Bridges Gassing

[Travis]

I might give that a try. It might even save some money not having to run my steamer.

 

[TheLabGuy]

What it looks like is a coon I trap in my sweet corn after it meets the barral of my shot gun.

I trapped 5 of those rat bastards last week and still I got up this morning and had almost 20 stalks down from their feeding orgy last night.

So I put out three traps tonight loaded with sardines.

Awww, we use to have pet coons. I've had about a dozen or so. The males stick around for about 6-9 months then they gotta go find themselves a female. Now the female coons, they'll stay with you forever. I had one female (Mischief) for about 6 years. She was a bad ass coon, she'd get tired of walking and jump on one of the dogs back and ride them. She'd ride on my motorcycle, she thought it was the coolest thing ever, she was a house pet. We kept some eggs on the bottom shelf of the refrigerator, every morning like clockwork she'd go to the fridge and I'd open it and she'd get herself an egg. Coons are a weird animal, they have to wash their hands before they eat...I wonder if we could teach some of our own species to do the same...HA!!!! Any young coon can be tamed, most take a few minutes to realize you aren't a threat and then they are your best pal. The adults are a different story, don't mess with them, they'll tear your arm off and then chirp at you asking for seconds. I think the largest one we had weighed over 40lbs, they can get big. I'd say let your chihuahua out, but that would be an appetizer Al....lol

 

[Al.]

My wife wants a pet skunk. I think you can get them that have had their sent glands removed.

I really wouldnt mind them if they didnt eat my corn. The stated alows us to trap them out of season if they are destroying our gardens.
Its kind of a grizzly operation. A necessary evil to keep the population under control because they are so destructive.


Rob Im suprised you dont ultrasonic your copings. If I have a cup full, (I use old porc bottles) my water turns cloudy and I empty it and add fresh and let it run another minute.

 

[DMC]

I quit using ultra sonic years ago when I couldn't find a clean cup. Just hold under running water in strainer works for me.

 

[TheLabGuy]

Rob Im suprised you dont ultrasonic your copings. If I have a cup full, (I use old porc bottles) my water turns cloudy and I empty it and add fresh and let it run another minute.

Problem with skunks is they like to dig. Sure, you can get them with the scent gland removed and they make a heck of a pet, a lot better than that barking gerbil you have...HA!!!!

You're right Al, I should be ultrasonic'ing my copings and I will start doing that, it's a better way. The old porcelain bottles is a great idea, then I don't have to be like Scott over there, scratching my head wondering where a bottle is

 

[charles007]

Been using porcelain bottles and tap water/ultrasonic since the beginning of time. Distilled water and steam cleaners, thought that's used to clean clothes....

 

[user name]

I just sandblast, rinse well, lay on a tissue (lotion/scent free),and into the oven. Way, way back in time, we would scrub the frames with comet or zud cleaner and rinse alot. I dont think sand had been invented yet...gold was under a hundred, and 'vacuum' was the talk about going high tech.

 

[desertfox384]

I could not find a true hot plate so i bought a little thing for melting candles (looks like a hot plate) but its not quite hot enough i dont think. I put my bridge on it for 10 minutes or so and it didnt get all that dry. So i put it under the muffle for 10 minutes at 450 deg. I did a wash coat at a higher temp then another 2 coats at the normal temp. Everything fired out ok until my 2nd porcelain bake. A big bubble on one of the abutments -i ground into it and it opened up even more to exposed metal, the opaque was stuck to the porcelain bubble. It is probably a 5mm x 2-3 mm hole. No other bubbles seen on the bridge.
I feel like im going in the right direction since the last few times i tried to pack this bridge it had a big hole plus 10 or so little ones.
Should I just let it dry longer?

 

[user name]

Yikes. Id look at my casting stuff. Contaminated crucible, deteriorating hoses, replace torch tip. Your problem isnt in the porcelain room.

 

[dmonwaxa]

I've been using a steam cleaner on metal with no problems. As was stated above, I firmly believe a bond coat is necessary. I find myself doing that with 2 or more coverage coats as necessary. On large cases that may have as much as 8-10 firings I have no problems with gassing. From experience what I have observed even when metal preparation is handelled immaculately the problem often leads back to casting. If the alloy is superheated to where it becomes pitted, then the repeated firings causes gas expansion leading to bubbling.

