btw. Made for a quick build. Roof of the dome is not as sexy looking as I'd like but tough luck and no one will see it anyway. Its not horrific just no sexy. It started going egg shaped which I had to try to recover from but again it should not do any harm. Arch is in and looks pretty good too. Just need to put the entrance arch in, chimney and insulation/final render. Over estimated the number of bricks, ordered 165 and going to have about 50 left over. Not to worry, my dad has the bug so has his eye on them. Terry will be glad to hear that the drink of choice this weekend was Cider. Pictures to follow tomorrow, just wanted to share the news Cheers Pete |
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Post by turkey on Jul 23, 2012 20:23:22 GMT
50 bricks sounds like the perfect number for the matching brick BBQ ;D egg showed oven, you mean you went for the high vault Pompeii custom variation design just as mine morphed into.  |
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Post by pistolpete on Jul 24, 2012 21:28:18 GMT
Had my first drying fire tonight, 3 hours of gentle burning. Lots of soot but its nice to see it with a glow coming out the arch at this time of night Another quick question. I saw on one of the posts that they had wrapped foil around the dome before insulating it. Worth it? Got a feeling it would be a pig to get it to stick enough to get the blanket on but it could also be a real quick win if it does what I think it would. Shiney side in of course! Cheers Pete |
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Post by tonyb on Jul 25, 2012 8:29:26 GMT
A few do but most don't. I've never been quite sure what the benefit was: thermal? mechanical? Having said that, I can't say I've come across any negative experiences.
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Post by turkey on Jul 25, 2012 20:00:38 GMT
it will act as a moisture barrier so not sure if that is good or bad the. If you use it make sure your dome is dry as it will be harder to get the water out due to the barrier.
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Post by faz on Jul 25, 2012 20:23:41 GMT
I can't see it adds much thermal insulation, as it won't reflect much heat if it is pressed against something else. And I agree with turkey that a foil layer is likely to act as a barrier to moisture when you're trying to dry the oven out.
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certainly not your every day engine. Plenty of grin factor!
