Scratch Builders-How I made steam/sand domes out of brass. Photos Inside. Updated 6/20!

Aaron,

I hear you, regarding a lot of work with few results. Kind of the nature of the beast when home fabricating. I finished my expansion links and am now re-doing my original piping on the boiler sides. Just was not quite satisfied. I think sometimes the first to third passes at something is just the learning curve.

Ron H 

Ron, 

I sure know what you mean.  A fabricator I am not, but I'm sticking at it!

The domes are wearing me out.  I decided to work on some other things until my brass tubing arrives.  Once it does, I'm going to cut a piece down the middle and then solder the straight piece into it. Should produce the look I want.  

I've given up trying to roll sheet brass into the shape I need.  I can't get it perfectly round and it look like hell from above if it is not. 

Here's my best effort:

AFTER I got these made and soldered on, I realized a major error.  Not sure how, but I screwed up the shape on my 4th attempt at this and with that, I cracked a cold one and said the hell with it.  Sometimes it's best to sit it aside for a day or so and get a fresh idea.

As you can see above, I made a nice dome for an FEF-3, which is cool if this was going to be a 3!  I was looking at FEF-3 photos and have no idea how my brain wasn't engaged prior to making this dome. 

I did manage to do this today:

Before:

During:

After:

Done until I get parts from PSC.  Also, I should have the brass tube this week, so I'll work on the domes again.

More to come.

Nice work. It's amazing how much detail is left off these models, even some of the more expensive ones.

Ron

Is that an ash pan you made for the bottom edge of the firebox?

Yes, my feeble attempt.  Still have detail parts to add.

Well, it does look real nice. Are you aware that the UP FEF locomotives were oil burners?

Thanks Hot Water,

I'm modeling an early life cycle FEF-1, from 1937, a coal burner.  I think I posted a picture on page 1 of this thread but can't remember.

OK, sorry. I missed, or forgot about, that from some time back. Looks like you are coming along nicely.

Nice ash pan.  I sometimes do that with 1/8" square bar.

On the domes - I generally use half-hard brass sheet, and .020 is about the right thickness for getting curves bent perfectly.  Use a steel rod.  Put the joint on the straight side, back it up with a small piece of brass, and use the solder as body putty.

The flange is the easiest part - I promise.  When your dome is done, screw it on, with a piece of thick paper between it and the boiler, and mark the paper appropriately. Transfer that to .020 HH brass, and repeat.  You may find you do not need a fillet - it will be pretty realistic without it.  But if you do, as above, a small amount of body putty . . .

Don't try to solder the dome to the boiler.  That is a loser - you may need to adjust something later.  I use 2-56 cap screws, and an allen wrench goes through a small hole in the belly.  The screw can actually come through the top of the dome - you file it off before painting.

Aaron,

Whatever technique you use, I suggest you make a fixture jig to solder up the work. This was the only way I could put together the multi-piece Alco pilots I made.

Flat piece of pine with small nails on each side of flat and curved pieces to retain position and shape as you tack pieces together. The pieces need to be held tightly.

It's really pretty easy.

Ron H

bob2 and Ron H,

First, thanks for the compliments on the ash pan.

Thanks to both of your suggestions, I was able to get one dome shaped today.  I used a combination of techniques and I'm very happy with the end result.

Still shaping to match the boiler curvature but will post 'how I did it' pictures when I'm done.  Need to finish the flange also.

It's starting to come together...Excited.

Aaron, I spent a few moments looking for brass, deep cup, freeze plugs online and realized that they are specialty applications and not like the old days where there was drawers of freeze plugs. But one site that I found had brass and copper "pieces", unfortunately from India. Nothing wrong with India mind you, just the hassle. Some of the "pieces" looked like common copper plumbing parts. Just like you can find at your local hardware store.  I know you are probably too far along on this project to benefit from this suggestion, but it might be helpful to others who are following this thread. 

David,

Thanks for the information.  Back in my days of engine building/drag racing, you could find those darn brass freeze plugs at every auto store in town!  Which is why I was so surprised when I couldn't find them anymore.  It would've saved me many hours of frustration and it was an excellent idea for a guy like me without a lathe.

The good thing about all that searching and frustration-I learned how to make domes myself and I'm confident now I can build about any type.  We'll see as I progress through different projects.  My method isn't the most time effective, but I get the job done.

Again, thank you for the great idea.  Should have dome pictures up tomorrow night, I ran out of solder so no pics tonight. 

Glad it's coming together.

