Resurrection of a CFEI 100 KVA Induction Furnace

[russ57]

  I got some experience with a DEC VAX machine, which left me with an enduring soft spot for VMS. To the point I currently have 6 MicroVAXes..... As much as I'd like an 8800, I don't think I've got suitable storage space for it!

One of my recent projects was migrating some mission critical apps on openVms from alpha hardware to an alpha emulator running on Linux running on vmware esx running on x64 hardware. One of the apps was originally running on Burroughs A series, ported to Vax.



-russ

[awemawson]

Progress on the foundry has been held up by 'other stuff', but also by a persistent roof leak many have tried to cure

The foundry is an 'addition building' to the welding shop which is an 'addition building' and the leak is where the three roofs join.

Initial problem is that the foundry fibre cement roof has been laid to too shallow a pitch (4 - 4.5 degrees - 'big six' should be at least 5 degrees) so water was tracking back up the corrugations and entering at joins - this has been solved by painting with a patent fibre loaded roof sealant.

However, the 'welding shop roof' tucks under the overhang of the 'main workshop roof' then the foundry roof abuts this but the levels prevented the roofer properly flashing the junction with (say) sheet lead. Joins have been 'reinforcing mesh' taped and again painted with the gunge and I really thought that the problem was solved until the wind came from a different direction and again we got water in 

This was traced to water entering the ridge of the main workshop and running down inside to the join. This was hopefully sealed a few days back but we've had no rain since.

I've just been out to inspect as we've had light drizzle for an hour or so, and darn me there is moisture on the floor - but now I'm confused as to whether perhaps this is not a leak but the floor sweating No sign of water where the previous ingress was.

To sort out in my mind the layout of the three roofs I went onto Goggle to try and expand the view and much to my amusement I find where the leak is was some very odd looking object. It took me some while to realise that it is one of the many roofers 'caught in the act' of trying to fix the leak 

[awemawson]

We've just had a bit of 'significant' rain in the last hour, and this shows that the roof IS still leaking and there's no point in trying to convince myself that it was the floor sweating 

I'm very tempted to try injecting squirty expanding foam in large quantities from below into the voids that must exits up between the three roofs, after all there have been many attempts to stop it coming in from above by people far more qualified than me.

Can it make things worse - answers on a post card please . . . .

[hermetic]

Two observations Andrew. It is usually possible, and indeed usually far easier to make things worse than it is to make them better! Trying to fix a leak from underneath doesn't work in my experience. I think you or someone else (preferably you and someone else) need to go up on crawling boards and have a look. Now is not the time of year, but if needs must you CAN paint Chromapol on to a wet roof, the water wicks up through it and it does work, even though it sound unlikely! If the big 6 is in decent condition, and it looks like it is leaking at one place only, you need to start at the top where the roofs meet, and work your way down, removing all the moss and dirt, and any previous attempts to repair the leak, and you need to look carefully. We had a recent leak on a built up felt flat roof, which dripped into the kitchen quite consistently, and I eventually found a tiny crack in the felt, which I scraped out and filled with Chromapol, even though I was very dubious that I had actually found the leak, but it cured it! Nothing more depressing than a leaking roof, I wish I lived closer I would be up and fix it!

[awemawson]

I think the count is now 5 (or may be 6 now) experienced roofers have attacked this without success Phil and every seam, join and overlap have been coated in several applications of Chromopol as have bolt heads etc.

Moss has been removed - the sheets are only about 10 /12 years old, and much crawling about on scaffold boards has been done !

Careful application of a hose pipe gradually working up the roof did at first reveal a weak spot, initially one fixing bolt head lowish down and then right on the ridge / apex of the workshop where water tracked down under the facia / barge board so some twenty foot from where the water emerged. Since then nothing shows up until it rains. This evening there wasn't even significant wind !

. . . but thanks for the thoughts and anyway a bit of googling has revealed that none of the expanding foams create fully closed cell product - the best seem to be 70% closed  cell so will become waterlogged.

