Making Progress in Montana

[swripley]

Re: Making Progress in Montana

DrakeRemoray,

Thanks for the photo! A couple of questions?what size is your oven? It doesn?t look like you left room for any insulation other than your thermal blanket, how many layers did you use? Any pointers on securing the thermal blanket? What roofing material do you plan to use? Did you cast your vent? This is something I plan to do and would love any pointers you have to pass on.

S

[DrakeRemoray]

Re: Making Progress in Montana

Swripley,
There is a thread about my oven here:
http://www.fornobravo.com/forum/f8/d...-oven-633.html
Post #42 starts to talk about the vent. Let me know if you have questions after you look at that...

As to insulation, There is about 2" of blanket and about 2" of loose vermiculite on the parts where the oven is widest. I ran the oven this weekend on Saturday AND Sunday. The enclosure got about 10 degrees hotter at the widest part, where the fire was sitting...not bad...

Drake

[JoeT62]

Re: Making Progress in Montana

10 degrees is not bad - perhaps I'll stay with the bigger oven. Plenty of time to decide yet.

[swripley]

Cast Vent - Refractory Concrete

Drake,

Hugely helpful! Thanks. Marcel's post to you got me thinking...(M) If I were making a casting such as yours for the re-bar included vent that gets quite hot, or for the re-bar included lintel that supports weight, I'd probably use a similar mix as recommended for refractory mortar for your dome bricks but I would substitute gravel for 3 or even 4 of the 8 parts sand: e.g. 4 parts sand, 4 parts gravel, 3 parts cement, 2 parts fire clay...


I have a few bags of Quickcrete Ready Mix left over from the structural poor. Anyone have an opinion on whether or not I could add fire clay to that and use to cast my lintel and vent?

Sharon

[swripley]

Re: Making Progress in Montana

Disregard my question about ready mix and fire clay. After posting it I dug further and came across wlively's post on Casting Vent that many of you participated in. I then got on the phone and found a local supplier that has KS-4 in stock for what seems like a pretty resonable price. So I think I will just go with that.

S

[DrakeRemoray]

Re: Making Progress in Montana

For others who come across this later here is a link to that thread.

http://www.fornobravo.com/forum/f8/c...highlight=KS-4

Again for the record, the cast lintels I made are the part of my oven that seem the weakest. I would probably just use angle irons if I did it again. The cast vent, on the other hand, is excellent and I get very little smoke out of the front of my oven.

Drake

[swripley]

Re: Making Progress in Montana

Thank you Drake,

I didn't think to include the link to the post I was referring to.

I have decided to follow your advise and go with angle iron and fire brick for my lintels. But will use KS-4 to cast my vent as long as I have a local sorce for it. The photos you posted on your casting are extremely helpful.

Sharon

[DrakeRemoray]

Re: Making Progress in Montana

I have decided to follow your advise and go with angle iron and fire brick for my lintels. But will use KS-4 to cast my vent as long as I have a local sorce for it.

Of course I think that is an excellent plan. I had a dream one night that the lintels in my oven collapsed

My other vent casting advice is that you are supposed to cure these refractory castables, so make sure it will fit in your indoor oven, or get access to a friend's large oven if needed. I also think you could cast the 4 side of the vent separately and mortar them together later...

Drake

[swripley]

Re: Making Progress in Montana

Drake,

I have posted to you several times and just got the Friends reference - very slow of me.

But on to my question - how hot did you cure your vent to? I purchased my KS-4 from an industrial supply and of course there are no directions on the package. Something I didn't discover until I got it home. I have been surfing the web for guidance and everything I come up with has firing up to at least 1000 degrees. How did you accomplish this in a home oven. Or did you just get it as hot as you could and let your oven curing process take it the rest of the way.

I have access to a colleague's kiln if I need to go hotter than I can get in my oven, but I want to make sure it is worth the effort to cart it up there.

Thanks!
Sharon

[Hendo]

Re: Making Progress in Montana

Sharon, sorry to usurp your thread for a minute, but:-

... the cast lintels I made are the part of my oven that seem the weakest. I would probably just use angle irons if I did it again. The cast vent, on the other hand, is excellent and I get very little smoke out of the front of my oven.Drake

Drake, it may be a dumb question, but why did you bother with the lintels at all? I've just been over your construction again, and surely your cast vent would be strong enough to be self supporting?

Cheers, Paul.

[DrakeRemoray]

Re: Making Progress in Montana

Or did you just get it as hot as you could and let your oven curing process take it the rest of the way.

This is exactly what I did....

As to curing it in your friend's kiln. Mine seems to be fine with the cure I did, but if you have access, no reason to skimp...

Hendo, that is a good question. Maybe I did not need them. Though the lintels are thicker than the vent and the vent and lintels support part of the dome over the oven opening, so I figured that they needed some rebar for support...

