Steel Boilers

[palmcoast]

Thanks to suggestions from forum users, the problem of the tapered barrel is resolved. Now I come to the matter of the plates. There are some serious difficulties in flanging 3/16" plate!, I can only think of making pairs of substatial press tools and forming the plates at red heat. Alternatively, to make the plates flat, of greater thickness sufficient to give a wide weld bead. I'm doubtful about the latter. with the probable flexing of the plates over a cycle of steaming. Also this would be departing from the original design, Martin Evans "Highlander". Any comments / ideas would be welcome.. Tom

[jasonb]

I don't recall seeing any model steel boilers with flanged plates, are you just trying to copy a copper boiler but in steel as 3/16" in steel sounds a bit thin by the time you have allowed for wasting.

Jason

[mutley]

If as Jason ask you are trying to use the copper boiler design for steel then dont. 3/16" plate is not thick enough under the current regs. You need to be looking at 6mm minimum. Steel boilers dont use flanged plates either. There are designs out there for this boiler, in steel but they have the disadvantage of a smaller firebox due to the thicker material necessary.

Andy

[palmcoast]

Well, Martin Evans states in his description of the boiler design,
that it could equally well be built in steel with the same material thickness. so I have been working on that basis, not having information to the contrary. Having only recently rejoined the model engineering scene, after a long time spent abroad, it seems that I have missed out on a lot of developments. So, where should I look for up to date information with respect to the boiler for Highlander. I find it hard to accept that 6mm steel is required for the barrel and plates, at that rate the thing would need a substantial crane to lift it. Assistance would be appreciated. I have just ordered a rolled tapered cylinder for the barrel, in 3/16 plate!! it was very expensive.. Tom

[jasonb]

You need to do some reading first.

1. Is your barrel from boiler plate with all the correct paperwork, you can't just use MS plate, and all materials need to have paperwork with their source and spec on.

2. Are you a qualified welder or going to submit test welds for a boiler inspector to test and approve.

3. Will the joints have the correct weld prep

4. Your insurance company will want to see an approved drawing

It goes on.

I don't know the size of a highlander boiler but the next traction engine I'm thinking of has a 6" dia boiler and all the platework is spec'd as 5SWG (0.212") though it will likely end up using metric plate so 6mm

Jason

[klendo]

Jason

Just a quick pointer parts 2 and 3 are not quite correct, as there are different rules for coded and non coded welders.

He doesnt need to be a coded welder and send in welds to be tested..

Parts 1 is correct but part 4 is nearly correct in that the boiler inspector himself will need to see the approved design if he is signing the boiler ticket as he is the one passing the boiler therefore with a valid certificate the insurance comany will accept it as the onus is on the boiler inspector to have done his job correctly.

[palmcoast]

Hi Jason, Thanks for your interest. Yes, the barrel is rolled from boiler plate and the makers are supplying all the parework... I have had a good deal of welding experience with gas, arc, mig and tig, in mild and stailess steel, . but I'm not formaly qualified. I understood, from recent comments on this site, that unqualified welders can produce boilers for their own use, but the testing regime is more onerous. As regards the drawings, I am working to those by the loco designer. who stated in his write up, that the boiler could be built in steel and the construction to be in 3/16" plate throughout. Now, that seems rather unlikely in respect of the plates as. if they are simply flat, then they should, I imagine, be at least 1/4". Then barrel, incidentaly, is 8 1/8" tapering to 7 5/8" over 21 1/4".. I have been unable to find much published information on steel boiler building. there is a need for someone with experience to produce a book!!
So, I was hoping that members of this forum could assist with my education on the subject,, which seems to be happening.. Thanks, and regards, Tom

[jasonb]

The point I was getting at in 2 & 3 is that you need to be a competent welder, without knowing what Paul was capable of I didn't want him thinking he could do it with a cheap Aldi or Lidle AC buzzbox.

Regarding drawings, I don't think it will be sufficient to present the inspector with a copper drawing and extract from an article. You will be modifying the design eg no flanged plates, Tapered barrel will be butt welded not a butt strap and soldered, Thicker firebox stays? etc So these alterations will have to be approved and suitable size welds used.

I think your best bet before going any further is to contact who will be inspecting the boiler be it at club level or an independant inspector and see what they will require from you to avoid any costly alterations.

