The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 06-08-2019, 08:26 PM   #1
arcticman
Junior Member
 
arcticman's Avatar
 
Join Date: Feb 2018
Location: ANCHORAGE
Posts: 94
MIG brazing patch panels with silica bronze

I brazed in a new (used) leading edge on a 67 hood. This is the first time using the MIG welder to do brazing. this is a nice way to go for restoration work.
Attached Images
   
arcticman is offline   Reply With Quote
Old 06-08-2019, 10:15 PM   #2
Fbks_Cruiser
In the land of the midnite sun
 
Fbks_Cruiser's Avatar
 
Join Date: Apr 2016
Location: Fairbanks, AK
Posts: 102
Re: MIG brazing patch panels with silica bronze

That looks really good! I hadnít heard of brazing with a mig welder. Iíll have to look into that.
__________________
1972 GMC K2500 Super Custom

Matt
Fbks_Cruiser is online now   Reply With Quote
Old 06-08-2019, 11:02 PM   #3
truckster
Senior Member
 
truckster's Avatar
 
Join Date: Jan 2001
Location: Orem, Utah
Posts: 4,638
Re: MIG brazing patch panels with silica bronze

That looks really good. Is it easier than MIG welding? I'm really good with structural stuff, but even with practice I have a hard time not blowing through sheet metal.
__________________
If I didn't build it or fix it, it's probably not mine.
truckster is offline   Reply With Quote
Old 06-08-2019, 11:56 PM   #4
rsgt
Registered User
 
rsgt's Avatar
 
Join Date: Apr 2009
Location: Lowell AR
Posts: 329
Re: MIG brazing patch panels with silica bronze

I have heard that plastic filler does not like to stick to brass. Maybe if it is epoxy primed first. Just a thought.
rsgt is offline   Reply With Quote
Old 06-09-2019, 06:29 AM   #5
Jrainman
Senior Member
 
Jrainman's Avatar
 
Join Date: Jul 2015
Location: North East PA
Posts: 502
Re: MIG brazing patch panels with silica bronze

I use silica bronze wire , it does take a bit to master, this type of mig wire you are not looking for a traditional steel wire bead when using this wire , If you do this, most likly you are compromising the silica bronze with to much heat, the main thing is to make sure the back of the panel has complete penatration and being such a low heat soft metal you need to have a small amount of gap when welding two sections together so the flow is even on both sides .

it has its advantages and dis advantages but when used in the right conditions it can be a excellent choice low heat , very easy to shape or grind ,and does not rust are some of its good qualitys. Also the choice in Mig machine plays a part in how good silica bronze wire reacts to your repair.
Jrainman is offline   Reply With Quote
Old 06-09-2019, 08:14 AM   #6
Hammond68
Registered User
 
Join Date: Mar 2018
Location: Bennettsville sc
Posts: 33
Re: MIG brazing patch panels with silica bronze

Truckster. You don't want to keep an arc going when putting in panels. Run on the hot side and just do a series of button tacks. Frames or something that will be stressed needs a continuous weld though.
__________________
1972 c10 cheyenne.
383 stroker 10-1
280 magnum comp cams
700r4 tranny.
Hammond68 is offline   Reply With Quote
Old 06-09-2019, 12:02 PM   #7
arcticman
Junior Member
 
arcticman's Avatar
 
Join Date: Feb 2018
Location: ANCHORAGE
Posts: 94
Re: MIG brazing patch panels with silica bronze

You are correct. It is not welding its brazing. Welding is a fusion process wereas brazing is an adhesion process. BIG difference and you dont want to confuse them.Back in the day we used tourch and rod. I've never had an issue with Bondo not stickig to bronze. The advantage I see with using a MIG is the control you have with heat and therefore less distortion. I also agree that a butt joint with a root gap to allow penitration to the back side is a good option but its not the only one as is the case with this hood. For this job I used a lab joint. As a matter of fact most of the brazing I've seen on vehicles is a lab joint. Some vehicle makers are recommending it be used when replacing QT. panels at the section with a butt joint.
arcticman is offline   Reply With Quote
Old 06-09-2019, 06:24 PM   #8
Hammond68
Registered User
 
