Lost Wood castings - no, not a joke.

This came out of an idle - perhaps Addled is more accurate - reply to another thread some time ago - regarding lathes and other matters, if my leaking memory serves.

I recall reading many years ago in Oppi Untracht's art-metal Tome about people using things other than wax in lost-wax castings. Bugs were some of the things.

This one: https://www.amazon.com/Metal-Techniques-Craftsmen-Decorating-Illustrations/dp/0385030274

(Quite the heady Tome for 7th grade.)

I've played with balsa wood some in the past. Jason, on the other hand, does Everdur. (Lord, how I envy him.)

This thread is to involve Lost balsa-wood castings in Everdur.

 

Organics can and often burn out cleanly from investment. Dennis is making the patterns and I'll cast them. Some of you might remember my attempt at lost hemp rope casting. I worked, but didn't. The rope wasn't smooth enough and the investment got stuck between the small fibers.

I think balsa with a light coating of something should burn out well. First time for me.
Thanks for the link on that book, I got a very condition book for 30bucks heading my way.

 

Thought occurs to me: shell "investment" might well behave as if it's alkaline - and alkali eats shellac. I'll see about getting some nitrocellulose lacquer, also.

The usual stuff - e.g. Deft - changed its formulation in the last few years. It's no longer clear in the can, but milky. Need to get the real deal, to make sure it 1) stands up to damp; 2) stands up to "shell" - and 3) when the time comes, it goes up in smoke without leaving residues.

 

It has a PH of 9-11 if that helps. I have shellac flakes, think I got them on amazon in a baggie.

 

Neutral ph is 7.

I think my suspicion is correct - if higher numbers indicate alkalinity. I know a dilute solution of sodium carbonate dissolves shellac. I have tested this in my own dishpan.

They DO: https://www.google.com/url?sa=t&sou...FjABegQIAhAF&usg=AOvVaw2X8xhSt_K_3ndV0un2dzqh

Seems one wants the spray-can Deft lacquer, as it's sho'-nuff Nitro lacquer - that, or pay lots more fo' the Mohawk!

https://www.rockler.com/mohawk-finishers-choice-clear-lacquer-quart-gloss

Note that lacquer seems to not like shellac...

 

Hence ample, uh, venting? Turn the shell doohickie upside down prior to pouring and blast compressed air through a vent? Reheat afterward, so it's a good temperature?

Further research shows that Minwax Sanding Sealer in the can is the real deal, also.

https://www.minwax.com/wood-product.../lacquer/minwax-lacquer-sanding-sealer#ghssds

Looked at the MSDS, shows it's sho'-nuff Nitro...

 

After burnout, the shell is safe to withstand flushing out with the garden hose. My kiln is on wheels and can be parked in the driveway so I expect a nice long 12hr burnout complete with smoke and flames. I kinda think balsa is the perfect material for this. Barry in Baton Rouge has done tree branches and turned them into table legs. By comparison, balsa should be child's play. Balsa works easy and is super soft. Best part, it doesn't expand! I wonder if the sprues and pouring cup should be made of balsa too? Not to throw the baby out with the bath water, but I wonder how much balsa expands when wet? Parts made of balsa, sprues and cup made of wax, shelled, BOILED to rid the wax, dry over night and into the kiln for a long burnout. Have to give that some thought.
Should work..

 

[If the balsa is well-lacquered, then it should be relatively waterproof. (Not much expansion.)

If the nitrocellulose soaks in decently... it should flash good. (Think old time British stringy Cordite)

Trouble is, I'm not at all sure what works as a pouring cup/whatever It's called as to the shape, and gating for casting, on my end, is almost entirely intuition...

Would this work? (Never done shell, and lost wax attempts were 20+ years ago...)

ATTACH]15807[/ATTACH]

 

To show that Solomon was right when he said, "there is nothing new under the sun," there's this:

https://www.google.com/search?client=ms-android-samsung-rev2&ei=nT5FYLjPG9Hb-gTInpXQBA&q="lost-wood+casting"+&oq="lost-wood+casting"+&gs_lcp=ChNtb2JpbGUtZ3dzLXdpei1zZXJwEAM6BAgAEEdQ5qUUWN3SFGCBux1oAHABeACAAZkBiAGQA5IBAzAuM5gBAKABAcgBCMABAQ&sclient=mobile-gws-wiz-serp

So I'm wondering - what are prefered tooling fasteners on your end?
I may well like 10 - 32, 1/4 - 28, and 5/16 - 24... but I'm weird, too. "He may well have a predilection for Whitworth fasteners..."

The reason this is important *is the screw used to tighten the stock in the dog determines the size of the boss what gets threaded.* Bigger screw, bigger place to be threaded, and so forth...

 

I like 1/4 20 stuff personally. You won't need to sprue the parts. I'll take care of that. Shell is gas permeable and vents actually aren't even required. But I still often add them for insurance.

 

So a 1/2 inch square (nominal) lump, 1/2 inch long. Tap drill will be a #7 or a #8. Probably want a fresh tap by a reputable manufacturer, and some *good, extreme pressure tapping lube.* No motor oil.

Nominal means,"it will be at least this big, but 1/64" over is possible/likely, to allow for cleanup, etc."

 

OH, I see. 1/2" square lumps should be fine.

 

I may be late to the party but could you seal the balsa with something like PAM Vegetable Spray (the poor mans mold release), Pledge Wax ( it will smell good) or brush on olive oil. I never tried any of these but they will burn out without any issue I would think.

 

Yes and no Bill. The trick is getting the 1st slurry dip to sorta adhere to the wood and wax system. Too slick and it runs off, too sticky and it embeds itself in the wood. See first five minutes of my cattle brand video for the issue of direct lost rope.

 

I tried HF super glue on my rope, maybe I'll have better luck with balsa.

 

I'll rub the lacquered parts down to a satin finish with a fresh green scotchbrite pad. That should help. (???)

 

Sounds good to me.

 

Here is some Balsa wood. I'll need to go to at least two more places over

the next two weeks to get more.