You may find this thread helpful as it shows the boiler prep required for a boiler of 8-9" dia

Jason

[kwil]

Nice bit of professional welding on that Link ("this thread" above) Jason

[palmcoast]

Hi Jason. Thanks for the comments and the very interesting photo's on the link. This is the sort of information I had been hoping for. I had already made contact with the local ME society, and will be seeing the boiler inspector in a week or so, There is also a coded welder "one man business" who I have got to know quite well, so I think that maybe he could do the welding , although I am fairly confident that I could do it and my welding gear is far removed from the DIY type.
Regarding the design/drawings, your comments on the changes noted, I had thought that changing the structure could be a problem, will have to see if the inspector has any input on that.
Thanks again, good of you to spare the time from your project.. Best regards, Tom

[weldsol]

Tom please be aware that if you pay someone to build your boiler as a part of their business then it may fall foul to CE marking and the resultant paper work / testing.

Paul

[davebreeze]

Dec 2, 2010 10:52:51 GMT palmcoast said:

Regarding the design/drawings, your comments on the changes noted, I had thought that changing the structure could be a problem, will have to see if the inspector has any input on that.

Changing the design is not necessarily a problem, you just have to either show that what you have done is common practice (ie. copy another steel boiler design), or do the calculations to show that your modifications are strong enough. The calculations are fairly straightforward, I went to a boiler testing seminar where there was a lecture about how to do the calculations, I could probably dig them out if you like.

[palmcoast]

Hi Paul, This could be complicated. I'm not thinking of putting any of the work out, wiith the exception of the boiler barrel rolling, at what point does it become a professionaly built boiler?

Dave, thanks for your offer, I would greatly appreciate any information that you could turn up..
I'm proposing to TIG weld the boiler, any thoughts on that. Thanks all, Tom

[jasonb]

Its a bit of a grey area having someone who is a professional do the welding thats why its best to talk with whoever will be issuing the ticket.

The fact that the boiler even if welded by a pro will not be offered on the open market for sale is the likely way around the situation.

If your TIG is upto it then there is no problem using that method

John Hainings "the Countrymans Steam Manual" is mostly devoted to boilers and can be picked up for a fiver and would be a good place to start. Although aimed more at traction engine boilers a lot is relevant to Locos possibly a bit dated regards technique as it was printed in the 80s and talks mostly of stick welding.

You may try contacting Andy (Mutley) to see if he knows a source for the steel boiler design.

There are a few more pics of a slightly larger boiler being preped in this album, some of the machine setups make interesting viewing as well

www.blackcountrysteam.co.uk/steve__jacks_worksshop.htm

Jason

[alanstepney]

Tom, before you do anything more, sort out the "test" situation.

Irrespective of the advice here, or your own ideas, if, at the end of the day, you cant get the boiler certified, you have wasted a lot of time and money.

Some clubs wont test steel boilers, and commercial inspectors may have different requirements, as may the actual insurance company.

[weldsol]

Tom re TIG welding the boiler What I did on mine was to TIG root then fill with E7018 MMA eletrodes.
On the material you will need test certs for all the materials that makes up the boiler
main tube ASTM 106 grade A or B with a 3.1 test certificate
plate LT50 material with a 3.1 test certificate
stay material BS EN 10025 S275JR with a 3.1 test certificate or 070M20 (En3B) with a 3.1 test certificate
Cert, for the welding consumables

Paul

[davebreeze]

Tom, I looked at the information I have and the calculations are intended for copper boilers, you could use them for steel but they include allowances for riveted joints and silver soldering so you'd have to know how to replace these with allowances for welded joints.

Alternatively Alan Stepney's website has calculations for steel boilers:

www.alanstepney.info/page17.html

[palmcoast]

Hi. All. Well, I have a wealth of information now! The link to alanstepney site gives me all I need to be able to modify the Highlander design to steel and provide the necessary calculations for whoever does the inspection/test. As I mentioned, I have a meeting with the local club's boiler inspector next week, so I hope to have all done to show him.
The last (for the time being!) question is; where can I source the materials when needed. ie. plate and tube of the approved type..
Your contributions have been most helpful and I would like to thank you all for them, I certainly would have gone astray without your help. Thanks to all. I'll let you know what the inspector thinks! Regards, Tom

[jasonb]

See the thread "boiler steel" at teh bottomn of the page

J