7 years in the waiting i get to start my 42" pompeii

[UtahBeehiver]

Nice looking set up. Coming together very well.

[thevance53@gmail.com]

what is suggested if you don't have overhead structure to support the guide/form? I have made a template for the shape, but hard to keep it true if there is nothing holding it at the top. Any suggestions?

[david s]

I've never used a set up like that to apply the vermicrete. It looks like a good idea, but involves a lot of work to set it up. I've done lots of ovens with the vermicrete layer and i'm pretty used to it, but i've never had a problem getting a really true spherical form, although in my build I have some protruding wire ties which work like a depth gauge. tapping the mix with the flat of the trowel and eyeballing the profile produces a very spherical form. I like to add a little powdered clay to a 10:1 vermicrete mix which helps to make it workable. The amount of water added is very important. Keep adding water until it just begins to pool at the bottom of your barrow or mixing bucket. Approx one third of the volume of vermiculite should be water although the finer the grade the more water is required.

Start at the base and make sure you leave the top flat so you can add the next layer on to it. As soon as the layer starts to lean in against the dome it becomes much easier. I prefer to apply it with hands, but make sure you wear rubber gloves or you'll regret it the next day.

[UtahBeehiver]

Mike, even though I had a rotating template, I agree with David that you can achieve good results with hand work. Are you installing cf blanket underneath or only vcrete?

[thevance53@gmail.com]

Yes, I have 1" of cf blanket and I will put approx 3" of p-crete over that. I have the CF rope gasket for the heat break as well. Thanks, don't want to hijack this thread.

[thevance53@gmail.com]

Oh, found the perlite at Lehi Block, if anyone in Utah was interested.

[leetheldc]

So I poured some test slabs and made a f up I used spray adhesive to stick the mother of pearl down and the glass but I used way to much as it has held most the aggregate to the form resulting in the pic a rough face slab i have taken the forms off a bit early maybe that hasn't helped. I have another slab I have done il let that set another day or so see if that is any better but I don't have much faith in it think I might have to do another test peice and spend a little more time maybe dotting the pieces down with silicon. I also cracked the slab getting it from the bottom form. I also spent yesterday making 12 corbels for my wood gutters just finished sanding the last one so all ready for oiling

[Gulf]

Lee,

I may have had larger objects to apply to the form than you. What ever I was sticking to the form, I applied only the bare minimum of acrylic latex caulk to stick it in place (not enough for it to squeeze out from under the object). I did not have any problems with any of the deco pulling loose from the concrete. I think that I waited about a week to remove the shelves from the forms. I removed the side forms before trying to remove the shelves. If you have an air compresser and the right needle attachmet, you can use compressed air to help separate the shelf from the form.

[leetheldc]

Lee,

I may have had larger objects to apply to the form than you. What ever I was sticking to the form, I applied only the bare minimum of acrylic latex caulk to stick it in place (not enough for it to squeeze out from under the object). I did not have any problems with any of the deco pulling loose from the concrete. I think that I waited about a week to remove the shelves from the forms. I removed the side forms before trying to remove the shelves. If you have an air compresser and the right needle attachmet, you can use compressed air to help separate the shelf from the form.

Ah caulk yes o didn't think about that il pick some up today and have a try with that. I do have a compressor but not sure which attachment you mean is it like a ball inflating needle?

[Gulf]

I have one of those dust blowing attachments. It came with a couple different size needles. I don't think that I acturally had a needle on it when I used it to help separate the forms. Looking back at my build, I think that I waited close to a month for the trickier shelves to cure.. There are better release agents out there. But, I carefully wiped vegetable oil on as much of the forms as I could without getting any on the sides of the glass and shells. Here is the only pic that I have of the dust blower attachment. When you do your final forms, you will want to seal the edges of the melamine so they don't take on water and swell. I taped mine. But, coating them with an oil based paint would probably be better.

[leetheldc]

I have one of those it didn't come with any attachments though but il give it try did you just blow it down the seams? Yes I suppose I should have used some form of release agent il take more time on the next test piece I can just flip the form pieces over and use them again I got some caulk so il have a go later on after I seal my paving. I will defiantly oil the edges I've got plenty lying around cheers for that one

[leetheldc]

I got the other test form prepared I just dotted a small dab of the caulk to the form like you said joe and the mother of pearl stuck in place great I have high hopes for this one il try to get some soap oil or some release agent tomorrow and maybe get it filled I have one sample left of the metallic pigment not the colour of choice but I need to see how it polishes And if the metallic shows before I go for the counters

[Gulf]

Looks great! Did you cut the shell? One trick that I used was prefilling the shells with colored concrete a week or so before. That gave me less to worry about during the big pour.

[Gulf]

Lee,

Sorry, I did not see post #252 until just now.

I have one of those it didn't come with any attachments though but il give it try did you just blow it down the seams?

I remove at least 3 sides and try to nudge the cast sideways. That usually does it. If not, I give it a few blasts of air down the longest side. Aim the the nozzle at a 45 degree angle between the cast and the bottom of the form. I would not use the air on a cast that hasn't cured for 3 or 4 weeks. It could blow some small chips loose. I'm jumping back and forth from small test casts to the larger casts. So, please bear with me . Your final pour needs to set 28 days before you try to release and flip the cast imo. Have some help with you if it is a fairly large piece. That is insurance for the cast and also for your back .

[leetheldc]

I got a load of the shells from eBay ready cut didn't cost much at all there is some great ones I'm going to use in the final pieces. Il keep that in mind about pre filling them. Looking at my final forms the size and angles I have on some of them I'm defiantly going to need that month you say to let them dry I did post a pic of the forms it seems to have gone. Here it is again the 2 big pieces that go round the oven will be a pain they are massive think I might need an army to help me flip them !