Author Topic: Group buy-group pour, bronze 24 PDR Coehorn golf ball mortar (Read 28221 times)

flagman1776 · « **Reply #300 on:** January 15, 2012, 09:17:40 AM »

I'd like to leave an even patina but by the time I'm done cleaning with Murphy's Oil Soap the patina is messed up. So I clean again with Never Dull & then wax over it. Always worked for my horse tach...

gunsonwheels · « **Reply #301 on:** January 15, 2012, 09:19:16 AM »

I use kids bubble blowing soap for a number of apps where I don't want the ammonia that is present in almost all cleaners that don't have bleach. Laundry detergent also works for those apps.

Double D · « **Reply #302 on:** January 15, 2012, 11:34:15 AM »

Besides ammonia which attack brass, brasso is an abrasive which will wear away, smooth and round off details.

More than one historic item has been slowly destroyed by our military insisting have a high shine on anything brass.

If you have been around this board any length of you will we have had number of such destroyed items posted.

GGaskill · « **Reply #303 on:** January 15, 2012, 03:42:10 PM »

All of the above.

Primarily the ammonia because it promotes stress corrosion cracking. But I looked up the MSDS for Brasso and found that the current incarnation of it has only a couple per cent ammonia in it. Still, I would stay away from using it on any copper alloy barreled firearm.

keith44 · « **Reply #304 on:** January 15, 2012, 04:18:11 PM »

I use semi-chrome paste to shine mine up, but leave the bore just water and mop cleaned, and lightly oiled

1Southpaw · « **Reply #305 on:** January 15, 2012, 05:44:40 PM »

Gary , put my name on the list to buy . Willbe gone till the first of April so no rush .
Thanks ......

RocklockI · « **Reply #306 on:** January 15, 2012, 06:07:00 PM »

Ernie ,did he come to you or did he talk you into coming down to see it ? You are on the list . Have yous guys shot it yet ?

Gary

Double D · « **Reply #307 on:** January 16, 2012, 02:41:41 AM »

Southpaw is in Snowbird land. He is sensitive to the cold.

He will never see this mortar. It should be headed to Virginia before he comes home in the spring

RocklockI · « **Reply #308 on:** January 17, 2012, 12:37:36 PM »

Today 3 more waxes went to the casters . Unfortunatly the wax I had given them back in early Dec. . It had shrinkage in the chamber area .

I have given them 7 mortars 4 are there now I have one useable mortar ,it went to Doug .
So ,Untill I see how this next batch is cast I am not making any more in wax . I ..may..consider going back to a foundery I have used .

Gary

Cat Whisperer · « **Reply #309 on:** January 17, 2012, 01:02:00 PM »

This enterpirse is not much different than farming, or playing the lottery!

Stick with it!

RocklockI · « **Reply #310 on:** February 08, 2012, 06:51:17 PM »

It is time for an update ! On the way to Seacoast today I recieved a phone call from the from the foundery today .

The last 4 waxes I had given them all turned out to be busts !
Out of the 7 waxes I have given them one has turned out and that was DD's

Obviously they dont know how to do it .....

I have another 4 waxes coming along ,I will farm out these waxes to three differant founderies and one more for the local foundery . They said 'we'd like one more chance at it but sprue it OUR way' ....meaning another sprue going right into the bottom of the underside .....we'll see ?

It is hard to believe that these 'art founderies' have no knowledge of anything thicker than 1/4" thick . These last 4 sucumbed to 'shrinkage' which means the feeders cooled and solidified B4 the barrel . That is bad because the bronze will shrink even if there is no reserve to feed it as it has already cooled ....! This causes bronze still cooling to pull away from the investment and then it cools and there is a void where the bronze should have been .

So there it is , I am hoping for one of these places will work out .
Gary

GGaskill · « **Reply #311 on:** February 08, 2012, 09:13:50 PM »

I am assuming you are casting trunnions down; is there a large shrink feeder above the muzzle with sprues that fill that area last? That makes the shrink feeder hottest when the pour finishes.

flagman1776 · « **Reply #312 on:** February 09, 2012, 06:57:26 AM »

Holy Cr*p. That s*cks, man!
Sorry... guess this is turning out to be the wrong kind of education.
Russ

RocklockI · « **Reply #313 on:** February 09, 2012, 06:09:20 PM »

Quote from: GGaskill on February 08, 2012, 09:13:50 PM

I am assuming you are casting trunnions down; is there a large shrink feeder above the muzzle with sprues that fill that area last? That makes the shrink feeder hottest when the pour finishes.

George, there is a feeder and two runners that go to the ends of the trunions ,it is cast muzzle down ,remember this mortar is to be cast with the bore in place .

The new procedure will be to add a third runner that goes into the bottom of the underside of the barrel . I think it will work and we should have success with ..no problem

!