Drake

[swripley]

Re: Making Progress in Montana

After a brief hiccup I am back on track! Two weeks ago I made my first stab at laying the floor. First mistake was to try to squeeze it into a day were I had a 2:00 commitment. If I have learned anything in this process it is to take your time and not rush for anything. They day was a disaster. Spent an entire morning trying to track down masonry sand, took a wrong turn, finally found the place, sunk into a mud hole up to me knees trying to load the sand by myself, but got my sand and got it for free ? I think they though I was nuts.

I mixed the underfloor paste according to the plans (or so I thought) but couldn?t seem to get the texture right. It was either too runny to hold the notches or so thick that it pulled up loose vermiculite. I got out of square some where along the way and ended up with some large gaps. Very disappointed in the experience I gave up and walked away from it for the day.

I spent the next day cutting brick for the soldier row with a bit more success. After much deliberation I decided to bite the bullet and buy a brick say. My puny little tile wet saw simply wasn?t going to do the job. And at $50 a day for rental, it wouldn?t take long to rack up a bill equal to the price of the saw. I got a 10? masonry saw at Harbor Freight $200 and a $30 blade. I don?t fool myself into thinking this is a fine piece of equipment that will last me for years, but it certainly is doing the job well for right now. It cuts trough the bricks like butter. And I can take as much time as I want to figure things out as I go along. No rushing to return it to the rental store.

I ended up taking the next week off as I had to leave town to attend a wedding in Sonoma. Turned out a break is just what I needed! I talked to several people who have ovens down there and renewed my enthusiasm for the project.

On Saturday, I took out my out my first failed attempt at the floor, cleaned up the mess and started fresh. This time I ?buttered? the back of the bricks with the paste. Worked like a charm. Had the floor down in no time and it was square and level. I had a few gaps but nothing more than 1/16? which I thought I could easily deal with later. I discovered that bricks aren?t perfect so I don?t need to be either.

I dry fit the soldier row and first two courses and figured out how to I was going to handle the oven opening. Got creative with the angle cuts, but I think it is going to work really well. By the end of the day on Sunday, I had the solider row done. Turns out laying brick is a lot like frosting a cake!

I?m taking an extra day off with the Fourth and plan to cast my vent first thing Tuesday morning to give it time to cure before firing it in my sister?s kiln next week. I had a thought I needed some advice on. All of the bits and pieces I have from cutting angles into my bricks got me to thinking. Could I break these up and use them as ?aggregate? in my KS-4? I was thinking that it might add some strength as well as stretch the refractory as I?m worried that I have enough to fill the form.

I?ve attached some photos of my progress thus far. Will continue to post as I go.

Thank you all for your advice and encouragement,

Sharon

[wlively]

Re: Making Progress in Montana

I used KS-4, see my post on your other thread.

I have the manuf specs for curing a KS-4 casting. I can post or email it to you. You only need to reach 500 degrees F which I did in my house oven. It is a specific time and temp schedule though so you have to be prepared for a good long cook. Mine took about 5+ hours.

While you could cast the vent in 4 pieces I think it is just as easy and stronger to cast in one piece. I took the left over foam board, bought a can of 3M spray adhesive and glued a rough shape. Then took a saw and cut a more exact shape, then sanded to final. I made things alot harder trying to make a smooth and elegant "15x6" rectangle transition to 8" round. But everything worked out quite well.

[RTflorida]

Re: Making Progress in Montana

Sharon, fine work so far. Your investment in the $200 HF saw should prove worthwhile. Many of us here on FB have bought the same saw and I believe it has performed flawlessly for everyone. Being in the tool business, I was very familiar with the reputation of their products and had never purchased a thing from them (with a store 10 minutes away), but I burned up my 15 yr old MK tile saw on the first dozen bricks. I had not budgeted $500 or $600 for a new saw for this project....so it was of to Harbor Freight. I literally put my saw through hell - cutting each brick to fit. Saw and blade cut the last brick just as easily as the first. I was impressed. Don't know if it will die the next time I plug it in, but at least my oven is done.
Good luck casting your vent. I didn't have the guts to try a castable refractory (zero previous experience with anything refractory). I chose the easy route and built my brick arch to accompany the Dura-vent pipe, call me chicken....
keep up the great work
RT

[dmun]

Re: Making Progress in Montana

Don't forget the eBay rental plan, you can often sell the used tool for a large fraction of what you paid for it. It can be cheaper than a rental, and you get to keep it for as long as you need it.

Advertise it as used for one weekend home project. Tell the story. Show pictures of the oven. Ebay buyers love stories. It also helps to keep the original packing. It makes it easier to ship, and makes it look well taken care of.