Help needed with an old cast iron Trolla 104 heater

here are the quick pix of the stove in question

That's sort of what I thought David
I'm not much of a welder but I think I can repair that already broken back panel
If I do have to drill out I hope they are just mild steel stove screws
What goop did you use on the joints David? Ordinary refractory cement?

WD40 is great for lubricating parts but almost useless for frozen steel bolts into cast iron.
Try this stuff, 10 times better Blaster - Home

For heating you don't need an oxy, just an ordinary propane torch, hot enough for the steel to expand and break the rust bond. Sometimes a tap with the hammer does the same thing. I would try tap with the hammer first and then add PB blaster and wait. If it does not let go with reasonable force (very reasonable) give it another tap and another drenching. Do not use an adjustable wrench, use only the right size ring spanner or socket.
Which part needs repairing?

When you put it back together, use a tap to clean the thread, make sure it is the right size, diameter and thread, by measuring the bolt that came out, then use new bolts and lubricate with lots of graphite in the hole and on the bolt.

If you look at the last picture Marc, you should see a big triangular crack that is around the centre lug
That panel needs to be repaired then the whole thing re-assembled
Never seen that "Blast' stuff I usually use Penetrene

Hmmm Interesting
Said stove just fell apart into the major component pieces
BONUS
Now I can see all of the bolt heads and lay a straight edge over the panels to see how much warpage there is, visually they look straight
I just hosed off most of the consolidated ash and rust and I'll just go and get a decent wire brush now and give it a good scrub, apart from the broken back section this actually looks like a pretty easy rebuild
Time will tell tho

I just tried some Loctite "Freeze & Release" it was on clearance and only $9- so worth a try
But I think it will be a grind and drill job
Not much meat in these cast lugs for tapping much larger so I'm wondering if drilling straight though and just using a nut and bolt would do the trick?

Drilling bolts out of cast, particularly that sort of cast is a bit tricky. if the drill bit cuts into the cast, it will go towards the cast since it is much easier to cut and you ruin your piece. You will have to drill with a small bit smack in the centre. Not too small that you risk to brake it though. Say your bolt is 8mm, a 4mm drill would just miss the cast thread. Use good quality drill bits and go slow. If you are lucky once the bolt is hollow, the remaining sleeve will come out easy, then you can clean the thread with the same size tap.

The baffle plate holders are also cast as are the baffles, those I'll just cut some Mild Steel for
Trying to find some refractory cement is proving to be a problem here if I don't want to pay Bunnings price for the premixed Selleys putty

What bolts?
M8.8 or stainless?
3 of them just snapped off but the other 11 came out reasonably easily
Of course 2 of those snapped bolts are the really important ones

Ooo interesting project.

I shall be watching

Just ordinary mild steel bolts if it's me, installed with lots of graphite.
Drilling out 3 bolts should be a reasonable task. Graphite is a dry lubricant that resists high temperatures and will make undoing the bolts later sort of easier.

Originally Posted by PlatypusGardens

Ooo interesting project.

I shall be watching

Don't expect miracles or a fast progress

I think I am going to have to weld this myself if using cement won't work but I spent an hour today with the wire brush and the propane torch after trying the freeze & release.
It is a little warped as to be expected
Here are a few pix of work so far, perhaps not in order

If all else fails, it will make a nice rustic speaker cabinet

Those side plates that hold the baffle in place look like they are sacrificial and also like they are original, almost completely eroded away where the fire is hottest, I turned them around, one of the baffle plates [ both cast BTW] broke in half but no problem as I was going to use mild Steel anyway
What looked like rust on the sides was a mixture of rust, ash and a very heavy carbon deposit
$38- for a 2kilo bucket of fireproof mortar from Pivot, better than the Selleys via bunnies

