Ok, I've got a no2 mk2 modified stove with some little perforations in the top of its vaporisation chamber on the burner head I know it sounds silly but could I use JB Weld smeared over the worn bit to fill the holes? or would it burn off with this monster of a stove (what kind of temps does the burner head reach anyway) If not then are there any other options? I've never done any silver soldering or brazing and wouldn't know where to begin Thanks Ade
No Ade it definitely will not work. You need to get it sil-brazed. I have never tried it, but look at Iani's recent post about his breakthrough into sil-brazing, it is very enlightening and encouraging. All the best - Steve.
Ok I think I might be looking at this silver soldering malarkey Thanks for the help and encouragement fellas Quick question tho, I have a butane/propane can and torch to go on it, but where do I get the solder rods and flux 8-[ I'm also wondering if I could use my paraffin blowtorch 8) 8)
Thanks kerophile 8) one for the printer me thinks! So where's the best place to get these supplies of rods and flux? I googled and was linked to maplin.. Surely that can't be the right stuff
The first thing to understand is that silver "solder" that we mention is not a soft solder but rather a silver-bearing hard brazing material. Tin/Lead soft solders are extensively used in the construction of tanks and pumps for classic stoves but have far too low a melting point to be used on a burner. The replacement soft solders, now displacing the lead-bearing variety, are a tin/silver alloy but again the MPt. is far too low to use on burners. The Easyflo range of silver-based brazes made by Johnson Matthey are the type you need, along with the matching powder flux. http://www.jm-metaljoining.com/products-pages.asp?pageid=63§ionid=3 Have a look on Ebay as there are some sellers of small amounts. THESE ARE EXAMPLES ONLY. I HAVE NOT USED THESE SELLERS ON THEIR PRODUCTS: http://www.ebay.co.uk/itm/SILVER-SO..._Metalworking_Supplies_ET&hash=item232155cf26 http://www.ebay.co.uk/itm/Silver-So...=UK_Trains_Railway_Models&hash=item5d34d5f8d5 Best Regards, Kerophile.
Right, thanks Kerophile, that's just the info I needed I've ordered the stuff I need from eBay, and I also bought some of the graphite yarn this seller was selling to pack the glands of model steam engines 8) thought it might just do to pack my regulator thingy Thanks for the help
Ok small update on this I used my dremel to grind the burner top down to a level surface, levelling off someone else's botched attempt Got it to nice shiny metal and pushed a pin into the holes to get rid of any thin and corroded metal, this made the hole bigger so I used a head off a nail to fill the hole ready for the sil brazing 8-[ I applied the flux and heated it with my old blowtorch head (one that looks like iani's) with a butane and propane mix. Got it red hot and applied the solder it wouldn't melt It's all Johnson matthey solder and flux My torch must be rubbish Now I've ground it down again and have to remove the dried flux.. Do I get a new torch? Has anyone got any preferences for the best torch.. I'm feeling deflated now..
Red hot is too hot. If you got it that hot, there's nothing at all wrong with your torch. Likely you got it too hot, burned off all the flux, then tried to apply the braze filler (not solder!) to the patch after the metal had already oxidized. Try watching this video where I braze the legs on an OmniDawg cap: [media=youtube]J_kd1CvbEGg[/media]p You'll see that I've cut small pieces of braze filler and put them in flux on the clean metal. That way I don't have to worry about when to add the filler - it'll just all melt when it's ready to go. If you watch closely you'll see the legs jump a bit when the filler metal finally melts and flows under the legs. The legs may be a bit red, but the cap surface is not. Here's another video where I put together a minicap: [media=youtube]3gBNHEOWZJ8[/media]p In the minicap example I've put four 1/4" pieces of braze filler wire just inside the cap in a bed of flux (black flux for the steel, white flux for your brass). When the cap gets to temperature you will see the braze filler seep out from the bottom edge as a silver puddle and follow the heat around that is provided by the torch. In both examples I am using MAPP gas, but that's only because it's faster, not better. Propane works just fine, too. I've also done brazing like this quite successfully with a kero-fueled blowtorch. Important factors to accomplish: - clean metal - spotlessly - proper fluxing of the metals with proper flux - small pieces of brazing filler at the spot of repair - gentle heat just to, and not beyond, the melt-n-flow temperature of the filler If the hole you have is too big, the filler will not bridge it. Typically, gap-fill silver braze filler will do 1/16-1/8" gap at best. If it's bigger than that you'll need some filler metal like a brass scrap or brass mesh to jump the gap. Good luck. (Pictures of what you are doing would be a help to anyone here at CCS who is trying to help you with your technique. It's hard to guess what you're doing, so I hope you'll try to help us out with some snaps on your next attempt.) Cheers, BD
