Yes the grinding and honing back to spec was the major hurdle before worrying about a coating or plating. I thought it would be downhill once the equipment proved capable of doing that.
It just never occured to me that I would hit a wall because of operator error once I did find a process that appeared hopeful
That was what brought this to a halt.

Some of the equipment like plasma spray is not even remotely in my budget unless I win the lottery or something The wire spray is the only process I know of that is affordable and the only thing I lack now is the gun
Some of the cutting edge technology you are seeing at your school I am certain is over 80k (US $) easily for a basic setup.

I am pretty sure that with some of the stuff I have seen at the metallizing shop before could be some extra work I could get on the side if I did get a gun. Some of the shafts from various equipment is insanely priced so spraying worn shafts would pay pretty good. They would not take up much of my time either.
Once I was setup I could let all the local machine shops and compressor repair shops, etc. know I could do it.

Hewy at Armacor told me that he had a roll of that material I could have for the cost of shipping because the spool is too dinged to sell. Plus he seems a little curious and/or knows he has a potential longterm customer if I ever get this going.
When I told him I got a shop and a big *** wire feeder that would handle the 1/16" wire that got his attention.
If I get a spool of wire sitting at the shop I know I won't be able to stand it until I start working on a gun.
So I guess I will call Hewy and get one on the way Which one of you guys can I count on to be here to help me get this going later next week?

 

FWIW, I thought of something a little different this morning:
why not grind (bore) the housings out a 16th or so and sleeve them like a piston engine?
a sleeve would be easy to make, especially compared to spraying and grinding housings, and the grinding the housings to accept it would reaquire a lot less precision than finish grinding the sprayed surface....

i dont see how they could move around... the shape wouldnt let them spin, and they could have tabs or somethign for that also, and they arent gonna move axially.

only thing i can think of is maybe getting too close to the water jacket...not sure how that might pan out...i dont have any housings in my dorm room, so i cant look and see.

just a thought

pat

 

If every inch of the insert was not bonded there would be big problems. The expansion/contraction rates of the insert and the housing would have to be exact (that ain't gonna happen ) or else the insert would distort. Clearances are too close for anything like that.
The original SIP (sheet metal insert) has angled ridges on the back side. The aluminum is cast while the insert is in the mold. The ridges are what locks the insert into the housing.
If you look at a housing from the side you can see what looks like teeth and from there it is easy to see how the insert is not effected by a different expansion rate.

This reminds me I need to call Hewy still.

 

oh well...maybe should ahve thought of that..still...ive done them on dirt bikes and diesel trucks before...seems like they work fine there... of course the shape is different, but the expansion/contraction would still cause the same problems, they use aluminum blocks on some of those, and even the iron ones i would think have very different expansion rates than a hardened cast iron sleeve.

maybe the lower thermodynamic efficency of the rotary engine magnifies the problem?

oh well it was just a quick idea anyway.

pat

 

oh ok...so the original aluminum housing is cast around the insert? that makes sense.

dont see how the ridges help with the expansion thing, thought those were just to hold it in place.

 

It kind of helps with the expansion problem through force. Since it is locked it mechanically controls the expansion in other words.

BTW I just talked to Hewy and he is sending me a 10lb roll. He has not heard back from the GM guy but he said that Mercedes is working on something now and he will get to see the results on that because it is being done at a university. That seemed strange but I have heard stranger.
Well I have to send them a fax to get this started....

 

We were having a clear out at work today ... 5S if anyone else has been through it (buzzword bullsh1t for clear your desk basically) and the old cabinet full of supplier catalouges got chucked in the skip ... well most of did, some of it got rescued. One of the rescued books was a book on flame spraying written by Metco in the 60's (judging by the book cover ... would need to check the publish date to be sure) but to cut to the point it shows many processes, with guides for how to use them and one picture that caught my eye was flame spraying coatings inside the bore of a small two stroke engine.

 

That is a heck of a neat find If you have a scanner I would like to see the pic of the bore getting sprayed.
I got my fax off to Armacor to get the wire on the way. I called my weld supply and have a MIG whip set up for a straight (180 degree is what they call them) head. The extra one I have I could not find a liner for.
So I just have to make a gun with the threads the same as what the head has.
I sure hope I get it working without too many hundred more hours

 

I wish I had this http://cgi.ebay.com/ws/eBayISAPI.dll...sPageName=WDVW

 

what the hell is that? it looks cool, judging by all the buttons and such

 

So what's stopping you?

I'm glad to see this idea gaining momentum again, btw.

Keep plugging away at it. Cheers.

 

It is a twin wire metallizing setup like the kind the shop used on mine. it is not real good for inside diameter work because the gun is so bulky but it would do side housings real well and I could at least test some of those if i had one.

 

The main thing stopping me on that is that while $1500 right now and 1000 miles of shipping cost, the final price on this unit is going to probably hit about 4k. Too many bills at the end of the month to commit to that kind of money.

 

Yeah, those big items are best found locally I guess. It's hard to see all that cool equipment go for such apparently low prices. I wish, I wish. he he It's fun to look anyway and let the imagination run wild. Everybody should have their own little machine shop.

Cheers, keep up the good work.

 

If by some freak of nature it goes for less than $2500 I will get it. That machine can make big money. The only other things you have to have are a big compressor and a lathe if you plan on repairing shafts and other big money jobs. But I won't hold my breath on that price.