Originally Posted by Moondog55

Don't expect miracles or a fast progress

That would make me a hypocrite

That broken section of cast iron is the major problem, that lug holds the single bolt that holds top and bottom together
Picture #'s 10 & 11
Would placing the bits on a table covered with sand hold everything in place while a do a couple of tacks with the stick welder?
I have a few sticks of "Weld-All" here which is supposed to be good for cast iron?
Welding shop up the road would do it for a XMas slab but that money goes to Cecile for her new sewing machine so she can make me my new skiing pants

I don't like your chances of welding that sort of cast yourself (no offence intended) in fact I think the welding shop mya have 50/50 chance/
Cast used for wood heaters is not the best, it is not like welding the head of an engine.
The problem with welding cast is that you need to heat it up, weld it and then keep it hot by burying it in dry sand to cool very slowly.
if you have an oxy you can use old engine rings to weld, or there are nickel rods that are supposed to be good for cast ... (?) Ringtail may have some other suggestion, but it is a part that has no replacement I would give it to a welding shop.
By the way, are you sure there are no parts available for that heater? I remember buying spares for an old Masport heater we had, parts still all available

Trolla went out of business in 1980
No offence taken either as I know 6mm cast is awfully thin and looses heat fast
I've got some "Weld-All" sticks here I used on the old brake discs but those are thick, I was thinking of welding on a sand table which my expert uncle says is one way to do it
Someone suggested just using the refractory mortar but is the mortar strong enough to hold up to the pressure of the bolt?

Here's a thought
I have some of these core drills with the diamond edge for drilling though tiles
Could I just use one of those to drill out the 6mm bolt and just use a slightly bigger bolt with all the holes sealed up with refractory?
Cast iron is much softer than a ceramic tile isn't it?
One of these bolts just will not drill out, new drill bit correct speed and the 1.5mm hole right in the centre and the 4.5mm bit wanders off to the side

You can do the same in a hooded barbeque. Heat up weld and back in the barbeque.

https://www.youtube.com/watch?v=0jqML4oo1RI

Originally Posted by Moondog55

Here's a thought
I have some of these core drills with the diamond edge for drilling though tiles
Could I just use one of those to drill out the 6mm bolt and just use a slightly bigger bolt with all the holes sealed up with refractory?
Cast iron is much softer than a ceramic tile isn't it?
One of these bolts just will not drill out, new drill bit correct speed and the 1.5mm hole right in the centre and the 4.5mm bit wanders off to the side

If you already have a pilot hole, don't jump to 4.5, go from 1.5 to 2.5 and 3.5. The 4.5 center does not sit well in 1.5mm and will tend to pull to one side, particularly if you are not using a pedestal drll

Originally Posted by Marc

If you already have a pilot hole, don't jump to 4.5, go from 1.5 to 2.5 and 3.5. The 4.5 center does not sit well in 1.5mm and will tend to pull to one side, particularly if you are not using a pedestal drll

Absolutely, work your way up.

And invest in a couple of these center drills

OK
I'll try the smaller drill bits first
The alternative which has been suggested elsewhere is to simply splint with a plate on each side and bolts through and hope the refractory cement is strong enough

Originally Posted by Moondog55

OK

The alternative which has been suggested elsewhere is to simply splint with a plate on each side and bolts through and hope the refractory cement is strong enough

No! Thinking about it mild steel and grey cast iron expand at different rates so that won't work in the long term unless using a cast iron plate would work
I will try welding it myself but just a tack on each side and drill a 6mm hole at the end of the crack and seal it with a short screw
it's a short term solution to a single winters heating and I need to keep the costs down as much as I can

Secondary question now
While this stove seems designed to use an ash bed for the wood to burn on I am wondering what effect on efficiency adding a layer of mild steel plate with a turn-up at the rear would have
The cast pimples on the base of the stove are about a quarter inch [ 6mm] high and that's a reasonable gap for airflow
My thinking is that this would allow some of the combustion air to heat up and enter at the back of the firebox just below the angled baffle plate.
also it may reduce the heat stress [ even if only a little] on the rear wall of the firebox.
I only want to do this once so I need to get it right the first time, especially if i can sell it afterwards to get the money back

Haven't you finished this yet?