I'll have 4 more waxes finished soon,it will be a month after that B4 I know anything more .

Gary

RocklockI · « **Reply #314 on:** February 15, 2012, 07:56:36 PM »

New update !

Four more waxes have been made . Yesterday Mike ,Bruce and I went to a foundery out east . Today Bruce and I went to a foundery in Denver . This place has cast bronze railroad parts so they are used to thicker bronze than an 'art' casting place . Any thing thicker the an 1 inch .....no clue .

Both founderies said it would only take couple of weeks ! ,so we'll see sooner than usual

Gary

KABAR2 · « **Reply #315 on:** February 16, 2012, 04:47:19 AM »

Well if that don't work I have a foundry near me that makes castings for ships etc...... if you want to send a wax this way we could give the east coast a try....

RocklockI · « **Reply #316 on:** March 08, 2012, 12:36:52 PM »

I got results from both new casters.....similar issues from each .

One guy didn't even follow my instructions and put one big sprue in the bottom

.
The other guy did the spruing correctly but still had bad results .

The large 'fins' are because the investment cracked

I will make these two presentable ,unfortunatly theres no way I can sell them at the quoted price

The guy who sprued it with 3 sprues said he knows how to correct the issuse .
I have only two more wax mortars left to figure this out .

Gary

gunsonwheels · « **Reply #317 on:** March 08, 2012, 12:55:12 PM »

Gary,

I worked most of my years at Boeing in a manufacturing R&D unit. My old machining and joining boss used to say "the only real failure is to do nothing at all..." Small comfort but some us out in boardland appreciate and believe your ARE getting closer to success. ...even if it is at the expense of each new "apparent failure". Thanks for all your dedication, effort and perseverance. I know it will eventually pay off!

GOW

GGaskill · « **Reply #318 on:** March 08, 2012, 01:09:05 PM »

That big sprue on the bottom is inexcusable. Cleaning it up requires a huge amount of work. The cracked investment kinda comes with the territory.

How are the bores?

RocklockI · « **Reply #319 on:** March 08, 2012, 02:15:02 PM »

The bores are not too bad but this gomer chamber seems to be more then they handle ?
I'll clean up the chambers and they'll be fine .

Cat Whisperer · « **Reply #320 on:** March 08, 2012, 03:11:56 PM »

Thomas Edison comes to mind.

Double D · « **Reply #321 on:** March 08, 2012, 05:53:22 PM »

I wonder if they were on to something when they made the originals solid and machined the bores?

GGaskill · « **Reply #322 on:** March 08, 2012, 06:14:36 PM »

Perhaps. I investment cast four similar mortars solid and they all came out, although I have machined only one of them. Now, I did the spruing, but I am not a professional.

RocklockI · « **Reply #323 on:** March 08, 2012, 07:38:04 PM »

Quote from: Double D on March 08, 2012, 05:53:22 PM

I wonder if they were on to something when they made the originals solid and machined the bores?

You correct Doug, but this was me trying to get costs down so I could offer them to the members fairly reasonable .

I am still 100% sure a cast in bore can be done because that has been the least of the issues .

It 'could be' that one of the two last waxes will be used to make a mold . M T and me have a friend who has done some muti piece molds in the past . He says it would be an easy mold to make .

Gary

Double D · « **Reply #324 on:** March 09, 2012, 03:10:14 AM »

Glad to see you back on the board Gary I was worried not seeing you...

jamesfrom180 · « **Reply #325 on:** March 09, 2012, 03:13:47 AM »

Just a though, how about casting the bore and machining the chamber?

onegreatshot · « **Reply #326 on:** March 09, 2012, 05:50:53 AM »

After reading all the thread posts, I believe their is to much intelligence and experience for this project to fail

Double D · « **Reply #327 on:** March 09, 2012, 10:06:41 AM »

Got my Handles for my mortar base today from Dom.

$35 for the set of 4.

Now to get my wood cut and sent of to a world famous carriage maker...

onegreatshot · « **Reply #328 on:** March 10, 2012, 06:05:59 AM »

Dbl D. any chance of seeing photo's of your carriage project???

. I will need to build one for myself when it is made. I have no idea how to build one but have friends who are handy with wood working. Now as to the handles does Dom sell those items to members?

dominick · « **Reply #329 on:** March 10, 2012, 07:51:26 AM »

Quote from: onegreatshot on March 10, 2012, 06:05:59 AM

Dbl D. any chance of seeing photo's of your carriage project??? . I will need to build one for myself when it is made. I have no idea how to build one but have friends who are handy with wood working. Now as to the handles does Dom sell those items to members?

Yes, The handles only [no bolts or square nuts] are for sale at $35 for a set of 4 plus shipping. shipping is $6.

Poll

I would buy...

Author Topic: Group buy-group pour, bronze 24 PDR Coehorn golf ball mortar (Read 28221 times)