. . . . foamed cement perhaps 

[tom osselton]

I wonder about flexseal anyone ever try it?
https://www.amazon.ca/s?k=flexseal&gclid=Cj0KCQiA7qP9BRCLARIsABDaZzjeyWuUOBDwmENH5bi0lONmaIxBqYzBqtxcHFNipUq6Get9wsl0ADcaAru0EALw_wcB&hvadid=208225827327&hvdev=c&hvlocphy=9001314&hvnetw=g&hvqmt=e&hvrand=5745184742793747989&hvtargid=kwd-300327936467&hydadcr=8147_9617955&tag=googcana-20&ref=pd_sl_16u0hohih7_e

[vtsteam]

My experience is probably similar to yours Andrew so I know I'm not saying something new, but ..... a persistent problem leak is often located far removed from where it appears in the building. Water leaks in, hits an internal horizontal member, and then travels a distance along that before falling off. If it hits another horizontal surface, it can then travel in another direction.

If 5 or 6 professional people have worked on a particular area and the leak is still occurring, then most likely the leak is not where it is thought to be. Maybe if you think about it definitely not being there, some other possibility will occur to you.

One other suggestion, which may not be practical, but if there's some way of tracing the water, you might get a clue about where it's entering. If you could spray with a hose a small patch of some colored water on different sections of roof (or different adjoining roofs) the color of the leaked water may give an indication of where the leak is coming from.

That's about all I could think of anyway. I do agree that trying to stop a leak from inside is probably not the best way. If the leak appears to be stopped from some expanding foam, there still can be water buildup inside -- and constant damp is destructive to structure. Or the leak may travel out of that patched area, and appear somewhere else.

Tough situation, especially with cold weather coming on. Fingers crossed, I hope you find the source. 

[Peter Cordell]

Could water coloring pigments/tracing dyes help narrow down the search or thermal camera should show cool damp patches?

[Muzzerboy]

You can buy tracer dye for this purpose. https://www.screwfix.com/p/monument-tools-flourescein-drain-dye-133g/31595

Could get messy though and would take some methodical working to avoid inconclusive results.

[awemawson]

My (possibly crackpot) idea at the moment is to rig a tarpaulin over the apex of the main workshop (where the last leak was found) and observe what happens in the following rain. If nothing comes in I can reduce the size of the tarpaulin and watch and see again.

I fear that dyes and. colorings will get awfully confusing very quickly.

[tom osselton]

Is there any product that is visible with a black light?

[hermetic]

Good idea Andrew, the reason I am still repairing roofes (Rooves?) is that I have no faith in the so called Professionals. I asked a local roofer to put another top sheet on my workshop roof, he has a good reputation, but a pair of "subbies" arrived and did the job when I was away, took them a day, and only cost a grand.............and was as rough as a bulls lug, which is why it got box profile sheets with insulation as soon as I could afford it. Can you take some pics when you are up there?
Phil

[Sea.dog]

Roofs 

[vtsteam]

My (possibly crackpot) idea at the moment is to rig a tarpaulin over the apex of the main workshop (where the last leak was found) and observe what happens in the following rain. If nothing comes in I can reduce the size of the tarpaulin and watch and see again.

Seems like a good plan to me.

[awemawson]

Implementing it won't be easy though Steve. Both flanks of the main workshop have 'lean too' buildings attached that have shallow pitch roofs, so fixing ropes isn't going to be straight forward. And the apex / end wall / ridge where the one leak was found is where the 415 volt three phase supply enters the building.