My crab cooker is ready to go.

It's the glue; ya canna get the good glue these days Cap'n
Actually still trying to drill out these pesky little screws

Hehe all good.



Still no luck with the screws...?
Are you doing it by hand or drillpress?

About the plate on the bottom of the firebox ... Slow combustion are supposed to work with a thick layer of ash at the bottom to protect the firebox. Because they are "slow" combustion, they don't need to keep the firewood up on a rack for the air to come around it and burn it "fast" and all the heat going up the tube.
An open fire, needs a lively fire because it relies only on heat reflected from the fire so the more air the better .. sort of.
Most slow combustion have on the bottom and the sides some form of insulation be it refractory bricks or mortar or something like it. A plate would function as a substitute for a layer of firebricks and delay the inevitable demise of the bottom of the firebox.
I wouldn't think that a plate even if above the box by a little bit, will allow much extra air in the fire for any length of time before it all gets plugged by ashes.

I just said "Bugger't" and drilled them all out 6.5mm, I'll not re-tap, I'll just use 1/4" Brownbuilt bolts
Point taken about the bottom plate Marc but if I can fold one up with high sides and a tight fit I'll make one

As for the heat going up the flue I have been thinking about that very problem.
So long as the top of the flue is 200C hotter than the bottom there will be plenty of draw and as the flue gases can be as hot as 800C I can rob a lot of that heat with a simple tube heat exchange. I'll get some LW angle and some Stainless steel jubilee clips and add fins to that first section of flue and put a 150mm collar around it to encourage vertical airflow

Oh Boy
It is so hot and dry here the "Rubbedin" Hot Spot refractory mortar is setting before I can get the thing assembled, bettet put it on hold until we get the cool change after Christamas

Excuses excuses

?PG / Marc? would you know if adding fireclay to the mortar would cream it up and slow down the cure?

Just being a smartarse

Originally Posted by PlatypusGardens

Just being a smartarse

You?
Surely not?
I phoned the 1800 number for Rubbedin and got a call back from the head mixer/batcher. To quote "Damned if I know-we just make the stuff from standard recipes but it is silica based"

Originally Posted by Moondog55

?PG / Marc? would you know if adding fireclay to the mortar would cream it up and slow down the cure?

Bricky sand has clay, so ... probably yes. As far as slowing it down. Don't know.

No grinding or metal cutting anything allowed today but I found a bit of 5mm MS plate for the bottom of the stove that will fit if I trim it 3mm narrower; 6mm to allow for expansion when it gets hot

OK all put back together and I'm waiting on the refractory to dry before I can turn it over to do the other side
In the end I am relying on the strength of the refractory cement to hold that broken lug in place [ "Rubbedin" say it is that strong when fired] and figuring out how best to do the flue.

Flue all sorted out and an order placed; just need to sell some camping gear so I don't need to dip into the ski savings account and as soon as we get a mild wet day I'll fire it up and slowly set the refractory

Found my 45 angle and did some quick work with a drill and a church key for the cap

Was cool enough and damp enough today for firing up the stove to not be a fire hazard
So I did just that
Even with a single 900mm section of flue it draws reasonably well and most of the joins are fine.
Some joins tho went "Bang" and the air-set just popped out in a piece and I would have sworn they were all bone dry
I'll turn it over and do them again I guess
The plate over the pot hole gets very hot, very fast, more that hot enough to melt snow and boil the billy and with the piece of 5mm plate on the bottom it gets hot fast
Pipe cap made from the A-10 tin works very well indeed

Last but one set of posts i think
Because this will be up close and personal to a polyester tent wall I thought I should moderate the direct radiated heat a smidgen
4.5 flue and a 5 inch outside that, left-over bits from the renos repurposed as air channels and all held together with wire rope twisted as tight as I could get it

OK Last post I promise



Wood heater in it's winter position