Becma suddenly not reaching welding temp

[RHarris]

Hey, so I am firstly I apologise for the slightly panicked introduction. I've read this forum a few times over the years and it has some really great content! I would contribute more if I had any knowledge worth sharing ;-)!

Alas I am in a sticky situation.

I have a single burner gas forge from Becma in Germany. Very similar to this one, only mine must be a slightly earlier version (as it's a few years old). Only different I can see is the doors are a bit thicker on this new one:

I have been running it on a hobby then part time basis, so not extensively. 

You can definitely forge weld in this forge. I have done so many times with both mild steel and wrought iron.

I ran it a few weeks ago and felt a bit bummed my stainless san mai experiment didn't go so well, but also felt like something wasn't running right.

This afternoon I prepped two billets perfectly of mild + high carbon san mai. Followed my normal procedure. It is definitely not reaching temperature.

This was in bright daylight (the forge, not anvil), so not ideal for gauging but I'd say I Was getting an orange colour at best and not evenly, definitely not to the temperature I weld at.

Any ideas where to trouble shoot with this? I've not experienced this before.

Some observations:

- It seemed to actually sound a little different

- There almost appeared to be a black spot in the center of the forge, on the floor. no idea if that's just some slag or material I've forgotten about, or what.

- My tank is probably 75% full (and is a big 47kg tank, there is definitely sufficient gas)

- I've maintained the walls, floor and doors with high temperature materials

- The hose seems fine, no leaks.

- The regulator also appears fine but I'm not sure how I'd test that, nor how I'd know if it were at fault

- I am pre heating the forge at a medium rate for about 15 mins then blasting it up high. Just doesn't seem to get there.

 

It's never a great timing when these things happen, is it?

 

I have been forging on a part time basis since the pandemic, as my day job stopped completely. There has also been considerable life trauma the past couple of years (as I'm sure many can relate), so for now this is my only income. I find it very peaceful and good for my soul. I think anyone who works with their hands will get that.

 

We were hoping to move in the next 18 months, which would involve moving the workshop. At which point I was hoping to transition to induction only. However, perhaps I may need to get a small replacement gas forge if I can't get this one going :/

 

Sorry for the ramble and if you have the time and any thoughts to spare, it would be sincerely appreciated. 

-Richard

[BillyBones]

Welcome aboard. I can not answer your question. Those who can i will guarantee you will want to pics of the forge running and a little other diagnostics. They will tell you what they need. 

We all have knowledge to share. Even if it has nothing to do with blacksmithing, you would be surprised at the little tidbits of info i have picked up here. 

Anywho just wanted to say welcome. Stay safe and keep it fun. 

[ThomasPowers]

Can you show us a picture of the flame coming out of the burner in the forge?  Can the regulator be turned up?  I had a student bump the regulator once changing the setting but not telling anyone...  Can you check if the burner orifice is not partially clogged? (A speck of rust or joint tape can migrate and cause issues.)

[Frosty]

Welcome aboard Richard, glad to have you. Just so you know the moderators will delete your link to the BECMA site. Posting links to commercial sites that don't pay for advertising is in violation of the site rules. Post pics of your forge, no sweat just not the site.

Pics of it running will help us evaluate the flame, One pic straight in the open door right after you light it, and another once it's as hot as it's getting, plus one from the side so we can see what the flame exiting the doorway (dragon's breath) looks like.

Till then, is the dark spot round and centered on the flame? If so it sounds like your burner is running rich which can be caused by two conditions. #1 doesn't appear to be possible unless there is a mechanism to control intake air I can't see in the picture. That leaves #2 which I believe the most likely. Propane can leave waxy residues that can partially block the jet orifice. Intuition says this would produce a lean flame by restricting the volume fuel of flow. However before it reaches that point it disrupts the shape of the jet of propane leaving the orifice and so inhibits combustion air entrainment while maintaining the same volume of fuel. 

That results in a fuel rich fuel air ratio and a cooler forge. The dark spot in the center of the flame on the opposing forge surface is caused by unburnt fuel impinging on the liner.

The above is just an educated guess and I'm only offering them as possible causes. Some pics as I described above will make it possible to offer better advice.

Ah, the cure I almost forgot. If you remove the jet and clean it with torch tip files it will clear the partial blockage but be careful torch cleaning files WILL remove metal from the orifice enlarging or changing it's shape and messing up with the shape of the jet of propane. So, be gentle and watch what comes out the other end. If nothing comes out STOP!

Frosty The Lucky.

