Author Topic: A Robinson from rejects.  (Read 49013 times)

Offline Jasonb

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Re: A Robinson from rejects.
« Reply #435 on: June 02, 2020, 04:59:14 PM »
This space or the space where there is no metal?

Bit of tape on the inside to contain some JBWeld as its put into the hole and good as new.

Did you see what the one on e-bay ended up going for?

Offline Alyn Foundry

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Re: A Robinson from rejects.
« Reply #436 on: June 02, 2020, 05:29:17 PM »
This space or the space where there is no metal?

Bit of tape on the inside to contain some JBWeld as its put into the hole and good as new.

Did you see what the one on e-bay ended up going for?

Ah Jason, this space.   ;)

A bit of " Ab Fab " is in the offing.

Yes it went remarkably cheap IMO. I put a crafty bid in myself because it looked to be a bargain at the time.

My Robinson " leftovers " are becoming scarce, managed to squeeze a quart from a pint pot yesterday evening. Turning a Gardner cylinder liner and Gardner piston into Robinson guise.

Cheers Graham.

Offline Alyn Foundry

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Re: A Robinson from rejects.
« Reply #437 on: June 04, 2020, 12:05:02 PM »
Any thoughts/comments?

I posted a picture of young Alan's " Blue " Robinson, nearly ready for its first run. Needless to say it eventually started but ran rather " fitfully " displaying signs of heavy preignition, knocking, thumping etc.

Upon closer examination we noticed air bubbles periodically bursting at the water base opening, obviously we had a cylinder liner to water jacket breach.

We have always used Loctite 638 for gluing the cylinder liners into place, my 30+ year old replicas are still running soundly after 1000's of hours.

My question, does this particular adhesive have a " shelf life " ? The three of us are currently building a Gardner and two Robinson's and over the last week we all glued up our cylinders. Yesterday Alan removed the liner by bringing up the assembly to just over 200 degrees C, allowing everything to cool slowly before cleaning and re applying the adhesive. I also had just glued mine. After the curing time had elapsed we did a simple mouth to casting pressure test, all 3 leaked.

All the usual preparation procedures were followed, scrupulous de greasing etc. Is the glue out of date?

Cheers Graham.

Online Jo

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Re: A Robinson from rejects.
« Reply #438 on: June 04, 2020, 12:29:05 PM »
Our old chemical lab used to reckon that Loctites went on for decades - if it was still liquid it would still set ok. If you are looking to comply with ISO regulations then it should be in date.

Much more likely to be a surface contamination that is causing the joint failure. Try using some industrial acetone on the surface before gluing. If you use Brake fluid cleaner to clean the surface be aware it acts as an accelerant on Loctite.

Jo
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Offline Jasonb

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Re: A Robinson from rejects.
« Reply #439 on: June 04, 2020, 01:20:19 PM »
As Jo says they usually say if it's liquid it will work

Offline Alyn Foundry

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Re: A Robinson from rejects.
« Reply #440 on: June 04, 2020, 01:39:04 PM »
Ok, thanks to you both.

Coming from a laboratory, Jo's message is quite reassuring as we still have about 25 ml left in the bottle.

How about Methyated spirits Jo? Or for that matter Isopropyl alcohol? Otherwise it's a VERY NECESSARY shopping trip in the offing?  :)

Cheers Graham.

Online Jo

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Re: A Robinson from rejects.
« Reply #441 on: June 04, 2020, 01:59:02 PM »
Methyated spirits has that horrible purple dye in it which will contaminate the surface. Isopropyl alcohol would be good as it does not leave a residue (there is a slight % of water in it but not much and that will evaporate)

I mentioned Brake cleaner as it is a common substance in most home workshops...

Jo
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Offline RayW

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Re: A Robinson from rejects.
« Reply #442 on: June 04, 2020, 08:42:09 PM »
Last bottle of Methylated Spirits I bought was clear, but not sure if it would still leave a residue. Excellent for removing engineers marking out blue from components.
Ray

Offline crueby

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Re: A Robinson from rejects.
« Reply #443 on: June 04, 2020, 10:11:25 PM »
The manufacturer of loctite says it has a shelf life of 2 years unopened, one year once opened. But, that may be just where it starts to degrade at some unspecified rate. I have some older that still works, though they do need shaking more to resuspend some of the particles.

Online Jo

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Re: A Robinson from rejects.
« Reply #444 on: June 05, 2020, 07:23:34 AM »
Last bottle of Methylated Spirits I bought was clear, but not sure if it would still leave a residue. Excellent for removing engineers marking out blue from components.

Strange that: Marking blue/Layout fluid is made by mixing methylated spirits with shellac and gentian violet  ::)

The non-drying engineer's blue is Prussian blue mixed with oil or grease.

Jo
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Offline derekwarner

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Re: A Robinson from rejects.
« Reply #445 on: June 05, 2020, 08:55:11 AM »
Prussian Blue, yes......the natural blue comparitor film applied to [edit.....one of the two] mating parts when scraping [edit, one mating] surface

Mechanically hand scraped in a herringbone, Z or X style pattern........depending on the components

Two mating flat surfaces are demanding to attain the nominated % coverage..........hand scraping a 10" diameter bronze helical worm wheel to attain a 90% coverage to the worm a little more challenging  :facepalm:

Prussian Blue is/was the only acceptable medium for the final tests for these components  ...and in accordance with American MIL Standards specification......

Derek









« Last Edit: June 06, 2020, 04:47:59 AM by derekwarner »
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Offline Alyn Foundry

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Re: A Robinson from rejects.
« Reply #446 on: June 05, 2020, 11:32:33 AM »
Good morning to All.

Thanks for your collective advice. Obviously we hadn't been as " scrupulous " as we should have! Although I have a few bottles of Isopropyl alcohol on stock I took Jo's advice and nipped out to our local Home Bargains, where for just 99 pence a bottle of Acetone ( nail varnish remover ) was purchased.

After yet more carful cleaning we reassembled our Robinson cylinders and set them on the water jacketed multi fuel stove overnight. Despite it being summer last night was a little chilly and a fire was lit.

This morning see's two cylinders that pass their initial pressure test, onward....

Cheers Graham.

Online Jo

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Re: A Robinson from rejects.
« Reply #447 on: June 05, 2020, 11:54:53 AM »
Thanks for your collective advice. Obviously we hadn't been as " scrupulous " as we should have! Although I have a few bottles of Isopropyl alcohol on stock I took Jo's advice and nipped out to our local Home Bargains, where for just 99 pence a bottle of Acetone ( nail varnish remover ) was purchased.

I hope it was pure Acetone and didn't have any "nail conditioner" in it   :Doh:

Jo
Enjoyment is more important than achievement.