CLOSET MODEL ENGINEER WITH QUESTION

[mauser]

Hi All, this is my first post. I am not a model engineer or any other kind of engineer, I took a different path in life but now I have come out and bought a ready built Paul Breisch Lil Brother. Always wanted a scale model stationary engine and now I've got one I'm over the moon. Thing is that it has been crudely put together and the castings are not great either. First things first, I need to dismantle and tidy up the castings. Obviously I will use file and paper but there are some deep gouges and what looks like chips here and there. First of what will probably be many dumb questions, what is the ideal filler I could use to fill the deep pits? Thanks

 

[stevehuckss396]

what is the ideal filler I could use to fill the deep pits? Thanks

If it were me I would treat it like a car. Maybe try to lead in the real deep damage. Bondo for the not real bad holes and then primer, sand, primer, sand ,primer......

 

[mauser]

ok, thanks for that. Bondo, that's not one we have here in England, is that just an ordinary car body filler ? I had thought about using plastic metal, is tht not a good idea? Noted what you said about the lead, hadn't thought of that, not got a clue how to put molten lead in the holes and cracks but I'll work something out. I suppose if I heat a small spoon and dip it in the lead pot I could transfer it that way. Any of you guys need a tea boy for a couple of months, I need to learn some new skills fast ? I just can't understand how a model engineer could spend all that time machining the parts but not clean up the castings, don't make any sence.

 

[portlandron]

If the material you want to fill is brass or bronze you could you solder which would be easier then lead and work just as will.

 

[stevehuckss396]

is that just an ordinary car body filler ?

Yes

 

[1Kenny]

Auto body filler would be easy for you to use if you don't have many tools. Clean the area real well before you apply it so it will stick good. If the parts have been oil soaked, you can put them in an oven for an hour or so at the same temperature as cakes are baked and that will dry out the metal.

Body filler is the same as bondo in the USA. If it is used on an aircraft it is called aerodynamic smoothing compound.

Kenny

 

[bearcar1]

Hi Mauser, and welcome. There is a product that goes by the name of JB Weld that is a two part epoxy like filler. I don't know if is available in the UK or not. Hardware stores or auto parts houses sell it here in the states. It mixes just like an epoxy and has good potting time. There is a website as well. Good stuff.

BC1
Jim

 

[Blogwitch]

Mauser,

Because you live in the UK you should be able to obtain Milliput, the standard grey one, from almost any model shop.

Unlike JB weld which is thin and gooey, Milliput is is two part putty. Mix equal amounts together really well, and fill in all indentations and hollows.

Now the best bit, as soon as the area is filled, you wet your fingers and smooth everything off to a really smooth finish. Once that is done, leave overnight to set.

No rubbing down, you can paint straight over the nice finish and you wouldn't know that there was ever anything wrong.

Bogs

 

[mauser]

Thanks for the welcome and all the help so far. Great forum.. I just hope you guys don't get fed up with my noobie questions.

 

[idahoan]

Hi Mauser

I have been working on a pair of Little Brother engines for more years that I care to admit. One of the latest projects has been to spruce up the castings a little. Give me a day or so and I will post some pictures of my progress so far.

I have been using an assortment of tools; Dremel, needle files, rifflers, etc. The filler that I have been using is a Devcon metal filled epoxy product 10110 Plastic Steel Putty; this stuff is about the color of cast iron, bonds very well and isn’t too bad to work with. I guess the one bad thing about it is that it is expensive; around $40.00 for a 1 pound kit.

I agree with your comments about the castings; they leave a lot to be desired. The bearing caps don’t match the base at all; and required considerable work (both with filler and machining) to make everything look right

Best regards,
Dave

 

[mauser]

Hi Dave, thanks for that. I am familiar with Devcon, we use it in the gun trade. I have just had a look at how my bearing caps fit and I was shocked to see a gap of about 45 thou, just forward of the caps. Way it is at the moment looks like someone has taken a hacksaw to it. Is, or was yours the same? Thing is, if I make all this neat and tidy around the bearing caps, with Devcon, or whatever else I decide to use from the helpful suggestions in the posts above, will I still be able to remove the caps if I should need to, bearing in mind I'm not a model engineer yet? Have you done any filling with lead Dave?

 

[robwilk]

I just hope you guys don't get fed up with my noobie questions.

I started with no knowledge and have asked many stupid questions but the guys on this forum are always willing to help.
Where abouts in the UK are you.?

Rob......

 

[idahoan]

Depending on how the block was machined that may be normal; there has to be clearance for the cap to be removed and installed. Mine didn't match on the bosses that form the area just behind the flywheel; if that makes sense.

The rear of the block on the pulley side was quite low which made the bearing cap hang out in space about .1” this area needed to be built up and contoured. I have 3 set of Little Brother Castings and they all have the same problem in this area.

I mounted the block with the bearing caps installed to a fixture plate on its side in the mill. Then drove around the boss with a ball end mill; erased the awful shift at the parting line.

No I've never done any lead filler work; that would be a whole new experience for me.

Dave

 

[Tin Falcon]

Mauser congrats on the engine purchase.
In a former trade I used to work with polyester putty of all sorts some auto grade and some marine grade. Sometimes in large quantity 5 gallons at a time sometimes bu the tea spoon.
Most auto body fillers are a mixture of a couple types of resin and a filler usually ground walnut shells. the premium grades of auto filler use talc for a filler. Talc will not absorb like walnut shells will. the premium talc stuff works like a dream. It sets quicker sands easier etc. I will say a half gallon of the premium stuff is a bout twice the money of a gallon of the standard grrade but it saves in time and agravation for small high end projects.
Tin

 

[mauser]

Rob, I'm in the south, Fordingbridge near Salisbury.

 

[Omnimill]

I'm in the south, Fordingbridge near Salisbury.

In that case you're not too far from:

http://www.modelengineershow.co.uk/

Well worth a trip if you can make it!

Vic.

 

[idahoan]

Hi Mauser

Here some pictures of the bases for my Little Brother engines. Hopefully you can see the body work I have done to them. I don't have any before pictures. You can see on the one with the main cap removed how much I needed to build up the base; now the caps fit the base the way they should.
I also re-machined the horseshoe cutout at the rear to give it a better shape.

Also a picture of the heads; another challenge on the engine was to turn that ugly lump of cast iron into a decent looking cylinder head.

Dave

 

[deverett]

Also a picture of the heads; another challenge on the engine was to turn that ugly lump of cast iron into a decent looking cylinder head.

Dave

Very nice job indeed on the cylinder head, Dave. How did you achieve that finish from the rough casting?

Dave
The Emerald Isle

 

[idahoan]

Hi Dave

Missed you at GEARS this summer; maybe next year?

The head was was a turning and milling job; last winter I was looking at them and decided that I just wasn't happy with the 3 bosses; so I set them up in the mill and worked them over to better match the mating components. Mixer, Muffler and push rod guide.

Lots of hand work with a Dremel and files to blend every thing in. the finish is a bead blast with very fine beads; they have darkened a bit sitting on the bench.

Hopefully I will get some time to work on them this winter. I have thought about starting a work in-progress thread; we'll see.

Best regards
Dave

 

[mauser]

Hi Dave, thanks for sharing the pictures. I have just compared your pictures to my sorry looking castings. I intend to do more or less what you have done, probably a lot less, and will have to use hand tools as I have no machines except a Dremmel. I like the horse shoe cut out, what a difference to mine. Particularly like the heads. While I think of it, what are the thread sizes for the grease cups and the cylinder luber ? I need to get some cups as mine doesn't have any and I can't identify the threads. All the last owner said was that they were American. Big help there.