[Mikey98118]

2 hours ago, RHarris said:

The regulator also appears fine but I'm not sure how I'd test that, nor how I'd know if it were at fault

 

All of the symptoms, combined with the time you have been running this forge, indicate a partial obstruction of the gas orifice. Most likely from a little ball of wax and tar; these form from impurities in the gas fuel.

[Irondragon Forge ClayWorks]

As the others have said. When my forge starts acting up, the first thing I do is clean the jet orifice. Nine times out of ten that fixes the problem for me.

[RHarris]

Billy, Thomas, Frosty, Mikey and IronDragon - that you all very much, I sincerely appreciate your help (and welcoming!).

Firstly, I apologise for the posting the link and thank you to the moderator for fixing that. I admit I signed up a year or two ago, read all the rules but then yesterday posted in more of a mad panic than anything else!

This is really interesting and I had absolutely no idea propane could produce this waxy greasy impurity over time. New knowledge to me.

As reading what you describe @Frosty, it occured to me that when I was taking the hoses apart yesterday I did notice one of the fittings seemed a tady greasy. I didn't think much of it.

Now that I've taken things apart further and inspected, I can see greasy waxy stuff over most of the fittings. Not loads, but there is some there.

I've specitically taken apart the jet/nipple bit. The outside is a bit covered in carbon but that specific part doesn't appear to be obstructed (unfortunately?), I almost wish it was then the answer would be clearer.

I have ordered a new hose and regulator that will appear in 2 days time. I figure if the hose is such is waxy, there could be some in the regulator as well.

As you describe re the "dark spot" is pretty much exactly as I see it as well Frosty.

I had a family event today so didn't have time to get it up and running/take photos, but I'll do this when the parts arrive, as per the suggestions of what would be handy to see.

I'm not replacing the on/off tap, as I see no issue with that. The jet part, I also see no issues with it yet, but have found a similar item I could replace it with if needed.

Thank you again for the help. Hopefully it'll get back to normal soon!

[Frosty]

Carburetor cleaner cuts the waxy build up pretty well though I don't know how it would effect the hoses.

Propane is drawn off oil wells, comes from gas deposits or is refined from crude, regardless it all has the same origins. Propane is also very chemically active so carrying paraffins in solution is to be expected. Having it condense out on hoses, fittings and pipe is just another liquid condensing out of solution. 

That never occurred to me until someone here pointed it out a while back, probably Mike but I'm not sure. One of the HVAC guys who services our boiler told me a LOT about about the fate of refractories in oil or gas boilers. Methane is relatively benign but propane tends to dissolve refractories if unburnt propane contacts it and fuel oil is almost as bad. Furnace burners have specially designed flame shapes to ensure all the fuel is burnt before it touches anything. 

Boy, talk about someone who LIKES fire!

Frosty The Lucky.

[Mikey98118]

I find it interesting that he has so much waxy build up. He probably needs to keep the valves and regulator, and clean them out for the next episode. BUT trying to clean out the gas hose is probably not a very safe idea.

[Frosty]

That was my thought too but I'd gone on long enough already without pondering imponderables. If it was working fine for years and suddenly started misbehaving I'd suspect a load of poor propane. Maybe it missed a filtering cycle or needed a little more heat or a higher draw in the fractioning tower. Poor quality control at the manufacturer. The jet could've been uniformly coated, not enough to show residue when rodding out but enough to alter the jet shape. 

Not knowing just what the residue is makes it guesswork picking a solvent to cut it and finding one that wouldn't damage the rubber hose too is too risky for my blood. However, propane rated rubber hose has better odds of not being degraded. Still pressurized flammable gas isn't the thing to gamble with. 

Some of the new chloride free carb cleaners that won't form phosgene are relatively safe for rubber. We get right back to tossing dice again.

Hose and regulator combinations are pretty reasonable online anymore makes it too inexpensive to just replace them. 

Frosty The Lucky.

[Leather Bill]

I've used propane in many applications for decades including home heat,cooking and engines.  I have used propane fueled farm tractors including one I bought in 1958 and still use.  I've never detected wax,greasy or other substances inside hose,regulators nor orfices.  That lead's me to suspect overseas manufactured hose and regulators as possible culprits.  If rebuild kits for gasoline carburators is any indication I can say for certain quility control is sorely lacking.  I've had carbs fail within monthes of rebuild.  On teardown,soft parts were deteroiated.  I've since put extra parts and fuel hose in sealed clear jar of gas and found some were damaged.  A furnace or tractor engine consumes more gallons in a year than a forge of this size would in a life time.  No research was done,just a thought.