I'm wondering if sand bags tied to ropes tied to tarpaulins might work with the bags (of necessity) resting on the slopes of the workshop roof. But we do get some pretty fierce winds at times and tarpaulin = sail = potential for a disaster   (there is an 11,000 volt three phase line not very far behind the workshop on this side)

[AdeV]

potential for a disaster   (there is an 11,000 volt three phase line not very far behind the workshop on this side)

Hmmm - where you see potential disaster, I see potential opportunity 

[awemawson]

Ade, I'm ahead of you. When I'd just applied for a 415v 3 phase connection when we moved here, some yellow coated men came knocking on the door wanting to know who owned the land, as they wanted a way leave to re-cable the 11 kV to 415 transformer and the (at that time) bare overhead 415 v 3P cables.

Having just been quoted £7,500 to string a wire from that very transformer to my barn to give me 3 phase in the workshop, I assured them that the land owner would, I was certain, grant a way leave if he got his feed installed F.O.C. And that's how I got a 160 amp per phase 415 volt three phase supply in the workshop 

[vtsteam]

Is it feasible to staple the tarp at it's top edge along a long 2 by 4 (while on the ground)?  Then maybe roll it a couple turns to make sure of the connection. and then clamp that timber at it's ends to the edge of the roof at either end? I really have no idea how wide these roofs are --- also no good mental picture of what the roofs look like/sizes, etc., so forgive the dumb suggestion (if it is).

If that's do-able at all, you could do the same with the bottom edge of the tarp. That might hold it better in the wind. You could add additional clamped cross battens after (not stapled) between for more security.

[awemawson]

Steve if you look at the Google Earth picture that I posted above, the main workshop is about 40 foot square and it’s flanking lean too’s are about 40 x 20 from memory, so it’s a substantial area of roof, but only the end with the foundry abutting the welding shop is the problem despite at least one leak coming from the ridge of the main workshop. 

Sadly clamping is off the menu as the roof edges at the ends are trimmed by 90 degree L sections of fibre cement  with no overhang and of course the lower edges project over the lean too’s with a very small gap that has been foam sealed.

[awemawson]

In the continuing exercise to try and waterproof the foundry building I've decided to re-make all the joins and laps in the roof using a re-enforcing mesh fibreglass tape. Using the same Cromopol compound that has fibres mixed in, the idea is to paint a layer on, embed the mesh, then put another layer on top. Two rolls of 150 mm wide mesh on order, and scaffold boards hoisted ready this morning onto the roof for when it arrives.

Meanwhile I've turned my attention to the roller shutter door. I know that rain has been penetrating under it. Unfortunately the concrete floor slab slopes marginally the wrong way INTO the building at one corner (remember this was laid as a yard not a floor!) resulting in the rubber base seal of the shutter having a harder job to do. To counter this I had hand laid a cement raised kerb for the shutter to close onto, but even so the seal wasn't very good.

I noticed that the rubber of the seal had gone hard over the years, and it's single 'lip' in places had folded under and taken on a 'set' not to return. So this morning a replacement arrived - this time with multiple lips and of course softer rubber.

It just clips on to the 75 mm wide bottom bar of the shutter so I fitted it this morning. It still fails the 'hose test'  playing a garden hose onto the shutter but this is pretty severe and it is still sealing to an imperfect threshold.

It's my intention to remove the hand laid kerb with a Kango back to base concrete, and mould a dead horizontal but somewhat wider one (maybe 10 inches) whose top will  slope outwards maybe by an inch, and when this is fully set, hand form shallow ramps inside and out from sharp sand and cement so that wheeled 'things' can still move around. This will form a smooth surface for the shutter seal and make any rain that penetrates flow back outside. All a  bit of a fag, but it should work.

One issue is that water hitting the shutter currently is entering the top of the seal where it grips the 75 mm bar, and flowing along inside the seal and out at the ends, but I think that this can be solved by using a brush full of the roofing gunge at the metal / seal joint.

[vtsteam]

Water, never where you want it when you want it, and always where you don't.

"It's darn slippery stuff, I tell you," he said, staring out the window at his now emptied 3000 gallon cistern, surrounded by a world of mud, more rain due in the afternoon, with a wood splitter and 3 more cords of wood to split in the middle of it.