Join Date: Mar 2018
Location: Bennettsville sc
Posts: 33
Re: MIG brazing patch panels with silica bronze

I've been a Welder for 30+ years. Tubes,pipe. 100% xray jobs. Im a welding encyclopedia. You can't fill a gap with braze. Braze is the same as solder. The only difference is it happens around 800 degrees. Solder is under 400 I believe. Both are a chemical bond. If you got good with running braze wire it would have its advantages. One disadvantage is lap joints only. Can't just butt it up and go. Must be good and clean also.
__________________
1972 c10 cheyenne.
383 stroker 10-1
280 magnum comp cams
700r4 tranny.
Hammond68 is offline   Reply With Quote
Old 06-09-2019, 07:04 PM   #9
72c20customcamper
Registered User
 
72c20customcamper's Avatar
 
Join Date: Jul 2018
Location: Napanoch new york
Posts: 901
Re: MIG brazing patch panels with silica bronze

Don't know if it's the same but body filler wouldn't stay on anything that was brazed. Of course this was with gas welding might have been the flux
__________________
Mark
72 c20 custom camper Husky edition,66 SS396 Chevelle 1964 Hawk, 63 Avanti,62 lark
1969 AMX ,02 Springer. 03 anniversary Fatboy.
81 Honda automatic 1600 miles
2012 Road Glide Ultra 2015 Honda Goldwing
1968 c20 stepside
72c20customcamper is online now   Reply With Quote
Old 06-10-2019, 01:30 AM   #10
franken
Registered User
 
Join Date: Jun 2013
Location: Somewhere
Posts: 2,387
Re: MIG brazing patch panels with silica bronze

Post #8, I agree because at least compared to steel, the brazing rod/wire is very weak.
Post #9, I'd guess flux is the issue as well.
For the OP is the wire flux core?
franken is offline   Reply With Quote
Old 06-10-2019, 10:45 AM   #11
arcticman
Junior Member
 
arcticman's Avatar
 
Join Date: Feb 2018
Location: ANCHORAGE
Posts: 94
Re: MIG brazing patch panels with silica bronze

Silica Bronze wire has no flux coating. It uses shielding gas Argon.
You can do butt joints provided you have correct root gap for proper capillary action to occur on back side allowing the joint to be finished on the top side.
an example would be sectioning a quarter Panel at the roof line or sill.
If you were replacing the lower section of a door skin (patch panel) a lap joint would be best.
Silica Bronze melts at 1900 F steel around 2700 F
arcticman is offline   Reply With Quote
Old 06-10-2019, 10:06 PM   #12
tj1970cst
Registered User
 
Join Date: Mar 2019
Location: Arlington, TN
Posts: 31
Re: MIG brazing patch panels with silica bronze

I didn't know you could use a mig to braze. I'm a pretty accomplished welder, as far as diy. Even done quite a bit of brazing.
I think your repair looks excellent.
tj1970cst is offline   Reply With Quote
Old 06-12-2019, 08:44 AM   #13
rjs53
Registered User
 
Join Date: Jan 2010
Location: nevada
Posts: 633
Re: MIG brazing patch panels with silica bronze

Quote:
Originally Posted by tj1970cst View Post
I didn't know you could use a mig to braze. I'm a pretty accomplished welder, as far as diy. Even done quite a bit of brazing.
I think your repair looks excellent.
X's 2. I'm not a welder by trade, my dad was and alot of my friends are. I think if talking structural which he's not, yea you'd do something different. Arcticman I think it looks great and will hold for a life time.
__________________
2003 Dodge 2500
1969 C10
2014 Camaro SS/RS/1LE
rjs53 is offline   Reply With Quote
Old 06-12-2019, 08:10 PM   #14
Jrainman
Senior Member
 
Jrainman's Avatar
 
Join Date: Jul 2015
Location: North East PA
Posts: 502
Re: MIG brazing patch panels with silica bronze

