Author Topic: Cast Trunnion Caps (Read 1948 times)

Powder keg · « **on:** October 14, 2006, 01:27:47 PM »

I've been working on my foundry the last couple of days. I am building some new flasks out of steel. I finished (just about

) my new molding toble. And I have a new pattern about done for caps for 1" dia. trunnions. I'll post some photos when my picture box gets back. I'left it in my wifes car

Later, Wes

Powder keg · « **Reply #1 on:** October 15, 2006, 03:21:00 PM »

Here ia a picture of my new burner. It was kind of a flop? I couldnt melt the brass with it. I had to swich to my smaller burner to finish up. I'm going to try a couple more things to get it to work better.

I finally got around to making some tongs. It's about time hu, George

Here is a picture of them. I feel a bunch safer poring now.

I went and visited a gentalman last weekend and he had the neatest stuff! One od the things were some flasks made out of sheet metal. I made me a couple of sets this weekend. I bent the metal after work on Friday. I love these! They are durable. You cant burn them up. You can clamp the two halfs togather. This keeps them from floating apart. I had that trouble last time I pored brass.

I'll post pictures of my pores when they cool.

Wes

Powder keg · « **Reply #2 on:** October 15, 2006, 04:31:35 PM »

Here is the trunnion bar. It turned out purfect. It's sitting on my new molding table. Those 2 X 2's lift out and you can get to the sand underneath. It works pretty good so far.

I was poring a plaque also and it didn't turn out. The metal froze before the cavity was filled

I'm going to see about hooking up Natural gas to my foundry settup. I'm just having to much trouble getting brass hot enough? Another project I need to do is build a heat shield for the wires on my Pyrometer that I built. They started to smoke last time I used it.

Later, Wes

accuratemike · « **Reply #3 on:** October 16, 2006, 02:22:05 PM »

Wes,
I built a furnace almost exactly like yours. I have not tried brass in it yet, so I don't know how it would work. Looking at the pic, is the blue line shop air ?. We use a shop-vac for burner air. We had to install a router speed control to slow the vacuum to a minimum flow to get the furnace really hot. It seemed that any air not being combusted was olny blowing heat through the system and hurting, not helping. I'm sure you play with the regulator to get the best flame, but you may try HVLP and see if she gets hotter. I like the tongs, we got ours from Budget Casting Supply. I have a 20# clay graphite crucible. Tongs were $237.40 for it. They were the single most expensive thing about getting into casting. I don't have a thermocouple yet, we try to eye things up. The lid will glow cherry red and become translucent around the vent while running. The lid is IRC-29 Castable Refractory about 2" thick. I always thought things were plenty hot in there. My furnace is shorter and fatter than yours (a short 30 gal. drum rather than tall). We used a 5 gallon steel can as the inside form for pouring the refractory. On our first run, the can melted and we had to pull what was left out. That was with a 20# propane can and shop-vac air. Good luck, MIKE

CannonKrazy · « **Reply #4 on:** October 16, 2006, 03:46:23 PM »

Hey guys,Thats a good looking pour Powder Keg.I had an idea similar to this awhile back.I posted about two months ago how to do this and I'm glad you posted your pictures.At the shop we heat treat alot of thick steel plate so heat is not a problem but being able to get to the crucible after the brass is melted is a problem.Please keep us informed as you cast other parts.

One other thing,where do you get your sand? Thanks

accuratemike · « **Reply #5 on:** October 16, 2006, 03:55:03 PM »

Ours came from http://www.budgetcastingsupply.com . A 100# box of #1020 Jupiter Blend-Petrobond Pre-mix Sand was $59.05 in '01. Enjoy, MIKE

Powder keg · « **Reply #6 on:** October 16, 2006, 05:31:07 PM »

This has been bugging me since last night. I got to thinking about it and the burner had a problem. It would only run with the opening choked back about 2/3's. I said to myself, Self, Your new burner is starving for gas? I drilled out the gas orfice in the burner from .040 to .079 and she burns like mad now

I had 14 pounds of brass melted in 35 to 40 min. It wasn't hot enough to pore though

New problem... My propane bottle ices up after about 35 to 40 min. Even the hose ices up? The bottle had a good quarter inch of the stuff on it. The gas pressure and flow both droped. I was able to pore in another 20 min. but if it had kept burning like when I first started, it would have been hot enough. I tried poring those trinkets and plaque again. The trinkets were good but the plaque froze to soon. It nearly made it though. How do you keep a propane bottle from freezing?