I'm not suggesting that equipment should be replaced but some may be able to save money and use higher quility by using gas welding hose and regulator.  An acetylene regulator will fit and despense propane from a grill bottle.   Before 1990 when RMA/CGA IP-7 standard was established requiring grade T hose for other than acetylene,grade R hose had been used by most shops regardless of gas and some still do.  if a shop has a torch,the regulaor and hose can supply a small forge simply by installing a left hand thread to accomindate the hose.  A used welding regulator,a leingth of welding hose and 3 fittings cost's about the same as a new propane hose/regulator set.    

[Mikey98118]

Well, people using propane from different suppliers in different areas, and at different times can have widely varying experiences right here in the good old USA.

For instance, years back a cheap skate buddy of mine bought his propane from the cheapest source he could find. His burner's MIG tip got plugged solid in about three weeks. At that time propane in this area all came from a Shell holding tank in a county north of Seattle (the plant has has since burned down). Propane of varying grades at varying prices were said to be pulled out of pipes at different levels above its bottom. The lower the pipe the more crud in the propane

While, I had to depend on hear-say evidence for that example, I have cut into dozens of old propane cylinders to help students build forges; some where quite clean, and others had tar in their bottoms. Furthermore, which were clean or filthy had nothing to do with the age of the cylinder. Just a little food for thought.

[RHarris]

Just a short side note here - I cannot recommend the Becma forges. I think they're really well made (in my limited experience), but the customer service is dreadful. When I ordered it, I think I had a 2-3 month wait until dispatch with no communication unless I hunted them down. I've contacted a few times over the years for things and they just try to sell you something without listening to the issue at all.

The response I got back this morning was that my forge is not suitable for forge welding. If I over heat the insulation, it could be destroyed. If this is the case, I must replace the insulation.

Good grief!!! I'd just told them I'd relined the forge regularly, forge weld in it regularly. It was actually rated as being a weldable one when purchased as well. Madness.

When I bought it, there were very few options in the UK, so I had this one imported from Germany. We were still in the EU then. I doubt anyone would import this now we've left the EU. There are also much more affordable options out there now that I'm sure will do the same job. But for anyone in Europe who may be considering one, just a "heads up". 

 

Frosty yeah I don't think I really fancy trying to clean out a hose that will probably cost me about £10 to replace, with the potential for explosions :). How often do you replace your hoses? Just if you see any leaks? I have read you should replace them every 5 years, but perhaps that is just a residential law.

There really wasn't much waxy stuff at all, I just noticed small amounts around the fittings. And interestingly none in the jet... I've given the jet hole a clean out anyway, as best I can.

Leather Bill I mentioned this waxy greasy issue to a fellow forger who's got decades of experience with propane, he's also never experienced it. So perhaps it is luck of the draw with what propane you get...

Mikey In the UK there are two propane suppliers, calor and flogas. They're very similar in price. I don't feel like one known as an inferior or cheap product, so perhaps I have just been unlucky somehow. That's real interesting that you've actually seen the crud at the bottom of the tanks yourself though.

This current tank I'm on was from when there was a gas crisis a few months back in the UK. Shortages. Perhaps they were scraping the bottom of the barrel, literally!
 

[RHarris]

Again trying to rule out possible issues, I've inspected the lining. Now I did some patch work on this in Oct and Jan, so I didn't suspect any issues. 

What I found was almost an inch of caked slag on the base of the forge. I assume from wrought iron and borax. But it was sat on top of the lining, had nearly eaten into anything at all... Not sure how... Perhaps the latest refractory cement I used is more agreeable. 

Anyway going to sort the base of the forge out before I start it up again of course. I should add what I'm calling the base is actually a layer I've built up with additional bricks and refractory cement, I'm nowhere near the original base which is some 1 1/4 thick I think. 

[RHarris]

Don't know how helpful this is but this is like a minute after I've lit it up. Do you the fuel air mix is behaving? I am just letting it run on low for a bit at the moment, will try cranking it up soon to see if it can reach the high temps. 

[Frosty]

Ah HAH gas shortage! You might have gotten propane off the bottom of the tank or perhaps the refinery rushed a batch. It happens. Heck, that particular batch might not have had as many BTUs per gallon as "normal" propane. 

I give my hoses a visual inspection if brief before opening the tank valve. Things get bumped and if the fittings holding the mig tips get misaligned the burners don't perform properly. The final leg of my propane circuit is copper tubing from an iron pipe plenum. I replace the hose when the outer rubber coating cracks enough to start losing bits. 

When I say this next, bear in mind my shop is ventilated to an annoying degree I was partially disabled before I got it sealed in, insulated and paneled so breezes flow pretty freely and warm air dissipates through the gaps in the eves. <sigh> Anyway, I almost never check for leaks, especially over my T burners and leak there just gets drawn into the fire with combustion air. A leak on the tank is a safe distance from the fire. I do perform a quick check when I shut it down though, I close the 1/4 turn shut off valves on the manifold before closing the tank valve. Propane WILL back flow through the regulator safely as designed but it takes a couple hours for the hose to drop to zero on the gauge.

