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Pete O
26th Sep 2021, 03:47 PM
I'm hoping to be able to buy some fillet wax strips and parting powder (been using talc with poor results) and fluxes for small brass pours and the like. Does anyone know a supplier- preferably east of Melbourne- who is happy enough to deal with small quantities?

clear out
27th Sep 2021, 08:26 AM
You got me wondering what was available here in Oz.
A quick google shows ‘Green sand Foundry’ in Vic.
They list plumbago and calcium carbonate.
Might be worth a try?
H.

Pete O
27th Sep 2021, 09:54 AM
Thanks for that, I just emailed him asking about fillet wax. Will see how we go.

clear out
27th Sep 2021, 03:15 PM
That would be interesting if fillet wax is still available.
I’ve never used it or leather fillets.
We were using putty at the naval dockyard where I did my apprenticeship.
Then car bog.
H.

OxxAndBert
27th Sep 2021, 08:07 PM
These guys have it in various sizes: https://www.barnes.com.au/wax-products-45
Not sure if it qualifies as hobby quantities though...

Steve

Pete O
28th Sep 2021, 12:08 AM
Yeah I had seen that page Steve, the quantities are a little larger than I was hoping to be able to get. Can't see myself getting through one of those packs in this lifetime.

I've been using car bog or the equivalent in the cheaper 'builders filler', my experience is that it always needs sanding after it goes off, which is not only laborious and time-consuming but in the tight sections of a pattern I find it impossible. If there's a way of getting around this then I am very ready to be shown it. I'm working on some fairly deep nooks and crannies on a pattern at present, to cast a set of numbers for my property entrance. I haven't been able to put a radius in the bottom of the internal features of the numerals and I was thinking that the wax fillets would be the answer.

clear out
28th Sep 2021, 09:22 AM
As these are not production patterns here’s a thought.
Use plasticine.
Make up a fillet rubber of the size you want with a ball bearing on a bit of brazing rod.
Roll a little snake of plasticine and put an appropriate piece in place and push in with the fillet rubber.
A suitably ground old hacksaw blade scraper would enable you to remove any squashout.

I modded the Ewheel patterns for Al from iron by adding ply to the centre spine and as it was only two off used plasticine for the large fillets. These worked fine in a production Foundry.

Car bog can be applied and then cleaned up/scraped off with the same hacksaw blade scraper. Done when just off or later when fully hard depending on the material it’s on.

Be careful if you make up fillet rubbers that when straightening the brazing rod on the ball bearing it doesn’t let go. Tends to act as an effective knife on the fingers holding the ball.
Dont ask me how I know.
H

Looked for my old fillet rubbers but they’re lost in the stash. Barnes have pics of these.
Here’s a quick pic of the small rad hacksaw blade ones for bog.
Leave the bur on from grinding and they scrape well.

Pete O
28th Sep 2021, 11:09 AM
Some great tips there Clear Out, thank you.

OxxAndBert
28th Sep 2021, 03:07 PM
I’ve got zero pattern making experience, but have done quite a bit of sealant and filler filleting over the years.
This is a filleting tool I was given a long time ago by a Canadian workmate who’d spent time with one of the big aircraft manufacturers in the US.

https://uploads.tapatalk-cdn.com/20210928/edf2a0fbc6da49039b4c33d85e8b0c56.jpg
https://uploads.tapatalk-cdn.com/20210928/1e9f508d2a2a9497cfe8d036fd71f4e0.jpg
https://uploads.tapatalk-cdn.com/20210928/4ba9904ae63f545c7dca9fd426046f69.jpg
https://uploads.tapatalk-cdn.com/20210928/90d527aa275214705f2e09841e49ee05.jpg

Would be easy to shape one up from a bit of 5mm rod.

Pretty sure fiberglass guys also use plasticine or a wax for filleting their molds.

I’m not sure what wax those commercial fillets are, but beeswax might be worth a try too.
It’s becomes softer just with handling, and able to be pushed into holes or formed, but then firms up once you stop handling it. A metal tool like the one above could be heated slightly and run over it to get a better finish.

Steve

Pete O
3rd Oct 2021, 05:53 PM
I made a visit to the toy shop yesterday morning and came away with a $5 packet of plasticine in a range of fluoro colours, then had at it last night and managed to get quite a nice fillet into all the details of my pattern. A proper ball-on-a-stick tool would be nice but with a bit of 6mm ground & polished round stock plus a loose ball bearing and some spit, I got a good result. I'm experimenting now with how some spray putty and a coat of paint will stick to the plasticine, as obviously the bare plasticine will just stick to the sand. So far so good though.

Pete O
7th Oct 2021, 10:59 PM
The spray putty didn't stick to the plasticine, unsurprisingly. I decided that lots and lots of parting powder would overwhelm the stickiness of the plasticine fillet.
The pattern pulled out of the sand perfectly!
394279

That was on about attempt number nine.
I've got sore shoulders from ramming this pattern so many times; I spent yesterday mulling and ramming and mulling and ramming, finally got a good mould, then poured short :doh:

Today I took advantage of the fact that the sand was still in good shape, drilled some holes to screw the matchplate to the flask as well as pinning it. Lots and lots of talc, then lots and lots of rapping vertically over the detail area of the matchplate, no sideways rapping. Very careful lifting, millimeter by millimeter each side. Pattern came away clean first time.:2tsup:

Had to wait for the rain to pass before setting up the furnace, spent the time scouring the shed for every possible piece of brass. Had the A6 crucible brim full, LOTS of dross from all that crappy old plumbing scrap. This was about a quarter of it, not including yesterday's failure cut up and thrown back in.

394280

Only someone who has spent weeks preparing and days executing the creation of something that could probably be obtained from bunnings for twenty bucks, will understand how good it felt to pull this out of the sand at the end of the day. For size reference, that's a cut-down 205-litre drum.
394281

clear out
10th Oct 2021, 09:15 AM
Short pours! been there, done that:doh:
Here’s a few below.
Hang em on the wall to remind you or cut them up to check the wall thickness.
I saw this ad in ‘Restored Cars’ mag, no current website but looks like they mainly do die cast trophy’s etc for car clubs.
If they have the dies no reason they can’t make pattern lettering.
H.