 

[desertfox384]

Well, this np stuff is a little hard for me to tell if its overheated. I used to use talladiums omega which i thought was great NP metal, casts easy. This rex cc stuff is horrible and i will switch back asap. - The button is rough at the bottom but not bubbly - some slag left over in the crucible. What do you all set your regulator at?

 

[Al.]

For sure overheated if the slag is stuck to the crucible and you have to scrape it off. It should fall right off.

 

[charles007]

preheat crucifies...really helps a lot. Using Tallidum np, I think your oxy should be around 32lbs.. sorry, been years since I used np

 

[desertfox384]

For sure overheated if the slag is stuck to the crucible and you have to scrape it off. It should fall right off.

I dont have to scrape it at all, just pull it out with my fingers.

 

[capickettcdt]

This has been a while back....but when I was using the Creation paste opaques we had issues with the drying. I shortened the dry time in the porcelain furnace and let the sagger points with opaqued copings dry on an electric coffee cup warmer. I think now they also have candle warmers that do the same thing. Just waited untill the surface looked dry then went to town. no more issue. Also we have a tendency to keep materials in trays and add, add, add. I've sen alot of problems solved over the years by cleaning out the old and replacing with new. A few metal grindings from your lab coat or hair that drop into the opaque while you are focused on your work will blow holes from the opaque right on up. Usually showing up right around glaze time!! Good luck!

 

[Gene]

I use Dsign paste , found that using a hot plate to predry helped alot with cracking and blisters. Then do @ 8 min dry into furnace. I was told years ago that the drying from a hot plate accually pulls op. onto the coping because heat comes from below. Don't know if it is true but works for me
Gene

 

[desertfox384]

Well so far i have been having good luck letting the copings dry on an electric candle warmer. What i do is stick a coffee mug over the sagger tray to hold the heat, otherwise it doesnt really dry the opaque. I ordered a new batch of talladiums np metal, new crucible and burs.

 

[labmanmike]

The only time I use a steamer is to clean the models before the case goes out the door. I just don't trust the steamer element to keep clean. I pretty much do the same as the other guys, just finish with proper stones, sandblast, distilled water in ustrasonic for a few seconds, then opaque. The 1st opaque needs to be somewhat shiney. then go to your eggshell finish. Hope it helps a little.... P.S. keep your torch tip clean

 

[pingvin]

desertfox384, what furnace do you use?

I use Ivoclar Programat 100. Ivoclar furnaces differ much to Vita furnaces. I had lots and lots of problems with bubbles in EX3, but this baking schedule is 100% bubble free for Ivoclar furnaces:

Co-Cr, sandblast, rinse under clean running water, dry with hear dryer.
Mix POBA in the jar with it's liquid, dilute extra if needed (in winter a drop or two).
Apply POBA, preheat furnace to 100 C, open, put in, close, start, press once (not twice) stop to hold temperature at 90 C. Hold for 20 min. Carry on with baking. Before first opaquer bake WAIT for the furnace to cool down (furnace head open),I usually wait until temperature reaches 60 C, then I put in first opaquer. When you close the furnace head the temperature rises to some 80 C, by presing start and stop (once) you control the rise of the temperature until it reaches 90. Dry for 20 minutes, then repeat.

This is 100% bubble free, I can guarantee this by several thousand baked crowns. If bubbles appear then opaquer or POBA froze during transport and has to be changed!

One of my first bridges looked like this (it is interesting that only one half of the bridge was infected, this is due to the fact that head of the furnace in Ivoclar is inclined in approximately 45 degree angle and that part of the bridge was closer to the heating chamber, and opaquer got more boiling:

 

[desertfox384]

Pingvin,
You got it! That bridge looks just like what was happening to me. Here is what I do now. To be safe I dont mix up my opaques in the jars - The book says dont mix up that oil with opaques so i just dont. I place opaqued copings on the tray under open muffle at 400 c. for 5-10 minutes or so and i also increased my dry time to 9 1/2 minutes on the opaque cycle. Ive had good success. Once in awhile i get a tiny crack or two on the 2nd opaque firing.