Degraded rubber in "propane" components is a sure sign they didn't use propane rated rubber. Bits of rubber can and will catch in the jet, as will thread tape gas rated or not if you don't apply it carefully. I much prefer thread paste as it can't produce little shreds to plug the works. You certainly can apply paste incorrectly and little drips or blobs migrate to where it can do the most harm. 

Yes, Borax flux eats common silicate based refractories. Borax is a strong base, down right caustic when molten. Silicates are dissolved by caustics Sodium Silicate is a good example. Silicates are resistant to acids and vulnerable to bases. 

Fire brick is a silicate based clay product and vulnerable to molten borax as you've come to expect in your forge. The pic is classic "pavement" of dissolved silicates, scale and bits and drips of iron. If you want to help keep that stuff clear scrape it out while it's molten at the end of a session, letting it cool to a solid means you have to break it out doing more damage to the liner.

I am no fan of using a firebrick as the floor of a forge, there are better easier alternatives. A hard firebrick is a heat sink requiring more fuel to bring to temperature and being about the same level insulator as an equal thickness of limestone it passes heat through to no good purpose. If you use an insulating firebrick molten flux will dissolve it like hot water on a sugar cube. That would be the old type light fire brick, newer types are better, some much. The Morgan Ceramics K-26 insulating firebrick is made from alumina ceramics and reasonably resistant to  hot flux AND stays hard at temps exceeding 2,600f. 

When people say "refractory cement" I have to grit my teeth, unfortunately even manufacturers are starting to use the term to describe castable refractories. I cringe because most refractory cements are designed to stick things like brick together NOT act as a flame face furnace liner. I'm trying to adjust my response to take that into account.

A good quality 3,000f high alumina  castable refractory will provide a flame face forge liner that will resist caustic erosion from borax based fire welding fluxes. 

If you're modifying the forge shape from a cylinder to have a flat floor the method I favor is laying a strip of ceramic blanket refractory full length in the bottom of the forge. Feather the edges so the floor meets the cylindrical walls smoothly. Rigidize and cure it. Lastly apply a layer of high alumina castable refractory to the entire interior as the flame face. Do this in more than one stage so gravity doesn't make un-set (pliable) refractory sag from hanging  overhead. Basically apply to one half of the cylinder, leaving it on the bottom until it sets. (hardens) THEN roll it over and apply the other half. 

The current favorite with the Iforge gang castable refractory this side of the pond is, "Kastolite 30 li". It isn't unanimous of course that's more an observed consensus regarding a effective product. Unfortunately folks your side of the pond can have trouble finding an equivalent product. 

Anyway, Kastolite is a water setting, 3,000f high alumina castable bubble refractory. Water setting means it comes dry, you add water and mix it like Portland cement concrete. Bubble alumina refers to evacuated silica spherules that take the place of some of the fine aggregate. The bubble component reduces the weight AND improves the refractory's insulating properties.

Kastolite remains concrete hard to it's maximum prolonged working temperature of 3,000f. There is a safety margin but 3kf is what they certify. 

I got interrupted before I could re-read and submit the above. This morning I'm looking at your burner flame and it looks a little rich but if you've been getting welding heat I wouldn't change it. You DO have a carbon monoxide detector installed. YES? A slightly rich flame is good for welding as it won't promote scale formation unfortunately the richer the flame the more CO produced. 

Frosty The Lucky.

 

[Steve Sells]

you mentioned Stainless Steel, you do realize you need special flux to forge weld that right?

[Mikey98118]

17 minutes ago, Frosty said:

Bits of rubber can and will catch in the jet, as will thread tape gas rated or not if you don't apply it carefully. I much prefer thread paste as it can't produce little shreds to plug the works. You certainly can apply paste incorrectly and little drips or blobs migrate to where it can do the most harm. 

I totally agree. I now use thread-locker. But, pipe goop is fine. Being a control freak, I prefer the other product mainly because of the convenient applicator. That is just personal preference. I used the tape for about fifteen years before deciding that it constitutes doing things the too hard way, and therefore, even a picky-butt should know better than to inflict it on newbies.

[Mikey98118]

As to the flame; the photo is a little washed out, so I won't venture a guess about whether is is a little reducing or not. Just can't tell. However, it is definitely an unusual shape; I don't consider it a bad shape, but just unexpected. It would be surprising if that flame in that forge doesn't reach welding temperature.