Later, Wes

accuratemike · « **Reply #7 on:** October 16, 2006, 06:46:58 PM »

Orifice??? I think we just used a chunk of 3/8" tube and a ball valve. It goes into the can through a piece of 1 1/4-1 1/2" pipe. I guess we have gas volume overkill. I'll look at it tomorrow. (We never use it, we built it for one job.) The tank never iced up. It was summer (and probably pretty dry) when we used it. My tank freezes up in the garage all of the time. I use a 40# and blue flame Pro-Com heater in the home shop. It usually is only on when it is cold. In the dead of winter I'm lucky to get 60° in here. It has to be a dew point thing to make the ice. When I shut it off and go to bed, it thaws all over the floor. Let me know how you stop that one. MIKE

Cat Whisperer · « **Reply #8 on:** October 16, 2006, 11:57:59 PM »

One of the obvious alternatives (note, not necessarily a 'solution') would be to have two sources of fuel. Switch to the second when the first freezes.

Rickk · « **Reply #9 on:** October 17, 2006, 01:03:37 AM »

If you are playting with Propane Orifices, you need to know about http://www.drillbitcity.com/ . They have super small carbide drills with fatter shanks so that they will fit in a normal drill chuck. They even have a "Propane Orifice" specialty set. You can also drill out a pre-made orifice to 1/4-28 and then it will accept MIG contact tips (although at .079 you are way past normal contact tip size).

Yo will to hook up dual tanks(or triple) before your regulator to keep the tanks from freezing. You will need dual flexible high pressure hoses with POL fittings on one end of each, as well as a T fitting.

Check out http://www.tejassmokers.com/ and http://www.cajunshoppe.com/pageidx.htm for propane burner stufff (regulators, hoses, adapters, pre-made venturis). I am making a home made BBQ grill setup and have been dealing with both companies quite a bit lately... both wasy to do business with.

If you put a needle valve in series with the orifice, you can compensate quite a bit for an oversized orifice and fine tune it. You can't really do that as well with just an adjustable regulator. Note that a needle valve does not eliminate the need for a regulator.

If the orifice gets too big, you may exceed the capacity of the regulator. If you can not get the rated max pressure out of a given regulator while gas is flowing, but you can if you put your finger over the orifice, you may need to use separate regulators on each propane tank. Adjust them so they each put out the same pressure independantly. You will definitly need a needle valve to adjust the gas flow if you do that, as adjusting the two regulators and keeping the pressures set the same will drive you nutso.

Rickk · « **Reply #10 on:** October 17, 2006, 04:10:21 AM »

You can also drop your propane tank in a big bucket of warm water, and keep adding warm water.

There was a web site someplace where a guy in New Zealand made a jet engine in his tool shed out of a couple of automobile turbochargers. He used propane for fuel. He put his propane tank in water, and then used the water to cool his Guiness. I believe he was trying to empty a 20# propane tank in somewheres around a minute flat, so he really had ice-up issues. :-)

http://www.asciimation.co.nz/beer/

accuratemike · « **Reply #11 on:** October 17, 2006, 03:08:12 PM »

Thanks for all of the propane info. And the turbine link too. Although off-topic...I have 2 turbines (the "store-bought" kind) at the house now. I have a Boeing T50-B-08 that is really a mock-up for one a buddy is running in a boat and my baby, an Allied Signal/Garrett AiResearch JFS100-13A. I am working on getting the JFS-100 started. 82# & 90hp. Maybe a little airboat or something. The New Zealander looks like he has fun. My first car was a '69 MGBGT. His looks alot nicer though. Enjoy, MIKE

Rickk · « **Reply #12 on:** October 17, 2006, 04:59:39 PM »

One other comment... you don't actually need to force air in there to make propane burn. A Venturi will make all that happen for you without a blower or compressed air. I have seen many blacksmith setups that just use induced draft like that. Even the guy that does my horsey's horsey shoes uses a single burner with induced draft to get steel dull red.

It may or may not be hot enough for your need, but it is easy enough to try. It just takes a pipe reducer and you have a "venturi". If the forced air is not needed, the nice thing is that the airflow automatically adjusts to the propane once you get a mixture set properly. That makes lighting easier. If you get too much air with just a venturi, you just block part of the opening off.

The links I posted will steer you torwards prefabbed venturies that screw onto a 3/4 inch iron pipe. They include an orifice (usually #56) and have an air adjustment butterfly on them. That is what I am using for my home made BBQ grill project. I had to reduce the venture size to a .035 hole even with a burner that is 4 feet of 1 inch pipe (with 500 1/8 inch holes). I have the air set about half way open. The one night that I fired it up with no cap on the end of the burner pipe, the larger venturi still in there, and the air opened all the way was pretty spectactular... fire shot out the end about 10 feet.

Rickk · « **Reply #13 on:** October 19, 2006, 02:02:13 PM »

I just made an interesting discovery while shoping for more parts and accesories for the home-made-Mega-BBQ grill I am working on....

I suggested in a previous post that Propane stuff could be found at some cajun cooking places.