[awemawson]

OK I've determined that water is getting in in three places 

A/ Under and round the roller shutter:

    The old bottom seal was replaced yesterday but the seal to shutter joint leaked. Last night I pryed back the outer upper lip, put roof seal gunge  under
     it, re-seated the seal then put more gunge in the angle where they join, and am pretty sure that is now water tight.

    The threshold 'kerb' that it comes down onto is uneven leaving a 1/2" gap in places - I'd intended to chop it out (it's soft sand and cement with added
    PVA) and re-instate it in sharp sand and cement but I've changed my mind - I'll still hack it out, but I've ordered a commercial moulded rubber
    threshold that incorporates a step as a dam and is bonded down with Everbuild Stixall that by all accounts seems amazing stuff and even can be
    installed under  water (It may have to!)

B/ Where the foundry corrugated sheet roof meets the bargeboard above the roller shutter.

    We tried sealing this junction with 'eaves closer' foam inserts and roofing gunge - it improved things but wasn't a full cure. It is this junction that I tried
    (and failed!) to improve today. The re-inforcing mesh arrived so I was up on the roof while the weather was good trying to install it. Sadly the mesh
     hasn't got the 'give' to  sink into the corrugations and still remain on the bargeboard - it just spans across. I had to pull off what I had done for a re-
    think. It did however successfully let me seal two gaping bargeboard joints.

C/ This is what I think of as the 'original leak' as it was the first that I was aware of.

     Water is running down the outermost corrugation of the main workshop roof and straight into the foundry. Theoretically water should never enter this
     corrugation as it is covered by the upper face of the bargeboard, and the sheet to bargeboard has already been taped and sealed as has the moulded
     ridge   capping. This corrugation emerges into the foundry due to the history of the three buildings being built sequentially and the roof being (lets be
     polite!)   imperfectly designed. I think that this leak is going to prove the hardest to cure.
     

[modeng200023]

Well Andrew, there is one thing that comes out of your roof capers.
You are getting plenty of exercise 

John

[awemawson]

Yes John, but not the sort that I like . . .  roofs are NOT my natural element . . oh and by the way that Cromapol is amazingly slippery if you accidentally put a hand or foot on it . . AMHIK . . 

I think the way forward with that particular joint with the corrugations is a squirt of expanding foam into each 'rabbit hole' and when set trim it off vertically and paint a thick layer of Cromapol over the foam.

. . . but I'm open to suggestions . . .

[vtsteam]

The roofing should lap over the barge board, and there should be an overhang past the barge board. That's the basic problem. Right now It forms wells which are actually the lowest points on your roof. The lowest point should have been the drip edge.

Water will sit in those wells, and no matter how you plug the roof/board juncture with goo and foam, that will eventually crack under exposure and freezing and thawing of those wells, and wick water in.

Around here in Vermont any damp juncture that has spray foam inside is sooner or later discovered by ants, who think it's an ideal nesting medium and excavate tunnels in it. It's similar to decaying wood which is easier to carve and more insulative than new wood. This is the downfall of some modern foam panel house construction methods here as well. Any sealing imperfections are eventually discovered by ants. In fact many embody insect repellents for that reason.

I think the only good solution is to eliminate those wells and cover the barge board so there's a continuing slope past the wall to a drip edge. What comes to mind, other than re-roofing properly, is somehow continuing the roof line over the BBoard. I can't think of any ideal easy way to do that. A hesitant suggestion from me would be to try to fill in for a short distance up the roof with overlapping lengths of new corrugated roofing.

Unfortunately this properly should tuck underneath the old roofing, and then overlap the BBoard. I suppose you could try to lap it over both, but then you are presented with having to seal the edge where the old and new roofing lap. Still this is a much smaller thickness joint than those wells, and the reinforcing mesh and goo would likely have a better chance of surviving, than they would in the present location. The other advantage would be the possibility of extending the roofing past the BB for a proper overhang. The overhang might help with your threshold water splash ingress as well