 

I have some PDF's of the book. ill e-mail as they are too large to attach

the first edition was in 1946, this one is from 1969.

 

hey Scali,
long time since I seen ya here, since the madrel bender project I guess

anyways hope this might spark a thought:
why not set you big smaw machine up to run twin carbon setup like 1" apart and blow a grainual material throught the arc. like a flame(plasma) spray setup. and if you use an pretty inert enviroment around the carbons I have seen them last a long time too.
wait since you have a roll of it the above isnt going to help you.
you could setup a thermal gun that has the two carbons for the arc(like above) and run the wire through the arc using your monster mig and with the amprage cranked up enough you could easily go into spray transfer the material to the housings. Maybe even without forced air, altough without the forced air it will be hard to control depth of application.

hmm rant off, let me go look a bit about the twin wire setups. and see what I can come up with.

later
Ryan

PS hell you could just use twin tugnstens too, but I dont know how large they are available in... also dunno if you have seen this site:
http://www.gordonengland.co.uk/aws.htm

 

Hi Hans it is good to hear from your again. Waco is close enough for you to come up sometime
I had seen that site a long time back and had been trying to figure out where I saw it so thanks for that
Those are worthy ideas and who is to say what it will take before this is all said and done. I do know that the closer the range that the material you are spraying is, the more problematic it becomes. I never thought of running the wire between two electrodes. You may really be onto something there. It opens up a whole new angle on this. For one I could run it off my big TIG in TIG mode. I could try AC.
It would seem to me the the cleaner the current you ran the easier it would be to control a spray pattern. That would only make sense.

In theory the better you could control the pattern the closer a range you could work in. This is definately something to think about.
I am not real sure just how large electrode quality tungsten is available in but I am going to find out.

 

The lack of easy access to some of this equipment is also one of my problems at the moment, having to rely on other companies to do the work, I do have access to a twin wire arc machine which has been useful but the best materials are more complex and need to be plasma sprayed from powders. I have been thinking about stripping the chrome off a couple of housings that I have and spraying them with a 75B bond coat mixed with a 90 MXC hard facing ie one roll of each wire on the machine and having them EDM wire cut back to spec.

Steiner, when I say seal I am talking about a compression seal that is somewhere in between a piston ring and an apex seal in terms of function as the piston that it is used in is rectangular, the basic material I have been using is a nitrided martensitic stainless steel with various hard coatings on it such as TiN, CrN etc

 

I'm probably way off base here, but what about a process for motorcycle cylinders called Nikasil? Could that be an inexpensive solution for repairing housings?

 

nikasil has already been mentioned a few pages back IIRC.

pat

 

The other technologies are not only hard to access but super expensive to get done around here. It would not be cost effective even if they did work. I found that much out real early on but that there were some options that would probably work from the twin wire application.
And as far as the material goes I am very confident that the material tested would have worked fine if they have not sprayed it so thick.
The fact I ground it with cubic zirconia and diamond for 16 hours under pressure and it would have taken another 30 to bring it back to spec says a lot.

The **** felt like oiled ceramic tile to the touch so the coefficient of friction was much better than the stock surface. It may even be too hard and too slick for seals to work unless heavier seal springs are used and maybe not even then.

It occurred to me that if the material is too hard for the seals to seat that this process could become more of a substrate for repairing the worn areas and then a plating applied to finish it out.

 

I am pretty sure that it is applied in mils and to actually fix a housing we need a thicker application.
But as I said at the end of my last post a plating may still need to be used after the surface is built back up if the seals would not seat. So some of these plating proccesses may still have to be considered if that is the case.
It may quickly become too expensive to do if all these proccesses are involved in the end.
Of it may turn out that to use them you have to use stronger seal springs which would be much more economical

 

Here is a link to the plasma process described at Gordon England
http://www.gordonengland.co.uk/ps.htm
At the very bottom it states "Disadvantages of the plasma spray process are relative high cost and complexity of process."
Relatively high in comparison with the wire and other processes is saying a lot. All of the processes are kind of high and just go up. At least any decent coatings being used. There are protective coatings that are pretty much a glorified galvanizing material.

I checked with my welding supply and they can get "really big" tungsten electrodes. I am not sure just how big because he told me that he had some 1/4" in stock he will sell me for $2 each because a customer screwed up and ordered the wrong size
He said he did not have the collets but I don't need collets for that. I figure I have to make some sort of tubes for them anyways, I with just use a set screw. I need to look into sprayer nozzles in different sizes and spray patterns that have a standard thread size.

I also need to find some sort of non-conductive high temp resistant tube material of some sort to put the tungsten holders through for the obvious reasons. Something readily available would be nice. Any ideas other than ceramics or glass?
I am also thinking of water cooling the gun as well.

 

I forgot to mention that when I talked to Hewy at Armacor he said that he would have his lab test samples that I send him (for free!). This will mainly help in fine tuning the process if I can get it to that point to where it looks okay.
They can test the final properties and give me the numbers on hardness, coefficient of friction, and the bond strength and some more stuff that may not really matter.

It would be interesting also to send a side housing to be tested before it is ran and then send it back after it has had the hell ran out of it.
They could test the area close to the eshaft hole so that any destructive testing would not keep me from being able to run it when it came back the first time.
Side housings would be the easier candidate to test with at least in the beginning.