[Frosty]

Good point Mike but I did say LOOKS but that may not be a strong enough qualifier. 

The flame is made by a flame holder type nozzle I've seen in various burners from the other side of the pond. I like the flame shape too. I'm liking multiple outlet nozzles more all the time, If I need point heat I have an oxy pro torch.

Frosty The Lucky.

[RHarris]

@Frosty thanks for your thoughts! Alas I have used the ptfe tape on the brass parts as I wasn't even aware of this paste stuff. I was very careful with cutting off any excess so I'm reasonably confident it's all clean in there. I think I may have mistyped what I said before - I was actually surprised that the slag/flux hadn't appeared to eat into the floor at all really. I'm not entirely sure what the high temp cement stuff was I used most recently but it certainly seems to be doing the job! Insulating but also appearing to not being eaten by the high temp or flux.

Indeed I also found like most that the cheap fire bricks dissolve like ice cubes. Trouble is I bought a whole box of them years ago so I sort of use them here and there to patch, just because I have them!

Perhaps if I keep this forge going longer than I once thought, I can look more into what types of refractory I can get over here and do a better job at it all.

I don't have a carbon monoxide detecter but my setup is that the forge and tank are actually outside a doorway. Minor faff to setup but the doorway isn't used for anything other than this forge so I store the forge right in the doorway, it's pretty easy to setup. For that reason I presume all the carbon monoxide is just being released outside and isn't building up anywhere? Worth noting I also forge in a good mask.

@Steve Sells I was attempting to weld it in an oxygen free environment, so not flux needed. However when I attempted that, I Was also experiencing none welding heat, so I stood no chance at welding it together!

@Mikey I will have to checkout this paste stuff then for the future! Sorry I agree the photo is turd. I found it difficult getting the photo without setting my phone on fire. The burner is a shower head type, is that responsible for the unusual flame shape? Or is it cursed?

UPDATE

So my attempt at replacing the hose setup failed. The tap has a 1/2 RHT BSP and the hose is a 3/8 BSP LHT. It seems getting a 1/2 RHT to 3/8 LHT reducer is rather difficult.

But anyway, I have half a new hose fitted to it and a new regulator.

Leak checked everything and fixed a couple of minor leaks.

Turned it on low and let it burn slowly for 30mins or so.

At this point I could already see it was working better.

Ramped it up and it got to welding temp easily.

In fact it was even getting a bit out of control. I was getting white hot very quickly and had to dial it down.

So I'm pleased it is working normally again! I guess the issue is I don't actually know what the problem was. Perhaps the regulator? Or the jet? The jet never seemed to be obstructed to have need cleaning when I took it apart but who knows.

Anyway, much appreciate you all sharing your thoughts. I at least understand it much better now and should I encounter the problem again in the future, I feel like I'll be able to problem solve more effectively!

Happy forging!

[Frosty]

Cool, glad its performing for you again. 

Please don't use the @  symbol with names, it doesn't work like other media and it can mess with the site's operating system then the mods have to go through and clean up the mess. We try really hard to avoid irritating the moderators and Admin gang. 

We'd love to see pics of what you do at the anvil. We LOVE pics.

Frosty The Lucky.

[Mikey98118]

4 hours ago, RHarris said:

The burner is a shower head type, is that responsible for the unusual flame shape? Or is it cursed?

Okay; with that cleared up, I definitely approve of that flame

As Frosty noted; it is actually multiple flames, and on top of that, they are sharper and much longer than the typical flames from ribbon burners; food for thought; especially considering how much easier they are to produce. I just love food for thought

[RHarris]

15 hours ago, Frosty said:

We'd love to see pics of what you do at the anvil. We LOVE pics.

Xxxx, I shall go through and remove the "at" signs, sorry about that. This is one from 2 years ago, a 30th birthday gift for my brother in law. I made it from wrought iron from by his parents place (where he grew up). I've changed my etching process since this but I am still pleased with it, had great balance and tackled dense starchy veg easily as well. It was quite tricky getting it to him, as he lives in Belgium.... this coincided with the UK leaving the EU more formally and the pandemic... but it got there eventually.

I have a life long love of cooking so kitchen knives are a natural choice for me. However, when we are able to move and I can build my own workshop, I would like to explore other areas much further.

I am using a large antique wrought iron with steel face anvil (not really sure of make of weight, no markings, I've looked very thoroughly). I'm also using a relatively small fly press, which I love. When we move, I am debating whether to move to a hydraulic press or the biggest fly press man can make. 

Happy forging everyone!

[Frazer]

Pretty. I love the pattern from the wrought. Did you use nickle sheet between the edge material and rest of the blade?