Ron H

The domes are complete.  I used several different techniques, not shown in the photos to get the end result.

Using the brass tube from Online Metals, I cut a piece slightly taller than needed.  My big hands can't hold on to those little pieces and later I cut it down to correct dimensions (below).

Here's how the the tube compared to the dome I was making, I couldn't keep the radius concentric on each end and kept making 'egg' shaped domes.  I'll try Bob's technique on the next project (below):

I marked center OD of the tube and used tape to serve as a vertical cutting guide.  My saw quit so I used a razor saw...ugh.  After cutting the tube vertically, it 'relaxed' and was bigger than original (below).

The brass sheet was the same width as my original tube diameter.  Hard to see in the picture, but I measured and scribed an equal distant line, equal to the tube radius on each end of the brass sheet. This aided in accurate placement of the tube and 'scaled' the dome to the correct length and width.  I used the Vise-a-grips to pull the tube back to the correct diameter for soldering (below).

My 'high speed press' I use to hold parts:

The straight section of the dome soldered in place:

The other side:

Cut dome from sheet and started rounding the corners:

Scribed a line around dome and marked with tape to get the correct height.  Cut dome:

Found center of boiler/dome and marked them for reference:

Here, I started to profile dome to boiler using a cutting tool, anyone notice I missed something important? 

Started on smaller second dome:

Profiled it and added the flange:

Rounded the edges of the flange:

Second dome installed:

At this point, I was marveling at my work when I realized I forgot the flange on the first dome!

So, here's how I corrected it.  Using masking tape, I made a pattern and transferred it to the brass sheet.  I decided it would be difficult to make the flange in one piece and slide over the dome to fit, so I cut it in half.  Then cut out the marked section, filed to fit, and installed.

The final dome/flanges:

Learned a lot and tried different techniques.  In the future, I hope to have a lathe to do the round domes.  Also, I won't forget the flange again, it was a lot of extra effort to make it that way, but well worth it.  A little filler at the dome/flange transition and it'll be done.

I'm very pleased with the results.  As Ron said, sometime attempts 3-5 are just practice runs!

Firewood, not sure you're still following along, but thanks for the article.  I've printed it out and spent time reading it.  The techniques can be used in brass also.  It should help when I'm ready to do a complete scratch built locomotive.  

Now on to the detail parts and stuff I'm really looking forward to building.

Excellent !!!

Outstanding work-congratulations!

Double-check those flanges with some good prototype photos. There are good shots on page 111 and the back inside cover of Kratville's book.

The more I think about it, the more I would opt for solid brass on this model.  I built my sand dome the way you did, except I used a very thick top to be able to carve a radius between sides and top.  Boiler contour is the main problem, but is easily done with a new crosscut file and a sanding drum.  Then the attach is by a screw, greatly facilitating the addition, and trimming, of the flange.

Nice work.  I wouldn't even attempt doing a flange after the dome is attached - I don't have that kind of patience.

Impressive. Making good progress.

At this point, I was marveling at my work when I realized I forgot the flange on the first dome!

That is a "Hat's Off" job and I am marveling at your work.

Thanks guys.  It's a lot of work but really something when you step back and see the result.

Bob, I reviewed the pictures in the Kratville book.  I corrected the rear dome flange. Not sure how I missed it the first time, thanks.

Hope to have some more parts this week so I can start building the front end.

I missed this until now.  Great project, great work!  Nice to see you doing an FEF-1.

I've been watching this thread for a while and was wondering if you were going to add some shape to the top of the domes?

For the round one you could use a dapping block.

For the oval, you could make a hammer form out of wood.

Excellent project!

Dave

Dave,

Where do I buy dapping blocks?  Hardware store?

Though I've done a lot of model building in resins and plastic, brass/metal is all new.  I'm slowly building a tool collection that makes life easier, I think I could use these blocks on many more projects.  Would be a worthwhile investment.  Plus, I like tools! 

Not a lot of progress to report on the FEF.  No parts have arrived and family arrives tomorrow, so it'll be a week or two before I get back to work on it.

Aaron,

EBay has em all.

Ron

Thanks again Ron.  I'll look for them today.

Anything new on the FEF?

No, I've been busy with other things since the last update.

Weekends have been full with family and I haven't had time to do much.  I was hoping to start on the rods last week, but it didn't happen. Probably next week, everynight this week is full and next weekend is busy also. 

I'm just a popular guy everybody wants to hang out with

I'll let you know when I get back to work!