He is not brazing, he is using a a mig wire in his mig machine ,the wire is silica bronz wire used with gas ,its not a flux core wire, what he is using it for is well suited , Why because there is much less of a chance he will distort his hood while welding with silica Bronze wire, because the heat is much less then steel wire and it also grinds and shapes very well and the weld wont rust like a steel carbon wire weld, it is not wise to but a joint, you must have a small gap between panels as I stated earlier , This type of mig welding is widly used in european car plants today, and it is the correct way to repair panels today in these cars ,this wire is not intended for structual use, but works very well for its intended use.
Jrainman is offline   Reply With Quote
Old 06-13-2019, 09:01 AM   #15
72c20customcamper
Registered User
 
72c20customcamper's Avatar
 
Join Date: Jul 2018
Location: Napanoch new york
Posts: 901
Re: MIG brazing patch panels with silica bronze

Dont want to get to into the debate but he is not welding but in fact brazing. Welding requires the melting of the base metal being joined and in most cases adding a filler. True Hammer welding uses no filler like making Damascus steel for a knife.

From what I have researched is that the silica bronze melts at around 1800 į carbon steel 2700į . So it's a chemical bond much like solder.

I am going to by a spool and futz around with it. Looks like a good option for panel repairs.
__________________
Mark
72 c20 custom camper Husky edition,66 SS396 Chevelle 1964 Hawk, 63 Avanti,62 lark
1969 AMX ,02 Springer. 03 anniversary Fatboy.
81 Honda automatic 1600 miles
2012 Road Glide Ultra 2015 Honda Goldwing
1968 c20 stepside
72c20customcamper is online now   Reply With Quote
Old 06-13-2019, 05:59 PM   #16
clay68c10
Senior Member
 
clay68c10's Avatar
 
Join Date: Aug 2004
Location: Centennial, CO
Posts: 2,063
Re: MIG brazing patch panels with silica bronze

I briefly played around with silicon bronze on a TIG. It was interesting for sure. Doesn’t take much current to get it flowing.
It is the choice of a lot of body guys in a MIG.
I can vouch that it does hammer/dolly very easily, and I’m an amateur.
__________________
68 C10 Bought in 89, wrecked in 03. Slow low $ rebuild started '17.
68 Cadillac Sedan de Ville
93 K1500 Short Step, 350, NV4500, EBL flash ECU. Vortec heads & roller cam someday...
02 E320
13 Tahoe LTZ
clay68c10 is online now   Reply With Quote
Old 06-13-2019, 06:49 PM   #17
67swb72klb
Registered User
 
67swb72klb's Avatar
 
Join Date: Dec 2010
Location: livingston co.mi
Posts: 2,161
Re: MIG brazing patch panels with silica bronze

This looks like a great option as long as fillers stick to it..
__________________
California 65 GTO---Texas 64 burb 283 ---Oklahoma 67 CST SWB BBW wood bed 327 2004r---New Mexico 72 k10 350 350 auto---Georga 72 short step project
67swb72klb is offline   Reply With Quote
Old 06-13-2019, 07:01 PM   #18
72c20customcamper
Registered User
 
72c20customcamper's Avatar
 
Join Date: Jul 2018
Location: Napanoch new york
Posts: 901
Re: MIG brazing patch panels with silica bronze

It's not cheap . My dealer priced a 10lb spool at 98$ and in need to use 100% argon. I have 75/ 25 argon co2. And tri mix so I would need another tank.
__________________
Mark
72 c20 custom camper Husky edition,66 SS396 Chevelle 1964 Hawk, 63 Avanti,62 lark
1969 AMX ,02 Springer. 03 anniversary Fatboy.
81 Honda automatic 1600 miles
2012 Road Glide Ultra 2015 Honda Goldwing
1968 c20 stepside
72c20customcamper is online now   Reply With Quote
Old 06-13-2019, 10:43 PM   #19
arcticman
Junior Member
 
arcticman's Avatar
 
Join Date: Feb 2018
Location: ANCHORAGE
Posts: 94
Re: MIG brazing patch panels with silica bronze

Ive been a collision repair Tech for close to 35 years never had an issue with boby filler not sticking to a repair. For restoration work you should apply a light coat of epoxy to the repair area prior to applying fillers.
arcticman is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 06:54 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.
Copyright 1997-2013 67-72chevytrucks.com