I found that if you check out Home Depot's Internet site, you can mail order many of the same exact name brand items though them at a cheaper price. Even better, they seem to have free shipping for many orders over $50 (seems to be good thru the end of the year).

I found propane regulator assemblies (for home made forge projects) as well as complete propane stoves (like you would use to melt lead for casting). The prices are really good.

just go to www.homedepot.com and do a search on the word "bayou" ... which will bring up the entire "Bayou Classic" product line.

The prices are so low that you will probably have to order more than you want to just to get over the $50 free shipping level.

For instance, they have a propane stove like you would use for melting lead for under $30, and a propane POL/adjustable Regulator/propane hose assembly for $18 bucks

Powder keg · « **Reply #14 on:** October 20, 2006, 08:56:30 AM »

I talked to the local propane dealer here and he said I should have better luck with a bigger bottle and an adjestable propane regulator. I've been using an acetalene reg. I'll do a test run on my new settup this weekend.

My burner has a venturi built into it. I'll post some better pictures of it when I'm out there later. I have a couple trinkets that I'm going to pore and I'll post some pictures of that also.

Wes

Rickk · « **Reply #15 on:** October 20, 2006, 09:16:28 AM »

a "BBQ" grade propane regulator is dirt cheap compaired to an Acetylene regulator.

You can get several adjustable versions... 0-10, 0-15, 0-20, and even 0-30. Most of them won't really go down to zero. I'm messing with a "0-20 psi" regulator and it's low setting is about 5 PSI. If that is not low enough for your burner your orfice is probably too big anyway, so a switch to s smaller orifice will bring the pressure requirements up.

Some of the better BBQ regulators have an output pressure gage on them, which is nice for a repeatable setting. It is also handy when working out orifice sizes on a home made burner.

Unlike or acetylene, an input pressure gage on a propane regulator is pretty much a waste of money, as it will read roughly the same untill the tank is totally empty.

All that aside, I would still think that your acetylene regulator would work fine. I stopped using acetylene in my gas welder and switched to propane/oxygen a couple of years ago. Other than an adapter for the propane bottle the old regulator works fine (I did have to switch to propane tips in the torch head).

A bigger gas bottle should help with freezing. Rumor has it they are cheaper to refill per unit of propane as well... you may pay by the pound of propane instead of a flat rate per fill up. Some places will fill bigger tanks, some only want to fill up BBQ grill size tanks. If your guy will do it you may be way ahead.

I would be curious about what a larger tank costs for just the empty tank.

Powder keg · « **Reply #16 on:** October 20, 2006, 11:35:56 AM »

The reason I built the bigger burner was to get a hotter burn, without the added air. Bigger pipe, more natural flow. The accetalyne reg. maxes out at 15 psi and this propane reg goes to 35 psi. I think? Ounce I got the orfice drilled bigger my new burner ran really good. Sure is loud:O) The only trouble was the freezing. I think the bigger bottle should take care of that problem? We'll see.

It was $50 to fill the bottle. I think it's a 35 pounder? It was empty.

Wes

GGaskill · « **Reply #17 on:** October 20, 2006, 12:23:04 PM »

I may have mentioned this before but the furnace in the art department foundry would hold a #90 crucible and had a 2" natural gas line and a 2 HP blower. You need a lot of air to burn a lot of gas. You also want to control the furnace atmosphere so you don't get porous castings.

Rickk · « **Reply #18 on:** October 20, 2006, 12:41:25 PM »

Natural gas has so low a pressure that they don't even measure it in PSI, they measure it in Water Column (W.C). If my fadiing memory is correct, 16 inches of water column works out to about 1 PSI. Matural Gas regulators are typically set to about 1 PSI-ish or even less. The pipes, and orifices are bigger because of that with natural gas.

Still, a 2" pipe is a whopper even for natural gas. I guess is takes a heck of a lotta btu's to melt that much stuff.

How did you control the furnace atmosphere?

GGaskill · « **Reply #19 on:** October 20, 2006, 01:30:10 PM »

The relationships between water head and psi are 1 ft H₂O=.4333 psi and 1 psi=2.31 ft H₂O. Residential gas mains are pressured at about 2 psi to my knowledge.

The instructor managed the furnace by adjusting the air flow to the gas flow. I think he maintained a slightly oxidizing atmosphere because it is better to lose a little copper (we used silicon bronze which is 94% Cu and 6% Si) than to take on hydrogen from unburned fuel or water vapor in the air (the foundry is only a couple miles from the Pacific Ocean so humidity was high most of the time.) My guess is he watched the color of the flame, aiming for a slight green tint, since there was a green tint to the exhaust from the top ring.

Powder keg · « **Reply #20 on:** October 20, 2006, 02:08:59 PM »

I can controle both the gass pressure and the air volume with a choke on the opening of the burner.

Wes