Here's an even better video of the brazing I did on a burner just today. [media=youtube]3jlzcu2V-MM[/media]e The closeup footage shows how the white flux becomes liquid and eventually clear. That color change signals that you are very near the melt temp of the filler. Toward the end I add a little filler freehand to the two front braze spots that were looking a bit anemic on filler. If you can go big screen with this video the details are pretty easy to follow. It'll also illustrate how badly my left hand shakes - part of the reason I prefer a static brazing setup over adding filler freehand. Hope this helps! BD
Wow thanks BernieDawg for all the time and effort put into answering my call for help I love this place I am going to clean up my no2 mk2 modified burner today and give it a second go using your wonderful videos as a guide! It's a steel burner with holes in the vaporisation chamber, and I used cellulose thinners to degrease it...(bad idea maybe) Sorry for not putting pictures up, but I only have access to my iPad right now and this can't do pics, I'll have to try and think of a workaround for adding pics I like the static placing of the filler idea much better. I think you're right about me heating too much as the flux burned and went black and insulated the steel from the filler rod.. Do you add detergent to the flux paste mix like it says?
My bad for not reading closely. Your stove looks like this, yes? (picture from onsite post): I don't use mix-it-yourself fluxes. I just buy the tubs of premix. Here's what I use: The black flux is on the left in the bigger tub. You can buy the smaller size with black flux, too. I've not had good luck with white flux and steel. The black flux, on the other hand, works a treat. And, anticipating someone saying "oh, but Gary, that's because you are brazing 4130 steel with chromium and nickel in the alloy", I'd say the black flux works better with all steels for me, not just the 4130. I'd think the black flux should make it easier for you, too. I'd guess a welding supply shop would have a similar product in the UK. One other thought... if you have holes in the top of the #2 vapo chamber it's probably because it has rusted through. 'Twere I (and not seeing exactly where the holes are), I'd consider a patch over the hole to reinforce the area around the hole. You could use brass or steel shim stock for this patch. Cheers, Gary
Yes that's my stove.. I'll have a look for some black flux paste as the mix yourself one is a little awkward! But! Having said that, I actually managed to finish my burner today using your advice and videos I gave it another go 8) This time I mixed the powder flux into a paste without any detergent and it seemed to be better IMO.. What I found worked for me was placing the paste onto where I wanted the solder, then putting the solder into place and using a small butane lighter I heated the flux to remove the water and set the so,der in place (as it seems to move around sometimes and fall off) Then I got the blow torch on it... Not as much heat this time and gently moving the torch around slowly bringing the heat up. Then moving in and melting the bugger It took three goes to get the filler solder to the right level, with cleaning and degreasing inbetween. Then ground the excess off with the dremel.. (wish I could insert Flickr photos here) I also smeared the burner with detergent and put my fingers over the outlets and blew thru it, this revealed tiny bubbles where the hole hadn't been quite filled If it fails in use then I will do as you say and use a cover over the top.. Just a thought.. Would the extra height of a top plate cover affect the flow of petrol vapor through the burner cap? Once again thank you BD for all the help
For mixing the flux, I use 1 part water, and 4 parts alcohol. When you heat it, damn water boils and splatters all over, but the alcohol just burns off, leaving the flux right where you want it. Murph
Heya Murph Per your suggestion, I'm adding both water and alcohol to the flux in my tubs as they inevitably dry out. Works great and makes a fun flame, too. Thanks for that suggestion that you made in a much earlier post. Intelleckt - I don't think a thin slip of metal brazed on the top of the vapo chamber of the #2 would make any serious problem with fuel/air vapor flow. You could always feather the edges with some 220 grit wet-dry sandpaper, then finish up with 320-400-600 to get a good smooth flow surface. Glad to hear you've got it dialed in nicely. BD
